摘要
为了实现微通道换热器表面结构的高效设计,本文将数值模拟和实验手段相结合,以超临界氮气(supercritical nitrogen,SCN_(2))为流体工质,研究了不同凹穴形状(直微通道、圆形、矩形和梯形)和椭圆度对微通道流动与传热特性的影响,揭示了SCN_(2)高效低阻强化换热机理。结果表明,相比于直微通道,圆形凹穴微通道中轴线上SCN_(2)速度达到稳定值所需入口段距离更短,这是由于凹穴能够促使流体流动/热边界层一直处于破坏与重建的交替状态。圆形凹穴内流体旋涡形状与凹穴几何结构保持一致,其流阻特性和换热性能最优,梯形凹穴微通道次之,矩形凹穴微通道最差。微通道综合性能随着凹穴椭圆度增加呈先升高后降低变化趋势,当椭圆度为1时,其综合性能最优。研究结果对提高微通道换热器设计制造能力具有重要的意义。
In order to realize the efficient design of the surface structure of the micro-channel heat exchanger,the effects of cavity shapes(straight micro-channel,circular,rectangular and trapezoidal)and ovality on the flow and heat transfer performance of micro-channel were studied by means of numerical simulation and experiment,using supercritical nitrogen as the fluid medium,the mechanism of fluid efficient and low resistance heat transfer enhancement was revealed.The results showed that compared with the straight micro-channel,the entrance distance required for the SCN_(2)velocity on the axis of the circular cavity micro-channel to reach a stable value was shorter,which was due to the fact that the cavity can promote the fluid flow/thermal boundary layer to be in the alternate state of destruction and reconstruction all the time.The shape of the fluid vortex in the circular cavity was consistent with the cavity geometry,and its flow resistance and heat transfer performance were optimal,followed by trapezoidal cavity micro-channel and rectangular cavity micro-channel.With the increase of ovality,the overall performance of cavity micro-channel increased firstly and then decreased.When the ovality was 1,the overall performance was optimal.The research results in this paper are of great significance for improving the design and manufacturing capability of micro-channel heat exchangers.
作者
韩昌亮
黄峄演
徐建全
HAN Changliang;HUANG Yiyan;XU Jianquan(College of Mechanical and Electrical Engineering,Fujian Agriculture and Forestry University,Fuzhou 350002,Fujian,China;Fujian Key Laboratory of Agricultural Information Sensing Technology,Fuzhou 350002,Fujian,China)
出处
《化工进展》
EI
CAS
CSCD
北大核心
2023年第11期5592-5601,共10页
Chemical Industry and Engineering Progress
基金
国家自然科学基金(22108050)
黑龙江省“百千万”重大科技专项(2020ZX10A0038)。
关键词
微通道
超临界氮气
凹穴
结构
流动与传热
micro-channel
supercritical nitrogen
cavity
structure
flow and heat transfer
作者简介
第一作者:韩昌亮(1987-),男,博士,副教授,研究方向为新能源换热器优化设计。E-mail:hanchangliang2022@163.com;通信作者:徐建全,副教授,硕士生导师,研究方向为节能环保与新能源技术。E-mail:xjq@fafu.edu.cn。
