倾斜角对周向重叠三分螺旋折流板换热器性能的影响  

Impacts of incline angle on performances of circumferential overlap trisection helical baffle heat exchangers

作　　者：董聪[1,2] 陈亚平[1] 吴嘉峰[1] 

机构地区：[1]东南大学能源与环境学院,江苏南京210096 [2]浙江科技学院机械与汽车工程学院,浙江杭州310023

出　　处：《中南大学学报（自然科学版）》2016年第6期2133-2140,共8页Journal of Central South University:Science and Technology

基　　金：国家自然科学基金资助项目(51276035;51206022);江苏省科技创新与成果转化专项引导资金资助项目(BY2011155)~~

摘　　要：对倾斜角为16°,20°,24°,28°,32°单头(即16°CO,20°CO,24°CO,28°CO和32°CO)和32°双头(即2-32°CO)6种周向重叠三分螺旋折流板换热器(coth STHXs)以及作为对比的弓形折流板换热器的进行数值模拟,并与已有的实验数据进行比较。采用速度矢量图和压力云图叠加速度矢量的方式分析特殊剖面上局部参数。研究结果表明:数值模拟结果与实际吻合良好。螺旋折流板方案壳侧通道存在迪恩涡二次流,相邻折流板重叠区内的管排可抑制缺口泄漏,周向重叠结构有利于强化传热;在相同流量下,壳侧换热系数随倾斜角的增大而减小。20°CO倾斜角方案的性能最优,在相同压降下,其壳侧换热系数比其他方案的系数高,且流道内的迪恩涡二次流明显较强。弓形折流板方案的性能最差,其流道中存在流动死区,且壳侧压降远高于所有螺旋折流板方案;在相同压降下,其壳侧换热系数最低,但在相同流量下的壳侧换热系数在所有方案中位列第3,紧随16°CO和20°CO方案之后。The six circumferential overlap trisection helical baffle shell-and-tube heat exchangers（coth STHXs） with single thread but baffle incline angles of 16°, 20°, 24°, 28°, 32°（16°CO, 20°CO, 24°CO, 28°CO, 32°CO） as well as double thread and baffle incline angle of 32°（2-32°CO）, as opposed to a segment baffle heat exchanger, were numerically simulated and compared with the available experimental data. Local parameter distributions of the velocity vectors or pressure contours plus velocity vectors on special sections were plotted and analyzed. The results show that the simulation results are satisfactory and in agreement with tests. The Dean Vortex secondary flow and bypass leakage between adjacent baffles in the spiral channel play essential roles in the heat transfer enhancement of the coth STHXs. The shell-side heat transfer coefficient decreases with the increase of incline angle at the same shell-side flow rate. The optimum scheme is 20°CO, and its shell-side heat transfer coefficient is the highest and Dean Vortex secondary flow in the spiral channel is strong at the same shell-side pressure drop. Nevertheless, the worst scheme is the segment baffle one,and there exist stagnant zones in the channel, whose shell-side pressure drop is much higher than those of othercoth STHXs schemes, and so its shell-side heat transfer coefficient is the lowest at the same shell-side pressure drop. The shell-side heat transfer coefficient of segment baffle scheme ranks the third, only 16°CO and 20°CO schemes exhibit better in terms of shell-side heat transfer coefficient.

关 键 词：三分螺旋折流板换热器 倾斜角 周向重叠 二次流 缺口泄漏 相邻折流板 数值模拟 

分 类 号：TK124[动力工程及工程热物理—工程热物理]