鱼雷涡轮机叶片顶部气封流场数值研究

摘要

A three-dimensional(3D) viscous and steady computational fluid dynamics(CFD) analysis is performed for calculating turbine rotor tip leakage flow field of a torpedo by solving RANS-Navier-Stocks equations. The effect of different seal structure on turbine passage efficiency and rotor tip leakage flow is studied. Different numbers of sealing fins at the rotor blade are simulated, and the influence of the number of sealing fins on turbine passage efficiency and rotor tip leakage flow characteristic is analyzed. The results show that the turbine efficiency is improved remarkably after applying the seal technology. Compared with comb-type seal structure, the labyrinth seal exhibits better airtight performance. The leakage flow in the labyrinth seal housing forms 3D vortex current which transform the kinetic energy of the leakage flow into heat energy, and leads to a decrease in the seal leakage flow rate of the labyrinth seal. Airtight performance gets better with increasing number of fins.%通过求解雷诺平均的NAVIER-STOKES方程组,数值计算了带气封围带结构的鱼雷涡轮机动叶顶部间隙内部3D流场及特性,研究了不同气封结构形式对涡轮机通流效率和动叶顶部泄漏流动的作用,比较了迷宫式气封不同齿数下动叶间隙泄漏气流的流动特性,分析了迷宫式气封齿数对鱼雷涡轮机通流效率和泄漏特性的影响.研究表明,在叶片顶部间隙中采用气封结构能够有效减小燃气泄露流量,提高涡轮机通流气动性能;在相同气封齿数下,迷宫式气封结构要比一般梳齿型气封结构密封效果好;迷宫气封通过气流在气封齿间空腔形成的3D涡流,将气流动能转化为热能,从而起到密封效果;气封齿数越多,密封效果越好,对涡轮机通流性能的改善也越大.