液体火箭发动机自然循环回路预冷非稳态数学模型

Unsteady Mathematic Models of Natural Circulation Loop Precooling of Liquid Rocket Engine

针对液体火箭发动机自然循环回路预冷过程中的非稳态流动与传热问题,构建了一组涵盖主要传热工况的管壁与低温流体间的传热模型,耦合了循环回路的释热方程和低温流体间的流动传热方程,并采用二分法迭代求解自然循环回路预冷过程中的非稳态循环流量,建立了液体火箭发动机自然循环回路预冷的一维非稳态均相流动数学模型.与已有传热模型相比,在膜态沸腾阶段引入了反环状流膜态沸腾模型和弥散流膜态沸腾模型,保证了膜态沸腾从全液相到全气相过渡过程中物理意义上的逻辑自洽性,并以输送管为例,验证了液体火箭发动机自然循环回路预冷模型的有效性.

The heat transfer models between the pipe wall and the cryogenic liquid were established to investigate the unsteady flow and heat transfer process of a natural circulation loop precooling of a liquid rocket engine. The models couple the heat release equation of the circulation loop and the flow and heat transfer equations of the cryogenic liquid. Moreover, the one-dimensional unsteady homogenous flow mathematic models were set up and solved with the bisection method to obtain the unsteady flow rate of the natural circulation loop. Unlike the existing precooling models, both the inverted annular model and the dispersed model are adopted in the prediction of filming boiling, which ensures the logicality integrity of the transition from full liquid region to full gas region. In addition, the unsteady precooling models of the natural circulation loop of a liquid rocket engine were validated by the calculation of a supply pipe.