Documents disponibles écrits par cet auteur

A comprehensive model of a miniature-scale linear compressor for electronics cooling / Craig R. Bradshaw in International journal of refrigeration, Vol. 34 N° 1 (Janvier 2011) 

Public ISBD [article]  in International journal of refrigeration > Vol. 34 N° 1 (Janvier 2011) . - pp. 63-73 Titre : A comprehensive model of a miniature-scale linear compressor for electronics cooling Titre original : Modèle extensif d'un compresseur linéaire miniaturisé utilisé pour refroidir les composants des systèmes électroniques Type de document : texte imprimé Auteurs : Craig R. Bradshaw, Auteur ; Eckhard A. Groll, Auteur ; Suresh V. Garimella, Auteur Année de publication : 2011 Article en page(s) : pp. 63-73 Note générale : Génie Mécanique Langues : Anglais (eng) Mots-clés : Linear  compressor  Compressor  model  Electronic  components  Cooling  Miniature-compressor Index. décimale : 621.5 Energie pneumatique. Machinerie et outils. Réfrigération Résumé : A comprehensive model of a miniature-scale linear compressor for electronics cooling is presented. Linear compressors are appealing for refrigeration applications in electronics cooling. A small number of moving components translate to less theoretical frictional losses and the possibility that this technology could scale to smaller physical sizes better than conventional compressors. The model developed here incorporates all of the major components of the linear compressor including dynamics associated with the piston motion. The results of the compressor model were validated using experimental data from a prototype linear compressor. The prototype compressor has an overall displacement of approximately 3 cm3, an average stroke of 0.6 cm. The prototype compressor was custom built for this work and utilizes custom parts with the exception of the mechanical springs and the linear motor. The model results showed good agreement when validated against the experimental results. The piston stroke is predicted within 1.3% MAE. The volumetric and overall isentropic efficiencies are predicted within 24% and 31%, MAE respectively. DEWEY : 621.5 ISSN : 0140-7007 En ligne : http://www.sciencedirect.com/science/article/pii/S0140700710002240 [article] A comprehensive model of a miniature-scale linear compressor for electronics cooling = Modèle extensif d'un compresseur linéaire miniaturisé utilisé pour refroidir les composants des systèmes électroniques [texte imprimé] / Craig R. Bradshaw, Auteur ; Eckhard A. Groll, Auteur ; Suresh V. Garimella, Auteur . - 2011 . - pp. 63-73. Génie Mécanique Langues : Anglais (eng) in International journal of refrigeration > Vol. 34 N° 1 (Janvier 2011) . - pp. 63-73 Mots-clés : Linear  compressor  Compressor  model  Electronic  components  Cooling  Miniature-compressor Index. décimale : 621.5 Energie pneumatique. Machinerie et outils. Réfrigération Résumé : A comprehensive model of a miniature-scale linear compressor for electronics cooling is presented. Linear compressors are appealing for refrigeration applications in electronics cooling. A small number of moving components translate to less theoretical frictional losses and the possibility that this technology could scale to smaller physical sizes better than conventional compressors. The model developed here incorporates all of the major components of the linear compressor including dynamics associated with the piston motion. The results of the compressor model were validated using experimental data from a prototype linear compressor. The prototype compressor has an overall displacement of approximately 3 cm3, an average stroke of 0.6 cm. The prototype compressor was custom built for this work and utilizes custom parts with the exception of the mechanical springs and the linear motor. The model results showed good agreement when validated against the experimental results. The piston stroke is predicted within 1.3% MAE. The volumetric and overall isentropic efficiencies are predicted within 24% and 31%, MAE respectively. DEWEY : 621.5 ISSN : 0140-7007 En ligne : http://www.sciencedirect.com/science/article/pii/S0140700710002240

Direct simulation of thermal transport through sintered wick microstructures / Karthik K. Bodla in Journal of heat transfer, Vol. 134 N° 1 (Janvier 2012) 

