Design And Performance Simulation Of An Experimental Rig For Infrared Stealth Research Of Exhaust System Of A Turbofan Engine

The objective of this thesis is to investigate the infrared stealth experiment device of the exhaust system of turbofan engine. The scheme design of infrared stealth experiment device and the Infrared Radiation (IR) behavior of experiment device installed with axisymmetrical convergent nozzle were investigated. On the numerical aspect of the study, the physical models were established with software of Unigraphics, the meshes were created with Gambit, the flow fields were computed with FLUENT. The IR characteristics were computed with an IR analysis software—TEESIRP(Turbine Engine Exhaust System Infrared Radiate Prediction)developed by research group.The overall design work of test equipment includes scheme design for test equipment, by-pass duct inlet design, size design for key components, fan selection and measurement design for flow parameters. The characteristic and advantage of this part is considerable usage of CFD technology and including several key points below. The first, the velocity distribution of by-pass section was calculated for various by-pass inlet forms using fluent software and the calculated results were compared to determine the by-pass inlet form which accords with the test equipment design requirements. The second, the velocity distribution of by-pass section was calculated for the combinations of various key size parameters which belong to key components of test equipment and also the calculated results was compared to determine the coincident design requirements. The last, it was calculated the needed dynamic pressure which the fan provided in the condition that the core and bypass flow rate accords with the design requirements and then fan model was chosen based on residual correction and performance curves of various fans which was provided by the fan company. The above research made good preparation for the forthcoming component design and assembly design.In the research of usage test equipment to simulate the infrared performance, it was calculated the infrared characteristic in the condition of axisymmetric nozzle installed. It was included flow calculation and infrared performance calculation in this part of work. Firstly the temperature filed, flow field and concentration field was calculated through fluent software calculation for various nozzles. Secondly, the spectral and spatial distribution of infrared intensity was calculated in the usage of TEESIRP software. Based on the finished calculation, the result reliability and the mechanism of infrared intensity distribution was demonstrated from the below aspects, analysis of radiation characteristic from gas, flow field parameters distribution, the projected area variation of different nozzle components. The part predicted and analyzed the infrared characteristic of test equipment under the design condition. And it also made good preparation for the development of test work and analysis of test phenomena.