波纹管层流传热与流动的三维数值模拟

应用计算流体力学软件FLUENT对波纹管在层流情况下的传热与流动问题进行了三维数值模拟。所模拟的波纹管的母线由多段凹凸圆弧组成(半径分别为R1和R2),其公称直径为20mm,长度为2m。模拟了几何参数R1、R2对其传热与流动性能的影响。在模拟过程中压力-速度耦合选用SIMPLEC格式,压力方程的离散选用Standard格式,其他方程的离散均选用QUICK格式。结果表明:与光管相比,层流情况下波纹管能显著强化传热,在雷诺数(Re)相等情况下,波纹管的R1越大、R2越小时的强化传热效果越好;在几何参数相同情况下,Re越大,强化传热效果越好,在所研究的范围内,Nu最大增加了199.5%。同时,波纹管还具有良好的流动性能,大部分Re的范围内流动阻力系数小于光管的情况,并且随着Re的增大而逐渐接近于光管的摩擦系数。

Three-Dimension Numerical Study on the Heat Transfer and Fluid Flow of Corrugated Tube

Three-dimension numerical study on the heat transfer and fluid flow of corrugated tube under the condition of laminar flow is performed by using the commercial CFD software package FLUENT. The profile of the investigated corrugated tube is composed of many concavo-convex arcs （the radius is R1 and R2 respectively）, its name diameter is 20 mm, and its length is 2 m. The effect of R1 and R2 on heat transfer and flow performance of the corrugated tube is simulated. The SIMPLEC scheme for pressure-velocity coupling, standard scheme for pressure equation discretization and QUICK scheme for other equation discretization are selected in this numerical simulation study. The numerical results show that the corrugated tube can enhance the heat transfer performance compared with smooth tube under the laminar flow condition, when Re is in the case of equality, the enhancement of heat transfer increases with the increasing of R1 and the decreasing of R2 ; when the R1 and Re are in the case of equality, the enhancement of heat transfer increasing with the increasing of the Re number, and the Nu number is increased by 199.5% maximum in the research scope. At the same time, the corrugated tube has excellent flow performance, its drag coefficient is less than the smooth tube＇s at the most Re number, which approximates the friction coefficient of the smooth tube with the Re number increasing.