Public ISBD [article]  in Journal of heat transfer > Vol. 134 N° 1 (Janvier 2012) . - 10 p. Titre : Direct simulation of thermal transport through sintered wick microstructures Type de document : texte imprimé Auteurs : Karthik K. Bodla, Auteur ; Jayathi Y. Murthy, Auteur ; Suresh V. Garimella, Auteur Année de publication : 2012 Article en page(s) : 10 p. Note générale : Heat transfer Langues : Anglais (eng) Mots-clés : Computational  fluid  dynamics  Computerised  tomography  Copper  Flow  simulation  Flow  through  porous  media  Fluidised  beds  Heat  pipes  Heat  transfer  Image  reconstruction  Mesh  generation  Microfluidics  Permeability  Pipe  flow  Porosity  Statistical  analysis  Thermal  conductivity Index. décimale : 536 Chaleur. Thermodynamique Résumé : Porous sintered microstructures are critical to the functioning of passive heat transport devices such as heat pipes. The topology and microstructure of the porous wick play a crucial role in determining the thermal performance of such devices. Three sintered copper wick samples employed in commercial heat pipes are characterized in this work in terms of their thermal transport properties––porosity, effective thermal conductivity, permeability, and interfacial heat transfer coefficient. The commercially available samples of nearly identical porosities (~61% open volume) are CT scanned at 5.5 µm resolution, and the resulting image stack is reconstructed to produce high-quality finite volume meshes representing the solid and interstitial pore regions, with a conformal mesh at the interface separating these two regions. The resulting mesh is then employed for numerical analysis of thermal transport through fluid-saturated porous sintered beds. Multiple realizations are employed for statistically averaging out the randomness exhibited by the samples under consideration. The effective thermal conductivity and permeability data are compared with analytical models developed for spherical particle beds. The dependence of effective thermal conductivity of sintered samples on the extent of sintering is quantified. The interfacial heat transfer coefficient is compared against a correlation from the literature based on experimental data obtained with spherical particle beds. A modified correlation is proposed to match the results obtained. DEWEY : 536 ISSN : 0022-1481 En ligne : http://www.asmedl.org/getabs/servlet/GetabsServlet?prog=normal&id=JHTRAO00013400 [...] [article] Direct simulation of thermal transport through sintered wick microstructures [texte imprimé] / Karthik K. Bodla, Auteur ; Jayathi Y. Murthy, Auteur ; Suresh V. Garimella, Auteur . - 2012 . - 10 p. Heat transfer Langues : Anglais (eng) in Journal of heat transfer > Vol. 134 N° 1 (Janvier 2012) . - 10 p. Mots-clés : Computational  fluid  dynamics  Computerised  tomography  Copper  Flow  simulation  Flow  through  porous  media  Fluidised  beds  Heat  pipes  Heat  transfer  Image  reconstruction  Mesh  generation  Microfluidics  Permeability  Pipe  flow  Porosity  Statistical  analysis  Thermal  conductivity Index. décimale : 536 Chaleur. Thermodynamique Résumé : Porous sintered microstructures are critical to the functioning of passive heat transport devices such as heat pipes. The topology and microstructure of the porous wick play a crucial role in determining the thermal performance of such devices. Three sintered copper wick samples employed in commercial heat pipes are characterized in this work in terms of their thermal transport properties––porosity, effective thermal conductivity, permeability, and interfacial heat transfer coefficient. The commercially available samples of nearly identical porosities (~61% open volume) are CT scanned at 5.5 µm resolution, and the resulting image stack is reconstructed to produce high-quality finite volume meshes representing the solid and interstitial pore regions, with a conformal mesh at the interface separating these two regions. The resulting mesh is then employed for numerical analysis of thermal transport through fluid-saturated porous sintered beds. Multiple realizations are employed for statistically averaging out the randomness exhibited by the samples under consideration. The effective thermal conductivity and permeability data are compared with analytical models developed for spherical particle beds. The dependence of effective thermal conductivity of sintered samples on the extent of sintering is quantified. The interfacial heat transfer coefficient is compared against a correlation from the literature based on experimental data obtained with spherical particle beds. A modified correlation is proposed to match the results obtained. DEWEY : 536 ISSN : 0022-1481 En ligne : http://www.asmedl.org/getabs/servlet/GetabsServlet?prog=normal&id=JHTRAO00013400 [...]

