考虑燃料雾化的气液两相连续旋转爆轰数值模拟

Numerical Simulation of Gas-Liquid Two-Phase Continuous Rotating Detonation Considering Fuel Atomization

关键词:  连续旋转爆轰发动机  两相爆轰  欧拉-拉格朗日模型  雾化  时空守恒元与求解元方法  传播模态

Key words:  Continuous rotating detonation engine  Two-phase detonation  Euler-Lagrange model  Atomization  Space-time conservation element and solution element method  Propagation mode

摘要:

为研究气液两相连续旋转爆轰发动机燃烧室内爆轰波的传播特性，以汽油为燃料，富氧空气为氧化剂，建立了欧拉-拉格朗日模型进行二维数值仿真，其中气相方程采用时空守恒元与求解元方法求解，液相方程采用标准四阶龙格库塔法求解。在两相旋转爆轰模型还考虑了液滴雾化破碎过程。计算结果表明：起爆后形成的初始爆轰波经过初始燃料填充区域后逐渐衰减，随后入口附近新生成的压力波经过一系列发展形成了自持稳定传播的旋转爆轰波；旋转爆轰波的传播模态受燃料与氧化剂的喷注压力和氧化剂填充比影响，在不同工况下旋转爆轰波呈现出4种传播模态，即稳定单波模态、稳定双波模态、不稳定双波模态和不稳定单波模态；在双波模态工况下，燃烧室内初始只形成1个爆轰波，后由入口附近局部爆炸产生的压力波发展为新的爆轰波，转化为双波模态后爆轰波的强度略有下降，但燃烧室整体推力更加平稳。

Abstract:

To study the propagation characteristics of detonation wave in the combustor of gas-liquid two-phase continuous rotating detonation engine， the Euler-Lagrange model was established for two-dimensional numerical simulation， using gasoline as fuel and oxygen-enriched air as oxidizer. The equations of gas phase and liquid phase were solved by space-time conservation element and solution element method and standard fourth-order Runge-Kutta method， respectively. The atomization and breakup of fuel droplets were also considered in the two-phase rotating detonation model. Numerical results show that the original detonation wave formed after ignition gradually attenuates after passing through the initial fuel filling area， and then the newly generated pressure wave near the inlet develops into a self-sustaining and stable rotating detonation wave. The propagation mode of the rotating detonation wave is affected by the injection pressure of fuel and oxidizer and the injection ratio of oxidizer. Under different injection conditions， the rotating detonation wave presents four propagation modes： stable single-wave mode， stable double-wave mode， unstable double-wave mode and unstable single-wave mode. In double-wave mode only one detonation wave is formed in the combustor at first and then a pressure wave caused by a local explosion develops into a new detonation wave. The strength of detonation waves decreases slightly after this conversion， but the overall thrust of combustor tends to be more stable.