Convection is identified as independent heat transfer mode from the first and second laws via mass flow by rooting the mass conservation equation in the natural convection flows over a vertical isothermal plate. The convective heat and entropy fluxes can be expressed by their potential differences with an exponential distribution of temperature difference and entropy difference for compressible fluids, and their thermodynamic relationship between two fluxes is given. The convective heat and entropy transfer coefficients, and the entropy generation rate are also determined by virtue of the convective fluxes. To examine the physical characteristics of convective heat and entropy transfer in the natural convection processes, a novel general integral boundary layer method is developed for determining the fluid velocity and temperature distributions without employing the Boussinesq approximation. The local and average Nusselt numbers, two transfer coefficients, two convective fluxes, and entropy generation rate are illustrated, a good agreement of present theory is found with the previous experimental data, correlating equations and integral solutions.

中文翻译：

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通过垂直等温板的对流模式重新表述第一定律和第二定律中的自然对流热和熵通量

通过将质量守恒方程建立在垂直等温板的自然对流中，对流被识别为通过质量流的第一和第二定律的独立传热模式。对于可压缩流体，对流热通量和熵通量可以用它们的势差以及温差和熵差的指数分布来表示，并给出了两种通量之间的热力学关系。对流热和熵传递系数以及熵产生率也由对流通量决定。为了研究自然对流过程中对流热和熵传递的物理特性，开发了一种新颖的通用积分边界层方法，用于在不使用 Boussinesq 近似的情况下确定流体速度和温度分布。给出了局部和平均努塞尔数、两个传递系数、两个对流通量和熵产生率，发现本理论与先前的实验数据、相关方程和积分解有很好的一致性。