涡轮叶顶间隙密封冷却综合特性评估方法

为了评估带气膜冷却涡轮叶顶间隙的密封和冷却综合特性,在强化传热综合因子中引入气膜冷却效率,推导出了密封冷却综合因子表达式.其物理含义为：主流在一定功率作用并喷入一定量冷气时,被评估的传热方式与基准传热方式传热性能比.数值模拟获得了动叶顶部隔板迷宫间隙气膜冷却和密封特性数据,利用该因子对密封冷却综合特性进行了评估.结果表明：在研究的吹风比内,迷宫结构的冷却效果相比于平叶顶间隙有所改进,随着吹风比减小,改进程度先增加后减小;密封效果只有在高吹风比时有所改进.密封冷却综合特性都得到了改进,吹风比越小,密封冷却综合特性越好.

Evaluating method of integrated sealing and cooling performances on the blade tip gap

In order to evaluate the sealing and the cooling performances of the blade tip gap, the film cooling effectiveness is introduced into the integrated factor of the enhanced heat transfer and friction coefficient. The integrated factor formula of the sealing and the cooling is deduced. This factor means the ratios of the performances of heat transfer of the evaluated structure to the based structure. The data of the film cooling and sealing of the blade tip gap with the divert plate labyrinth is obtained by numerical simulation. The results show that the cooling performances of the labyrinth have been improved in the range of the studied blowing ratios. The improvement degree increases firstly and then declines with the decrease of the blowing ratios. The sealing performances improve only at the high blowing ratio. The integrated sealing and cooling performances both become better with the smaller blowing ratios.