| Gas turbine as an important power machinery in modern society of production,manufacturing,aviation,power generation and other fields was widely used in the national production,military,national defense applications.With the increase in the demand for gas turbine power,the turbine inlet temperature is getting higher and higher,more than the material tolerance temperature,so efficient cooling technology research is essential.The film cooling is now the most widely used in the gas turbine turbine blade cooling technology,so the study of the film cooling is necessary.The effect of different flow conditions on the cooling effect of film cooling is mainly studied in this paper.The effect of different flow conditions on the cooling effect of the film is discussed.Different flow conditions include mainstream,airconditioning conditions are different.In this paper,the effect of pulsating jet on the cooling effect of the airflow is mainly studied in this paper.The effect of the pulsating jet on the cooling effect is analyzed.Pulsating injection method to select the pulsation velocity sine wave form.Because of the high degree of nonuniformity in the study of the flow conditions,and the process of film cooling itself is highly unsteady and complex,the method of this paper adopts large eddy simulation(LES).The effect of pulsating jet on the cooling effect of film was studied.The results show that the pulsating jet can effectively improve the cooling efficiency,reduce the separation of cooling air,improve the Coverage results of the cooling air,and improve the cooling efficiency of the air-cooled jet.For the low blowing ratio,the constant jet condition corresponds to the better cooling air effect,the pulsating jet is not conducive to the cold air in the cooling plate surface coverage.And the pulsating frequency has a great influence on the pulsating film cooling.For the blow ratio 1.0 working conditions,the pulsating Strouhal number St = 1.0 corresponds to a better cooling effect.For the blow ratio of 1.5 cases,pulsating St = 0.5 corresponds to a better cooling effect.Then,the numerical simulation of the air film cooling in the periodic sweep mode is carried out.The sweep of the two cases(blowing ratio M = 0.5 and 1.0)is mainly studied.For the blowing ratio of M = 1.0 conditions,the cycle of sweep flow can make the average cooling efficiency becomes high,the main mechanism is to sweep the flow of air to increase the lateral diffusion capacity,better air-conditioning effect,more efficient.And the cooling efficiency is improved as the scanning speed increases.For the blowing ratio of M = 0.5 conditions,due to the small amount of cold air,uniform flow conditions under the cold air in the flat surface has a better coverage,cooling efficiency is higher.The mainstream speed of a periodic scan destructed the original cold air coverage,reduced cooling efficiency,and the cooling effect is deteriorated. |
PDF Full Text Request