摘要
根据螺旋半圆管夹套的结构特点,提出了简化的物理模型;采用数值方法求解了恒定热负荷条件下夹套内流体充分发展的层流流场和温度场,并与激光多普勒测速仪测得的速度场和已有的传热实验结果进行了对比。研究了夹套的结构和换热流体Prandtl数Pr对夹套内流体流动及换热特性的影响。结果表明:层流状态下,夹套管的横截面上存在两涡结构的二次流;随着曲率k的增大,二次流函数值增大,二次涡的强度增强,流动阻力增加。二次流对夹套内的换热起强化作用,k值越大,换热流体的Pr越小,二次流的相对强化换热作用越明显。增大k或Pr可以强化夹套内的换热,但强化效果不同;夹套内换热面的中心部位是需要强化换热的重点部位。
Based on the structural features,the simplified physical model of the half-coil jacket was proposed.On the boundary condition of constant thermal load,the developed flow field and the temperature field in the half-coil jackets were analyzed by a numerical method.The results were compared with the velocity field measured by the laser Doppler velocimetry and the experimental results reported in the literatures.The effects of the jacket structures and the fluid Prandtl number on the flow and heat transfer characteristics were investigated.The results show that on the laminar condition,there are two eddies of secondary flow on the cross-section of the half-coil jacket.With the increase of curvature k,the value of stream function and the flow resistance increase while the intensity of secondary flow eddies enhances.The secondary flow can enhance the heat transfer in the half-coil jacket.On the condition of a larger k value and a smaller Pr,the relative effect of secondary flow on the heat transfer enhancement is more evidence.With the increase of k or Pr,the heat transfer in the jackets can be enhanced,but the effects of k and Pr on the heat transfer enhancement are different.The center of the heat transfer surface in the jacket is the critical area which should be enhanced for heat transfer.
出处
《化工学报》
EI
CAS
CSCD
北大核心
2010年第11期2796-2803,共8页
CIESC Journal
基金
辽宁省高校创新团队项目(2007T143)
辽宁省教育厅项目(2008S117)
关键词
螺旋半圆管夹套
流动特性
强化传热
二次流
half-coil jacket
flow characteristics
heat transfer enhancement
secondary flow
