固體推進劑非均勻燃燒退化面的模擬計算

Numerical Simulation of Non-Uniform Grain Regression for Solid Propellants

本文主要發展應用於固體火箭發動機推進劑退化燃面的模擬分析方法，運用最小距離法的特性，進一步發展適用於非均勻燃燒速率問題的最小時間法，經由數值分析與案例驗證，說明此方法確實可作為模擬固體火箭發動機內彈道性能及應用於多維燃燒室流場模擬分析的基礎工具。

In this study, the efficient numerical method has been proposed to simulate the internal ballistic of a solid rocket motor (SRM) with multiple propellants. The essential feature for this method is depicted by transforming the original initial-value-problem for the solid propellant surface regression into an associated boundary-value-problem which can be described by the Eikonal equation. A fixed mesh covering simulation domain is established. The solution variable is taken as the arrival time of the burning surface. At first, the arrival time is estimated from the initial burning surface which is then reconstructed with the updated arrival time as the simulation time evolves. Meanwhile, active / inactive regions can be distinguished from the existing burn surface to enhance computational efficiency. The flow-field in the solid-propellant combustor can be simultaneously solved with the proposed surface regression model in a coupled manner. By examining theoretical results from the physical model and computational results of the test problems, we are confident that the proposed numerical methodology can serve as an effective tool for the SRM grain design.