Numerical Study on the Unsteady Film Cooling Characteristics of Turbine

Abstract

In view of the main flow pulsation phenomenon and the new pulsating film cooling mode in the aeroturbine engine, the numerical calculation method is used to study the film cooling characteristics under the condition of the main flow velocity pulsation and cooling gas velocity pulsation with the classical circular film hole as the research object. In order to eliminate the influence of other factors on the film cooling characteristics of turbine blades as much as possible, a circular film hole of flat plate model similar to the small curvature section of turbine blades was established, and the influence of different cooling air pulse frequency, blowing ratio and mainstream pulse frequency on the film cooling characteristics was analyzed in depth. The results show that: with the increase of cooling air pulse frequency, the film cooling efficiency of cooling gas pulsation scheme can be achieved approximately the steadystate condition with blowing ratio of 1.0 while only half of the cooling air flow is consumed; at high blowing ratio, the cooling effect will be better when using the cooling air pulsating film cooling scheme compared with the steady-state scheme; in the main pulsating frequency range of the study, the frequency of main flow pulsation has little effect on film cooling efficiency.