基于地面试验的涡扇发动机装机推力损失分析

为评定涡扇发动机装机推力损失,基于推力直接确定方法开展了发动机推力测量地面试验。通过改进完善安装节推力数据处理方法、进气道冲压阻力计算方法来提高总推力测量精度,分析表明:台架试验推力测量最大误差为2.41%,11架次飞行后停机状态发动机总推力测量误差小于0.8 kN,基本满足推力测量评定的需求。以相同状态台架试验数据为基准,对比发现:随着发动机功率状态增大,总推力损失呈明显增大趋势,中间状态换算总推力损失达到了17.95%,最大状态换算总推力损失达到了27.72%。通过分析风扇换算转速、换算流量等关键参数,得出:装机后受进气道的影响,导致换算流量明显小于同等状态下台架试验的换算流量,同时进气道内气流总压的过大损失,是造成装机后发动机推力损失明显的主要原因。

Analysis on Installed Gross Thrust Loss of Turbofan Engine on Ground Test

In order to evaluate installed gross thrust loss of one turbo-fan engine, the thrust measurement on ground test was carried out on direct thrust determination method. The accuracy of gross thrust measurement was improved by developing the processing method of mount thrust data, the computational method of air-inlet ram drags. The results show that the maximum error of thrust measurement was 2.41% in bed test and the errors in shutdown condition after landing are less than 0.8 kN among 11 flights, so the method basically meets thrust evaluation requirement. It is found that installed gross thrust loss presents a significant increase with the increase of engine power condition. The loss of corrected gross thrust reaches 17.95% in military intermediate condition and 27.72% in military maximum condition taking corrected gross thrust in the same condition in bed test as the benchmark. Through analysis of the key parameters such as corrected fan speed and corrected mass flow, it is concluded that due to the influence of the air-inlet, the mass flow is significantly less than that in the same condition in bed test and there is the excessive loss of the total pressure in the air-inlet. The two factors results in the installed gross thrust loss.