新型板壳式换热器壳程流动与换热的数值模拟

Numerical simulation of shell-side flow and heat transfer characteristics in new type plate-shell heat exchanger

提出一种新型的板壳式换热器,建立2种不同板束截面形式的换热器模型,利用FLUENT软件对壳程流体的流动和换热进行数值模拟,从多个方面对板壳式换热器壳程湍流流动与强化传热进行了探讨。模拟结果表明,由于换热板片特殊的蜂窝结构,靠近板片壁面的流体产生了明显的周期性波浪式流动,这种流动加剧了流体的湍流强度及边界层的扰动,起到了壳程强化传热的效果。对于2种不同截面形式的换热器,圆形截面形式的换热器壳程空间利用率较高,流体流动充分,热交换效果更好,在同流量下,其壳程对流换热系数比方形截面形式的高35%—40%,压降高17%—19%,单位压降下的壳程对流换热系数高15%—19%。该数值模拟结果对板壳式换热器的研究具有一定的理论意义和工程实用价值。

A new type plate-shell heat exchanger was proposed. Calculation models were built up for the heat exchanger with two different plate bundle cross-sections. Numerical simulations were carried out for the shell-side fluid flow and heat transfer with Fluent software. The turbulent flow and heat transfer enhancement in shell-side were discussed in several aspects. The simulation results show that due to the special honeycomb structure of the plate, the fluid near the wall has a clear cyclical wave flow, which increases the fluid flow turbulence intensity and boundary layer disturbance, to strengthen the heat transfer effect in shell side. For two different forms of heat exchanger cross-section, the heat exchanger with circular cross-section can get higher space utilization, fully fluid flow, and better heat exchange effect. At the same flow rate, the heat transfer coefficient of the heat exchanger with circular cross-section is higher than that with square cross-section by 35% -40%, pressure drop is higher by 17% - 19%, and the unit pressure drop heat transfer coefficient of shell side is higher by 15%-19%. The numerical results have theoretical and practical value for plate-shell heat exchanger study.