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表面热传递过程是工业流程与工艺中经常遇到的现象,对表面热传递研究有利于工业过程的优化与效率提高.对表面热传递现象性能参数科学意义探讨的最终目的是为技术发展服务.本文以恒热流平行通道表面热流密度不同影响对流换热特性的数值模拟为模型,基于(火积)耗散概念及广义热阻原理,分析了相同流动状态时表面传热系数随流动发展的特征,结果表明只有在特殊情况下表面传热系数定义式与广义式实现相等,大多数情况下两种计算方法的结果明显不同.其原因是定义式的温差定义形式未能准确使用热流管上的温度导致,这一差异表明热量输运环节包含对流换热时,其热阻串联公式只是近似一维热量传递时的应用.由于在充分发展段内的(火积)耗散维持不变,恒热流条件下通过耗散形式求得的广义式是准确的热流管内表面传热系数值.而未充分发展段(火积)耗散亦在变化,广义式与定义式均未准确表达出热流管内的热量传输性能,未充分发展段上表面传热热阻性能的计算方法仍待发展.
The surface heat transfer process is a phenomenon often encountered in industrial processes and processes, and the study of surface heat transfer is conducive to the optimization of industrial processes and efficiency. The ultimate goal of the scientific significance of the performance parameters of surface heat transfer phenomena is to serve the development of technology. Based on the concept of (fire product) dissipation and the generalized thermal resistance principle, this paper analyzes the numerical simulation of convection heat transfer characteristics under the same flow regime with the characteristics of flow development The results show that the definition of surface heat transfer coefficient is equal to the generalized realization only in special cases and the results of the two methods are obviously different in most cases.The reason is that the definition of the definition of temperature difference can not be used accurately on the heat pipe The difference in temperature indicates that the heat transfer process involves convective heat transfer when the series equation of thermal resistance is only approximate for one-dimensional heat transfer. Since the dissipation of (fire product) in a fully developed section remains unchanged, The generalized formula obtained by dissipative form under the heat flow condition is the accurate heat transfer coefficient of the inner surface of the heat pipe, Dissipation is also changing. Both the generalized and the definitive expressions do not accurately express the heat transfer performance in the heat pipe. The calculation method of the heat transfer resistance on the surface of an undeveloped segment is yet to be developed.