实际叶型前缘冲击冷却换热的液晶显示实验研究

采用液晶显示技术,对两种实际叶型的前缘凹面的模拟表面在大冲距范围内进行了射流冲击热实验,并与半圆凹面的换热进行了比较.研究结果表明,在小冲击距时,随着冲击面曲率的增大,滞止区内的换热较之半圆面有所增强;在实验参数范围内,两实际叶型表面的Nus比半圆面约高12%;对于相对喷嘴间距为227的情况,所研究的3种曲面的Nus随相对冲距的变化存在一个极值点;对于相对喷嘴间距为135的情况,未发现有极值点.此外,还给出了换热准则关系式

Liquid Crystal Thermography Applied to Jet Impingement Heat Transfer for Leading Edge of Blade

Liquid crystal thermography is applied to examine the jet impingement heat transfer of concave surface simulating the turbine blade. The test results show that for small nozzle to plate spacing, the Nusselt number in the stagnation region increases with increasing curvature. The heat transfer is enhanced compared to that for a semi circular surface. For the parameter range studied, the Nusselt number is larger than that of a semi circular surface by 12%. When the relative nozzle spacing equals to 2 27, there exists a maximum for a plot of Nusselt number versus nozzle to plate spacing. Heat transfer correlations are obtained.