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针对某带有叶顶汽封的300MW汽轮机高压第二压力级及其后相邻的静叶,采用三维非定常数值模拟的方法,研究了叶顶汽封间隙泄漏流的流场结构,叶顶汽封腔室内涡动的频谱特性以及叶顶泄漏流与主流掺混后的流场对下游静叶性能的影响。研究结果表明:叶顶汽封泄漏流动总体随时间呈现周期性波动,汽封间隙出、入口的波动最复杂、频率成分最多。叶顶汽封泄漏流的传播会在下级静叶通道内引起较大的流动损失,泄漏流体中存在径向速度分量,致使掺混后的低能流体逐渐向下级静叶的中叶展处发展,使下级静叶的流场结构发生了改变。
Aiming at the high pressure second pressure stage and the adjacent vane of a 300 MW steam turbine with a vane seal, the three-dimensional unsteady numerical simulation method is used to study the flow field structure of the vane leakage gap, The spectral characteristics of the vortex in the sealed chamber and the influence of the flow field of the tip leakage flow and the mainstream mixing on the downstream vanes. The results show that the leakage flow of the blade tip seal shows periodic fluctuations with time, the fluctuation of the seal gap is the most complicated and the frequency components are the most. The propagation of the leakage flow of the top steam seal will cause a large flow loss in the lower stator vane passage, and the radial velocity component exists in the leakage fluid so that the mixed low-energy fluid will gradually develop toward the middle leaf of the lower stator vortex The flow field structure of the lower vane has changed.