内置扭带换热管三维流动与传热数值模拟

对自转扭带换热管内流体的运动进行了分析，根据流体在自转扭带管内的切向运动特点，提出将自转扭带等效虚拟于静止扭带的思路。建立内置螺旋扭带换热管流体流动的三维物理模型，采用大型CFD软件FLUENT6.0中的RNG k-ε模型对内置扭带换热管内的流动与传热进行了数值模拟，得到了内置扭带换热管流体流动的速度、压力、湍流强度场分布规律及传热特性。比较了静止、旋转及旋转等效虚拟静止扭带换热管的传热和阻力降特性，分析了不同螺距对强化传热和阻力降的影响。速度场的模拟值与激光测速仪试验值进行了比较，二者吻合较好。

NUMERICAL SIMULATION OF THE THREE DEMENSIONAL FLUID FLOW AND HEAT TRANSFER OF HEAT EXCHANGER TUBES WITH TWISTED-TAPE INSERT

The fluid flow of self-rotating twisted-tape inserted tube is analyzed. According as tangential motion characteristic of fluid in self-rotating twisted-tape inserted tube, a conception of self-rotating twisted-tape being dummied as equivalent still twisted-tape is put forward. A three-dimensional physics and mathematical model of twisted-tape-inserted tubes are presented. RNG k-e turbulent model is adopted to simulate flow field and enhanced heat transfer of heat exchanger tubes with twisted-tape insert numerically. The distribution laws of the velocity field, pressure field, turbulent characteristic field and enhanced heat transfer characteristic of twisted-tape-inserted heat exchanger tubes are obtained. The heat transfer and pressure drop characteristic of still twisted-tape-inserted tubes, self-rotating twisted-tape inserted tubes and dummy equivalent still twisted-tape inserted tubes are compared. The influences of different twist pitch on enhanced heat transfer and pressure drop are analyzed. Numerical simulation calculation value of the velocity field is compared with the experimental data measured by laser doppler velocimeter (LDV) system. The numerical simulation results show reasonably good agreement with the experimental results.