部件三维仿真模型与发动机循环参数分析的耦合方法研究

Coupling Method Between Three-Dimensional Component Simulation Model and Aero-Engine Cycle Parameter Analysis

关键词:  变循环发动机  核心机驱动风扇级  维度缩放  迭代耦合方法  改进完全耦合方法

Key words:  Variable cycle engine  Core driven fan stage  Zooming  Iterative coupled approach  Modified fully coupled approach

摘要:

为了将基于部件三维仿真模型获取的部件工作特性耦合于发动机循环参数分析，提高整机性能预估的可信度，提出了改进完全耦合方法。结合核心机驱动风扇级（Core driven fan stage，CDFS）三维仿真模型和变循环发动机（Variable cycle engine，VCE）零维仿真模型，使用迭代耦合和改进完全耦合方法建立了VCE多维度仿真模型，研究了修正因子计算方法及边界参数松弛处理方法对VCE多维度仿真模型的影响，对比了迭代耦合与改进完全耦合方法的差异。结果表明，采用改进完全耦合方法时，直接将基于部件高保真度仿真模型得到的压比和等熵效率应用于发动机循环参数分析，可避免非线性方程组线性化过程对部件高保真度仿真模型的重复调用，同时计算过程不依赖于部件通用特性图。对于迭代耦合方法，采用优化方法或者常规方法计算修正因子的计算速度无明显差异。采用优化方法计算修正因子或者对边界参数进行松弛处理均可以抑制改进完全耦合方法中迭代残差的振荡，加速收敛。改进完全耦合方法与迭代耦合方法计算结果无明显差异，且在使用优化方法计算修正因子时收敛速度基本一致。

Abstract:

In order to integrate the working characteristics obtained from three-dimensional component simulation model into aero-engine cycle parameters analysis and improve the reliability of engine performance estimation， the modified fully coupled approach was proposed. The multi-level variable cycle engine （VCE） simulation model was established using iterative coupled approach and modified fully coupled approach based on three-dimensional core driven fan stage simulation model and zero-dimensional VCE simulation model. Then the effects of calculation method for correction factor and relaxation of boundary parameters on multi-level VCE simulation model were studied and the differences between iterative coupled approach and modified fully approach were compared. The results indicate that the pressure ratio and isentropic efficiency obtained from high-fidelity component simulation model are applied to engine cycle parameter analysis when modified fully coupled approach is employed， and the repeated calls of high-fidelity component simulation model during the linearization process of the nonlinear equations can be avoided. What’s more， the computational process of modified fully coupled approach does not depend on the component default characteristic map. As for iterative coupled approach， there is no obvious difference in convergence rate between the optimization method and normal method which are used to calculate the correction factors. By using optimization method to calculate the correction factors or the relaxation of boundary parameters， the vibration for iterative residual of modified fully coupled approach can be suppressed and the convergence rate can be accelerated. There is no obvious difference between the results of modified fully coupled approach and iterative coupled approach and the convergence rate of the two approaches are the same when the optimization method is used to calculate the correction factors.