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International journal of refrigeration |
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Ajouter le résultat dans votre panierScroll profiles in scroll compressors / Qiang Jianguo in International journal of refrigeration, Vol. 36 N° 7 (Novembre 2013)
in International journal of refrigeration > Vol. 36 N° 7 (Novembre 2013) . - pp. 1796-1808
Titre : Scroll profiles in scroll compressors : general criteria and error sensitivity Titre original : Profils de spirales dans des compresseurs à spirale : critères généraux et sensibilité à l'erreur Type de document : texte imprimé Auteurs : Qiang Jianguo, Auteur ; Zhenquan, Liu, Auteur Année de publication : 2014 Article en page(s) : pp. 1796-1808 Note générale : Refrigeration Langues : Anglais (eng) Mots-clés : Scroll compressor; Geometry; Surface Résumé : General criteria for scroll profiles that include the evolute, orbiting movement, differential, and integrative conditions are proposed. The profile error sensitivity is defined based on the composite meshing error and meshing clearances of the scroll profiles. A case study on regular polygon involutes as scroll profiles indicates that the general criteria are satisfied when the edge number of the two involutes of a regular polygon is equal to the common multiple of the doubled number of scroll wraps on one scroll. The profile error sensitivity of the involutes of a base circle is shown to be controlled by the radial machining error, which is extremely low. The involute of a base circle is the ideal profile for a scroll compressor because it contains low error sensitivity and more stable dynamic characteristics. En ligne : http://www.sciencedirect.com/science/article/pii/S0140700713002648 [article] Scroll profiles in scroll compressors = Profils de spirales dans des compresseurs à spirale : critères généraux et sensibilité à l'erreur : general criteria and error sensitivity [texte imprimé] / Qiang Jianguo, Auteur ; Zhenquan, Liu, Auteur . - 2014 . - pp. 1796-1808.
Refrigeration
Langues : Anglais (eng)
in International journal of refrigeration > Vol. 36 N° 7 (Novembre 2013) . - pp. 1796-1808
Mots-clés : Scroll compressor; Geometry; Surface Résumé : General criteria for scroll profiles that include the evolute, orbiting movement, differential, and integrative conditions are proposed. The profile error sensitivity is defined based on the composite meshing error and meshing clearances of the scroll profiles. A case study on regular polygon involutes as scroll profiles indicates that the general criteria are satisfied when the edge number of the two involutes of a regular polygon is equal to the common multiple of the doubled number of scroll wraps on one scroll. The profile error sensitivity of the involutes of a base circle is shown to be controlled by the radial machining error, which is extremely low. The involute of a base circle is the ideal profile for a scroll compressor because it contains low error sensitivity and more stable dynamic characteristics. En ligne : http://www.sciencedirect.com/science/article/pii/S0140700713002648
in International journal of refrigeration > Vol. 36 N° 7 (Novembre 2013) . - pp. 1809–1820
Titre : Variable wall thickness scroll geometry modeling with use of a control volume approach Titre original : Modélisation par géométrie de défilement de l'épaisseur variable des parois grâce à l'utilisation d'une approche par régulation du volume Type de document : texte imprimé Auteurs : Bryce R. Shaffer, Auteur ; Eckhard A. Groll, Auteur Année de publication : 2014 Article en page(s) : pp. 1809–1820 Note générale : Refrigeration Langues : Anglais (eng) Mots-clés : Scroll compressor; Scroll expander; Geometry; Variable wall thickness Résumé : In a scroll-type compressor, compression is achieved through relative contact between two spiral curves. Since the scroll invention by Leon Creux (1905), multiple methods have been developed for calculating scroll geometry. What can generally be considered the most classical method, is defining each scroll curve as the involute of a circle. Gravesen and Henriksen (2001) introduced a new method to calculate scroll geometry by deriving each scroll curve from the radius of curvature parameterized with involute angle. This allows a wide range of involute geometries to be considered not included in the classical method. In this paper, Gravesen's method is extended to the tip region to include all tip geometries involved in a two arc configuration resulting in a more comprehensive scroll geometry definition. Lastly, with parametric representation of all scroll geometry, the pocket volume can be easily solved using a derived control volume approach. En ligne : http://www.sciencedirect.com/science/article/pii/S0140700713002077 [article] Variable wall thickness scroll geometry modeling with use of a control volume approach = Modélisation par géométrie de défilement de l'épaisseur variable des parois grâce à l'utilisation d'une approche par régulation du volume [texte imprimé] / Bryce R. Shaffer, Auteur ; Eckhard A. Groll, Auteur . - 2014 . - pp. 1809–1820.
Refrigeration
Langues : Anglais (eng)
in International journal of refrigeration > Vol. 36 N° 7 (Novembre 2013) . - pp. 1809–1820
Mots-clés : Scroll compressor; Scroll expander; Geometry; Variable wall thickness Résumé : In a scroll-type compressor, compression is achieved through relative contact between two spiral curves. Since the scroll invention by Leon Creux (1905), multiple methods have been developed for calculating scroll geometry. What can generally be considered the most classical method, is defining each scroll curve as the involute of a circle. Gravesen and Henriksen (2001) introduced a new method to calculate scroll geometry by deriving each scroll curve from the radius of curvature parameterized with involute angle. This allows a wide range of involute geometries to be considered not included in the classical method. In this paper, Gravesen's method is extended to the tip region to include all tip geometries involved in a two arc configuration resulting in a more comprehensive scroll geometry definition. Lastly, with parametric representation of all scroll geometry, the pocket volume can be easily solved using a derived control volume approach. En ligne : http://www.sciencedirect.com/science/article/pii/S0140700713002077
in International journal of refrigeration > Vol. 36 N° 7 (Novembre 2013) . - pp. 1821–1829
Titre : Characterization of a vapor injection scroll compressor as a function of low, intermediate and high pressures and temperature conditions Titre original : Caractérisation d'un compresseur à spirale à injection de vapeur en fonction des conditions de pressions et de températures basses, moyennes et élevées Type de document : texte imprimé Auteurs : E. Navarro, Auteur ; A. Redón, Auteur ; José Gonzálvez-Maciá, Auteur Année de publication : 2014 Article en page(s) : pp. 1821–1829 Note générale : Refrigeration Langues : Anglais (eng) Mots-clés : Compressor; Injection cycle; Economizer; Extreme conditions; Heat pumps Résumé : The interest in two stage cycles has increased in the last years and some compressor manufacturers have commercialized compressors adapted to work in these conditions. Nevertheless, the information supplied by them usually is limited to certain design conditions defined by the application and extrapolation to other conditions is not straightforward. In this article a test campaign of an injection scroll compressor is presented. This test campaign was divided in two parts, on the first one a wide range of evaporating and condensing pressures for the intermediate conditions recommended by the manufacturer were measured, and the compressor behavior was systematically compared with single stage compressor of the same volume. On the second part an experimental study of the influence of the intermediate conditions on the performance have been done. The study has included the evaluation of the separate influence of intermediate gas superheat, intermediate pressure and wet injection. En ligne : http://www.sciencedirect.com/science/article/pii/S0140700713001175 [article] Characterization of a vapor injection scroll compressor as a function of low, intermediate and high pressures and temperature conditions = Caractérisation d'un compresseur à spirale à injection de vapeur en fonction des conditions de pressions et de températures basses, moyennes et élevées [texte imprimé] / E. Navarro, Auteur ; A. Redón, Auteur ; José Gonzálvez-Maciá, Auteur . - 2014 . - pp. 1821–1829.
