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由于水轮机主流道和密封间隙流道空间尺度相差较大,为同时获得水轮机流道和密封通道内的流动特性以及水封间隙泄漏特性,充分考虑叶道流和间隙流的相互干扰,采用非一致网格界面插值技术以及基于Vreman亚格子模型的全局动态大涡模拟方法,不仅得到主流道内速度、压力以及涡量的分布,同时捕捉到了微通道间隙内的流动特征以及不同间隙宽度对密封渗漏流动特性及顶盖压力分布的影响。计算结果表明,主叶道内的强旋拧涡带,密封间隙内旋涡结构以及尾水涡带都直接影响转轮的动态平衡,流体从间隙进入梳齿空腔后产生很强的旋涡而耗散部分动能,而且不同尺度密封间隙流道内产生的旋涡结构不同,耗散能量差异较大,反映出密封渗漏流量的不同。
Because of the great difference in the spatial scale between the main runner and the seal clearance runner of the turbine, in order to obtain both the flow characteristics in the runner and the seal passage of the turbine and the leakage characteristics of the seal, the mutual interference of the runner and the clearance flow is taken into full consideration. The grid interface interpolation technique and the global dynamic large eddy simulation method based on the Vreman sub-lattice model not only get the distribution of velocity, pressure and vorticity in the main channel, but also capture the flow characteristics in the microchannel gap and the leakage of the seal with different gap width Flow characteristics and roof pressure distribution. The calculation results show that the strong vortex vortex in the main vane, the vortex structure in the seal gap and the wake vortex all have a direct impact on the dynamic balance of the runner. When the fluid enters the comb tooth cavity through the gap, it produces a strong vortex and dissipates Part of the kinetic energy, and the vortex structures generated in the flow channels of different scales of the seal gap are different, and the difference of the dissipated energy is large, which reflects the difference of the sealing leakage flow.