新型人字形组合板式换热器及导流区的数值模拟

基于计算流体动力学(Computational fluid dynamics,CFD)方法,运用SOLIDWORKS三维建模软件和FLUENT软件对一种新型人字形组合板式换热器及四种新型导流区进行研究。分析了不同设计参数的新型人字形组合板式换热器换热系数和压降,得到优化后的设计参数;从流型、压降、出口流体均匀分配程度等方面对市面上常见的2种导流区进行分析,在此基础上提出4种新型导流区,通过数值模拟研究其导流效果。结果发现:新型人字形组合板式换热器J型板较市面上常见的M型板的综合性能更优。当组合板中大波纹倾角板片(②板片)的倾角为60°,波纹截距为18 mm、16 mm或者14 mm中某一值时,随着组合板中小波纹倾角板片(①板片)波纹倾角增大,无论是冷流体还是热流体,表面传热系数和压降均增大。当①板片的波纹倾角为30°或40°,②板片的波纹截距变化对组合板片的性能影响不大;当1板片的波纹倾角为50°,②板片的波纹截距变化对组合板片的性能影响较大。导流区的设计对流体分布情况起主要影响作用。市面上常见的某种常规型导流区导流效果差,压降大,某公司M系列巧克力块型的导流区导流效果较好,压降小。4种新型导流区比常规型导流区的导流效果更好,压降介于常规型和巧克力块型之间,其中新型导流区Ⅲ的导流效果最好,压降很小。

Numerical Simulation of New Combined Plate Heat Exchangers and Distribution Region

New combined plate heat exchangers and four kinds of new distribution regions of plate heat exchanger have been established by SOLIDWORKS software, and simulated by FLUENT software based on Computational Fluid Dynamics method. Heat transfer coefficient and pressure drop of new combined plate heat exchangers have been analyzed, according to which the optimal parameters have been chosen. The normal distribution area has been analyzed according to its flow pattern, pressure drop and distribution performance. Four kinds of new distribution area have been proposed based on the analysis. The results show that new combined plate heat exchanger J plate could maintain the performance in terms of heat exchange and the pressure drop decrease compared with normal M plate. While the corrugation angle of big corrugation angle plate (plate②) of combined plate is 60 degrees and the corrugation intercept is 18mm or 16mm or 14mm, the convection heat transfer coefficient and the pressure drop increase with the increasing of the corrugation angle of small corrugation angle plate (plate①) whether for hot or cold fluid. While the corrugation angle of plate① is 30 or 40 degrees, the corrugation intercept of plate② has little influence on combination performance. While the corrugation angle of plate① is 50 degrees, the corrugation intercept of plate② has great influence on combination performance. Distribution region strongly influences the distribution of working fluid in plate heat exchangers. Normal distribution region has poor distribution performance along with large pressure drop. The distribution region of M series has better distribution performance and smaller pressure drop. New-designed distribution regions present better distribution performance and smaller pressure drop, as well. Among them, distribution regionⅢ shows the best distribution performance and less pressure drop.