汽轮机空心静叶缝隙抽吸性能研究

采用Fluent软件对某600MW汽轮机末级空心静叶栅内的蒸汽流场与缝隙抽吸性能进行了三维数值计算,讨论了缝隙结构参数对抽吸性能的影响。结果表明:随着缝隙位置从叶片前缘向尾缘的移动,静叶背弧上缝隙的抽汽量急剧减少;内弧上缝隙的抽汽量先略微增大后减小,在缝隙相对位置ψ=0.723 4时达到最大值;随着缝隙角度的增大,缝隙抽汽量先增大后减小,在缝隙角度α=45°时达到最大值,约占叶栅通道总蒸汽量的1.8%;随着缝隙宽度的增加,缝隙抽汽量先减小后增大,在缝隙宽度为2mm时达到最小;缝隙抽吸能力与缝隙出口处的腔室大小、空腔内形成的涡核位置和涡半径以及抽吸工质的流线的长短有关。

Numerical Simulation on Suction Performance of Steam Turbine Hollow Stationary Blade

The steam field within hollow stationary cascade in the last stage of a 600MW steam turbine and the slot-suction performance blade were simulated with the CFD software Fluent.The effects of the slot structure parameters on the suction performance were discussed.The results show that with the slot position varying from foreside edge to trailing edge of blade,the steam mass flux sucked by slot located on the convex side decreased rapidly,but the steam mass flux sucked by slot located on the concave side increased slightly to the maximum at the slot relative position ψ=0.723 4,and then decreased gradually.As the degree of slot increased,the steam mass flux sucked became larger and then smaller,the maximum value occurred at angle 45 which accounted for about 1.8% of the total mass flux passing the cascades channel.As the width of the slot increased,the steam mass flux sucked decreased to the minimum value at width of 2.0 mm and then increased.In addition,the slot suction ability had connection with the volume of inner hollow region,vortex nucleus position in the inner hollow region,vortex core radius and the streamline length of suction working substances.