间隙高度对涡轮叶顶间隙流动的影响

叶顶间隙流动是导致涡轮动叶中产生流动损失的主要原因之一.对某动力涡轮第一级内三维流动的数值计算结果表明,流体在经过动叶叶顶间隙以后在约25%叶顶轴向弦长处(τ=3mm)在叶顶与吸力边夹角处卷起形成间隙涡,造成流动阻塞,同时在间隙内叶片顶部10%叶顶轴向弦长处(τ=3mm)开始在压力边出现叶顶分离涡,使得间隙流动损失增加.随着间隙高度增大,通过间隙的流量增加,间隙涡形成位置后移,间隙涡、叶顶分离涡尺寸变大,在流道内影响范围增大,导致流动损失变大.     

A liquid crystal thermography calibration with true color image processing

Liquid crystal thermography is a high-resolution, non-intrusive optical technique for full-field temperature measurement. We present the detailed calibration data for the thermochromic liquid crystal （TLC） with a useful range of 41-60 ℃. The calibration is done with true color image processing by using an isothermal calibrator. The hue-temperature curve of the TLC is obtained, and the measurement uncertainty is analyzed. Combined with the image noise reduction technique of a 5×5 median filter, the measurement accuracy of the liquid crystal thermography can be significantly improved by approximately 57.1%.