大功率汽轮机叶轮轮缘传热系数的研究

提出了大功率汽轮机叶轮轮缘总传热系数的计算方法.介绍了汽轮机动叶片叶身平均对流换热表面传热系数和叶片流道下壁面对流换热表面传热系数的计算方法和计算公式.把汽轮机叶片对叶轮的传热简化为肋片传热,使用肋片传热模型计算汽轮机叶片流道的等效传热系数,采用圆筒壁模型计算汽轮机叶轮轮缘的总传热系数,并给出了应用实例.在汽轮机转子的温度场与热应力场有限元分析中,该计算方法为确定叶轮轮缘的传热边界条件提供了依据.

Heat Transfer Coefficient of Wheel Rims of Large Capacity Steam Turbines

A way of calculating the overall heat transfer coefficient of wheel rims of large capacity steam turbines is being suggested.Method and formulae for calculating the mean forced convection heat-transfer coefficient of the blade surface,as well as for the blade passage's bottom wall,are introduced.The heat transmission from blade to rim is being simplified on the analogy of heat transmission in ribs.A rib heat transfer model is then used to calculate the equivalent heat transfer coefficient of the blade passage.The overall heat transfer coefficient of the wheel rim is then calculated by a cylindrical surface model.A practical calculation example is being presented.The proposed method is helpful for determining the heat transfer boundary condition in finite element analyses of temperature and thermal stress fields of steam turbine rotors.Table 1 and refs 10.