固体运载火箭级间热分离仿真气体模型研究

目前,计算流体力学和飞行力学耦合仿真是模拟运载火箭级间分离较为流行的方法,而发动机内外流动建模则是运用该方法的关键。工程上,常用的方法是将发动机燃气与外部大气当作同一种气体组分处理,未考虑内外流动的多组分与燃烧效应。分析了化学非平衡流模型、双组分气体模型和常规单组分气体模型在火箭级间热分离流场计算中的适用性。化学非平衡流模型由于过高的计算消耗,不适用于火箭研制工程中大规模的参数化研究。而热化学等级较低的双组分气体和单组分气体模型由于计算量较低,具有较好的工程适用性。双组分气体模型计入了火箭燃气的特性,计算消耗远低于化学非平衡计算,且能够较好地预测火箭级间段的流动分离,在计算效率和计算保真度之间做出了较好的平衡,未来在工程研究中有较大的应用潜力。

Gas Modeling of a Solid Rocket Motor for the Simulation of Hot Stage Separation

The coupled simulation of CFD and flight mechanics is popular for the study of rocket stage separation. An appropriate plume model is crucial for this simulation. In the earlier work, the gas mixture of rocket exhaust and external air are usually simulated as one gas species and the multi species effects and combustion effects are not considered. In this work, the nonequilibrium gas model, two-species-calorically-perfect-gas model and single-species-calorically-perfect-gas model for simulating the flow of rocket stage separation are investigated. The nonequilibrium gas model is not practical for the parameter study in the industry because of its high computation consumption. The two-species-calorically-perfect-gas model and single-species-calorically-perfect-gas model, which have lower thermochemical level and require less computation consumption, are feasible to be frequently applied in the industry. With the two-species-calorically-perfect-gas model, more dynamics behavior of the motor exhaust can be taken into account in the simulation and the flow separation at the inter-stage section predicted more accurately. However, its CPU consumption is much lower than the nonequilibrium computation. Therefore, it can balance between the computation efficiency and fidelity and has potential to be applied in the industry.