超大拓展表面三维微肋管换热器的对流换热及抗积灰特性研究

工业烟气含尘的特点易导致换热器积灰,进而制约烟气余热的高效回收。本文针对一种具有超大拓展表面的三维微肋管换热器的对流换热与积灰特性进行了研究。首先,对比研究了光管与三维微肋管的对流换热特性;接着,基于所建立的积灰数值模型,探究了三维微肋管的积灰特性,并揭示了烟气流速与飞灰粒径对其积灰特性的影响规律。结果表明,相对于传统光管,三维微肋管的换热面积可增大约2.9倍;换热性能平均能提高16%;积灰后渐进污垢热阻最大能减小70%;同时,清灰周期更长,运行经济性更佳。综合而言,三维微肋管相比传统光管,在增强换热的同时,还能有效减轻积灰,因此可作为高效的抗积灰传热元件,应用于含尘烟气的余热回收场合。

Study on Heat Transfer and Fouling Characteristics of 3D Micro-finned Tube Heat Exchanger With Extra-large Expanded Surface

The dust content in flue gas is an important reason that restricts the recovery efficiency of waste heat from flue gas.In this paper,heat transfer and fouling characteristics of a 3 D micro-finned tube(3 DMFT)heat exchanger are studied.Firstly,the heat transfer characteristics of circular tube and 3 DMFT are compared.Then,the fouling characteristics of 3 DMFT are explored,and the effect of gas velocity and particle diameter on fouling is revealed.The results show that,compared with circular tube,the heat transfer area of 3 DMFT can be increased by 2.9 times;the heat transfer performance can be increased by 16% on average;the asymptotic fouling resistance can be reduced by 70%;meanwhile,the cleaning time is longer,which means the operation economy is better.To sum up,compared with traditional circular tube,the 3 DMFT can enhance heat transfer,and also effectively reduce fouling.Therefore,it can be used as an efficient and anti-fouling heat transfer element in waste heat recovery systems.