To improve the prediction of flow and heat transfer in turbine blade internal cooling channel, the difference between four sets of data/formula for the calculation of air properties in case of large temperature increasing was discussed firstly. By comparing with the wide-used heat transfer empirical correlations, the influences of characteristic fluid temperature definitions and turbulence models on heat transfer coefficient were studied. Then research was focused on the influence of large temperature difference on the flow and heat transfer in a smooth circular internal cooling channel. Data of Nusselt number and correlations of temperature-modify-coefficient varying with temperature ratio and Reynolds number were gotten at ratio of fluid temperature to wall temperature rang from 0. 5 to 0. 9, and Reynolds number rang from 20000 to 60000. Results show that when the heat transfer coefficient is defined with the sectional-mass-averaged fluid temperature and Realizable κ-ε turbulence model is used; the numerical results of local and averaged Nusselt number consistent with the results of Cnielinski correlations quite well. Remarkable influence of large temperature difference on heat transfer coefficient is observed with maximum Nusselt number decrease of 30%. Numerical results show that temperature-modify-coefficient decreases with the decrease of temperature ratio, and decreases with the increase of Reynolds number.%为了提高涡轮叶片内冷通道流动传热计算精度,首先讨论了大温差下空气物性不同计算方法间的差异,并通过与管内常用传热经验关系式结果的对比,研究了不同定性温度取值方法和湍流模型对数值模拟结果的影响.在此基础上侧重研究了大温差对光滑圆形内冷通道内的流动传热的影响,温度比变化范围0.5 ～0.9,通道Re数范围20 000～60 000,得到了传热Nu数和温度修正因子随温度比与Re数的变化数据和拟合关系式.结果表明采用截面平均流体温度定义传热系数和采用Realizable k-ε湍流模型可使局部和平均传热系数与Gnielinski公式结果符合良好.大温差对通道传热的影响显著,Nu数最大降幅可达30％.计算显示温度修正因子随温度比的减小而减小,随Re数的增大而减小.
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