基于可变高增压方式的航空活塞发动机变海拔工作特性仿真研究

以一台直列四冲程压燃式航空活塞发动机为研究机型，通过GT-Power构建一维热力学模型，首先对比研究了不同海拔下固定截面增压（fixed geometry turbocharger, FGT）、可变几何截面增压（variable geometry turbocharger, VGT）和两级可变几何截面增压（twinvariable geometry turbocharger, TVGT）对发动机性能的影响；然后基于搭建的TVGT增压系统，探究了高、低压级VGT叶片开度对发动机变海拔条件下工作特性的影响。结果表明：在不同海拔和转速工况下，发动机匹配TVGT增压系统后，其海拔适应性更佳。针对TVGT系统，在不同海拔下，当高压级VGT叶片开度位于0.2～0.4范围内，低压级VGT叶片开度位于0.6～0.8范围内时可以获得较高的动力性及经济性。通过对高、低压级VGT叶片开度的优化，在巡航工况转速3 397 r/min时可在6 000 m海拔下实现106.8%的功率恢复目标，可满足发动机对高海拔工作运行的功率恢复要求。

Research on Different Altitude Working Characteristics of Aviation Piston Engine Based on Variable High Pressure Supercharging Method

Using an inline four stroke compression ignition aviation piston engine as the research model， an one-dimensional thermodynamic model was constructed by using GT Power. Firstly， the effects of fixed cross-section turbocharging（FGT）， variable geometry turbocharging（VGT）， and two-stage variable geometry turbocharging（TVGT） on engine performance were compared and studied at different altitudes. Then， based on the constructed TVGT turbocharging system， the influence of high and low pressure VGT blade opening on the operating characteristics of the engine under variable altitude conditions was explored. The results show that under different altitude and speed conditions， the engine with a TVGT turbocharging system has better altitude adaptability. For the TVGT system， high power and economy can be achieved at different altitudes when the opening of the high-pressure stage VGT blades is in the range of ［0.2，0.4］， and the opening of the low-pressure stage VGT blades is in the range of ［0.6，0.8］. By optimizing the opening of high and low pressure VGT blades， a power recovery target of 106.8% can be achieved at an altitude of 6 000 m under cruising conditions at a speed of 3 397 r/min， which can meet the power recovery requirements of the engine for maximum working altitude.