The present numerical study uses finite volume formulation to investigate the thermal performance of cylindrical heat sinks with different minichannel profiles and working fluids, including nanofluid and pure water. The numerical simulations are carried out in the laminar flow regime. The considered minichannel profiles include straight, converging-diverging, zigzag, and wavy. First, the straight design and the nonstraight ones with equal amplitudes were compared based on their thermal performance, and it was observed that the wavy minichannel has an edge over the other profiles in the studied range of Reynolds numbers. Then, the wavy design was chosen and further investigated by changing the amplitude of the walls’ waveform for both working fluids. It was found that larger wave amplitudes raise the pressure drop and the heat transfer coefficient; however, the thermal performance parameter, which compares the relative importance of these two parameters, still follows an increasing trend. For the wavy minichannel heat sink, the thermal performance factor can increase up to 17% when the waviness is increased from 0.25 to 0.75 mm. Finally, after fitting the obtained numerical data, novel predictive correlations are derived based on different thermal and hydrodynamic parameters of the wavy heat sinks. This is achieved by the optimization of independent variables using a genetic algorithm.

中文翻译：

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圆柱型散热器的热性能增强，数值模拟和预测模型

本数值研究使用有限体积公式来研究具有不同微通道轮廓和工作流体（包括纳米流体和纯水）的圆柱形散热器的热性能。数值模拟是在层流状态下进行的。所考虑的微通道轮廓包括直线形，会聚发散形，锯齿形和波浪形。首先，基于热性能，比较了直设计和等振幅的非直设计，发现在研究的雷诺数范围内，波浪形微通道在其他轮廓上具有优势。然后，选择波浪形设计，并通过更改两种工作流体的壁波形幅度进一步进行研究。发现更大的波幅会增加压降和传热系数；但是，比较这两个参数的相对重要性的热性能参数仍然遵循增加的趋势。对于波浪形微型通道散热器，当波纹度从0.25毫米增加到0.75毫米时，热性能系数可以提高到17％。最后，在对获得的数值数据进行拟合之后，基于波浪形散热器的不同热力学和流体动力学参数，得出了新颖的预测相关性。这是通过使用遗传算法优化自变量来实现的。在对获得的数值数据进行拟合之后，基于波浪形散热器的不同热力学和流体动力学参数，得出了新颖的预测相关性。这是通过使用遗传算法优化自变量来实现的。在对获得的数值数据进行拟合之后，基于波浪形散热器的不同热力学和流体动力学参数，得出了新颖的预测相关性。这是通过使用遗传算法优化自变量来实现的。