Refrigeration
Langues : Anglais (eng)
in International journal of refrigeration > Vol. 36 N° 7 (Novembre 2013) . - pp. 1821–1829
Mots-clés : Compressor; Injection cycle; Economizer; Extreme conditions; Heat pumps Résumé : The interest in two stage cycles has increased in the last years and some compressor manufacturers have commercialized compressors adapted to work in these conditions. Nevertheless, the information supplied by them usually is limited to certain design conditions defined by the application and extrapolation to other conditions is not straightforward. In this article a test campaign of an injection scroll compressor is presented. This test campaign was divided in two parts, on the first one a wide range of evaporating and condensing pressures for the intermediate conditions recommended by the manufacturer were measured, and the compressor behavior was systematically compared with single stage compressor of the same volume. On the second part an experimental study of the influence of the intermediate conditions on the performance have been done. The study has included the evaluation of the separate influence of intermediate gas superheat, intermediate pressure and wet injection. En ligne : http://www.sciencedirect.com/science/article/pii/S0140700713001175
in International journal of refrigeration > Vol. 36 N° 7 (Novembre 2013) . - pp. 1830–1849
Titre : Dynamic model for the orbiting scroll based on the pressures in scroll chambers : Part I: Analytical modeling Titre original : Modèle dynamique de la volute rotative fondé sur les pressions dans les chambres de compression des systèmes à spirale — Partie I : modélisation analytique Type de document : texte imprimé Auteurs : Qiang Jianguo, Auteur ; Bin Pen, Auteur ; Zhenquan, Liu, Auteur Année de publication : 2014 Article en page(s) : pp. 1830–1849 Note générale : Refrigeration Langues : Anglais (eng) Mots-clés : Scroll compressor; Pressure; Dynamics; Modeling Résumé : This two-part work proposes a dynamic model for the orbiting scroll based on the pressures in the scroll chambers. In Part I, the scroll mechanism and characteristic polygon of the scroll compressor are defined, the geometry of the multi-wrap compressor is described, the modification and construction methods for one multi-wrap scroll are presented, and the dynamic model is developed. Thereafter, the overturning moment and theoretical driving power of the scroll mechanism are discussed. This dynamic model can predict the pressure distribution on wrap surfaces as well as the variations of the axial force, tangential force, radial force, overturning moment, self-rotation moment, and resistance moment. This dynamic model provides better understanding of scroll compressors and other types of scroll machines. The investigations on scroll compressors using this model and the model verification are reported in Part II. En ligne : http://www.sciencedirect.com/science/article/pii/S0140700713000273 [article] Dynamic model for the orbiting scroll based on the pressures in scroll chambers = Modèle dynamique de la volute rotative fondé sur les pressions dans les chambres de compression des systèmes à spirale — Partie I : modélisation analytique : Part I: Analytical modeling [texte imprimé] / Qiang Jianguo, Auteur ; Bin Pen, Auteur ; Zhenquan, Liu, Auteur . - 2014 . - pp. 1830–1849.
Refrigeration
Langues : Anglais (eng)
in International journal of refrigeration > Vol. 36 N° 7 (Novembre 2013) . - pp. 1830–1849
Mots-clés : Scroll compressor; Pressure; Dynamics; Modeling Résumé : This two-part work proposes a dynamic model for the orbiting scroll based on the pressures in the scroll chambers. In Part I, the scroll mechanism and characteristic polygon of the scroll compressor are defined, the geometry of the multi-wrap compressor is described, the modification and construction methods for one multi-wrap scroll are presented, and the dynamic model is developed. Thereafter, the overturning moment and theoretical driving power of the scroll mechanism are discussed. This dynamic model can predict the pressure distribution on wrap surfaces as well as the variations of the axial force, tangential force, radial force, overturning moment, self-rotation moment, and resistance moment. This dynamic model provides better understanding of scroll compressors and other types of scroll machines. The investigations on scroll compressors using this model and the model verification are reported in Part II. En ligne : http://www.sciencedirect.com/science/article/pii/S0140700713000273
in International journal of refrigeration > Vol. 36 N° 7 (Novembre 2013) . - pp. 1850-1865
Titre : Dynamic model for th orbiting scroll based on the pressures in scroll chambers : Part II: Investigations on scroll compressors and model validation Titre original : Modèle dynamique de la volute rotative fondé sur les pressions dans les chambres de compression des systèmes à spirale-Partie II: étude éffectuée sur les compresseurs à spirale et validation du modèle Type de document : texte imprimé Auteurs : Qiang, Jianguo, Auteur ; Peng, Bin, Auteur ; Zhenquan, Liu, Auteur Année de publication : 2014 Article en page(s) : pp. 1850-1865 Note générale : Refrigeration Langues : Anglais (eng) Mots-clés : Scroll compressor; dynamics; model; investigation Résumé : This two-part study proposes a dynamic model for the orbiting scroll based on the pressures in scroll chambers. Part II investigates scroll compressors by using the dynamic model developped in this work to predicate the dynamic characteristics of the scroll compressors and the dynamic model is validated by comparing the predicted results with the experimental results of the powers of two air scroll compressors. This study utilizes two air scroll compressors and ten virtual scroll compressors to investigate the pressure distribution on the wrap surfaces of orbiting scrolls, the component forces and moments of orbiting scrolls, the overturning moment of the scroll mechanism, and the theoretical driving power of scroll compressors. The effects of scroll type (such as modified-wrap scroll, truncated-wrap scroll, multi-wrap scroll, odd-wrap scroll, and even-wrap scroll) on the dynamic performance of the scroll compressor based on the pressures in scroll chambers are also analyzed. En ligne : http://www.sciencedirect.com/science/article/pii/S0140700713000364 [article] Dynamic model for th orbiting scroll based on the pressures in scroll chambers = Modèle dynamique de la volute rotative fondé sur les pressions dans les chambres de compression des systèmes à spirale-Partie II: étude éffectuée sur les compresseurs à spirale et validation du modèle : Part II: Investigations on scroll compressors and model validation [texte imprimé] / Qiang, Jianguo, Auteur ; Peng, Bin, Auteur ; Zhenquan, Liu, Auteur . - 2014 . - pp. 1850-1865.
