三角槽道层流脉动流的流场分布特性及热量输运规律研究  

Study on flow field distribution characteristics and heat transfer law of laminar pulsating flow in triangular channel

作　　者：章颢缤 杨景山 蹇钊 宓霄凌 黄其 徐超[1] ZHANG Haobin;YANG Jingshan;JIAN Zhao;MI Xiaoling;HUANG Qi;XU Chao(North China Electric Power University,Beijing 100096,China;CGN Solar Energy Development Co.,Ltd.,Beijing 100071,China;Zhejiang Cosin CSP Technology Research Institute Co.,Ltd.,Huzhou 313000,China)

机构地区：[1]华北电力大学,北京100096 [2]中广核太阳能开发有限公司,北京100071 [3]浙江高晟光热发电技术研究院有限公司,浙江湖州313000

出　　处：《流体机械》2024年第8期8-16,共9页Fluid Machinery

基　　金：国家重点研发计划重点专项(2022YFB2405200)。

摘　　要：为了解析小尺度周期性扩缩结构流道与脉动流结合的复合强化传热机理,以水为工质,对三角槽道层流脉动流动特性及热量输运规律进行了研究。以“二次流”为切入点、“涡及涡运动”为视角,分析了Strouhal数(St)、脉动振幅(A)等脉动参数对三角槽道层流脉动流动及传热过程的影响,揭示了二次流强度与三角槽道层流脉动流传热的关联性。结果表明:通过调节St与A优化涡旋运动状态,可将场协同角(β)缩减5°以上,增强温度梯度与速度矢量两者的协同性,最大传热效率可提升55%以上;St的设置旨在优化涡心运动路径,存在最优St值,使传热效率提升40%以上;A的设置旨在提升涡旋强度及尺寸,当A<100%时,最大传热效率提升约15%;St和A对于层流脉动传热的影响情况,还可采用二次流强度定量反馈,以寻求较优的St和A匹配数值,有效控制传热效率及能耗量。研究结果可为解决高黏度、低流速等工程环境(如光热电站熔盐系统管路、熔盐电加热器换热管)或者小尺度异型管道的流动及传热问题提供参考。In order to analyze the composite enhanced heat transfer mechanism of pulsating flow in the small-scale channel of periodic expansion and contraction,the flow characteristics and heat transport rules were studied for the laminar pulsating flow in the triangular grooved channel.By taking“secondary flow”as the starting point,and“vortex and vortex motion”as the viewing angle,the effects of Strouhal number(St)and pulsating amplitude(A)on laminar pulsating flow in the triangular grooved channel and the heat transfer process were analyzed,and the correlation between the intensity of secondary flow and the heat transfer enhancement of laminar flow was revealed.The results show that the field coordination angle(β)can be reduced by more than 5°by adjusting St and A to enhance the synergy between temperature gradient and velocity vector,and the heat transfer efficiency can be improved by more than 55%.Otherwise,St is set to optimize the path of the vortex,and there is an optimal St value which can increase the heat transfer efficiency by more than 40%.Pulsating amplitude is set to improve the strength of the vortex,and the maximum heat transfer efficiency is increased by nearly 15%when A is less than 100%.The effect of Strouhal number and pulsating amplitude on vortex motion can be fed back quantitatively by secondary flow intensity so as to find optimal value matching between St and A,and effectively control heat transfer efficiency and energy consumption.The research results can provide reference for solving the problems of flow and heat transfer in engineering environment(molten salt system pipelines and molten salt electric heater heat exchange pipes of CSP power station)with high viscosity and low flow rate,or in the small-scale special-shaped pipelines.

关 键 词：脉动流 涡旋 二次流 场协同 

分 类 号：TH12[机械工程—机械设计及理论]