一种新型裂解炉炉管强化传热数值模拟

Numerical simulation of a new type intensified heat transfer radiation tube for cracking furnace

利用计算流体动力学(computational fluid dynamic,CFD)方法对含新型内插件强化传热辐射炉管(fortified induced turbulence,FIT)进行了流体流动与传热特性的研究,采用RNG双方程模型求解了动量方程和能量方程,给出了FIT炉管内的流体流动和传热特性,包括速度场、湍动强度和温度场的分布;计算了FIT炉管的强化传热因子和压降。研究结果表明,FIT炉管内插件迫使流体流动由活塞流转变为旋转流,增强了流动湍流程度,符合流动-能量场协同理论,同时流体边界层由于FIT炉管的特殊结构而减薄。FIT炉管具有增强辐射传热、减薄边界层、增加比表面积和旋流增强等强化传热特性。相比于普通当量圆炉管,FIT强化传热炉管的整体传热能力提高了20%左右,证明该新型炉管强化传热效果显著,可以在工程实际中应用。

The flow and heat transfer characteristics of fortified induced turbulence（FIT） tube with inserts were studied with computational fluid dynamics（CFD）. The momentum and energy equations were solved by using RNG turbulent flow model. The flow and heat transfer characteristics of FIT tube,namely velocity field,turbulent flow field,temperature field were presented and pressure drop,intensified heat transfer factors were calculated. The heat transfer of FIT tube was intensified because swirling flow instead of piston flow by using special tape placed inside the FIT tube caused more turbulence and hydrodynamic boundary layer was cut thinner. Multiple mechanism elements（radiation factor,surface factor,twist factor and boundary layer cutting factor） to intensify the heat transfer of furnace radiant tube were established in the analysis. Compared with plain tube,FIT tube showed a significant increase of heat transfer by about 20%,and could be used as a good heat transfer radiation tube.