Dynamic analysis of an electrostatic compressor / Abhijit A. Sathe in International journal of refrigeration, Vol. 33 N° 5 (Août 2010) 

Public ISBD [article]  in International journal of refrigeration > Vol. 33 N° 5 (Août 2010) . - pp. 889-896 Titre : Dynamic analysis of an electrostatic compressor Titre original : Analyse dynamique d'un compresseur électrostatique Type de document : texte imprimé Auteurs : Abhijit A. Sathe, Auteur ; Eckhard A. Groll, Auteur ; Suresh V. Garimella, Auteur Année de publication : 2010 Article en page(s) : pp. 889-896 Note générale : Génie Mécanique Langues : Anglais (eng) Mots-clés : Diaphragm  compressor  Refrigeration  Modelling  Simulation  Mechanical  property Index. décimale : 621.5 Energie pneumatique. Machinerie et outils. Réfrigération Résumé : This paper presents an analytical approach for modeling the transient dynamic forces in a diaphragm compressor which operates under the action of an electrostatically actuated diaphragm. An experimentally validated, quasi-static model for a diaphragm compressor for electronics cooling was previously developed in which dynamic effects were neglected. In the new model, the dynamic forces induced due to the finite time necessary for deflection of the diaphragm are taken into consideration using the segmentation approach developed earlier. Results from the analytical model compare favorably with those from a detailed numerical simulation as well as with experimental measurements available in the literature. The analytical dynamic model is applied to two different pumping devices to illustrate the effects of the dynamic forces on the overall performance of the device. The effect of pumping frequency of the device on the operating voltage is also explored. DEWEY : 621.5 ISSN : 0140-7007 En ligne : http://www.sciencedirect.com/science/article/pii/S0140700710000745 [article] Dynamic analysis of an electrostatic compressor = Analyse dynamique d'un compresseur électrostatique [texte imprimé] / Abhijit A. Sathe, Auteur ; Eckhard A. Groll, Auteur ; Suresh V. Garimella, Auteur . - 2010 . - pp. 889-896. Génie Mécanique Langues : Anglais (eng) in International journal of refrigeration > Vol. 33 N° 5 (Août 2010) . - pp. 889-896 Mots-clés : Diaphragm  compressor  Refrigeration  Modelling  Simulation  Mechanical  property Index. décimale : 621.5 Energie pneumatique. Machinerie et outils. Réfrigération Résumé : This paper presents an analytical approach for modeling the transient dynamic forces in a diaphragm compressor which operates under the action of an electrostatically actuated diaphragm. An experimentally validated, quasi-static model for a diaphragm compressor for electronics cooling was previously developed in which dynamic effects were neglected. In the new model, the dynamic forces induced due to the finite time necessary for deflection of the diaphragm are taken into consideration using the segmentation approach developed earlier. Results from the analytical model compare favorably with those from a detailed numerical simulation as well as with experimental measurements available in the literature. The analytical dynamic model is applied to two different pumping devices to illustrate the effects of the dynamic forces on the overall performance of the device. The effect of pumping frequency of the device on the operating voltage is also explored. DEWEY : 621.5 ISSN : 0140-7007 En ligne : http://www.sciencedirect.com/science/article/pii/S0140700710000745

Linear compressors for electronics cooling / Craig R. Bradshaw in International journal of refrigeration, Vol. 36 N° 7 (Novembre 2013) 

Public ISBD [article]  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

Melting of phase change materials with volume change in metal foams / Zhen Yang in Journal of heat transfer, Vol. 132 N° 6 (Juin 2010) 

