| Most of the previous researches on film cooling are based on simple abstract models and single cascade models,so the film cooling characteristics obtained by such research are deviated from the actual blades.Moreover,due to the large differences in the curvature and pressure gradient distribution of each blade profile,the film cooling characteristics of different blade profiles are bound to be different.Therefore,this paper takes different blades as the research object,and summarizes the influence mechanism of blade shape changes on film cooling.This article can lay the foundation for the development of similar design methods for film cooling.Firstly,the front-loaded and after-loaded blades are used as reference models to study the influence of blade load distribution on blade film cooling.It was found that the load distribution method changed the blowing-off level of the jet at the leading edge of the blade,the spanwise offset level of the jet with compound angle,and the mixing intensity of the mainstream and jet at the trailing edge of the suction surface by changing the curvature and pressure gradient of the blade surface..At low cooling air flow,the film cooling efficiency of the after-loaded blade is higher than that of the front-loaded blade,especially on the pressure side.At high cooling air flow,the film cooling efficiency of the front and after-loading blades is similar.Secondly,the variation of the load distribution of the front-loaded and after-loaded blades was quantified by the profile parameters.Based on this,the influence mechanism of the key modeling parameters of the blade on the film cooling of the blade is studied,and the influence of the blade profile parameters on the film cooling of the blade is quantified through the correlation coefficient.Then,the influence of load distribution mode on endwall film cooling is studied.It is found that the load distribution mode changes the coverage area of the endwall cooling jet by changing the cooling air distribution mode of the endwall and the degree of lateral deflection of the jet.Compared with the front-loaded blade,the film cooling efficiency of the after-loaded blades is unevenly distributed along the flow direction and the lateral direction.Finally,the cooling efficiency of various endwall film-cooling hole layout methods is considered.It is found that the film-cooling hole layout method in which the film-cooling holes are distributed along the pressure contours and the jet direction is along the main flow direction can weaken the influence of the secondary flow of the endwall,so the cooling jet can cover the end wall evenly.Moreover,when the similar design is carried out through the parameterization of the film-cooling hole and the layout method along the pressure contour,the film cooling efficiency of the endwall of the front and after loading blade is evenly distributed and similar.The difference in cooling efficiency between the two blades mainly comes from the cooling air distribution mode of the endwall.On the whole,similar designs of endwall film cooling are feasible. |
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