矩形截面螺旋通道内流体绕管流动特性的数值研究

Numerical Analysis on Flow Characteristics Around the Tube in a Spiral Channel with Rectangular Cross Section

基于Fluent软件采用数值计算方法建立了混合计算模型,对螺旋通道和直通道内流体绕换热管的换热特性进行研究,对比了2个通道中流体绕换热管流动的热工特性。结果表明:螺旋通道内侧脱点角度小于外侧脱点角度,且脱点均分布在湍流区域内;螺旋通道比直通道具有更高的Num;β=15°和20°螺旋通道换热管壁面迎风侧Num相比直通道分别提高4.0%和4.5%,背风侧则分别提高14%和18%;当螺旋角β=40°附近,螺旋通道达到最佳强化换热管壁面换热效果,螺旋通道内换热管壁面Num相比直通道提高19%。

Using Fluent software and numerical calculation method,a hybrid calculation model was established to study the heat-transfer characteristics of fluid flow around the heat-exchange tube in a spiral channel and a straight channel,and to compare the thermal characteristics of fluid flow around a heat-exchange tube in above two channels.Results show that the inner detachment angle of spiral channel is smaller than outer detachment angle,and the detachment points are distributed in the turbulent region.The Num of spiral channel is higher than that of straight channel;in the case ofβ=15°and 20°,compared with straight channel heat-exchange tube,the Num of spiral channel heat-exchange tube is respectively 4.0%and 4.5%higher on the windward side,and 14%and 18%higher on the leeward side.Aroundβ=40°,the heat-transfer performance is maximally enhanced for the tube in spiral channel,when the tube wall Num is increased by 19%,compared with the straight channel.