民用客机辅助动力装置本体权衡研究

The trade-off research on auxiliary power unit for civil airplanes

对两型典型APU进行权衡研究,主要研究APU部件、构型、起动发电系统、变速技术、燃油模块和防喘控制,得到不同本体形式优缺点。民用客机APU基本采用离心压气机,回流式环形燃烧室和轴流涡轮的结构。从动力压气机引气的APU体积小、重量轻、可靠性高,适用于要求重量轻和空间小的支线客机。从负载压气机引气的APU油耗低,引气控制好,更适用于要求低油耗的干线飞机。与分开设计对比,起动/发电机一体化具有重量轻、寿命长、可靠性高的优点。采用变速技术的APU经济性、环保性更好,但控制系统和飞机电源系统要求更高,存在性能裕度不足的风险。采用电机驱动燃油泵,重量轻、控制精度高,但控制系统复杂,燃油流量范围小;APU燃油消耗量大,燃油系统参与导叶和防喘阀控制,一般采用轴驱动燃油泵。从动力压气机引气的APU,一般在设定的工作条件下开关防喘阀;带负载压气机的APU,采用流量法来判别。

This paper conducts a trade-off study on the two typical APU,mainly studying APU components,config-uration,starting generator system,variable speed technology,fuel module and anti-surge control,to obtain the ad-vantages and disadvantages of different body forms.Generally,the civil airliner APU adopts a structure of centrifu-gal compressor,reversed-flow type annular chamber and axial flow turbines.The APU bleeding air from the power compressor is small,light and high reliability,and is suitable for regional passenger planes that require small and light.The APU bleeding air from the load compressor has characteristics of low fuel consumption,good bleed air control,making it more suitable for large aircraft that requires low fuel consumption.Compared to the starter and generator separately,the APU integrated design starter/generator system had the advantages of light weight,longer service life,and higher reliability.The use of variable speed technology was more economical and more environ-mentally friendly,but it needed frequency conversion power and better control system to meet aircraft requirement.There was a risk of insufficient performance margin.Using a motor driven gear wheel pump,it was lightweight and had high control accuracy,but the control system was more complex and the fuel flow range was small.The APU required high fuel consumption,and the fuel system was involved in control guide vane and anti-surge,usually u-sing a shaft driven pump.The APU bleeding air from the power compressor usually switches on and off the anti surge valve under specific working conditions.The APU bleeding air from the loaded compressor will be identified by compressor flow.