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Numerical Analysis of Heat Transfer and Pressure Drop in Helically Micro-Finned Tubes
Processes ( IF 3.5 ) Pub Date : 2021-04-24 , DOI: 10.3390/pr9050754 Muhammad Ammar Ali , Muhammad Sajid , Emad Uddin , Niaz Bahadur , Zaib Ali
Processes ( IF 3.5 ) Pub Date : 2021-04-24 , DOI: 10.3390/pr9050754 Muhammad Ammar Ali , Muhammad Sajid , Emad Uddin , Niaz Bahadur , Zaib Ali
In this study, the pressure drop and heat transfer characteristics of smooth tube and internal helically micro-finned tubes with two different fin-to-fin height ratios i.e., equal fin height and alternating fin height, are computationally analysed. The tube with alternating fin height is analysed for proof of concept of pressure drop reduction. A single phase steady turbulent flow model is used with a Reynolds number ranging from 12,000 to 54,000. Water is used as working fluid with inlet temperature of 55 °C and constant wall temperature of 20 °C is applied. Friction factor, heat transfer coefficient, Nusselt number, and Thermal Performance Index are evaluated and analysed. The numerical results are validated by comparison with the experimental and numerical data from literature. The results showed that the thermal performance is enhanced due to helically finned tube for a range of Reynolds numbers, but at the expense of increased pressure drop as compared to a smooth tube. The helically finned tube with alternating fin heights showed a 5% decrease in friction factor and <1% decrease in heat transfer coefficient when compared with the equal fin heights tube, making it a suitable choice for heat transfer applications.
中文翻译:
螺旋微细管内传热和压降的数值分析
在这项研究中,通过计算分析了具有两个不同的翅片与翅片高度比(即相等的翅片高度和交替的翅片高度)的光滑管和内部螺旋微翅片管的压降和传热特性。分析翅片高度交替的管,以证明降低压降的概念。使用单相稳态湍流模型,雷诺数范围为12,000至54,000。将水用作入口温度为55°C且壁温恒定为20°C的工作流体。评估并分析了摩擦系数,传热系数,努塞尔数和热性能指标。通过与文献中的实验数据和数值数据进行比较,对数值结果进行了验证。结果表明,对于一定范围的雷诺数,由于采用螺旋翅片管而提高了热性能,但与光滑管相比,其代价是压降增加。与相同翅片高度的管相比,具有交替翅片高度的螺旋翅片管的摩擦系数降低了5%,传热系数降低了<1%,这使其成为传热应用的合适选择。
更新日期:2021-04-24
中文翻译:
螺旋微细管内传热和压降的数值分析
在这项研究中,通过计算分析了具有两个不同的翅片与翅片高度比(即相等的翅片高度和交替的翅片高度)的光滑管和内部螺旋微翅片管的压降和传热特性。分析翅片高度交替的管,以证明降低压降的概念。使用单相稳态湍流模型,雷诺数范围为12,000至54,000。将水用作入口温度为55°C且壁温恒定为20°C的工作流体。评估并分析了摩擦系数,传热系数,努塞尔数和热性能指标。通过与文献中的实验数据和数值数据进行比较,对数值结果进行了验证。结果表明,对于一定范围的雷诺数,由于采用螺旋翅片管而提高了热性能,但与光滑管相比,其代价是压降增加。与相同翅片高度的管相比,具有交替翅片高度的螺旋翅片管的摩擦系数降低了5%,传热系数降低了<1%,这使其成为传热应用的合适选择。