内置转子组合式强化传热装置换热管内流体流动与传热数值模拟

Numerical Simulation of Turbulent Flow and Heat Transfer in Heat Exchange Tube Inserted with Rotors-Assembled Strand

建立了换热管内流体流动与传热三维数学模型,对内置转子组合式强化传热装置换热管内流体流动与传热特性进行数值模拟并与实验结果进行比较。模拟结果表明,内置转子组合式强化传热装置换热管内冷热流体产生了置换混合的效果,充分换热,管内温度梯度小于1 K,进出口温差较光管提高了29%;流场变为复杂的三维螺旋流,加剧了流体的湍流强度及边界层的扰动,使传热强化并起到清洁污垢的作用,但管内压降较光管增加了4.7 kPa;与光管相比,表面对流传热系数的平均值提高了7%,而且表面对流传热系数的分布也变得均匀。实验结果与模拟结果符合较好。

Three-dimensional flow and heat transfer model of concentric tubes was established and used to simulate flow and heat transfer characteristics inside heat exchange tube inserted with rotorsassembled strand. The results were compared with experimental data. Fluid was mixed completely and heat was exchanged fully, temperature gradient was less than 1 K, and temperature difference of fluid between inlet and outlet increased by 29% than that of the tube without rotors. Flow field varied from linearity to complex three-dimensional flow field which made turbulence more intense leading to enhance convective heat transfer and to clean the tube from fouling at the same time, but pressure drop increased by 4.7 kPa. In addition, heat transfer coefficient increased by 7% and distributed evenly. By comparison, numerical simulation results showed reasonably good agreement with experimental data.