A Comparative Study of Film Cooling with Combined Impingement and Film Cooling

Abstract

In order to cool the gas turbine vane or blade and raise the operating temperature, two standard convective cooling methods are used: jet impingement cooling and film cooling. The current study uses computational analysis to analyze and compare film cooling effectiveness with and without multi-jet impingement cooling on a flat plate. Ansys Fluent software is used to perform computational analysis on a flat plate. The computational results were compared with the experimental result using K-ω SST turbulence model and validated with literature data. The flat plate is used for the conjugate heat transfer study on the hot surface (named interaction surface), cold surface (called target surface), and inside the film hole. Different heat transfer parameters such as heat flux, Nusselt's number, and effectiveness are compared for the two cases, i.e., film cooling with impinging jets (IFC) and film cooling without impingement cooling (FC). It is observed that the FC case shows lower effectiveness as compared to the IFC case. The average Nusselt number for the IFC cases is almost three times larger than FC. The film exit temperature values are higher FC case, but it is more uniform in the IFC case. Interaction surface heat flux and Nusselt number values show higher values on the upstream wall of the film hole for IFC than in the FC case.

Keywords

• jet impingement cooling
• film cooling
• combined impingement film cooling
• turbulent kinetic energy
• nusselt's number