螺旋线圈强化管内单相流体传热的研究

Research on Forced Convection Heat Transfer in a Horizontal Tube With Spiral Spring Inserts

研究了内插螺旋线圈的水平圆管内水的对流强化传热及流阻特性 ,探索了螺旋丝径不变 ,螺距变化对传热及流体阻力的影响 ;螺距不变 ,螺旋丝径变化对传热及流体阻力的影响。实验采用2 5mm× 2mm的紫铜圆管 ,实验段长 1 .68m ,管内走水 ,Re数的范围在 30 0 0～ 2 5 0 0 0之间。通过对实验数据的多元线性回归 ,得到了传热与流体阻力的实验关联式 ,采用 (Nus/Nu) 3.5/ ( fs/ f)作为评估传热与流阻性能的综合判据 ,实验结果表明 :在实验范围内 ,(Nus/Nu) 3.5/ ( fs/ f)的值在 1 .2～ 1 0 .7之间 ,大于 1 。

Experimental study of forced convection heat transfer in a horizontal circular tube with spiral spring inserts is performed to investigate the characteristics of fluid flow and heat transfer. The influence of the spring wire diameter is studied when the coil helix pitch is a constant, meanwhile, the influence of the coil helix pitch is also analyzed when the diameter of spring wire is a constant. The range of Reynolds number is from 3 000 to 25 000; The experimental tube is φ25 mm × 2 mm and the tube length is 1.68 m;The fluid inside the tube is water. According to the experimental data, the heat transfer correlation and flow drag correlation are obtained. (Nu3,/Nu)3.5/(f3/f) is used as the criterion to evaluate the combined effect of heat transfer and flow drag; The range of (Nu3,/Nu)3.5/(f3/f) is from 1. 2 to 10.7, which declares that the spring wire in circular tube enhances heat transfer effectively.