航空发动机推力直接测量飞行试验

建立了基于推力直接测量原理的发动机总推力计算模型,合理忽略了某些次要力简化了计算模型。在推力销上加装剪力应变桥路,建立载荷标定方程和温度修正方程获取发动机安装节推力;利用进气道测量耙测试参数,计算飞行中进气道冲压阻力和压差阻力。在某型飞机上开展了推力直接测量飞行试验,获得了某小涵道比涡扇发动机飞行总推力,并分析了空中平飞加速过程总推力和各推(阻)变化规律。结果表明:飞行马赫数处在约0.98~1.02时,总推力随飞行马赫数增大而急剧增大;高度为8km、飞行马赫数为1.42时发动机最大状态总推力相对值为123.78%,高度为11km、飞行马赫数为1.69时总推力相对值为119.70%,均高于相同状态地面台架推力值。通过分析进气道压差阻力百分比,验证了发动机空中总推力测量结果具有较高的准确性以及推力直接测量技术的可行性。

Direct thrust measurement flight test of aero-engine

Gross thrust calculation model based on direct thrust measurement method of aero-engine was established, and also simplified by neglecting some secondary forces reasonably. Mount thrust was obtained through load calibration equation and thermal correction equation before installing the shear strain gages on thrust pins. Ram drag and pressure drag of the air-inlet were calculated by the test parameters of the air-inlet measurement rake. Direct thrust measurement flight tests were carried out on an aircraft, and gross in-flight thrust of a low bypass ratio turbofan engine was gained. The variation laws of gross thrust and all kinds of thrusts (drags) during level acceleration flight were analyzed. Results showed that gross thrust increased rapidly with the increase of flight Mach from 0.98 to 1.02. Relative value of gross thrust for the maximum power was 123.78% at an altitude of 8km and flight Mach 1.42 and the value was 119.70% at an altitude of 11km and flight Mach 1.69. By analysis of air-inlet pressure drag percentage, the conclusions demonstrate that measurement results of gross in-flight thrust have high accuracy and direct thrust measurement technique is feasible.