摘要
利用数值模拟研究微尺度下方波脉冲冲击阵列的传热特性,验证模型的合理性后,不断改变方波脉冲特性,分析各项参数对冲击换热能力的影响。通过分析流场云图,详细阐述了方波脉冲微射流强化换热的机理。计算结果表明:提高时均雷诺数可有效强化占空比为0.5的方波脉冲射流阵列的换热能力;通过改变脉冲频率来强化换热能力的实际效果与流态有关,在强化频段内,紊流的换热系数增幅可达20%,层流的增幅也可达到7.5%;在合理的参数条件下,方波脉冲射流可有效增强冲击效应和涡流扰动,从而强化射流阵列的换热能力。
The heat transfer performances of the micro-jets array impingement were studied by numerical simulations.After validating the model,the effects of rectangular pulses were analyzed on heat transfer characteristics by adjusting the pulse parameters.Then,some reasons for using rectangular pulse jets to enhance the heat transfer were discussed by flow field analysis.All of the simulations show that,if the duty ratio of the pulses is0.5,the heat transfer characteristics of the micro-jet array will be effectively enhanced when the mean-time Reynolds number is increasing.The enhancement of heat transfer by the adjustment of frequency is highly dependent on the flow regime of the jets.In the proper frequency band,the heat transfer coefficient of turbulence flow can increase by20%,and the coefficient of laminar flow can increase by7.5%.Under rational conditions,rectangular pulses jets can strengthen the impact effects and the disturbance of vortex in the cavity,therefore,the micro-jet array can obtain better heat transfer performance.
作者
吕远征
夏国栋
陈永昌
LV Yuanzheng;XIA Guodong;CHEN Yongchang(College of Environmental and Energy Engineering,Beijing University of Technology,Beijing 100124,China)
出处
《振动与冲击》
EI
CSCD
北大核心
2018年第6期117-123,共7页
Journal of Vibration and Shock
基金
国家自然科学基金(51276004)
关键词
数值模拟
微尺度
脉冲冲击
传热
numerical simulation
micro scale
impulse impact
heat transfer
