不同螺旋缠绕异形管换热器壳程性能数值研究

Numerical Research on Shell Side Performance of a Helically Coiled Special-shaped Tube Heat Exchanger

缠绕管的形状对螺旋缠绕管换热器的传热能力有重要影响,本文建立了具有不同截面形状的螺旋缠绕管换热器模型,数值研究了八种不同截面形状的缠绕管对螺旋缠绕管换热器壳程流动与传热性能的影响。相比于传统圆管,三叶管和水滴管对壳程流体造成的扰动较大,增强了螺旋缠绕管换热器的综合换热性能,而三叶管则具有最大换热能力。进一步分析了不同冲刷方式对螺旋三叶管换热器和螺旋水滴管换热器壳程性能的影响,结果表明:在相同的进口工况下,螺旋三叶管换热器壳程努塞尔数相比于传统圆管提高了11.8%~15.5%,阻力系数增大了41.9%~49.6%;螺旋水滴管换热器壳程努塞尔数相比于传统圆管提高了2.8%~4.3%,阻力系数增大了3.2%~6.8%;在雷诺数为2 603~5 206的工况条件下,管截面与流动方向夹角为0°的三叶管换热器综合换热性能最好,而管截面与流动方向呈逆流形式的水滴管换热器综合换热性能优于顺流形式。

The shape of the helically coiled tube has significant impacts on the heat transfer capacity of helically coiled tube heat exchangers.Eight different helically coiled tubes with different cross-sectional shapes are established in this paper.The effects of different cross-sectional shapes on the shell side heat transfer performance of helically coiled tube heat exchangers are investigated by numerical simulation.Compared with the traditional round tube,the trilobal tube and drop-shaped tube are likely to cause larger perturbation to the shell side,which enhances the comprehensive heat transfer performance of the helically coiled tube heat exchanger.The trilobal tube gets the largest heat transfer performance among the studied eight tubes.The effects of different scouring methods on the shell side performance of helically coiled trilobal and helically coiled drop-shaped tube heat exchangers are further analyzed.The results show that,under the same inlet conditions,the shell side Nusselt number of helically coiled trilobal tube heat ex-changer is increased by 11.8%~15.5%,and the drag coefficient is increased by 41.9%~49.6%compared with the traditional round tube type.The shell side Nusselt number of the helically coiled drop-shaped tube heat exchanger is increased by 2.8%~4.3%,and the drag coefficient is increased by 3.2%~6.8%compared with the traditional round tube type.In the studied range of Reynolds number from 2603 to 5206,the comprehensive heat transfer per-formance of the trilobal tube heat exchanger with the angle of o°between the tube cross-section and the flow direc-tion is the best,while the drop-shaped tube heat exchanger with the tube cross-section and the flow direction of the countercurrent form of the integrated heat transfer performance is the best.The comprehensive heat transfer per-formance of the water drop tube in reverse flow direction is better than that of the layout along the flow direction.