拉瓦尔喷管计算模型的改进及其整机仿真验证

根据拉瓦尔喷管的典型工作状态.建立了零维拉瓦尔喷管气体动力学模型,并将其集成到发动机整机部件级模型中,开展了发动机整机加速动态仿真.仿真结果表明:①随着喷口面积的不断收小,发动机低压转速加速曲线存在一段"先降后升"区域,这与实际试车结果吻合;②贴口正激波被推出管外的瞬间,出口马赫数从亚声速突变至超声速,但喷管出口流量、发动机推力变化连续,未见突变现象.

Improvement of Laval nozzle calculation model and simulative verification in aero-engine performance calculation

Based on analyzing typical operating regimes of Laval nozzle, a 0-D pneumatic model was built in order to evaluate the influence of Laval nozzle on the performance of aero-engine. The Laval nozzle model was integrated into a whole aero-engine component-level model. Numerical Simulations were performed in order to study transient performance of aero-engine when nozzle throat and outlet areas decreased during accelerating process from idle to middle state. Results show that low pressure rotor speed decreases during some specific regimes, along with the reduction of Laval nozzle area in accelerating process, which is also existent in real aero-engine rig tests. Besides, after normal shock clinging to nozzle outlet section was pushed out, there was a mach number break from subsonic to supersonic in nozzle outlet section, however, both the outflow rate and thrust changed smoothly without any break at the accelerating curve.