Research On Noise Airworthiness Assessment Of Civil Aircraft Engine Turbine

With the development of large aircraft, the civil aircraft of our country will be used all around world, the engine noise airworthiness certification is the factor which determine whether its aircraft can be put into market, so the engine noise assessment and its certification technology research receives more and more attention of researchers.The history of turbine noise assessment is started as early as late 1960 s, the employees of Royce-Rolls Smith and Bushell firstly give turbine noise empirical correlation formula by making several experiments, with the technology development and aircraft manufactures research, more and more noise prediction model is given and revised, at present, NASA has developed ANOPP program by completing different engine parts noise researches, which is most advanced in the noise prediction technology. Most of these research abroad is confidential for our country and our engine noise research is just started. Although some scholars has carried out engine parts noise prediction and noise reduction researches, turbine noise assessment research is nearly vacant, so our country can't completely make noise airworthiness assessment for ourselves developed engine.Considering all of these facts, this article make the research on turbine noise, including noise production and propagation, an aero-engine turbine noise airworthiness assessment program is developed by Matlab Gui software based on analysis of noise prediction method at home and abroad, and noise airworthiness analysis of some kind of engine is made by using this program. This program can predict sound pressure level, A weighted sound pressure level,overall sound pressure level and EPNL at various distance, angle and different 1/3 octave center frequency, and draws different sound pressure level contour line in the rectangle area with length 240 m and width 120 m, besides it can also analyze the relation between turbine noise EPNL and turbine rotating speed, turbine diameter and number of turbine blades, all of these result can be presented in figure by Matlab code, and the data is stored in form of Excel sheet by making link between Matlab workspace and Excel. Last but not least, this article make the verification of prediction model by comparing the turbine noise prediction result and turbine static tested noise data of one aero-engine manufacture, and do the airworthinessanalysis based on the noise airworthiness certification regulation, and the result perhaps can provide some technical reference for our civil aero-engine development.