共查询到19条相似文献,搜索用时 31 毫秒
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用有限时间用经济分析法导出了在Qa(T~n)和Qa(△T)~n下内可逆卡诺热泵的最佳利润率与供热系数间的关系,并藉此讨论了四种传热规律时内可逆卡诺热泵的有限时间经济最优性能的特点,得到了一些新的普适结果。 相似文献
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A numerical analysis has been made to examine the possible deviation of the instantaneous heat transfer to a growing spherical bubble from the quasi-steady heat transfer to a nongrowing bubble. It has been confirmed that the instantaneous Nusselt number has a negative dependency on the temperature difference or, more directly, on the bubble growth rate. But the degree of the dependency is much lower than that previously predicted. The significant dependency of Nusselt number on the temperature difference as demonstrated by some experimental works presumably resulted, for the most part, from some effect other than that of the bubble growth rale increasing with the temperature difference. 相似文献
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The stable method of soloing inverse problems in heat transfer and inverse problems concerning thermal stress control in elements of complex shapes is presented. Based on the discrete form of Duhamel's integral and on so-called future time steps, a simple and accurate method of solving one- and multi-dimensional inverse problems is developed. Two examples illustrating the application of the described method are presented. 相似文献
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ABSTRACT A steady heat conduction problem is considered, that is described by the heat conduction equation and the thermal boundary conditions (i.e., Dirichlet, Neumann, Henkel, and radiation conditions on the external boundary, and radiation condition on the hole boundary). An arbitrary behavioral functional is defined and its first-order sensitivity is derived using both the direct and the adjoint approaches. The shape optimization problem is next formulated and two optimization functionals are discussed. The simple numerical example is presented. 相似文献
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针对低纬度岛屿地区全年温度高、湿度大,空调全年运行时间长而常规能源运输成本高,传统高能耗空调系统难以适应的问题,提出一种利用深层海水供冷的闭式空调系统。根据换热特性的差异,将换热管道分为沿程垂直换热管道和海底换热盘管两部分,通过数值模拟研究管径、流速等参数对垂直管段和海底换热盘管段传热性能的影响。研究结果表明:垂直管段管径在0.6 m以内,流速在1~2 m/s范围可保证较高的换热性能;对于海底换热盘管段,最佳管径为0.025~0.050 m,最佳流速为0.4~0.8 m/s。在此基础上建立适用于垂直管段优化设计的费用年值数学模型,计算其比摩阻、流速,形成设计用水力计算表,并给出适用于海底换热盘管段工程设计的设计线算图及其修正公式。 相似文献
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