基于双时间步法的航空发动机过渡态仿真

对于航空发动机非线性大偏差过渡态过程的仿真,容积动力学法在实时性和鲁棒性方面具有优势。这一方法通过建立容腔部件的控制方程并进行简化,可以得到描述主燃烧室、外涵道和加力燃烧室等部件的常微分方程,并采用时间推进法求解发动机稳态工作点,采用显式欧拉法求解过渡态过程。本文进一步发展了该方法,对于过渡态过程,采用隐式求解以保证计算格式的收敛性,消除由二阶差分带来的非物理振荡,并引入双时间步法以简化隐式求解过程,使得仿真程序收敛迅速。仿真实验证明,该方法计算精度高,鲁棒性强,能够满足非线性大偏差条件下对于发动机实时仿真的要求。

Dual time step method in transient simulation of aero engine

Gas domain dynamics method is found most suitable for the simulation of nonlinear transient process of aero-engine. In this method, a serials of ordinary differential equations which describe the working process of main combustor, bypass duct and afterburner are established and simplified. Time marching method is used to solve steady state, and explicit Euler method is used to calculate the transient process. The gas domain dynamics method is further developed. For the transient process, implicit scheme was employed to ensure convergence and to diminish the artificial vibration generated by second order difference scheme. A dual time step method was introduced to simplify the process of implicit calculation, as well as to shorten the time needed for solution in one time step. Simulation tests showed this new method was good in accuracy and robust. It can be used in real time simulation of aero-engine working at nonlinear high excursion condition.