Public ISBD [article]  in Journal of heat transfer > Vol. 132 N° 6 (Juin 2010) . - pp. [062301-1/11] Titre : Melting of phase change materials with volume change in metal foams Type de document : texte imprimé Auteurs : Zhen Yang, Auteur ; Suresh V. Garimella, Auteur Article en page(s) : pp. [062301-1/11] Note générale : Physique Langues : Anglais (eng) Mots-clés : Convection  Enthalpy  Finite  volume  methods  Flow  simulation  Flow  through  porous  media  Melting  Metal  foams  Phase  change  materials  Thermal  diffusivity Index. décimale : 536 Chaleur. Thermodynamique Résumé : Melting of phase change materials (PCMs) embedded in metal foams is investigated. The two-temperature model developed accounts for volume change in the PCM upon melting. Volume-averaged mass and momentum equations are solved, with the Brinkman–Forchheimer extension to Darcy's law employed to model the porous-medium resistance. Local thermal equilibrium does not hold due to the large difference in thermal diffusivity between the metal foam and the PCM. Therefore, a two-temperature approach is adopted, with the heat transfer between the metal foam and the PCM being coupled by means of an interstitial Nusselt number. The enthalpy method is applied to account for phase change. The governing equations are solved using a finite-volume approach. Effects of volume shrinkage/expansion are considered for different interstitial heat transfer rates between the foam and PCM. The detailed behavior of the melting region as a function of buoyancy-driven convection and interstitial Nusselt number is analyzed. For strong interstitial heat transfer, the melting region is significantly reduced in extent and the melting process is greatly enhanced as is heat transfer from the wall; the converse applies for weak interstitial heat transfer. The melting process at a low interstitial Nusselt number is significantly influenced by melt convection, while the behavior is dominated by conduction at high interstitial Nusselt numbers. Volume shrinkage/expansion due to phase change induces an added flow, which affects the PCM melting rate. DEWEY : 536 ISSN : 0022-1481 En ligne : http://asmedl.aip.org/vsearch/servlet/VerityServlet?KEY=JHTRAO&ONLINE=YES&smode= [...] [article] Melting of phase change materials with volume change in metal foams [texte imprimé] / Zhen Yang, Auteur ; Suresh V. Garimella, Auteur . - pp. [062301-1/11]. Physique Langues : Anglais (eng) in Journal of heat transfer > Vol. 132 N° 6 (Juin 2010) . - pp. [062301-1/11] Mots-clés : Convection  Enthalpy  Finite  volume  methods  Flow  simulation  Flow  through  porous  media  Melting  Metal  foams  Phase  change  materials  Thermal  diffusivity Index. décimale : 536 Chaleur. Thermodynamique Résumé : Melting of phase change materials (PCMs) embedded in metal foams is investigated. The two-temperature model developed accounts for volume change in the PCM upon melting. Volume-averaged mass and momentum equations are solved, with the Brinkman–Forchheimer extension to Darcy's law employed to model the porous-medium resistance. Local thermal equilibrium does not hold due to the large difference in thermal diffusivity between the metal foam and the PCM. Therefore, a two-temperature approach is adopted, with the heat transfer between the metal foam and the PCM being coupled by means of an interstitial Nusselt number. The enthalpy method is applied to account for phase change. The governing equations are solved using a finite-volume approach. Effects of volume shrinkage/expansion are considered for different interstitial heat transfer rates between the foam and PCM. The detailed behavior of the melting region as a function of buoyancy-driven convection and interstitial Nusselt number is analyzed. For strong interstitial heat transfer, the melting region is significantly reduced in extent and the melting process is greatly enhanced as is heat transfer from the wall; the converse applies for weak interstitial heat transfer. The melting process at a low interstitial Nusselt number is significantly influenced by melt convection, while the behavior is dominated by conduction at high interstitial Nusselt numbers. Volume shrinkage/expansion due to phase change induces an added flow, which affects the PCM melting rate. DEWEY : 536 ISSN : 0022-1481 En ligne : http://asmedl.aip.org/vsearch/servlet/VerityServlet?KEY=JHTRAO&ONLINE=YES&smode= [...]

Sensitivity analysis of a comprehensive model for a miniature-scale linear compressor for electronics cooling / Craig R. Bradshaw in International journal of refrigeration, Vol. 36 N° 7 (Novembre 2013) 

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A study of critical heat flux during flow boiling in microchannel heat sinks / Tailian Chen in Journal of heat transfer, Vol. 134 N° 1 (Janvier 2012) 

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