Refrigeration
Langues : Anglais (eng)
in International journal of refrigeration > Vol. 36 N° 7 (Novembre 2013) . - pp. 1850-1865
Mots-clés : Scroll compressor; dynamics; model; investigation Résumé : This two-part study proposes a dynamic model for the orbiting scroll based on the pressures in scroll chambers. Part II investigates scroll compressors by using the dynamic model developped in this work to predicate the dynamic characteristics of the scroll compressors and the dynamic model is validated by comparing the predicted results with the experimental results of the powers of two air scroll compressors. This study utilizes two air scroll compressors and ten virtual scroll compressors to investigate the pressure distribution on the wrap surfaces of orbiting scrolls, the component forces and moments of orbiting scrolls, the overturning moment of the scroll mechanism, and the theoretical driving power of scroll compressors. The effects of scroll type (such as modified-wrap scroll, truncated-wrap scroll, multi-wrap scroll, odd-wrap scroll, and even-wrap scroll) on the dynamic performance of the scroll compressor based on the pressures in scroll chambers are also analyzed. En ligne : http://www.sciencedirect.com/science/article/pii/S0140700713000364
in International journal of refrigeration > Vol. 36 N° 7 (Novembre 2013) . - pp. 1866–1873
Titre : Experimental testing of an oil-flooded hermetic scroll compressor Titre original : Essais expérimentaux effectués sur un compresseur à spirale hermétique noyé par l'huile Type de document : texte imprimé Auteurs : Ian H. Bell, Auteur ; Eckhard A. Groll, Auteur ; James E. Braun, Auteur Année de publication : 2014 Article en page(s) : pp. 1866–1873 Note générale : Refrigeration Langues : Anglais (eng) Mots-clés : Air conditioning; Refrigeration; Flooded compression Résumé : In this work, a residential air conditioning compressor designed for vapor injection has been modified in order to inject large quantities of oil into the working chamber in order to approach an isothermal compression process. The compressor was tested with oil injection mass flow fractions of up to 45%. At an evaporating temperature of −10 °C and condensing temperature of 30 °C, the overall isentropic efficiency was up to 70% at the highest oil injection rate. Overall, over the testing envelope investigated, there are no significantly negative effects experienced for the compressor and the compressor isentropic efficiency and refrigerant mass flow rate improve monotonically as the oil injection rate is increased. En ligne : http://www.sciencedirect.com/science/article/pii/S0140700713000212 [article] Experimental testing of an oil-flooded hermetic scroll compressor = Essais expérimentaux effectués sur un compresseur à spirale hermétique noyé par l'huile [texte imprimé] / Ian H. Bell, Auteur ; Eckhard A. Groll, Auteur ; James E. Braun, Auteur . - 2014 . - pp. 1866–1873.
Refrigeration
Langues : Anglais (eng)
in International journal of refrigeration > Vol. 36 N° 7 (Novembre 2013) . - pp. 1866–1873
Mots-clés : Air conditioning; Refrigeration; Flooded compression Résumé : In this work, a residential air conditioning compressor designed for vapor injection has been modified in order to inject large quantities of oil into the working chamber in order to approach an isothermal compression process. The compressor was tested with oil injection mass flow fractions of up to 45%. At an evaporating temperature of −10 °C and condensing temperature of 30 °C, the overall isentropic efficiency was up to 70% at the highest oil injection rate. Overall, over the testing envelope investigated, there are no significantly negative effects experienced for the compressor and the compressor isentropic efficiency and refrigerant mass flow rate improve monotonically as the oil injection rate is increased. En ligne : http://www.sciencedirect.com/science/article/pii/S0140700713000212
in International journal of refrigeration > Vol. 36 N° 7 (Novembre 2013) . - pp. 1874–1882
Titre : Thermal modeling for the motor in semi-hermetic screw refrigeration compressors under part-load conditions Titre original : Modélisation thermique du moteur d'un compresseur frigorifique à vis semi-hermétique sous conditions de charge partielle Type de document : texte imprimé Auteurs : Wenqing Chen, Auteur ; Ziwen Xing, Auteur ; Jiubing Shen, Auteur Année de publication : 2014 Article en page(s) : pp. 1874–1882 Note générale : Refrigeration Langues : Anglais (eng) Mots-clés : Semi-hermetic compressor; Motor; Thermal analysis; Part-load Résumé : In the semi-hermetic screw refrigeration compressor, the motor is mostly cooled down by suction refrigerant before it flows into the compressor suction port. To investigate cooling effects of the motor and performance of the compressor under part-load conditions, a lumped parameter model describing heat-transfer characteristics inside the motor and a part-load model of screw refrigeration compressor are developed and validated. Heating effects at compressor suction end and heat conduction from the male rotor screw to the motor shaft are taken into account. Nodes representing refrigerant inside the motor cooling passages are modeled separately. Temperature rise of refrigerant through the motor increases when the compressor load drops by either suction volume variation or speed variation. With drop of the compressor load, stator winding temperature goes up in the case of suction volume variation by slide valve motion, but it lows in the case of speed variation by frequency conversion. En ligne : http://www.sciencedirect.com/science/article/pii/S0140700713001746 [article] Thermal modeling for the motor in semi-hermetic screw refrigeration compressors under part-load conditions = Modélisation thermique du moteur d'un compresseur frigorifique à vis semi-hermétique sous conditions de charge partielle [texte imprimé] / Wenqing Chen, Auteur ; Ziwen Xing, Auteur ; Jiubing Shen, Auteur . - 2014 . - pp. 1874–1882.
Refrigeration
Langues : Anglais (eng)
in International journal of refrigeration > Vol. 36 N° 7 (Novembre 2013) . - pp. 1874–1882
Mots-clés : Semi-hermetic compressor; Motor; Thermal analysis; Part-load Résumé : In the semi-hermetic screw refrigeration compressor, the motor is mostly cooled down by suction refrigerant before it flows into the compressor suction port. To investigate cooling effects of the motor and performance of the compressor under part-load conditions, a lumped parameter model describing heat-transfer characteristics inside the motor and a part-load model of screw refrigeration compressor are developed and validated. Heating effects at compressor suction end and heat conduction from the male rotor screw to the motor shaft are taken into account. Nodes representing refrigerant inside the motor cooling passages are modeled separately. Temperature rise of refrigerant through the motor increases when the compressor load drops by either suction volume variation or speed variation. With drop of the compressor load, stator winding temperature goes up in the case of suction volume variation by slide valve motion, but it lows in the case of speed variation by frequency conversion. En ligne : http://www.sciencedirect.com/science/article/pii/S0140700713001746
in International journal of refrigeration > Vol. 36 N° 7 (Novembre 2013) . - pp. 1883–1893
Titre : Grid deformation strategies for CFD analysis of screw compressors Titre original : Stratégies des grilles de déformation pour l'analyse des compresseurs à deux vis Type de document : texte imprimé Auteurs : Sham Rane, Auteur ; Ahmed Kovacevic, Auteur ; Nikola Stosic, Auteur Année de publication : 2014 Article en page(s) : pp. 1883–1893 Note générale : Refrigeration Langues : Anglais (eng) Mots-clés : Twin screw compressor; CFD; Space conservation; Deforming grids; Key-frame re-meshing Résumé : Customized grid generation of twin screw machines for CFD analysis is widely used by the refrigeration and air-conditioning industry today, but is currently not suitable for topologies such as those of single screw, variable pitch or tri screw rotors. This paper investigates a technique called key-frame re-meshing that supplies pre-generated unstructured grids to the CFD solver at different time steps. To evaluate its accuracy, the results of an isentropic compression-expansion process in a reciprocating piston cylinder arrangement have been compared. Three strategies of grid deformation; diffusion equation mesh smoothing, user defined nodal displacement and key-frame remeshing have been assessed. There are many limitations to key-frame re-meshing. It requires time consuming pre-processing, has limited applicability to complex meshes and leads to inaccuracies in conservation of calculated variables. It was concluded that customized tools for generation of CFD grids are required for complex screw machines. En ligne : http://www.sciencedirect.com/science/article/pii/S0140700713000972 [article] Grid deformation strategies for CFD analysis of screw compressors = Stratégies des grilles de déformation pour l'analyse des compresseurs à deux vis [texte imprimé] / Sham Rane, Auteur ; Ahmed Kovacevic, Auteur ; Nikola Stosic, Auteur . - 2014 . - pp. 1883–1893.
