Effects of varying non-axisymmetric contours of the turbine endwall on aerodynamics and heat transfer Aspects:A sensitivity analysis study

Abstract Non-axisymmetric endwall contouring of gas turbines has been widely employed as an effective way to improve the aerodynamic performance or heat transfer features. Though efforts have been exerted by previous investigators to generate improved contoured endwall designs, better understandings of the physics behind the phenomenon that non-axisymmetric contoured endwall configurations change the aerodynamic or heat transfer performances are still in demand. In this study, a global sensitivity analysis (GSA) methodology is used to determine shape changes at which locations on the endwall have the most significant impact on the aerodynamic or endwall heat transfer performances. Then, typical non-axisymmetric contoured endwall cases found by a multi-objective optimization approach are studied to understand further why shape changes in such locations impact the passage aero-thermal aspects so much. The results show that the most prominent areas for the passage aerodynamic performance are at the passage mid-pitch from the passage forepart to the aft part by impacting the stream-wise acceleration features. The locations at the passage's aft part influence the heat transfer features most due to high velocity, thus large heat transfer coefficient values there.