Improved Scaling Analysis for Heat Transfer in a Circular Tube With Various Supercritical Fluids Using Computational Fluid Dynamics Simulations
Improved Scaling Analysis for Heat Transfer in a Circular Tube With Various Supercritical Fluids Using Computational Fluid Dynamics Simulations
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DOI：
10.1080/01457632.2016.1156432
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发表时间：
2017-01
影响因子：
2.3
通讯作者：
U. S. Tejaswini;D. N. Basu;M. Pandey
中科院分区：
文献类型：
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作者：
U. S. Tejaswini;D. N. Basu;M. Pandey
超临界水冷却器反应堆(SCWR)的运行条件远高于水的临界点，没有工业规模的支持，不可能通过实验室实验来研究其传热特性。最可行的替代方案可以是通过用适当选择的结垢流体进行流体对流体的缩放来缩小操作参数。然而，通过简单的分析标度，不可能包含像SCWR这样复杂系统的所有现象学因素。这项研究证明了流体对流体比例在这种情况下的局限性，并建议纳入计算流体动力学模拟作为更好的比例的后续步骤。采用的方法是从已发表的文献中得出结论。二氧化碳和R134a被认为是结垢流体，以确定适合实验室规模模拟的SCWR的参数范围。以直径8 mm、长1500 mm的圆管为例进行了数值模拟。进行了网格相关性试验，选择了标准的κ−ϵ湍流模型。建立的计算模型与已有的实验数据吻合较好。解析缩小的参数不能模拟原型的轴向和径向温度分布。增加壁面热流和降低质量流量是实现更好的轮廓匹配的两个可能的选择。报告了针对特定原型条件的定标参数的修正值。与R134a相比，以二氧化碳为模型流体的剖面显示出与水的更好的一致性，因此建议在实验室实验中使用。
ABSTRACT The operating conditions of supercritical water cooler reactor (SCWR) are well above the critical point of water, so it is not possible to investigate its heat transfer aspects through laboratory experiments without industry-scale support. The most feasible alternative can be to scale-down the operating parameters by fluid-to-fluid scaling with a suitably chosen scaling fluid. However, it is impossible to incorporate all phenomenological factors of an intricate system like the SCWR through simple analytical scaling. This study demonstrates the limitation of fluid-to-fluid scaling in such situations and suggests the incorporation of computational fluid dynamics simulation as a subsequent step for better scaling. A scaling methodology from the published literature is adopted. Carbon dioxide and R134a have been considered as scaling fluids to identify the parameter ranges suitable for lab-scale simulation of the SCWR. A circular tube of 8 mm diameter and 1500 mm length is taken for simulation. A grid dependency test is done and the standard κ − ϵ turbulence model is selected. The developed computational model showed amicable agreement with existing experimental data. Analytically scaled-down parameters failed to simulate the axial and radial temperature profiles of the prototype. Increase in wall heat flux and reduction in mass flow rate are suggested as two possible options for achieving better profile matching. The modified values of scaled parameters with respect to a particular prototypical condition are reported. Profiles with CO2 as model fluid show better agreement with water as compared to R134a and hence this is recommended for use in lab experiments.