Refrigeration
Langues : Anglais (eng)
in International journal of refrigeration > Vol. 36 N° 7 (Novembre 2013) . - pp. 1883–1893
Mots-clés : Twin screw compressor; CFD; Space conservation; Deforming grids; Key-frame re-meshing Résumé : Customized grid generation of twin screw machines for CFD analysis is widely used by the refrigeration and air-conditioning industry today, but is currently not suitable for topologies such as those of single screw, variable pitch or tri screw rotors. This paper investigates a technique called key-frame re-meshing that supplies pre-generated unstructured grids to the CFD solver at different time steps. To evaluate its accuracy, the results of an isentropic compression-expansion process in a reciprocating piston cylinder arrangement have been compared. Three strategies of grid deformation; diffusion equation mesh smoothing, user defined nodal displacement and key-frame remeshing have been assessed. There are many limitations to key-frame re-meshing. It requires time consuming pre-processing, has limited applicability to complex meshes and leads to inaccuracies in conservation of calculated variables. It was concluded that customized tools for generation of CFD grids are required for complex screw machines. En ligne : http://www.sciencedirect.com/science/article/pii/S0140700713000972
in International journal of refrigeration > Vol. 36 N° 7 (Novembre 2013) . - pp. 1894–1904
Titre : Numerical and experimental investigations of the effects of the breakup of oil droplets on the performance of oil–gas cyclone separators in oil-injected compressor systems Titre original : Etudes numériques et expérimentales sur les effets de la désagrégation des gouttelettes d'huile sur la performance des séparateurs d'huile et de gaz à cyclone dans les systèmes à compresseur à injection d'huile Type de document : texte imprimé Auteurs : Xiang Gao, Auteur ; Jinfeng, Chen, Auteur ; Jianmei Feng, Auteur Année de publication : 2014 Article en page(s) : pp. 1894–1904 Note générale : Refrigeration Langues : Anglais (eng) Mots-clés : Oil–gas cyclone separator; Numerical simulation; Breakup of oil droplets; Separation efficiency Résumé : A numerical simulation was conducted of the dynamic trajectories and the separation performance of oil droplets, with a focus on the breakup of oil droplets in an oil–gas cyclone separator. The separation efficiency was also studied experimentally, and the oil droplets' diameter distributions before and after the separator were measured with a Malvern particle size analyser to verify the simulation model. Both the experimental and simulation results showed that the breakup of oil droplets occurred in the separation process, clearly influencing the separation efficiency. In addition, the results indicated that inlet velocity played an important role in separation efficiency, as it not only significantly affected the tangential velocity inside the separator, but also determined the possibility and degree of the breakup of oil droplets. En ligne : http://www.sciencedirect.com/science/article/pii/S0140700713001515 [article] Numerical and experimental investigations of the effects of the breakup of oil droplets on the performance of oil–gas cyclone separators in oil-injected compressor systems = Etudes numériques et expérimentales sur les effets de la désagrégation des gouttelettes d'huile sur la performance des séparateurs d'huile et de gaz à cyclone dans les systèmes à compresseur à injection d'huile [texte imprimé] / Xiang Gao, Auteur ; Jinfeng, Chen, Auteur ; Jianmei Feng, Auteur . - 2014 . - pp. 1894–1904.
Refrigeration
Langues : Anglais (eng)
in International journal of refrigeration > Vol. 36 N° 7 (Novembre 2013) . - pp. 1894–1904
Mots-clés : Oil–gas cyclone separator; Numerical simulation; Breakup of oil droplets; Separation efficiency Résumé : A numerical simulation was conducted of the dynamic trajectories and the separation performance of oil droplets, with a focus on the breakup of oil droplets in an oil–gas cyclone separator. The separation efficiency was also studied experimentally, and the oil droplets' diameter distributions before and after the separator were measured with a Malvern particle size analyser to verify the simulation model. Both the experimental and simulation results showed that the breakup of oil droplets occurred in the separation process, clearly influencing the separation efficiency. In addition, the results indicated that inlet velocity played an important role in separation efficiency, as it not only significantly affected the tangential velocity inside the separator, but also determined the possibility and degree of the breakup of oil droplets. En ligne : http://www.sciencedirect.com/science/article/pii/S0140700713001515
in International journal of refrigeration > Vol. 36 N° 7 (Novembre 2013) . - pp. 1905–1915
Titre : Analytical and CFD modeling of the fluid flow in an eccentric-tube centrifugal oil pump for hermetic compressors Titre original : Modélisation analytique et à l'aide de la mécanique des fluides numérique de l'écoulement du fluide dans une pompe d'huile centrifuge à tubes excentriques pour les compresseurs hermétiques Type de document : texte imprimé Auteurs : Marcus Vinícius C. Alves, Auteur ; Jader R. Barbosa Jr., Auteur ; Alvaro T. Prata, Auteur Année de publication : 2014 Article en page(s) : pp. 1905–1915 Note générale : Refrigeration Langues : Anglais (eng) Mots-clés : Reciprocating compressor; Lubricant; Oil; Pumping; CFD Résumé : A model is presented for calculating the volume flow rate in an eccentric-tube centrifugal oil pump for reciprocating compressors. The oil pump assembly consists of a pick-up tube with an inclined inlet that is mounted off-center with the crankshaft symmetry axis. The pick-up tube is connected to the shaft channel, a helical groove machined on the crankshaft that facilitates the supply of lubricant to the bearings. The analytical models for the pick-up tube and shaft channel were developed independently and were coupled via a numerical procedure to determine the steady-state volume flow rate in the assembly. The steady-state results were verified against a CFD model, which was also used to evaluate the fluid flow in the oil pump assembly during a start-up transient. A parametric analysis was conducted to quantify the influence of some oil pump geometric parameters, such as the pick-up tube diameter and the shaft eccentricity. En ligne : http://www.sciencedirect.com/science/article/pii/S0140700712001880 [article] Analytical and CFD modeling of the fluid flow in an eccentric-tube centrifugal oil pump for hermetic compressors = Modélisation analytique et à l'aide de la mécanique des fluides numérique de l'écoulement du fluide dans une pompe d'huile centrifuge à tubes excentriques pour les compresseurs hermétiques [texte imprimé] / Marcus Vinícius C. Alves, Auteur ; Jader R. Barbosa Jr., Auteur ; Alvaro T. Prata, Auteur . - 2014 . - pp. 1905–1915.
