Abstract Using nano fluid and curved pipes are two efficient methods for improving heat transfer rate. In the present research, turbulent flow in curved tube and helically coiled tubes is numerically investigated in developing flow. In addition, convective heat transfer is investigated in helically coils under constant wall heat flux. Heat transfer in Nano fluids is solved using homogeneous model or two-phase model. In the present study, the four-equation model is applied, considering slip mechanisms between two phases. This model is simplified in comparison with two-phase model; it can be used as an efficient model for numerical solution of nanofluid heat transfer. Governing equations are solved in OpenFOAM. Three turbulent models, komegaSST, SAS and LES are used. The results illustrate a better agreement of these models with experimental data, in comparison with homogeneous model.

中文翻译：

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基于四方程模型的弯管和螺旋管中纳米流体湍流强制对流的数值研究

摘要 利用纳米流体和弯管是提高传热率的两种有效方法。在目前的研究中，弯曲管和螺旋盘管中的湍流在发展流动中进行了数值研究。此外，在恒定壁热通量下研究了螺旋盘管中的对流传热。纳米流体中的传热使用均质模型或两相模型求解。在本研究中，应用四方程模型，考虑两相之间的滑动机制。与两相模型相比，该模型得到了简化；它可以用作纳米流体传热数值求解的有效模型。控制方程在 OpenFOAM 中求解。使用了三种湍流模型，komegaSST、SAS 和 LES。结果表明这些模型与实验数据有更好的一致性，