矩形翼强化半圆螺旋通道内流体流动与换热

Rectangular Wings Enhance Fluid Flow and Heat Transfer in Semicircular Spiral Channel

采用数值模拟方法研究矩形翼强化半圆形截面螺旋通道内流体的流动与传热特性.数值模拟获得了安装矩形翼后半圆截面螺旋通道的流场结构及涡旋演变过程,考察矩形翼的长高比(Г=1.5~2.5)、螺旋通道无量纲曲率(δ=0.05~0.125)对螺旋通道内流体流动与换热特性的影响.结果表明:在螺旋通道内安装矩形翼后,诱导产生了一个大涡旋,Г值越大,诱导产生的纵向涡旋强度越大,同时流体流动阻力系数f和壁面平均努塞尔数Nu显著增加.研究范围内,相对于单一螺旋通道,f和Nu值分别增加16.33%和13.24%,综合强化传热因子J在1.035~1.082之间.无量纲曲率δ越大,矩形翼诱导产生的纵向涡旋强度越大,强化换热效果越好.

Based on numerical simulation,the fluid flow and heat transfer characteristics by a semicircular cross-section spiral channel with a rectangular wing are studied.The flow field structure and vortex evolution process of the spiral channel with the half circle section after the rectangular wing are obtained by numerical simulation.The influence of the rectangular wing aspect ratioГand the dimensionless curvatureδof the spiral channel on the fluid flow and heat transfer characteristics in the spiral channel is investigated within the range ofГ=1.5~2.5 andδ=0.05~0.125.The results show that a large vortex is induced by rectangular wings in the semicircular spiral channel.The greater theΓvalue is,the greater intensity of the induced longitudinal vortex will become.At the same time,the flow resistance coefficient f and the average Nusselt number of the heated wall Nu are both improved significantly.In the researched range,the maximum f and Nu values increased by 16.33%and 13.24%respectively compared with those values of the single spiral channel.Comprehensive enhanced heat transfer factor J is in the range of 1.035~1.082.With the increase of the dimensionless curvatureδ,the strength of the vortex behind the rectangular wing becomes stronger,which leads to better heat transfer enhancement effect.