Aerodynamic Stability Assessment And Software Research Of High Bypass Ratio Turbofan Engine

Based on the urgent demand for our country's military airlifter and civil aircraft' engine, to develop high bypass ratio turbofan engine is a matter of great urgency, and the problem of how to assess its' aerodynamic stability urgently need to be solved. Currently due to the special structure, the scope of application and other reasons of high bypass ratio turbofan engine, the processes and methods for assessing the stability of low bypass ratio turbofan engine can't verify the stability of high bypass ratio turbofan engine well. Besides, domestic engine stability evaluation system mostly adopts two-dimensional model, it cannot reflect the large radial scale of high bypass ratio turbofan engine's fan rotor, also it cannot show the different characteristics of the ability to resist the radial distortion. Therefore, it is particularly important to carry out research on the processes and methods for assessing the stability of high bypass ratio turbofan engine, and develop the three-dimensional model software to analyze whole engine aerodynamic stability.Aim at the characteristic of high bypass ratio turbofan engine's aerodynamic stability, this paper analyzed and arranged the processes and methods for assessing the stability of high bypass ratio turbofan engine, proposed the idea that flat baffle distortion experiment is not suitable for assessing the stability of high bypass ratio turbofan engine and assessing the ability to resist the radial distortion of fan/compressor in different radial ring sections respectively. At the same time, based on the three-dimensional body force model, this paper developed a new analysis model named CSAC-3s to research the inlet distortion on high bypass ratio turbofan engine. And by using this model, calculated and simulated a high bypass ratio turbofan engine under inlet circumferential and flat baffle total-pressure distortion, showed the fan rotor's different characteristics of the ability to resist the distortion in different radial part, assessed the transformation of total-pressure/total-temperature distortion in engine. The results show: Different radial part of fan rotor has different ability to resist the distortion; Total-pressure distortion is decreasing in engine, furthermore the fan and booster stage has large attenuation amplitude; Single lunette-shaped flat baffle is not suitable for assessing the stability of high bypass ratio turbofan engine.