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Buoyancy Effect on the Flow Pattern and the Thermal Performance of an Array of Circular Cylinders

机译：浮力对圆形圆柱阵列流型和热性能的影响

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摘要

In this paper, we found, by means of numerical simulations, a transition in the oscillatory character of the flow field for a particular combination of buoyancy and spacing in an array of six circular cylinders at a Reynolds number of 100 and Prandtl number of 0.7. The cylinders are isothermal and they are aligned with the earth acceleration (g). According to the array orientation, an aiding or an opposing buoyancy is considered. The effect of natural convection with respect to the forced convection is modulated with the Richardson number, Ri, ranging between -1 and 1. Two values of center-to-center spacing (s = 3.6d-4d) are considered. The effects of buoyancy and spacing on the flow pattern in the near and far field are described. Several transitions in the flow patterns are found, and a parametric analysis of the dependence of the force coefficients and Nusselt number with respect to the Richardson number is reported. For Ri=-1, the change of spacing ratio from 3.6 to 4 induces a transition in the standard deviation of the force coefficients and heat flux. In fact, the transition occurs due to rearrangement of the near-field flow in a more ordered wake pattern. Therefore, attention is focused on the influence of geometrical and buoyancy parameters on the heat and momentum exchange and their fluctuations. The available heat exchange models for cylinders array provide a not accurate prediction of the Nusselt number in the cases here studied.
机译：在本文中，我们通过数值模拟发现，在六个雷诺数为100和普朗特数为0.7的六个圆柱阵列中，对于浮力和间距的特定组合，流场的振动特性发生了转变。气缸是等温的，并且与地球加速度（g）对齐。根据阵列方向，考虑辅助浮力或相对浮力。自然对流相对于强制对流的影响由Richardson数Ri调制，范围在-1和1之间。考虑了中心到中心间距的两个值（s = 3.6d-4d）。描述了浮力和间距对近场和远场流动模式的影响。发现了流型中的几个过渡，并报告了力系数和努塞尔数相对于理查森数的依赖性的参数分析。对于Ri = -1，间距比从3.6变为4会引起力系数和热通量的标准偏差转变。实际上，由于近场流以更有序的唤醒模式重新排列而发生过渡。因此，注意力集中在几何和浮力参数对热和动量交换及其波动的影响上。在本文研究的案例中，可用的气缸阵列热交换模型无法准确预测Nusselt数。

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  • 来源
    《Journal of Heat Transfer》 |2017年第2期|022501.1-022501.10|共10页
  • 作者

    Francesco Fornarelli; Antonio Lippolis; Paolo Oresta;

  • 作者单位

    Department of Mechanics, Mathematics and Management, Polytechnic of Bari, via Orabona 4, Bari 70125, Italy INFN sez. Lecce, Lecce 73100, Italy;

    Department of Mechanics, Mathematics and Management, Polytechnic of Bari, via Orabona 4, Bari 70125, Italy;

    Department of Mechanics, Mathematics and Management, Polytechnic of Bari, via Orabona 4, Bari 70125, Italy INFN sez. Lecce, Lecce 73100, Italy;

  • 收录信息 美国《科学引文索引》(SCI);美国《工程索引》(EI);
  • 原文格式 PDF
  • 正文语种 eng
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