Refrigeration
Langues : Anglais (eng)
in International journal of refrigeration > Vol. 36 N° 7 (Novembre 2013) . - pp. 1905–1915
Mots-clés : Reciprocating compressor; Lubricant; Oil; Pumping; CFD Résumé : A model is presented for calculating the volume flow rate in an eccentric-tube centrifugal oil pump for reciprocating compressors. The oil pump assembly consists of a pick-up tube with an inclined inlet that is mounted off-center with the crankshaft symmetry axis. The pick-up tube is connected to the shaft channel, a helical groove machined on the crankshaft that facilitates the supply of lubricant to the bearings. The analytical models for the pick-up tube and shaft channel were developed independently and were coupled via a numerical procedure to determine the steady-state volume flow rate in the assembly. The steady-state results were verified against a CFD model, which was also used to evaluate the fluid flow in the oil pump assembly during a start-up transient. A parametric analysis was conducted to quantify the influence of some oil pump geometric parameters, such as the pick-up tube diameter and the shaft eccentricity. En ligne : http://www.sciencedirect.com/science/article/pii/S0140700712001880
in International journal of refrigeration > Vol. 36 N° 7 (Novembre 2013) . - pp. 1916–1924
Titre : Modeling the stiction effect in automatic compressor valves Titre original : Modélisation des effets du frottement dans des soupapes automatiques de compresseurs Type de document : texte imprimé Auteurs : Rodrigo A. Pizarro-Recabarren, Auteur ; Jader R. Barbosa Jr., Auteur ; Cesar J. Deschamps, Auteur Année de publication : 2014 Article en page(s) : pp. 1916–1924 Note générale : Refrigeration Langues : Anglais (eng) Mots-clés : Compressor valves; Reed valves; Lubricating oil; Stiction force Résumé : The stiction effect is a source of thermodynamic losses in compressor suction and discharge systems. Deformation of the lubricant film between the valve and the seat delays the valve opening, as larger pressure differences between the cylinder and the discharge or suction chambers are needed to overcome the stiction force. A model is presented for the dynamic behavior of a ring-shaped lubricant oil film between a discharge valve and the seat. The valve is allowed to move under the action of an external force due to the time-dependent pressure difference between the cylinder and the discharge chamber. The main contributions of the model are the consideration of a finite oil amount between the valve and the seat and relationships for calculating the film thickness initial condition. At typical conditions of discharge systems of domestic refrigeration compressors, viscous effects are the dominant component in the oil stiction force under dynamic conditions. En ligne : http://www.sciencedirect.com/science/article/pii/S0140700713002764 [article] Modeling the stiction effect in automatic compressor valves = Modélisation des effets du frottement dans des soupapes automatiques de compresseurs [texte imprimé] / Rodrigo A. Pizarro-Recabarren, Auteur ; Jader R. Barbosa Jr., Auteur ; Cesar J. Deschamps, Auteur . - 2014 . - pp. 1916–1924.
Refrigeration
Langues : Anglais (eng)
in International journal of refrigeration > Vol. 36 N° 7 (Novembre 2013) . - pp. 1916–1924
Mots-clés : Compressor valves; Reed valves; Lubricating oil; Stiction force Résumé : The stiction effect is a source of thermodynamic losses in compressor suction and discharge systems. Deformation of the lubricant film between the valve and the seat delays the valve opening, as larger pressure differences between the cylinder and the discharge or suction chambers are needed to overcome the stiction force. A model is presented for the dynamic behavior of a ring-shaped lubricant oil film between a discharge valve and the seat. The valve is allowed to move under the action of an external force due to the time-dependent pressure difference between the cylinder and the discharge chamber. The main contributions of the model are the consideration of a finite oil amount between the valve and the seat and relationships for calculating the film thickness initial condition. At typical conditions of discharge systems of domestic refrigeration compressors, viscous effects are the dominant component in the oil stiction force under dynamic conditions. En ligne : http://www.sciencedirect.com/science/article/pii/S0140700713002764
in International journal of refrigeration > Vol. 36 N° 7 (Novembre 2013) . - pp. 1925–1937
Titre : Modeling of a semi-hermetic CO2 reciprocating compressor including lubrication submodels for piston rings and bearings Titre original : Modélisation d’un compresseur à piston semi-hermétique au CO2, y compris des sous-modèles pour la lubrification des segments de piston et des paliers Type de document : texte imprimé Auteurs : Bin Yang, Auteur ; Craig R. Bradshaw, Auteur ; Eckhard A. Groll, Auteur Année de publication : 2014 Article en page(s) : pp. 1925–1937 Note générale : Refrigeration Langues : Anglais (eng) Mots-clés : Reciprocating compressor; Model; CO2; Optimization; Friction Résumé : A comprehensive model for a semi-hermetic CO2 reciprocating compressor is presented. This comprehensive model is composed of three main sub-models simulating the geometry and kinematics, the compression process, and frictional power loss. Valve and leakage sub-models are included in the compression process model. The frictional power loss model includes the friction at the bearings and between the piston ring and cylinder wall. The predicted results of the comprehensive model are validated using external compressor performance measurements of compressor input power and mass flow rate. The mass flow rate and compressor input power are predicted to within 4.03% and 6.43% mean absolute error, respectively, compared to the experimental datum. Additionally, a parametric study is presented which investigates compressor performance as a function of the stroke-to-bore ratio. En ligne : http://www.sciencedirect.com/science/article/pii/S0140700712002770 [article] Modeling of a semi-hermetic CO2 reciprocating compressor including lubrication submodels for piston rings and bearings = Modélisation d’un compresseur à piston semi-hermétique au CO2, y compris des sous-modèles pour la lubrification des segments de piston et des paliers [texte imprimé] / Bin Yang, Auteur ; Craig R. Bradshaw, Auteur ; Eckhard A. Groll, Auteur . - 2014 . - pp. 1925–1937.
