Aero-Thermal Performance of Purge Flow in Turbine Cascade Endwall Cooling

Abstract

The endwall and blade film cooling systems are the typical solution adopted within gas turbines to allow further increase of turbine inlet temperature, avoiding critical material thermal stresses. Due to complex secondary flow field in the blade passage, endwallis more difficult to cool than blade surfaces. In the matter of fact, in endwall film cooling studies, it is necessary to investigate the interaction between coolant air and the secondary flow. In present study, the flow field of high-pressure turbine cascade has been investigated by 5-holes pitot tube to reveal the secondary flows behavior under the influenced of purge flows while the heat transfer measurement was conducted bythermochromic liquid crystal (TLC). Experimental has significantly captured theaerodynamics effect of purge flowat blade downstream close to the endwall region. Furthermore, TLC measurement illustrated that the film cooling effectiveness and heat transfer coefficient contours were strongly influenced by the secondary flow on the endwall.