Experimental Research On Leading Edge With Cooling Film In Deposition Environment

With the development of modern aviation industry,the thrust of aircraft engine becomes higher and higher,and the temperature of turbine inlet becomes higher and higher.In this kind of high temperature environment,the foreign matters inhaled during the operation of engine,impurities in aircraft fuel and products of incomplete combustion can cause deposits on the surface of turbine blades.These deposits increase the roughness of the blade surface and reduce the working efficiency of the turbine.At the same time,the deposits will also cause the film cooling hole to be blocked and the film cooling effectiveness will be reduced,which will shorten the life of the turbine blade.Based on the small open wind tunnel,the deposition of the leading edge of the turbine was simulated.The experiment focused on the effect of particle deposition on film cooling efficiency,and discussed the effect of the diameter and jet angle of film cooling hole on film cooling efficiency and deposition rate in the deposition environment.In addition,the growth of particles without film cooling and the coverage of particles at different mainstream temperatures were studied.The specific research contents are as follows:(1)The deposition of particles was studied in the environment without film cooling.The main purpose of the experiment is to obtain the deposition rate and analyze the deposition changes with time and mainstream temperature.The results showed that the growth rate of particle deposition mass decreases gradually,and the deposition rate will increase first and then decrease and the highest deposition rate can reach 13.56%.The mainstream temperature has a significant effect on the deposition of particles.The highest deposition rate was 4.14% at 60 ?.(2)Under the condition of film cooling,the effects of different diameter and jet angle of film cooling hole on the cooling effectiveness at stagnation line and deposition rate of the test piece were analyzed.The results showed that the film cooling efficiency is significantly reduced after deposition,and at the same location,the film cooling efficiency is reduced by 11.6% at most due to deposition;the larger the jet angle is,the lower the film cooling efficiency is,and the higher the deposition rate is.The deposition rate at 65 ° jet angle is 0.4% which is higher than that at 25 °.For different the diameter of film holes(1.5mm,3mm,4.5mm),the film cooling efficiency at 4.5mm is the highest and the film cooling efficiency at 3mm is the lowest under the same film hole spacing ratio,and the maximum difference between the film cooling efficiency is 3.2%.The deposition rate first decreases and then increases with the diameter of film hole,and the lowest is about 0.41% when the diameter of film hole is 3 mm.(3)Through the study of the influence of the two factors of the diameter of film hole and jet angle on the film cooling efficiency and deposition rate,the optimal solution was obtained by the method of constraint solution to the target sequence,and the result is the diameter is 3mm and jet angle is 25 °.Under this kind of film hole,the average film cooling efficiency after deposition is 35.714%,and the deposition rate is 0.4%.