Abstract: In order to investigate single-tube heat transfer enhancement principles of heat exchange tube with helical coil inserts，the flow and heat transfer characteristics were simulated using Fluent software. The effects of spring application on flow field，pressure drop and heat transfer performance were investigated. The pitch of coil spring was set as 2 mm，4 mm，5 mm. The effects of spring pitch on the heat transfer enhancement performance were analyzed. The numerical results showed that the fluid in tube with helical coil inserts presents the helical flow，the cutting speed and the radial velocity of flow near the wall had been improved to some extent. Thus the fluid was mixed completely，boundary layer was disturbed fully and heat was exchanged thoroughly. And the temperature difference between inlet and outlet increased as well, with the maximum increase of 0.9 ℃. Under the conditions of the same Reynolds number，the Nusselt number in tube with helical coil inserts was higher than plain tube，but pressure drop and friction factor increased obviously. With the reduced spring pitch, heat transfer was enhanced and friction factor was increased.

Key words: heat exchanger, heat transfer enhancement, helical coil inserts, numerical simulation

摘要： 为研究内置螺旋弹簧换热管单管强化传热原理，采用Fluent软件对内置螺旋弹簧换热管内流体流动与传热特性进行数值模拟，考察了弹簧的应用对管内流场、压降和换热性能的影响，并分别取螺旋弹簧节距p分别为2 mm、4 mm、5 mm初步研究了弹簧的节距对强化传热效果的影响。模拟结果显示：弹簧管内流体呈螺旋流动状态，管壁附近流体切向速度和径向速度有一定程度的提高，从而加剧了管内流体的混合及边界层的扰动，充分换热，弹簧管进出口温度差较光管有所增加，最高增加了0.9 ℃；相同雷诺数条件下，内置螺旋弹簧换热管Nu数均高于光管，而压降和阻力系数相比光管有明显增加，随着弹簧节距减小换热增强而摩擦阻力系数增加。

关键词: 换热器, 强化传热, 螺旋弹簧, 数值模拟