基于激光散斑背景纹影的高焓等离子体流场测量  

Flow structure measurement of high-enthalpy plasma based on laser-speckle background oriented schlieren

作　　者：石伟龙 张子俊 李晓辉 甘才俊[1] SHI Weilong;ZHANG Zijun;LI Xiaohui;GAN Caijun(China Academy of Aerospace Aerodynamics,Beijing 100074,China)

机构地区：[1]中国航天空气动力技术研究院,北京100074

出　　处：《实验流体力学》2025年第1期95-102,共8页Journal of Experiments in Fluid Mechanics

基　　金：国家重点研发计划项目(2019YFA0405300)。

摘　　要：高频感应等离子体风洞是一种重要的高焓流场模拟设备,因其存在高焓、极低密度和强自发光等极端流场条件,传统流场显示和测量方法无法得到有效流场结构。本文针对高频感应等离子体风洞的流场特性,研究了基于激光散斑的背景纹影技术。激光散斑背景相比于传统打印/喷涂散斑背景,其散斑成像质量与相机焦距无关,且具有高亮度、短脉冲时间和单色性等优点,系统灵敏度和抗杂光干扰能力显著提高。本文采用光流算法计算背景散斑位移,提高了低密度流场微小位移的计算精度;在高频感应风洞测量获得了球头模型脱体激波结构,并与数值模拟结果进行了对比,试验得到的激波形状和位置与数值模拟结果吻合较好,验证了背景纹影技术在极端流场条件中的测量有效性。The inductively coupled plasma wind tunnel is an important facility for simulating high-enthalpy fluid.Due to its extreme conditions,such as high enthalpy,very low density,and strong self luminosity,traditional flow visualization and measurement methods cannot effectively capture flow structures.Focusing on the flow field characteristics of the inductively coupled plasma wind tunnel,this study investigates the laser speckle background oriented schlieren technique.Compared to conventional printed or sprayed backgrounds,the quality of laser speckle imaging is independent of the camera's focus length,and it offers high brightness,short pulse time,and monochromaticity,which significantly improves the system's sensitivity and anti-interference capabilities.The optical flow algorithm is applied to calculate the displacement of the laser speckles,enhancing the accuracy of small displacement calculations in low-density flow fields.The structure of the detached shock wave over a spherical cylinder was obtained in the inductively coupled plasma wind tunnel.The shape and position of the shock wave were in good agreement with the numerical results,verifying the effectiveness of the background oriented schlieren technique under extreme flow conditions.

关 键 词：高焓流场 等离子体 背景纹影 激光散斑 光流算法 

分 类 号：V411.7[航空宇航科学与技术—航空宇航推进理论与工程]