Experimental investigation on flow and heat transfer characteristics of helium in rectangular narrow slit channel

IF 4.9 2区工程技术 Q1 ENGINEERING, MECHANICAL

International Journal of Thermal Sciences Pub Date : 2024-11-13 DOI:10.1016/j.ijthermalsci.2024.109530

Changzhong Li , Chenglong Wang , Yanyu Sun , Ronghua Chen , Wenxi Tian , Guanghui Su , Suizheng Qiu

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Abstract

Helium is utilized as coolant in high temperature gas cooled reactors. Rectangular narrow slit channels are commonly present in the core. The flow and heat transfer properties of helium significantly affect the core temperature and flow distribution. This paper experimentally investigates the flow and heat transfer properties of high temperature helium in rectangular narrow slit channel. The Reynolds numbers ranged from 468 to 9357, the temperature ratio of wall to bulk from 0.91 to 1.22, the helium outlet temperature up to 945 K, and the maximum heat flux density up to 0.101 MW/m². In the experiment, the total and local convective heat transfer coefficients, along with the friction factors, are measured. Correlation equations for the Nusselt number and friction factor with respect to Reynolds number are derived. The primary findings are as below: the friction factors of helium in rectangular narrow slit channels are significantly larger than those calculated by current empirical correlations. In the turbulent zone, the measured local Nusselt numbers are in excellent accordance with the Gnielinski correlation; however, a significant discrepancy exists in the laminar zone. New flow heat transfer correlation equations are proposed on the bases of experimental data. Upon comparison, the total Nusselt numbers fall in the error of 10 %, and almost all local Nusselt numbers and the friction factors fall in the error of 20 %.

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矩形窄缝通道中氦气流动和传热特性的实验研究

高温气体冷却反应堆使用氦气作为冷却剂。堆芯中通常存在矩形窄缝通道。氦气的流动和传热特性对堆芯温度和流动分布有很大影响。本文通过实验研究了高温氦气在矩形窄缝通道中的流动和传热特性。雷诺数从 468 到 9357 不等，壁面温度比从 0.91 到 1.22 不等，氦气出口温度高达 945 K，最大热流密度高达 0.101 MW/m2。在实验中，测量了总对流传热系数和局部对流传热系数以及摩擦因数。得出了努塞尔特数和摩擦因数与雷诺数的相关方程。主要发现如下：氦气在矩形窄缝通道中的摩擦因数明显大于当前经验相关系数的计算值。在湍流区，测得的局部努塞尔特数与 Gnielinski 相关性非常吻合；然而，在层流区存在显著差异。根据实验数据提出了新的流动传热相关方程。经比较，总努塞尔特数的误差在 10%以内，几乎所有局部努塞尔特数和摩擦因数的误差都在 20%以内。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

International Journal of Thermal Sciences 工程技术-工程：机械

CiteScore

8.10

自引率

11.10%

发文量

531

审稿时长

55 days

期刊介绍： The International Journal of Thermal Sciences is a journal devoted to the publication of fundamental studies on the physics of transfer processes in general, with an emphasis on thermal aspects and also applied research on various processes, energy systems and the environment. Articles are published in English and French, and are subject to peer review. The fundamental subjects considered within the scope of the journal are: * Heat and relevant mass transfer at all scales (nano, micro and macro) and in all types of material (heterogeneous, composites, biological,...) and fluid flow * Forced, natural or mixed convection in reactive or non-reactive media * Single or multi–phase fluid flow with or without phase change * Near–and far–field radiative heat transfer * Combined modes of heat transfer in complex systems (for example, plasmas, biological, geological,...) * Multiscale modelling The applied research topics include: * Heat exchangers, heat pipes, cooling processes * Transport phenomena taking place in industrial processes (chemical, food and agricultural, metallurgical, space and aeronautical, automobile industries) * Nano–and micro–technology for energy, space, biosystems and devices * Heat transport analysis in advanced systems * Impact of energy–related processes on environment, and emerging energy systems The study of thermophysical properties of materials and fluids, thermal measurement techniques, inverse methods, and the developments of experimental methods are within the scope of the International Journal of Thermal Sciences which also covers the modelling, and numerical methods applied to thermal transfer.