摘要
针对内置弹簧换热管在强化传热过程中产生较大阻力的问题，提出了一种插入分段式弹簧的方法，并通过Fluent软件对内置不同长度的弹簧换热管某一截面处的流动特性进行数值模拟，分别取每段弹簧的长度分别为50mm、100mm、150him、200mm，得到了在内置不同长度弹簧的换热管内某一截面处的速度场；然后分别取不同丝径和圈径的分段式弹簧，对换热管内某一截面的流体径向速度场进行数值模拟，研究弹簧的丝径与圈径对强化传热的影响．结果表明：在换热管两端插入分段式弹簧使得管内流体径向速度提高了2～3倍，加快了管内壁区域流体的流动，使得边界层变薄，不仅加强了边界层流体的扰动，而且一定程度上降低了流体流动的阻力，从而提高了换热效率．在雷诺数相同时，内置分段式弹簧换热管相对于光管Nu数提高了2～4倍；随着丝径和圈径的增大，强化传热效率得到提高而流动阻力随着相应增加．
To investigate the problem of the resistance increasing in the process of enhancing heat trans- fer,a method based on inserting the sectional spring was put forward. The flow characteristics of a cross-section were simulated using FLUENT software. The velocity fields within a cross-section of the inserted sectional springs with different length of the heat exchange tubes were obtained after the length of each sectional spring was set as 50 mm,100 mm,150 mm,200 mm. By taking different wire diameter and circle diameter of the sectional springs, the radial velocity of fluid field within the heat exchange tube was simulated. The results show that inserting the sectional springs into both ends of heat ex- change tube increases the radial velocity of the fluid 2-3 times,accelerates the fluid flow in the inner wall region,makes the boundary layer thinner,which not only strengthens the perturbation of boundary lay- er, but also reduces the flow resistance to some extent, thus improving heat transfer efficiency. Under the conditions of the same Reynolds number,the Nusselt number in the heat exchange tube of inserted sectional spring is higher 2 4 times than that in the plain tube. With the increase of wire diameter and circle diameter,heat transfer efficiency is improved and the flow resistance is increased.
出处
《武汉工程大学学报》
CAS
2014年第3期58-62,共5页
Journal of Wuhan Institute of Technology
基金
武汉工程大学机电工程学院对本研究工作的支持
关键词
分段式弹簧
强化传热
数值模拟
sectional spring
enhanced heat transfer
numerical simulation
