不同膨胀状态下拉瓦尔喷管内耦合传热数值研究

摘要

A conjugate heat transfer( CHT) code was developed to study the flow structure and heat transfer of a nozzle under different expansion states.Navier-Stokes equations were used to govern both fluid and solid regions,cell-center based finite volume method was adopted to solve the governing equations,and k-ω SST model was used for turbulence closure.The CHT process is real-ized by keeping the heat flux on the coupled surface to be consistent.The CHT code is validated by experimental data,then used to numerically investigate a nozzle under different expansion states. The simulated results show that the flow separation occurs in the nozzle under over-expanded state,and the convective heat transfer is enhanced in the separation region and the nozzle wall is cooled by the gas in the downstream region of the separation with a relatively low level.The local convective heat transfer increases with the nozzle inlet pressure.%为研究不同膨胀状态下拉瓦尔喷管内流场结构及壁面传热特性，开发了一套耦合传热程序。流体区域和固体区域的控制方程均采用Navier-Stokes方程，计算方法为基于格心的有限体积法，湍流模型采用k-ωSST模型，通过保证流固耦合界面上的热流密度连续，实现耦合传热。验证该耦合传热程序后，对处于不同膨胀状态下的喷管进行了数值模拟。计算结果表明，过膨胀状态下喷管产生流动分离，分离点附近的对流换热增强，而在之后的绝大部分区域内气体是对壁面进行冷却，但冷却强度较低。当地对流换热会随着喷管入口压力的增加而增强。