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Adiabatic wall temperature evaluation in a high speed turbine / V. Pinilla in Journal of heat transfer, Vol 134 N° 9 (Septembre 2012) 

Public ISBD [article]  in Journal of heat transfer > Vol 134 N° 9 (Septembre 2012) . - 09 p. Titre : Adiabatic wall temperature evaluation in a high speed turbine Type de document : texte imprimé Auteurs : V. Pinilla, Auteur ; J. P. Solano, Auteur ; G. Paniagua, Auteur Année de publication : 2012 Article en page(s) : 09 p. Note générale : heat transfer Langues : Anglais (eng) Mots-clés : thin  film  gauges;  gas  turbine;  convective  heat  transfer Index. décimale : 536 Chaleur. Thermodynamique Résumé : Engine development requires accurate estimates of the heat loads. Estimates of the convective heat fluxes are particularly vital to assess the thermomechanical integrity of the turbomachinery components. This paper reports an experimental heat transfer research in a one and a half turbine stage, composed of a high-pressure turbine and a low-pressure vane. Measurements were performed in a compression tube facility at the von Karman Institute, able to reproduce engine representative Reynolds and Mach numbers. Double-layered thin film gauges were used to monitor the time-dependent temperature distribution around the airfoil. Several tests at different metal temperatures were performed to derive the adiabatic wall temperature. This research allowed quantifying the independent effects on the unsteady heat flux of the gas temperature fluctuations and boundary layer unsteadiness. DEWEY : 536 ISSN : 0022-1481 En ligne : http://asmedl.org/getabs/servlet/GetabsServlet?prog=normal&id=JHTRAO000134000009 [...] [article] Adiabatic wall temperature evaluation in a high speed turbine [texte imprimé] / V. Pinilla, Auteur ; J. P. Solano, Auteur ; G. Paniagua, Auteur . - 2012 . - 09 p. heat transfer Langues : Anglais (eng) in Journal of heat transfer > Vol 134 N° 9 (Septembre 2012) . - 09 p. Mots-clés : thin  film  gauges;  gas  turbine;  convective  heat  transfer Index. décimale : 536 Chaleur. Thermodynamique Résumé : Engine development requires accurate estimates of the heat loads. Estimates of the convective heat fluxes are particularly vital to assess the thermomechanical integrity of the turbomachinery components. This paper reports an experimental heat transfer research in a one and a half turbine stage, composed of a high-pressure turbine and a low-pressure vane. Measurements were performed in a compression tube facility at the von Karman Institute, able to reproduce engine representative Reynolds and Mach numbers. Double-layered thin film gauges were used to monitor the time-dependent temperature distribution around the airfoil. Several tests at different metal temperatures were performed to derive the adiabatic wall temperature. This research allowed quantifying the independent effects on the unsteady heat flux of the gas temperature fluctuations and boundary layer unsteadiness. DEWEY : 536 ISSN : 0022-1481 En ligne : http://asmedl.org/getabs/servlet/GetabsServlet?prog=normal&id=JHTRAO000134000009 [...]

Investigation of the flow field on a transonic turbine nozzle guide vane with rim seal cavity flow ejection / M. Pau in Transactions of the ASME . Journal of fluids engineering, Vol. 132 N° 11 (Novembre 2010) 

Public ISBD [article]  in Transactions of the ASME . Journal of fluids engineering > Vol. 132 N° 11 (Novembre 2010) . - 09 p. Titre : Investigation of the flow field on a transonic turbine nozzle guide vane with rim seal cavity flow ejection Type de document : texte imprimé Auteurs : M. Pau, Auteur ; G. Paniagua, Auteur Année de publication : 2011 Article en page(s) : 09 p. Note générale : fluids engineering Langues : Anglais (eng) Mots-clés : pressure;  flow  (dynamics);  shock  (mechanics);  cavity  flows;  nozzles;  turbines;  cavities Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : Ensuring an adequate life of high pressure turbines requires efficient cooling methods such as rim seal flow ejection from the stator-rotor wheel space cavity interface, which prevents hot gas ingress into the rotor disk. The present paper addresses the potential to improve the efficiency in transonic turbines at certain rim seal ejection rates. To understand this process, a numerical study was carried out, combining computational fluid dynamic (CFD) simulations and experiments on a single stage axial test turbine. The three dimensional steady CFD analysis was performed, modeling the purge cavity flow ejected downstream of the stator blade row at three flow regimes: subsonic M2=0.73, transonic M2=1.12, and supersonic M2=1.33. Experimental static pressure measurements were used to calibrate the computational model. The main flow field-purge flow interaction is found to be governed by the vane shock structures at the stator hub. The interaction between the vane shocks at the hub and the purge flow has been studied and quantitatively characterized as a function of the purge ejection rate. The ejection of 1% of the core flow from the rim seal cavity leads to an increase in the hub static pressure of approximately 7% at the vane trailing edge. This local reduction of the stator exit Mach number decreases the trailing edge losses in the transonic regime. Finally, a numerically predicted loss breakdown is presented, focusing on the relative importance of the trailing edge losses, boundary layer losses, shock losses, and mixing losses, as a function of the purge rate ejected. Contrary to the experience in subsonic turbines, results in a transonic model demonstrate that ejecting purge flow improves the vane efficiency due to the shock structure modification downstream of the stator. DEWEY : 620.1 ISSN : 0098-2202 En ligne : http://fluidsengineering.asmedigitalcollection.asme.org/Issue.aspx?issueID=27439 [...] [article] Investigation of the flow field on a transonic turbine nozzle guide vane with rim seal cavity flow ejection [texte imprimé] / M. Pau, Auteur ; G. Paniagua, Auteur . - 2011 . - 09 p. fluids engineering Langues : Anglais (eng) in Transactions of the ASME . Journal of fluids engineering > Vol. 132 N° 11 (Novembre 2010) . - 09 p. Mots-clés : pressure;  flow  (dynamics);  shock  (mechanics);  cavity  flows;  nozzles;  turbines;  cavities Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : Ensuring an adequate life of high pressure turbines requires efficient cooling methods such as rim seal flow ejection from the stator-rotor wheel space cavity interface, which prevents hot gas ingress into the rotor disk. The present paper addresses the potential to improve the efficiency in transonic turbines at certain rim seal ejection rates. To understand this process, a numerical study was carried out, combining computational fluid dynamic (CFD) simulations and experiments on a single stage axial test turbine. The three dimensional steady CFD analysis was performed, modeling the purge cavity flow ejected downstream of the stator blade row at three flow regimes: subsonic M2=0.73, transonic M2=1.12, and supersonic M2=1.33. Experimental static pressure measurements were used to calibrate the computational model. The main flow field-purge flow interaction is found to be governed by the vane shock structures at the stator hub. The interaction between the vane shocks at the hub and the purge flow has been studied and quantitatively characterized as a function of the purge ejection rate. The ejection of 1% of the core flow from the rim seal cavity leads to an increase in the hub static pressure of approximately 7% at the vane trailing edge. This local reduction of the stator exit Mach number decreases the trailing edge losses in the transonic regime. Finally, a numerically predicted loss breakdown is presented, focusing on the relative importance of the trailing edge losses, boundary layer losses, shock losses, and mixing losses, as a function of the purge rate ejected. Contrary to the experience in subsonic turbines, results in a transonic model demonstrate that ejecting purge flow improves the vane efficiency due to the shock structure modification downstream of the stator. DEWEY : 620.1 ISSN : 0098-2202 En ligne : http://fluidsengineering.asmedigitalcollection.asme.org/Issue.aspx?issueID=27439 [...]