Refrigeration
Langues : Anglais (eng)
in International journal of refrigeration > Vol. 36 N° 7 (Novembre 2013) . - pp. 1925–1937
Mots-clés : Reciprocating compressor; Model; CO2; Optimization; Friction Résumé : A comprehensive model for a semi-hermetic CO2 reciprocating compressor is presented. This comprehensive model is composed of three main sub-models simulating the geometry and kinematics, the compression process, and frictional power loss. Valve and leakage sub-models are included in the compression process model. The frictional power loss model includes the friction at the bearings and between the piston ring and cylinder wall. The predicted results of the comprehensive model are validated using external compressor performance measurements of compressor input power and mass flow rate. The mass flow rate and compressor input power are predicted to within 4.03% and 6.43% mean absolute error, respectively, compared to the experimental datum. Additionally, a parametric study is presented which investigates compressor performance as a function of the stroke-to-bore ratio. En ligne : http://www.sciencedirect.com/science/article/pii/S0140700712002770
in International journal of refrigeration > Vol. 36 N° 7 (Novembre 2013) . - PP. 1938–1950
Titre : Dynamic analyses for the rotor-journal bearing system of a variable speed rotary compressor Titre original : Analyses dynamiques pour le système de palier de rotor d'un compresseur rotatif à vitesse variable Type de document : texte imprimé Auteurs : Zengli, Wang, Auteur ; Xiaoling, Yu, Auteur ; Feilong, Liu, Auteur Année de publication : 2014 Article en page(s) : PP. 1938–1950 Note générale : Refrigeration Langues : Anglais (eng) Mots-clés : Variable speed rotary compressor; Rotor-journal bearing system; Dynamic analysis; Vibration characteristics Résumé : In the rotary compressor, the rolling piston and the contacted rotor-journal bearing system are main moving components. They suffer very large periodically varying loads introduced by the inertia force, the contact force and the gas force. These loads change rapidly with speed variation of the compressor. They always lead to serious vibration of the system, and then result in abrasion and performance reduction. In this paper, the dynamic behavior of the rotor-journal bearing system were calculated by solving three-dimensional numerical model using finite element method, and the vibration characteristics of the system were investigated according to the calculation results. The natural frequencies and vibration modes were obtained. The stress, displacement and axis orbit of the rotor center were calculated considering the speed variation of the motor. Via the established numerical model, vibration characteristics of a newly designed compressor can be predicted, and optimization can be done to reduce the vibration. En ligne : http://www.sciencedirect.com/science/article/pii/S0140700713000686 [article] Dynamic analyses for the rotor-journal bearing system of a variable speed rotary compressor = Analyses dynamiques pour le système de palier de rotor d'un compresseur rotatif à vitesse variable [texte imprimé] / Zengli, Wang, Auteur ; Xiaoling, Yu, Auteur ; Feilong, Liu, Auteur . - 2014 . - PP. 1938–1950.
Refrigeration
Langues : Anglais (eng)
in International journal of refrigeration > Vol. 36 N° 7 (Novembre 2013) . - PP. 1938–1950
Mots-clés : Variable speed rotary compressor; Rotor-journal bearing system; Dynamic analysis; Vibration characteristics Résumé : In the rotary compressor, the rolling piston and the contacted rotor-journal bearing system are main moving components. They suffer very large periodically varying loads introduced by the inertia force, the contact force and the gas force. These loads change rapidly with speed variation of the compressor. They always lead to serious vibration of the system, and then result in abrasion and performance reduction. In this paper, the dynamic behavior of the rotor-journal bearing system were calculated by solving three-dimensional numerical model using finite element method, and the vibration characteristics of the system were investigated according to the calculation results. The natural frequencies and vibration modes were obtained. The stress, displacement and axis orbit of the rotor center were calculated considering the speed variation of the motor. Via the established numerical model, vibration characteristics of a newly designed compressor can be predicted, and optimization can be done to reduce the vibration. En ligne : http://www.sciencedirect.com/science/article/pii/S0140700713000686
in International journal of refrigeration > Vol. 36 N° 7 (Novembre 2013) . - pp. 1951–1964
Titre : New non-dimensional performance parameters for the characterization of refrigeration compressors Titre original : Nouveaux paramètres de performance adimensionnels pour la caractérisation des compresseurs frigorifiques Type de document : texte imprimé Auteurs : Emilio, Navarro-Peris, Auteur ; José-M. Corberán, Auteur ; Luigi Falco, Auteur Année de publication : 2014 Article en page(s) : pp. 1951–1964 Note générale : Refrigeration Langues : Anglais (eng) Mots-clés : Compressor; Correlation; Refrigerants; Modeling; Efficiency Résumé : Pierre (1982) developed general correlations of compressor performance for a wide range of open piston compressors based on a vast amount of data provided by the most important open compressors manufacturers at that time. Based on a wide experimental test campaign with 6 different hermetic and semihermetic compressors, this paper assesses the potential of Pierre's correlations to describe the performance of modern compressors. A full review of the functionals proposed by Pierre in order to improve their accuracy was then performed and as a result the authors found that it is possible to improve the characterization by employing a nondimensional definition of the compressor performance instead of using the efficiencies. These new parameters provide a much more consistent estimation at the borders of the correlation range than the usual correlation obtained following the ARI standard, and could be even employed to extrapolate the performance of the compressor to non-tested conditions with reasonable accuracy. En ligne : http://www.sciencedirect.com/science/article/pii/S0140700713001710 [article] New non-dimensional performance parameters for the characterization of refrigeration compressors = Nouveaux paramètres de performance adimensionnels pour la caractérisation des compresseurs frigorifiques [texte imprimé] / Emilio, Navarro-Peris, Auteur ; José-M. Corberán, Auteur ; Luigi Falco, Auteur . - 2014 . - pp. 1951–1964.
Refrigeration
Langues : Anglais (eng)
in International journal of refrigeration > Vol. 36 N° 7 (Novembre 2013) . - pp. 1951–1964
Mots-clés : Compressor; Correlation; Refrigerants; Modeling; Efficiency Résumé : Pierre (1982) developed general correlations of compressor performance for a wide range of open piston compressors based on a vast amount of data provided by the most important open compressors manufacturers at that time. Based on a wide experimental test campaign with 6 different hermetic and semihermetic compressors, this paper assesses the potential of Pierre's correlations to describe the performance of modern compressors. A full review of the functionals proposed by Pierre in order to improve their accuracy was then performed and as a result the authors found that it is possible to improve the characterization by employing a nondimensional definition of the compressor performance instead of using the efficiencies. These new parameters provide a much more consistent estimation at the borders of the correlation range than the usual correlation obtained following the ARI standard, and could be even employed to extrapolate the performance of the compressor to non-tested conditions with reasonable accuracy. En ligne : http://www.sciencedirect.com/science/article/pii/S0140700713001710
in International journal of refrigeration > Vol. 36 N° 7 (Novembre 2013) . - pp. 1965–1973
Titre : A computationally efficient hybrid leakage model for positive displacement compressors and expanders Titre original : Modèle hybride des fuites fiable sur le plan des calculs, pour les compresseurs volumétriques et les détendeurs Type de document : texte imprimé Auteurs : Ian H. Bell, Auteur ; Eckhard A. Groll, Auteur ; James E. Braun, Auteur Année de publication : 2014 Article en page(s) : pp. 1965–1973 Note générale : Refrigeration Langues : Anglais (eng) Mots-clés : Compressor; Expanders; Simulation; Leakage Résumé : An empirical frictional correction factor to the isentropic nozzle model has been developed for application to refrigerant leakage modeling in scroll, rotary and other similar compressors and expanders. This correction factor is derived by calculating the leakage mass flow rate with a compressible, variable area, real gas properties model and referencing the results to an isentropic nozzle model. The ratio of flows is correlated to the Reynolds number, a characteristic length and the leakage gap width. A representative selection of fluids and geometries are employed. For all the correlations, at least 93% of the points are predicted within an absolute error band of 20%. En ligne : http://www.sciencedirect.com/science/article/pii/S0140700713000200 [article] A computationally efficient hybrid leakage model for positive displacement compressors and expanders = Modèle hybride des fuites fiable sur le plan des calculs, pour les compresseurs volumétriques et les détendeurs [texte imprimé] / Ian H. Bell, Auteur ; Eckhard A. Groll, Auteur ; James E. Braun, Auteur . - 2014 . - pp. 1965–1973.
