一个几近等反力度涡轮级的计算及讨论

利用导叶反扭和前倾,算出叶高反力度只变化0.032,且峰值在叶根附近的涡轮,而间隙站压力仍在叶尖最高。对此作出分析及讨论。并提出进一步研究方向。

COMPUTATION AND DISCUSSION OF A NEARLY CONSTANT DEGREE OF REACTION TURBINE STAGE

This paper is a further step of trial from the previous effort (Literature 1, 2) to obtain an even nearly constant degree of reaction turbine stage. The tension spline streamline curvature method applied to a nearly constant shroud diameter flowpath is similar as before. But the nozzle vanes leading edge positive lean angle is increased to 18°, and their reverse to conventional exit angle twist increased to 22. 5°.The variations of main gas dynamic parameters, total pressure loss coefficients and stage efficiencies along the blade height are shown together with the corresponding conventional stage of same flowpath for comparison. A reaction difference of only 0. 032 is achieved, yet owing to the stage exit pressure being highest at shroud, the nozzle exit pressure is still highest at shroud.It seems apparent that in order to minimize nozzle vane secondary flow and shroud clearance leakage losses, an optimum pressure gradient along nozzle vane exit is decisive in future study.