论文部分内容阅读
针对Sandia实验室关于正庚烷喷雾的实验数据,基于CONVERGE软件采用大涡模拟方法对以正庚烷为燃料喷入超临界环境中的雾化过程进行了数值模拟。以实际气体状态方程Soave-Redlich-Kwong(SRK)和Peng-Robinson(PR)两个方程为基础,重点研究了两状态方程对超临界状态下燃料喷雾的发展过程、射流密度变化、燃料喷雾的质量分数随温度变化的影响,并用模拟所得与实验结果进行对比。结果表明,同一时间下PR方程模拟的燃料喷雾的贯穿度更大;两实际气体状态方程下射流表面都有大的密度梯度,并与实验所得的密度值相吻合;PR方程对超临界工况的计算更优于SRK方程。燃料质量分数随温度的变化符合实际的情况,密度值的急剧变化验证了射流表面是一个介于液体与超临界流体之间的混合层,并可以通过密度梯度来推测混合层位置。
Aiming at the experimental data of Sandia laboratory on n-heptane spray, a large-eddy simulation method based on CONVERGE software was used to simulate the atomization process of n-heptane fuel injected into supercritical environment. Based on the equations of Soave-Redlich-Kwong (SRK) and Peng-Robinson (PR), the evolution of fuel spray in supercritical state, the variation of jet density, Mass fraction with the temperature changes, and the simulation results obtained with the experimental results were compared. The results show that the penetration of the fuel spray simulated by the PR equation is greater at the same time. The large density gradients on the jet surface under the two equations of actual gas state coincide with the experimentally obtained density values. The PR equation is more suitable for the supercritical conditions The calculation is better than the SRK equation. The change of fuel mass fraction with temperature is in accordance with the actual situation. The sharp change of density value verifies that the jet surface is a mixed layer between liquid and supercritical fluid, and the position of mixed layer can be inferred by density gradient.