脉冲风洞油流和液晶热图流动显示技术

SURFACE OIL FLOW TECHNIQUE AND LIQUID CRYSTAL THERMOGRAPHY FOR FLOW VISUALIZATION IN IMPULSE WIND TUNNELS

介绍适合脉冲风洞进行表面流动显示的油流和液晶热图技术。前者用油滴流动迹线显示表面流线方向和形状，后者用液晶层反射光的波长（即颜色）分布显示表面温度分布。用这两种方法在定常流时间７ｍｓ至５００ｍｓ的脉冲风洞中成功地获得了尖前缘翼、钝翼和方台的三维干扰流油流和液晶热图清晰照片，清楚地显示出三维干扰流动特征。结果表明，用油流、液晶热图和薄膜电阻温度计热流分布测量得到的干扰流特征位置完全吻合，证实了显示方法的可靠性。

This paper describes flow visualization techniques with surface oil flow andliquid crystal thermograph that are suitable for use in impulse wind tunnels. The formerprovides a record of oil traces that show surface-streamline direction and shape,the latterprovides a color pattern displayed by liquid crystal coating that shows surface temperaturedistribution. High spatial resolution photographs of oil flow pattern and liquid crystal thermograph have been obtained and shown to be very useful to reveal the detailed features ofinteraction flows induced by sharp and blunt fins and square step in impulse wind tunnelswith running times from 8ms to 500ms. The results indicate that the characteristic line positions of the interaction flow obtained from oil flow pattern,liquid crystal thermographand heat transfer measurements by thin film gages are in good agreement.