Experimental investigations were performed on the overall cooling effectiveness η of a flat effusion wall over a wide range of blowing ratio(M=0.47～5.27).The effusion wall had a staggered multi-hole pattern typical ...Experimental investigations were performed on the overall cooling effectiveness η of a flat effusion wall over a wide range of blowing ratio(M=0.47～5.27).The effusion wall had a staggered multi-hole pattern typical of gas turbine combustor application,with a ratio of hole pitch to row spacing P/S=1∶2,a porosity PS/d2=72,and an inclination angle α=30°.The current paper documented distribution of the overall cooling effectiveness on the wall surface,based on infrared imaging of the 2-D surface temperature field.Experimental results indicate:(1) The overall η increases along with the streamwise distance for the wide range of M due to the superposition effect of the multi-row film cooling.(2) The overall η substantially benefits from the multi-hole inside convective cooling.The hole convective cooling not only complements the weakest film protection at initial rows but also helps mitigate the temperature gradient.(3) The overall η increases asymptotically with increasing M,unlike adiabatic η mostly published in the past,which decreased after M reached a specific level.The current work showcased the end cooling outcome jointly driven by the filming cooling mechanism and the hole inside convective cooling mechanism.展开更多
文摘Experimental investigations were performed on the overall cooling effectiveness η of a flat effusion wall over a wide range of blowing ratio(M=0.47～5.27).The effusion wall had a staggered multi-hole pattern typical of gas turbine combustor application,with a ratio of hole pitch to row spacing P/S=1∶2,a porosity PS/d2=72,and an inclination angle α=30°.The current paper documented distribution of the overall cooling effectiveness on the wall surface,based on infrared imaging of the 2-D surface temperature field.Experimental results indicate:(1) The overall η increases along with the streamwise distance for the wide range of M due to the superposition effect of the multi-row film cooling.(2) The overall η substantially benefits from the multi-hole inside convective cooling.The hole convective cooling not only complements the weakest film protection at initial rows but also helps mitigate the temperature gradient.(3) The overall η increases asymptotically with increasing M,unlike adiabatic η mostly published in the past,which decreased after M reached a specific level.The current work showcased the end cooling outcome jointly driven by the filming cooling mechanism and the hole inside convective cooling mechanism.
