150 MW汽轮机高压缸级内流场的数值模拟

采用Numeca软件对带隔板汽封和叶顶间隙汽封的高压缸二、三级叶栅流动进行了数值模拟,并与不带汽封的二、三级叶栅流场进行了比较.结果表明,汽封泄漏损失使级效率显著下降,汽封出口处的低能流体使端壁的附面层变厚,端壁摩擦损失增大;隔板汽封出口处的气体周向速度较小,导致了较大的负攻角流动,它与下排叶栅的横向流动相结合大大促进了下通道涡的发展.

Numerical Simulation of Stage Flow Filed in High Pressure Casing of 150 MW Steam Turbine

The flow filed of No.2 ant No.3 stages with diaphragm seal and tip clearance seal in HP casing was numerically simulated by commercial software Numeca,and the results were compared with that without seals.The results show that the seal leakage loss decreases the stage efficiency notably.Affected by the low-momentum fluid from seals,the endwall boundary layers become thicker resulting in higher endwall friction losses than those without seals;simultaneously the fluid from diaphragm seal with low tangential velocity leads to large negative attack angle flow,which combined with the cross flow in next row cascades increases the lower half passage vortex greatly.