本文係探討於外部蒸汽流場作用下的紊流薄膜凝結熱傳，研究的熱傳裝置包括了水平橢圓管、圓球、斜圓管以及半橢圓體等。建模過程以Colburn Analogy來預測高速蒸汽下的汽液界面剪力，並採用Kato (1968)的紊流模式，而蒸汽邊界層的切線流速則以勢流理論來決定。本文中探討層流、紊流以及層流轉換成紊流等三種流場下的薄膜凝結熱傳特性。研究結果顯示，於高速蒸汽下之紊流薄膜凝結熱傳，具有比層流凝結更高的熱傳係數。而由於隨著凝結液之雷諾數的增加，轉換成紊流凝結模式前的層流凝結區域所佔的範圍不大，雖然對於局部熱傳有所影響，但對於平均熱傳的影響則較不顯著。
此外，文中歸納出影響橢圓管、圓球、斜圓管及半橢圓體等各種熱傳機構的熱傳係數及凝結液膜厚度之相關重要參數，這些參數包括過冷效應、福祿數 (Fr)、雷諾數、系統壓力、橢圓管的偏心率及斜圓管之傾斜角度等。由結果可知，等長軸之水平橢圓管，由於受到外部高速蒸汽勢流的影響，減低橢圓的偏心率會提高熱傳係數。而具傾斜角度之斜圓管，在本文中亦可規劃出一最佳之（管長/管徑）比，以及最佳傾斜角度。
此外，減低過冷效應、提高福祿數 (Fr) 及增加系統壓力將使文中之四種不同熱傳機構的熱傳率提高。再者，為驗證本文的合理性與正確性，進一步與相關文獻的實驗及理論數據進行比較，結果證實以本文的理論模式，可以成功預估在高速蒸汽下的紊流薄膜凝結熱傳。

The study investigated heat transfer in turbulent film condensation with external flow of vapor, and the research devices include the horizontal elliptical tube, sphere, inclined circular tube and half oval body. The Colburn analogy is used to define the local liquid-vapor interfacial shear that occurs under high velocity vapor. An eddy diffusivity model along with an expression by Kato (1968) is used to model turbulence. And the high tangential velocity of the vapor flow at the boundary layer is determined by potential flow theory. Film condensation heat transfer coefficients investigated in the present study include laminar condensation, turbulent condensation and transition from laminar to turbulent condensation. The results show that heat transfer in turbulent film condensation under the high velocity vapor has a higher heat transfer coefficient than that in laminar film condensation. Along with the increase in Reynolds number of the condensate film, the range of laminar film condensation before transiting to turbulent condensation is not large. Although the range has some influence on local heat transfer coefficient, it doesn’t have a significant influence on mean heat transfer coefficient.
Furthermore, the study concludes some important parameters that will influence the heat transfer coefficient and condensate film thickness of various devices like horizontal elliptical tube, sphere, inclined circular tube, and half oval body. And the former parameters include sub-cooling, Froude number, Reynolds number, system pressure, eccentricity of elliptical tube, and inclined angle of tube. As we can know from the results, because of the influence of external high velocity vapor, in the case of a horizontal elliptical tube with a vertical semi-major axis and different eccentricity, the decrease in eccentricity of the elliptical tube will bring out an increase in heat transfer. As for the inclined tube, the study can design an opticmal ratio of length and radius, and an opticmal inclined angle. Decreasing sub-cooling parameters, increasing Froude number, and increasing system pressure will enhance the heat transfer coefficient of the four various devices in the study. Besides, for confirming the reasonability and accuracy of the study, the present results are, then, compared with the results obtained from previously published theoretical and experimental data. And the comparative results confirm that the theory model in the study may be used successfully to estimate the heat transfer in turbulent film condensation under high velocity vapors.

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