熵函数法在航空发动机涡轮效率计算中的应用

为提高涡轮效率计算精度,将熵函数法引入到涡轮效率计算过程中,借助变比热法等熵绝热过程基本方程,准确求解涡轮进出口截面理想等熵焓差,进而得到涡轮效率。利用该方法,对某型核心机的变比热涡轮效率进行计算,得到不同因素对涡轮效率的影响规律,并完成敏感性分析。分析结果表明：熵函数法能够将涡轮效率计算误差减小到1%～2%之间;压气机引气量的增加会导致涡轮效率计算值偏高,而压气机出口漏气量越小、高压轴效率越高,涡轮效率计算值越低;压气机出口漏气量对涡轮效率的影响最大,而高压轴效率敏感度最低。

Application of Entropy Function Method in Calculating Aero-engine Turbine Efficiency

In order to improve calculation precision of turbine efficiency,the entropy function method is introduced to calculate turbine efficiency.Ideal isentropic enthalpy difference on the sections of turbine inlet and outlet is calculated accurately with isentropic adiabatic equation based on variable specific heats,and then turbine efficiency is figured out.With the method,turbine efficiency of a certain core engine based on variable specific heats is calculated.Influence rule of different factors on turbine efficiency is obtained,and sensibility analysis is investigated on the results.Analysis results show that the entropy function method can decrease calculation error of turbine efficiency to the range between 1% and 2%.The increase of compressor bleed air capacity causes calculated value of turbine efficiency higher.The less compressor outlet leakage capacity and the higher high pressure shaft efficiency is,the lower calculated value of turbine efficiency is.Compressor outlet leakage capacity has the most effect on turbine efficiency,but the high pressure shaft efficiency has the lowest effect.