NPLS流场测量技术在高超声速风洞中纳米粒子跟随性数值仿真

从描述粒子运动的微观层次出发，采用双向耦合技术，建立了一种适用于稀薄条件下两相流动的DSMC数值模拟方法。对相间相互作用进行解耦处理，实现了气固两相间动量和能量相互作用的模拟。采用基于DSMC方法的稀薄两相流双向耦合算法，对NPLS测量技术高超声速流场测量中纳米粒子的跟随性进行了数值研究。通过Φ50nmTiO₂粒子在不同高超声速流场条件下气相-纳米粒子两相流场的仿真，表明在稀薄度很小的流场中，纳米粒子的跟随性很好。而随着流场稀薄度增加，流场中纳米粒子的跟随性降低，纳米粒子在流场中的分布与气相流场分布差异变大，通过NPLS测量得到的激光散射信号不能反映流场结构。

Numerical simulation of nano-particle following features for NPLS measurement technology used in hypersonic wind tunnel

A numerical simulation approach is presented to simulate the rarefied two phase flow by applying two-way coupling technique in DSMC method. The interaction between the rarefied gas and solid particles is dealt with in a decoupled way to compute the momentum and energy exchange between phases. A numerical study of nano-particle following features for NPLS measurement technique used in the hypersonic wind tunnel is carried out by employing the DSMC method suited to simulate the rarefied two phase flow. The 50nm TiO₂ particles in various rarefaction two phase flow cases are simulated. The results show that nano-particle following features are satisfactory in the low rarefaction flow. As the degree of the flow rarefaction rises, the following features decrease deteriorate the difference between particle and gas distributions increase, and therefore the flow structure can't be obtained from NPLS correctly.