Abstract

In this paper, experimental and numerical study has been carried out to investigate impingement cooling with a row of five circular jets, varied between target positions on a realistic leading edge region of gas turbine blade geometry. Experimental data is collected from a transient thermochromic liquid crystal measurement technique at the target surface. Numerical study was conducted with the geometry using commercial computational fluid dynamics software to analyze the fluid flow. The unique aims of the study are to observe the effects of variation in jet location, and those specific to realistic target and nozzle geometries. Distributions of local and average Nusselt number show that a location targeting the concave surface at 90° demonstrates an overall higher heat transfer coefficient, especially in the stagnation region, and toward the airfoil sides, with significantly fewer swirls. The experiment was performed with the following parameters: distance from nozzle to target of 1.7 to 2.1 jet diameters, pitch between jets of 4.4 jet diameters, and concave target diameter of 8.0 jet diameters. The jet Reynolds number range during this test was 20,000 − 40,000. A standard flat target plate impingement test is also experimentally conducted and compared against existing literature for method validation.

摘要

在本文中，已经进行了实验和数值研究，以研究一排五个圆形射流的冲击冷却，这些射流在燃气轮机叶片几何形状的现实前缘区域的目标位置之间变化。实验数据是从目标表面的瞬态热致变色液晶测量技术收集的。使用商业计算流体动力学软件对几何进行了数值研究，以分析流体流动。该研究的独特目的是观察射流位置变化的影响，以及特定于现实目标和喷嘴几何形状的影响。局部和平均努塞尔数的分布表明，以 90° 凹面为目标的位置表现出整体较高的传热系数，尤其是在停滞区域，朝向翼型侧面，涡流明显减少。使用以下参数进行实验：从喷嘴到目标的距离为 1.7 到 2.1 的射流直径、4.4 的射流直径的射流间距和 8.0 的射流直径的凹目标直径。该测试期间的喷射雷诺数范围为 20,000 - 40,000。还通过实验进行了标准的平板靶板撞击测试，并与现有文献进行了比较以进行方法验证。