为了对水下固体火箭发动机典型具有相变过程的复杂流动问题进行研究,本文依据水-蒸汽相变的热力学原理,建立了蒸发-冷凝过程的判别标准,设计了一种解决水下超音速燃气射流复杂相变过程的计算模型。根据VOF(volume of fluid)模型原理,通过对基本方程的源项进行修改实现了相变的数值传质、传热过程。经过实验与数值模拟结果的对比分析,验证了该计算模型仿真结果的可行性和可信度,运用该模型完成了典型工况的水下高温、高速燃气射流问题中相变过程的仿真计算,并对其过程进行了分析。仿真结果表明:该模型对解决复杂工况下的相变为题具有很好的适用性,可以为相应的工程问题提供很好的帮助。
The infrared radiation signature of the plume from solid propellants with different energy characteristics is not the same. Three kinds of double-base propellants of different energy characteristics are chosen to measure the infrared spectral radiance from 1000 cm 1 to 4500 cm 1 of their plumes. The radiative spectrum is obtained in the tests. The experimental results indicate that the infrared radiation of the plume is determined by the energy characteristics of the propellant. The radiative transfer calculation models of the exhaust plume for the solid propellants are established. By including the chemical reaction source term and the radiation source term into the energy equation, the plume field and the radiative transfer are solved in a coupled way. The calculated results are consistent with the experimental data, so the reliability of the models is confirmed. The temperature distribution and the extent of the afterburning of the plume are distinct for the propellants of different energy characteristics, therefore the plume radiation varies for different propellants. The temperature of the fluid cell in the plume will increase or decrease to some extent by the influence of the radiation term.
对水下固体火箭发动机的动态特性进行了研究,根据动网格及VOF(Volume of Fluid)基本原理,构建了用于水下固体火箭发动机动态射流响应的轴对称模型;根据壁面积分基本原理及被动方式求解水下工作发动机推力的计算方法,成功模拟了发动机的受力运动;对不同工况下发动机工作情况进行仿真,研究了水下发动机动态模型下的射流结构,发现在来流作用下,射流气体会受到来流边界层的挤压,产生颈缩现象,之后逐渐向外膨胀;研究结果显示,在来流边界层作用下,射流所产生的激波在向下游发展之前,将经历多次折射,该研究结果与文献中相关实验结果较吻合;对发动机不同工况下的推力脉冲峰值进行分析,找出了动态模型下发动机点火初期推力脉冲峰值特征随工作环境的变化规律。最后,对有/无轴向浮力时的发动机动态特征进行了对比分析。
