主动引射自由射流试验系统舱压的仿真建模分析

Modeling Analysis on Vacuum Pressure of a Free Jet Test System with Active Ejector

关键词:  冲压发动机  自由射流试验  舱压  引射器  变工况模拟

Key words:  Ramjet  Free jet test  Pressure of vacuum chamber  Ejector  Variable working condition simulation

摘要:

为了准确预测主动引射自由射流试验过程的舱压动态变化规律，对用于固体冲压发动机试验的自由射流试验系统的关键气动过程建模和仿真分析。建立了试验系统和固体冲压发动机试验件的数学模型与仿真流程图，对比了仿真结果与试验结果的差异，分析了在不同工作时段的冲压发动机对舱压变化的影响，对模拟马赫数和高度均变化的变工况虚拟试验仿真，获得引射器进口总压和冲压发动机对舱压的影响规律。研究结果表明，仿真舱压与试验舱压的曲线变化规律一致，建模方法能有效模拟主动引射自由射流试验系统舱压的动态变化，还能模拟冲压发动机工作对舱压的影响，并具备变工况模拟功能，可用于预测新试验工况或新产品试验时的舱压，指导试验方案设计和系统性能优化。

Abstract:

To simulate the dynamic changing law of the vacuum chamber’s pressure which is the key parameter of the free jet test system used for solid propellant ramjet， a mathematic model of the free jet test system’s primary aerodynamic mechanism was established. First， according to the mathematical equation， the simulated chart of the test system and ramjet article was built. Then， not only the simulated result was compared with the test result， but also ramjet’s effect on the chamber’s pressure during its different working phase was compared with that without ramjet. In the end， the virtual experiment function of variable working condition simulation of the Mach and height was implemented to study the effects of the total pressure of ejector inlet and ramjet on the chamber’s pressure. The results showed that the curve of the simulated chamber’s pressure was consistent with that of the experimental pressure and this mathematic model of the free jet test system not only could be applied in well predicting the dynamic changing of the chamber’s pressure， but also could simulate the ramjet’s effects on the chamber’s pressure and the variable test condition simulation. This simulation method can be used to predict the chamber’s pressure or the system’s started state for new test condition or new article test and conduct the test project design and system optimization.