中文摘要：

采用数值计算方法研究了蜂窝叶顶密封的几何尺寸对汽轮机高压缸两级内气动性能的影响,分析了蜂窝密封的几何参数,包括密封间隙、蜂窝孔深、蜂窝孔径对透平级气动性能的影响规律。研究结果表明：随着蜂窝密封间隙的增大,动叶下游静叶内二次流损失增加,透平级内总总等熵效率下降,密封内泄漏量近似线性增加;随着蜂窝孔深的增大,总总等熵效率先增大后基本趋于定值,泄漏量则随孔深的增大先减小然后趋于定值;蜂窝孔径对透平级气动性能的影响主要取决于孔内和密封出口的泄漏流场结构,随着蜂窝孔径的增大,总总等熵效率逐渐增大,泄漏量逐渐减小;蜂窝密封间隙的变化对主流流场的影响显著,蜂窝孔径的变化对主流流场的影响次之,而蜂窝孔深对主流流场的影响较弱。

英文摘要：

Effects of honeycomb shroud seal dimensions on the aerodynamic performance of the steam turbine stages in the high-pressure cylinder are investigated by using a computational fluid dynamics method.Critical geometrical parameters,including the sealing clearance,hole-depth and hole-diameter,of the honeycomb seal are selected as research objectives to compute the performance of two turbine stages in a range of geometrical dimensions.Numerical results show that as the sealing clearance increases,the secondary loss downstream the rotor blade increases,the total-total isoentropic efficiency of turbine stages decreases and the leakage increases at an approximately linear rate.When the hole-depth increases,the total-total isoentropic efficiency increases at first and then keeps constant,while the leakage rate in the honeycomb seals decreases at first and then keeps constant.The effects of the honeycomb diameter on the leakage rate and stage efficiency are mainly determined by the flow field structure in the honeycomb cells and seal outlet region.As the hole-diameter increases,the total-total isoentropic efficiency increases while the leakage rate decreases.The variation of sealing clearance has a pronounced influence on the main flow field structure,while the change of hole-depth has less effect on the aerodynamic performance of turbine stages than that of sealing clearance.Among the three geometricalparameters,i.e.the sealing clearance,the hole-depth and the hole-diameter,the variation of hole-depth has weakest influence on the main flow field structures in the turbine stages.