本研究探討單相與兩相模型氧化銅奈米流體於三維強制對流等熱通量之C型渠道之數值計算。應用控制體積法求解氧化銅奈米流體強制對流之耦合、穩態、三維橢圓偏微分方程式。研究參數包括雷諾數、奈米粒子體積濃度、無因次渠道深度、無因次渠道高度以及無因次轉角處之寬度 。
首先以奈米流體於混沌流之層流熱傳增益與參考文獻的可用數據做驗證，最大誤差在3%以內，再進一步擴展至C型渠道幾何形狀的設計。在混沌渠道內，流體流動方向改變造成混合效果與熱傳性能的增強。從數值結果中發現，雖然C型混沌渠道可以提高傳熱能力，但C型渠道引起幾何的擾動造成壓降增加導致泵浦功率的增加。提供模型的數值結果顯示單相模型與兩相模型對於奈米流體在流場與熱傳特性上有些不同。發現兩相模型在熱場上與單相模型有很大的差異，但流場方面單相與兩相模型幾乎是相同的。
此外，在比較單相模型與兩相模型的數值結果後，使用實驗設計(DOE)，反應曲面法(RSM)，基因演算法 (GA)得到目標函數E與四個設計參數即無因次渠道深度、無因次渠道高度、無因次轉角處之寬度以及奈米粒子體積濃度之間的關係式。熱性能係數的預測值及CFD模擬結果，兩者在各雷諾數下的誤皆差在10%內。並從數值最佳化結果顯示單相模型與兩相模型之最佳組C型渠道較原尺寸C型渠道分別達到16%與22%的熱傳增益。

In present study, a C-shaped channel is selected as geometry of the chaotic channel, and the nanofluid at various particle concentrations are simulated by single and two-phase model in the laminar flow. The parameters studied include Reynolds number, nanoparticle volume concentration, the dimensionless depth, the dimensionless height and the dimensionless width.
The laminar heat transfer enhancement using nanofluid in a chaotic flow is validated with the available in the literature first, the maximum discrepancy within 3%, and then further extend to design the C-shaped geometry. Numerical simulations reveal that the combination of nanofluid and chaotic channel can be an effective way to increase the effect of heat transfer. The results show that single-phase and two-phase models predict almost identical hydrodynamic fields but very different for thermal field. In addition, the multi-parameter constrained optimization procedure integrating the design of experiments (DOE), response surface methodology (RSM), genetic algorithm (GA) and computational fluid dynamics (CFD) is proposed to design the nanofluid laminar convection of three-dimensional C-shaped channel. The numerical optimization indicates that the enhancement of the objective function E can achieve 16% and 22% with single and two-phase models, respectively.

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