本文探討紊流蒸氣於等熱通量三維斜角肋條渠道內強制對流之數值計算。應用控制體積法求解紊流強制對流橢圓、耦合、穩態之三維統御偏微分方程式。統御方程式則使用標準k-ε紊流模型求解。研究參數包含斜角肋條高度(0.0475≤e⁄D≤0.1425)，斜角肋條間距(0.475≤p⁄D≤1.425)，斜角肋條角度(30°≤θ≤90°)以及雷諾數(30000≤Re≤70000)。
數值結果先與參考文獻做數值驗證，最大誤差在3%內。文中探討雷諾數(Re)、肋條高度(e/D)、肋條間距(p/D)、斜角肋條角度( )，對於摩擦因子以及平均紐賽數之影響。數值結果顯示，熱傳效應的提升皆伴隨著有較大之摩擦因子，且摩擦因子最小及最大值分別出現在θ=30°及θ=60°。並進一步得到在不同位置的三個切平面之速度向量、溫度及紊流動能分布圖，來說明其熱傳特性。
此外，於數值驗證後，使用反應曲面法(RSM)結合計算流體力學(CFD)，來進行本文之數值模擬最佳化。本文之目標函數定義為熱性能係數E，利用迴歸分析得到其與三種設計參數即斜角肋條高度、斜角肋條間距與斜角肋條角度間之關係式，並以基因演算法(GA)求得於不同雷諾數下之最佳斜角肋條幾何外型。由迴歸分析所得性能係數關係式與計算流體力學之結果相當接近，其誤差約為0.25%。數值最佳化結果顯示，於此斜角肋條渠道中，其目標函數E約有20%的增益。

In this study, numerical simulations of turbulent steam forced convection in a three-dimensional angled ribbed channel with constant heat flux are investigated. The elliptical, coupled, steady-state, three-dimensional governing partial differential equations for turbulent forced convection are solved numerically using the finite volume approach. The parameters studied include angled rib height ratios, angled rib pitch ratios, rib angles and Reynolds numbers.
The effects of Reynolds number, angled rib height ratio, angled rib pitch ratio, and rib angle on the friction factor ratio and averaged Nusselt number are investigated. Numerical results show that the increase in heat transfer is accompanied by an increase in the friction factor ratio of the steam flow.
In addition, after the validation of the numerical results, the numerical optimization of this problem is also presented by using response surface methodology (RSM) coupled computational fluid dynamic (CFD). The objective function E which is defined as thermal performance factor has developed correlation functions with three design parameters (e/D, p/D and θ) which is given by regression analysis, and obtained optimal geometric shape of angled rib at different Reynolds number by genetic algorithms (GA). The predicted optimal performance factor E (e/D = 0.1425 , p/D = 0.475 , θ = 30° , Re = 30,000) of regression function is closely agreed with those from the CFD computational results within 0.25% difference. The numerical optimization indicates that the enhancement of the objective function E can achieve 20% in this angled ribbed channel.

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