Research On Controlling Of Infrared Radiant With Cooling Of Components At Aeroengine Exhaust System

In recent years,as the development of the radar stealth technology,each militarily superior country around the world paid much attention to the infrared detection and guidance technology which developed rapidly.Now,infrared search and track system is another enormous threat to military flight vehicle besides radar system.The heating parts of engine exhaust system are the important infrared radiation source for military flight vehicle.So it is much important that research of infrared suppression and infrared radiant intensity reduction of heating parts of engine exhaust system to improve the survival ability of military flight vehicle of our country.The paper researches one aero engine,the heating parts of which are cooled by external cooling air in order to reduce infrared radiant intensity of engine exhaust system.At first,one primary air film cooling project is presented for the engine structure and the working condition,based on understanding of infrared suppression technology.And then,numerical simulation of original flow field of the exhaust system is conducted by using commercial CFD software,and flow field parameters are obtained for design of air film.Base on a lot of numerical simulations and engineering calculations of different film hole diameter,X/D value,flow angle and different cooling air pressure,air film cooling project for the engine have been worked out and corresponding redesign has been fulfilled.Comparing with the test results,the paper designed a program to calculate the inside cone wall temperature under the film cooling,and the infrared radiation within 3?5 micron.According to film cooling temperature program,the research group made the corresponding parts of the exhaust system.Then infrared stealth test of whole engine after redesign is conducted according to the air film cooling project.At last,compared with the calculation results and the test results,verify the infrared radiation effect.The infrared suppression technology of heating parts of engine exhaust system has been researched in this paper with theoretical and experimental method,and find out engineering design method of air film cooling for heating parts.It has shown that air film cooling can reduce infrared radiant intensity effectively in the case of no influence to normal working of engine,and it is effective for infrared suppression of military flight vehicle.