Abstract The efficient cooling of turbo-generators especially in the end-windings region directly affects the power output rating. Modeling the coolant flow passing through the stator end-winding of a high-powered generator, however, remains a challenge due to a large number of parts with irregular geometries as well as the intricacy of cooling flow paths. This paper focuses on a numerical investigation of flow and heat transfer in stator end-winding aiming at replacing the geometry of winding with a porous medium model. Using computational fluid dynamics analysis to examine the viscous and inertial contributions to the pressure drop of airflow in the stator end-winding region, a generalized porous medium model is developed for the real physical geometry of winding together with a correlation for interfacial Nusselt number. The results indicate that the inertial effect considerably prevails over the viscous effect, that is, viscous contribution becomes small and almost negligible. It is shown that not only the pressure drop characteristics match closely within both real and porous models, but also the heat transfer results agree as well which means that the replaced porous model can amply describe the macroscopic behavior of the winding.

中文翻译：

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使用多孔介质方法分析绕组中的空气流动和传热

摘要 汽轮发电机组特别是端部绕组区域的高效冷却直接影响额定功率输出。然而，由于大量具有不规则几何形状的部件以及冷却流路的复杂性，对通过大功率发电机定子端绕组的冷却剂流进行建模仍然是一个挑战。本文重点研究定子端部绕组中流动和传热的数值研究，旨在用多孔介质模型代替绕组的几何形状。使用计算流体动力学分析来检查对定子绕组端部气流压降的粘性和惯性贡献，为绕组的真实物理几何形状以及界面努塞尔数的相关性开发了广义多孔介质模型。结果表明，惯性效应明显优于粘性效应，即粘性贡献变小，几乎可以忽略不计。结果表明，不仅在真实模型和多孔模型中压降特性密切匹配，而且传热结果也一致，这意味着替换的多孔模型可以充分描述绕组的宏观行为。