湍流度对二维内冷叶片外换热的 影响

发动机叶片外换热准确预测一直是理论界和工程界的一个难点。利用数值方法对影响叶片外换热的湍流度这一因素进行了系列研究。在对文献经典叶片MARK Ⅱ的5411 Run42工况进行计算模型验证的基础上,通过改变湍流度,得到了叶片外侧对流换热系数随湍流度的变化规律。结果表明:1增加湍流度使叶片外侧对流换热系数增加;但继续增加湍流度反而使叶片外侧对流换热系数略有降低;2湍流度的增加使叶盆叶背前缘的外侧对流换热系数增加10%;3在某一确定的湍流度下,压力面随流向距离弧长比X/S的增大叶片外侧对流换热系数先增加后降低,吸力面随着X/S的增大叶片外侧对流换热系数呈现先增高后降低,再升高再降低的趋势;4增加湍流度,吸力面除靠近前缘位置叶片外侧对流换热系数增大外,其余位置湍流度对叶片外侧对流换热系数几乎无影响。

Effect of turbulence intensity on surface heat transfer of 2-D inner-cooled blades

Precise prediction of engine blade surface heat transfer is always difficult in theory and engineering field. The paper conducts a series of research about the influence of upper stream turbulence intensity on blade surface heat transfer. The classical blade MARK II on 5411 Run42 condition is studied. With the verification of simulation model, the regularity of upper stream turbulence intensity and blade surface heat transfer is concluded by changing the intensity. The result shows that: 1) The large upper stream turbulence intensity can strengthen the surface heat transfer. However the increasing intensity will reduce the heat transfer coefficient a little. 2) The surface heat transfer coefficient has a 10% increase on the area near the front point of basin and back of blade. 3) At a certain intensity, surface heat transfer coefficient begins to increase and then reduces with the increase of X/S on the pressure surface while the coefficient begins to increase and reduce and then repeats the increase and deduce. 4) The high turbulence intensity brings a scarcely increase on the surface heat transfer coefficient of suction surface but the area near the front point.