Refrigeration
Langues : Anglais (eng)
in International journal of refrigeration > Vol. 36 N° 7 (Novembre 2013) . - pp. 1965–1973
Mots-clés : Compressor; Expanders; Simulation; Leakage Résumé : An empirical frictional correction factor to the isentropic nozzle model has been developed for application to refrigerant leakage modeling in scroll, rotary and other similar compressors and expanders. This correction factor is derived by calculating the leakage mass flow rate with a compressible, variable area, real gas properties model and referencing the results to an isentropic nozzle model. The ratio of flows is correlated to the Reynolds number, a characteristic length and the leakage gap width. A representative selection of fluids and geometries are employed. For all the correlations, at least 93% of the points are predicted within an absolute error band of 20%. En ligne : http://www.sciencedirect.com/science/article/pii/S0140700713000200
in International journal of refrigeration > Vol. 36 N° 7 (Novembre 2013) . - pp. 1974–1981
Titre : A comprehensive model of a novel rotating spool compressor Titre original : Modèle complet de compresseur innovant à bobine rotative Type de document : texte imprimé Auteurs : Craig R. Bradshaw, Auteur ; Eckhard A. Groll, Auteur Année de publication : 2014 Article en page(s) : pp. 1974–1981 Note générale : Refrigeration Langues : Anglais (eng) Mots-clés : Spool compressor; Comprehensive model; Novel compressor; Geometry model Résumé : A comprehensive simulation model of a novel rotating spool compressor is presented. The spool compressor provides a new rotary compression mechanism with easily manufactured components. A detailed analytical geometry model of the spool compressor is presented, which includes the geometry of the vane. This geometry model is included in an overall comprehensive compressor model that includes sub-models for friction, leakage, and heat transfer. The results of the comprehensive model were validated using experimental data from a prototype compressor. The prototype compressor has an overall displacement of 23.9 cm3, and was operated using R410A as the working fluid. The model predicts the volumetric efficiency, discharge temperature, and shaft power of the prototype compressor to within 3.13% MAE, 16.5 K and −13.2 W average deviation, respectively. The trends and spread in the data indicate that additional effort should be focused on the operation of the active sealing elements within the compressor. En ligne : http://www.sciencedirect.com/science/article/pii/S0140700713001680 [article] A comprehensive model of a novel rotating spool compressor = Modèle complet de compresseur innovant à bobine rotative [texte imprimé] / Craig R. Bradshaw, Auteur ; Eckhard A. Groll, Auteur . - 2014 . - pp. 1974–1981.
Refrigeration
Langues : Anglais (eng)
in International journal of refrigeration > Vol. 36 N° 7 (Novembre 2013) . - pp. 1974–1981
Mots-clés : Spool compressor; Comprehensive model; Novel compressor; Geometry model Résumé : A comprehensive simulation model of a novel rotating spool compressor is presented. The spool compressor provides a new rotary compression mechanism with easily manufactured components. A detailed analytical geometry model of the spool compressor is presented, which includes the geometry of the vane. This geometry model is included in an overall comprehensive compressor model that includes sub-models for friction, leakage, and heat transfer. The results of the comprehensive model were validated using experimental data from a prototype compressor. The prototype compressor has an overall displacement of 23.9 cm3, and was operated using R410A as the working fluid. The model predicts the volumetric efficiency, discharge temperature, and shaft power of the prototype compressor to within 3.13% MAE, 16.5 K and −13.2 W average deviation, respectively. The trends and spread in the data indicate that additional effort should be focused on the operation of the active sealing elements within the compressor. En ligne : http://www.sciencedirect.com/science/article/pii/S0140700713001680
in International journal of refrigeration > Vol. 36 N° 7 (Novembre 2013) . - pp. 1982–1997
Titre : Modeling of a novel spool compressor with multiple vapor refrigerant injection ports Titre original : Modélisation d'un compresseur à rotor innovant muni de plusieurs orifices d'injection du frigorigène sous forme de vapeur Type de document : texte imprimé Auteurs : Margaret M. Mathison, Auteur ; James E. Braun, Auteur ; Eckhard A. Groll, Auteur Année de publication : 2014 Article en page(s) : pp. 1982–1997 Note générale : Refrigeration Langues : Anglais (eng) Mots-clés : Spool compressor; Novel compressor; Compressor modeling; Injection; Economizing; Air conditioning units Résumé : A model of a novel rotary spool compressor has been developed to explore the effect of multiple injection ports on compressor and cycle performance. The thermodynamic model includes the effects of heat transfer and leakage and is numerically solved to predict the compressor power consumption and mass flow rate. Saturated vapor injection is modeled assuming that the injection pressures and the timing of the injection process can be controlled.
The model predicts that adding a single injection port will provide a 12% increase in the cycle coefficient of performance (COP) when the compressor runs at 1907 rpm with R-22 evaporating at −7 °C, condensing at 49 °C, and 15 °C of superheat. Adding a second, non-optimized injection port increases the COP by 16% compared to the cycle without injection. The model is used to investigate the effect of injection pressure, port location, and port diameter on cycle performance.En ligne : http://www.sciencedirect.com/science/article/pii/S0140700713000765 [article] Modeling of a novel spool compressor with multiple vapor refrigerant injection ports = Modélisation d'un compresseur à rotor innovant muni de plusieurs orifices d'injection du frigorigène sous forme de vapeur [texte imprimé] / Margaret M. Mathison, Auteur ; James E. Braun, Auteur ; Eckhard A. Groll, Auteur . - 2014 . - pp. 1982–1997.
