某型舰用汽轮机末级、次末级叶片弯扭改型设计

Modification Design Involving the Bending and Twisting of Both the Last Stage and Last-but-one Stage Blades of a Naval Steam Turbine

应用S2流面正问题计算程序、S1流面计算程序和全三元Euler方程计算程序对某型舰用汽轮机低压末级、次末级静叶进行了弯扭改型设计 ,分析了舰用汽轮机变工况时叶栅流场的特点和采用弯扭叶片后机组性能的变化。结果表明 :在低工况运行时 ,弯扭叶片抑制了根部反动度随负荷降低而加速下降的趋势和顶部反动度随负荷降低而增大的趋势 ,提高了叶栅低工况运行时的抗分离能力 ,同时顶部漏泄损失也有所减小。

With the use of a positive problem calculation program of S2 stream surface, a calculation program of S1 stream surface and a full three dimensional Euler equation conducted was a blade modification design calculation. The latter involves the bending and twisting of the low pressure last stage and the last but one stage stator blades of a naval steam turbine. An analysis was performed of the cascade flow field characteristics during the off design operating conditions of the naval steam turbine and also the performance variation of the turbine unit after the adoption of the bent and twisted blades. The results of the analysis indicate that during a low load operation the bent and twisted blades can suppress the following two tendencies, i.e. an accelerated decrease of the reaction at the blade root and an increase in reaction at the blade tip both occurring with the reduction of load. Because of the above, enhanced is the anti separation capability of the cascades during a low load operation. Meanwhile, the leakage loss at the blade tip has also somewhat decreased.ndencies ,i .e .anacceleratedde