基于缩比模型的非能动余热排出热交换器二次侧新装导流板效应实验研究

Research on the Effects Caused by Newly Installed Baffles at Secondary Side of a PRHR HX Based on Scaled Experiment

为了减弱内置换料水箱(IRWST)在非能动余热排出热交换器(PRHR HX)余热排出过程中的热分层现象,建立了分离效应缩比实验台架,在PRHR HX二次侧管束区域新装不同数量的导流板,通过实验评价导流板设计方案对IRWST内温度分布、流动特性及PRHR HX传热效果的影响。结果表明:导流板设计方案能够有效改变水箱自然循环特性,提高水箱下部冷流体的利用率,从而降低IRWST内的热分层程度,4导流板、8导流板设计方案分别使IRWST内热分层程度降低了32.3%和37.3%;但导流板造成竖直管束间浮升流体最大流速降低,使得传热系数有所减小,工程应用中需综合考虑各类因素的影响,得到最优化设计方案。

Abstract： To reduce the thermal stratification extent in the in-containment refueling water storage tank （IRWST） during the operation of passive residual heat removal heat exchanger （PRHR HX）, a scale-down test facility was set up to analyze the separation effect, where the baffles were newly installed at secondary side along verticle tube bundle of the PRHR HX, and subsequently, the temperature distributions, flow characteristics and the PRHR HX heat-transfer effects were evaluated by experiments. Results show that the baffles can change the natural convection characteristics, increase the heat-transfer potential of cold fluid in the lower region, and reduce the stratification phenomenon in IRWST. The two design plans respectively with four and eight baffles can reduce the thermal stratification extent by 32.3% and 37.3%, accordingly. However, the maximum velocity of the flowing up fluid is also reduced, leading to the decrease of the heat-transfer coefficient. As a result, different factors should be taken into consideration to develop the optimal design. Key words： PRHR HX~ IRWST~ baffle~ thermal stratification~ heat-transfer effect