Refrigeration
Langues : Anglais (eng)
in International journal of refrigeration > Vol. 36 N° 7 (Novembre 2013) . - pp. 1982–1997
Mots-clés : Spool compressor; Novel compressor; Compressor modeling; Injection; Economizing; Air conditioning units Résumé : A model of a novel rotary spool compressor has been developed to explore the effect of multiple injection ports on compressor and cycle performance. The thermodynamic model includes the effects of heat transfer and leakage and is numerically solved to predict the compressor power consumption and mass flow rate. Saturated vapor injection is modeled assuming that the injection pressures and the timing of the injection process can be controlled.
The model predicts that adding a single injection port will provide a 12% increase in the cycle coefficient of performance (COP) when the compressor runs at 1907 rpm with R-22 evaporating at −7 °C, condensing at 49 °C, and 15 °C of superheat. Adding a second, non-optimized injection port increases the COP by 16% compared to the cycle without injection. The model is used to investigate the effect of injection pressure, port location, and port diameter on cycle performance.En ligne : http://www.sciencedirect.com/science/article/pii/S0140700713000765
in International journal of refrigeration > Vol. 36 N° 7 (Novembre 2013) . - pp. 1998–2006
Titre : Sensitivity analysis of a comprehensive model for a miniature-scale linear compressor for electronics cooling Titre original : Analyse de la sensibilité d'un modèle exhaustif de compresseur linéaire miniaturisé pour le refroidissement de composants électroniques Type de document : texte imprimé Auteurs : Craig R. Bradshaw, Auteur ; Eckhard A. Groll, Auteur ; Suresh V. Garimella, Auteur Année de publication : 2014 Article en page(s) : pp. 1998–2006 Note générale : Refrigeration Langues : Anglais (eng) Mots-clés : Linear compressor; Sensitivity study; Miniature system; Electronics cooling; Loss analysis Résumé : A comprehensive model of a linear compressor for electronics cooling was previously presented by Bradshaw et al. (2011). The current study expands upon this work by first developing methods for predicting the resonant frequency of a linear compressor and for controlling its piston stroke. Key parameters governing compressor performance – leakage gap, eccentricity, and piston geometry – are explored using a sensitivity analysis. It is demonstrated that for optimum performance, the leakage gap and frictional parameters should be minimized. In addition, the ratio of piston stroke to diameter should not exceed a value of one to minimize friction and leakage losses, but should be large enough to preclude the need for an oversized motor. An improved linear compressor design is proposed for an electronics cooling application, with a predicted cooling capacity of 200 W a cylindrical compressor package size of diameter 50.3 mm and length 102 mm. En ligne : http://www.sciencedirect.com/science/article/pii/S0140700712002356 [article] Sensitivity analysis of a comprehensive model for a miniature-scale linear compressor for electronics cooling = Analyse de la sensibilité d'un modèle exhaustif de compresseur linéaire miniaturisé pour le refroidissement de composants électroniques [texte imprimé] / Craig R. Bradshaw, Auteur ; Eckhard A. Groll, Auteur ; Suresh V. Garimella, Auteur . - 2014 . - pp. 1998–2006.
Refrigeration
Langues : Anglais (eng)
in International journal of refrigeration > Vol. 36 N° 7 (Novembre 2013) . - pp. 1998–2006
Mots-clés : Linear compressor; Sensitivity study; Miniature system; Electronics cooling; Loss analysis Résumé : A comprehensive model of a linear compressor for electronics cooling was previously presented by Bradshaw et al. (2011). The current study expands upon this work by first developing methods for predicting the resonant frequency of a linear compressor and for controlling its piston stroke. Key parameters governing compressor performance – leakage gap, eccentricity, and piston geometry – are explored using a sensitivity analysis. It is demonstrated that for optimum performance, the leakage gap and frictional parameters should be minimized. In addition, the ratio of piston stroke to diameter should not exceed a value of one to minimize friction and leakage losses, but should be large enough to preclude the need for an oversized motor. An improved linear compressor design is proposed for an electronics cooling application, with a predicted cooling capacity of 200 W a cylindrical compressor package size of diameter 50.3 mm and length 102 mm. En ligne : http://www.sciencedirect.com/science/article/pii/S0140700712002356
in International journal of refrigeration > Vol. 36 N° 7 (Novembre 2013) . - pp. 2007–2013
Titre : Linear compressors for electronics cooling : energy recovery and its benefits Titre original : Compresseurs linéaires pour le refroidissement des composants électroniques : récupération d'énergie et avantages Type de document : texte imprimé Auteurs : Craig R. Bradshaw, Auteur ; Eckhard A. Groll, Auteur ; Suresh V. Garimella, Auteur Année de publication : 2014 Article en page(s) : pp. 2007–2013 Note générale : Refrigeration Langues : Anglais (eng) Mots-clés : Linear compressor; Reciprocating compressor; Capacity control; Electronics cooling Résumé : A comprehensive model of a linear compressor for electronics cooling was previously presented by Bradshaw et al. (2011) then enhanced and used for a sensitivity analysis of the leakage gap, eccentricity, and piston geometry by Bradshaw et al. (2013). The current work utilizes the previously developed model to explore the energy recovery characteristics of a linear compressor as compared to those of a reciprocating compressor. The impact of dead (clearance) volume on both a linear and reciprocating compressor is analyzed. In contrast to a reciprocating compressor the overall isentropic efficiency of the linear compressor remains relatively unaffected by an increase in dead volume up to a certain point. This behavior is attributed to the ability of the linear compressor to recapture the energy of the compressed gas during the expansion process. This characteristic behavior allows a linear compressor to be used for efficient capacity control from roughly 35–100%. En ligne : http://www.sciencedirect.com/science/article/pii/S014070071300025X [article] Linear compressors for electronics cooling = Compresseurs linéaires pour le refroidissement des composants électroniques : récupération d'énergie et avantages : energy recovery and its benefits [texte imprimé] / Craig R. Bradshaw, Auteur ; Eckhard A. Groll, Auteur ; Suresh V. Garimella, Auteur . - 2014 . - pp. 2007–2013.
Refrigeration
Langues : Anglais (eng)
in International journal of refrigeration > Vol. 36 N° 7 (Novembre 2013) . - pp. 2007–2013
Mots-clés : Linear compressor; Reciprocating compressor; Capacity control; Electronics cooling Résumé : A comprehensive model of a linear compressor for electronics cooling was previously presented by Bradshaw et al. (2011) then enhanced and used for a sensitivity analysis of the leakage gap, eccentricity, and piston geometry by Bradshaw et al. (2013). The current work utilizes the previously developed model to explore the energy recovery characteristics of a linear compressor as compared to those of a reciprocating compressor. The impact of dead (clearance) volume on both a linear and reciprocating compressor is analyzed. In contrast to a reciprocating compressor the overall isentropic efficiency of the linear compressor remains relatively unaffected by an increase in dead volume up to a certain point. This behavior is attributed to the ability of the linear compressor to recapture the energy of the compressed gas during the expansion process. This characteristic behavior allows a linear compressor to be used for efficient capacity control from roughly 35–100%. En ligne : http://www.sciencedirect.com/science/article/pii/S014070071300025X
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