内置自旋扭带圆管内压降特性的数值模拟研究

Numerical simulation of pressure drop characteristics in a circular tube with self-rotating twisted tape inserts

为了直观地描述内置自旋扭带圆管内压降的特性,采用RNG k-ε湍流模型对内置静止扭带、自旋扭带圆管及空管的压降特性进行数值模拟研究,并进行了内置3种型号自旋扭带圆管压降特性的数值模拟和试验研究。研究表明:自旋扭带管的压力降约为空管的2倍,而静止扭带管的压力降差不多达到空管的3倍;在含有自旋扭带或静止扭带的管段内,压力沿轴线方向线性变化,与理论分析趋势一致;扭带压降(流体与自旋扭带的摩擦力引起的压力降)的理论计算值、数值结果均与试验结果比较一致;影响扭带压降的因素是流体轴向流速、扭带宽度及扭带节距;流体轴向流速增大,扭带压降也增大;扭带宽度增大,扭带压降也增大;扭带节距增大,扭带压降略有下降。

In order to visually describe the pressure drop characteristics in a circular tube with selfrotating twisted tape inserts, the RNG k-6 turbulent model was used to simulate the pressure drop characteristics in a circular tube with self-rotating twisted tape, static twisted tape or none inserts. The numerical simulation and experimental study of pressure drop characteristics in a circular tube with 3 types of self-rotating twisted tape inserts were presented. The results indicated that the pressure drop of the tube with self-rotating twisted tape is about twice of the empty tube and the pressure drop of the tube with static twisted tape is nearly three times of the empty tube. In the section of tube with self-rotating twisted tape or static twisted tape inserts, the pressure shows a linear variation along the axial direction, which is consistent with the theoretical analysis. The theoretical and numerical results of pressure drop caused by friction resistance between the fluid and the twisted tape are consistent with the experimental results. The flow axial velocity, the width and the half-pitch of twisted tape are the factors to the pressure drop of twisted tape. The faster the flow axial velocity,the larger the pressure drops of the twisted tape. The larger the width of the twisted tape, the larger the pressure drop of the twisted tape. With the half-pitch of the twisted tape increasing, the pressure drop of the twisted tape decreases slightly.