摘要
为研究蒸气在矩形小通道内的冷凝传热特性,建立一种基于两相流型的矩形小通道内冷凝传热模型。新模型较以往引入较少的经验参数以降低误差,可较为准确的预测流型处于环状流、环波状流、波状流、弹状流、塞状流及分层流时的传热特性。新模型适用于蒸气质量流速35~55 kg×(m^(2)×s)-1,蒸气干度0.1~0.9,饱和压力0.1~0.4 MPa。结果表明:新模型预测精度在±20%内。平均冷凝传热系数随蒸气饱和温度的降低及蒸气质量流速的增大而增加。不同流型对上下壁面处的温度及冷凝传热系数的影响也不同:环状流时,上下壁面间的差值很小;随着流型由环状流变为波状流最后发展到分层流,差值逐渐增大;到分层流后期,由于液池增速变缓,差值增加的速度也随之减小。
A new model of condensation heat transfer in rectangular small channels based on two-phase flow pattern was established to investigate steam condensing in small rectangular channels.The model introduced less empirical parameters to reduce errors and could better predict heat transfer characteristics for annular flow,annular-wavy flow,wave flow,slug flow,plug flow and stratified flow.The new model was tested over the following range of conditions:mass velocities from 35 to 55 kg×(m^(2)×s)-1,vapor qualities from 0.1 to 0.9 and saturation pressure from 0.1 to 0.4 MPa.The results show that the model prediction accuracy is within±20%.The average condensation heat transfer coefficient increases with the decrease of saturation temperature and increase of mass flux.Different flow patterns have different effects on temperature and condensation heat transfer coefficients at the upper and lower walls.The difference between the upper and lower walls was small in annular flow.As the flow pattern changes from annular flow to wavy flow and finally to stratified flow,the difference gradually increased.Finally,at the later stage of stratified flow,as the growth rate of the liquid pool slowed down,the rate of difference decreased.
作者
严彦
董继先
高秀峰
YAN Yan;DONG Ji-xian;GAO Xiu-feng(College of Mechanical and Electrical Engineering,Xi’an Polytechnic University,Xi’an 710049,China;College of Mechanical and Electrical Engineering,Shaanxi University of Science&Technology,Xi’an 710021,China;School of Chemical Engineering and Technology,Xi’an Jiaotong University,Xi’an 710048,China)
出处
《高校化学工程学报》
EI
CAS
CSCD
北大核心
2021年第4期632-639,共8页
Journal of Chemical Engineering of Chinese Universities
基金
国家自然科学基金(51375286)
陕西省教育厅科研计划项目(19JK0374)
西安工程大学博士科研启动项目(BS201807)。
关键词
流型
矩形通道
凝结
传热
数值模拟
flow pattern
rectangular tube
condensation
heat transfer
numerical simulation
