近似等反力度涡轮级设计的研究

等反力度涡轮的概念 ,五十年代已在苏联提出1 ] ,六十年代美国提出可控涡设计涡轮2 ]时 ,实际也作了这方面的实践 3]。综合运用导叶前倾 8.5°,以及导叶反扭、即尖部出气角比内部多偏离轴向 6°,达到根尖反力度只差 0 .1的级 ,效率比常规级高 2 %。一、等及近似等反力度涡轮级设计按照众所孰知的轴对称径向平衡方程 p /ρ r =c2u/ r + c2mcosφ/ Rm- cm( cm/ m) sinφ + Fr式中 p-静压 ,ρ-密度 ,cu-周向分速 ,cm-子午分速 ,r-半径 ,Rm-曲率半径 ,φ-流线斜角 ,Fr-径向力。曾试算过依靠外廓型线先向内收后向外扩 ,主要以第二离心力 c2…

DESIGN OF AN APPROXIMATELY CONSTANT DEGREE OF REACTION TURBINE STAGE

This paper is a successful trial of an approximately constant reaction stage designed by through-flow streamline curvature method for the first time tension splines.The tip to root reaction difference within 0.1 is attained mainly by the nozzle vanes with positive lean angle of 15° at leading edge and a reverse to usual exit angle twist of 11.6°.To avoid undesirable tip clearance increase in hot running state which would lead to excessive leakage loss,the shroud diameter is kept essentially constant with only a slight taper from nozzle inlet to axial clearance mid-section and then turning outward to the rotor shroud constant diameter.The variations of main gasdynamic parameters,total pressure loss coefficients and stage efficiency along the blade height are shown in figures together with those for a corresponding conventional stage of same meridional geometry for reference purpose which is seen giving even a little (0.20%) higher efficiency.Nevertheless,owing to lack of accurate loss model,especially in regard to leakage loss and shock loss,the efficiency results including their comparison are subject to experimental verification,although the design of constant reaction in general is credible.