燃气透平榫头/榫槽装配间隙流动与换热特性研究

Study on Flow and Heat Transfer Characteristics of Tenon Joint Gap Between Gas Turbine Blade and Disk

为精确设计燃气轮机二次空气系统,针对燃气透平动叶榫头/榫槽间隙内的流动与换热问题开展研究。以燃气透平动叶榫头/榫槽配合面S形间隙结构为研究对象,试验研究了榫头/榫槽装配间隙内的流阻与换热特性,并数值分析了其详细流动结构。首先,采用压力扫描阀和热色液晶测温技术测量了榫头/榫槽内的流阻和努塞尔数分布。然后,利用试验结果对所采用的数值计算方法进行了考核,并进行了网格无关性验证。最后,详细分析了5种雷诺数、5种结构参数榫头/榫槽高度及5种间隙宽度下榫头/榫槽装配间隙结构内部流动与换热特性。结果表明:在试验测量范围内,左侧壁面的平均努塞尔数始终比右侧高10%左右;随着雷诺数的增大,榫头/榫槽装配间隙的阻力损失系数和换热强度均逐渐增大,当雷诺数从15000增大到35000时,平均阻力系数增大了2倍,两侧面整体平均努塞尔数均增大了1.1倍;随着榫头/榫槽装配间隙相对高度的增大,阻力损失系数及壁面努塞尔数均逐渐减小;随着榫头/榫槽装配间隙宽度的增大,试验范围内平均阻力系数增大了30.7%,左右两侧面平均努塞尔数分别增大了95.5%和94.9%。

In order to design the secondary air system of gas turbine accurately,the flow and heat transfer in the tenon joint gap of gas turbine rotor blade and disk are studied.The flow resistance and heat transfer characteristics of the S shaped tenon joint gap between blade and disk in gas turbine are investigated experimentally,and detailed flow field is studied numerically.Firstly,the flow resistance and Nusselt number of the gap are measured by pressure scanning valve and thermochromic liquid crystal,respectively.Then the turbulence model used in numerical calculation is validated by the experimental results,and the grid independence is verified.At last,the effects of flow and structure parameters on tenon joint gap flow and heat transfer are analyzed,in which,five different Reynolds numbers,five different relative heights of the gap and five different widths of the gap are conducted.The results show that the average Nusselt number on the left wall is consistently around 10%higher than that on the right side.As the Reynolds number increases,the flow resistance coefficient and heat transfer intensity of the assembly gap increase gradually.When the Reynolds number increases from 15000 to 35000,the average flow resistance coefficient and the average Nusselt number on both sides increases by 300%and 110%respectively.With the increase of the relative height of the assembly gap,the flow resistance coefficient and the wall average Nusselt number decrease gradually.Increasing the gap width leads to a 30.7%average flow resistance coefficient increase within the test range,with the average Nusselt number on both sides increasing by 95.5%and 94.9%respectively.