混合板式换热器板通道的数值模拟研究

Numerical Simulation of Hybrid Plate Heat Exchanger's Plate Channel

本文采用二维非稳态数学模型、周期性充分发展边界条件对混合板式换热器中的板通道内的流动和换热进行数值模拟。在Re=4407～22035工况范围内,计算了半圆型、半椭圆Ⅰ型和半椭圆Ⅱ型三种不同纵截面形状波纹板通道内的流动和换热性能。数值模拟结果分析表明,波纹通道内的流动会因为流体从凸面流向凹面时产生回流而形成涡,即产生扰动,强化了后面的换热,但同时增大了阻力。并得出半圆型通道换热最强,Nu为椭圆Ⅱ型的1.4倍;但其阻力最大,压降为椭圆Ⅱ型的1.9倍。

This paper adopted a two-dimensional unsteady state mathematical model and a periodic boundary condition in the walls to simulate plate channel＇s heat transfer and flow performances. In the conditions that Reynolds numbers are from 4407 to 22035, this paper has calculated plate channels＇ heat transfer and flow performances in different cross section shapes （the semicircle, the semi-ellipse I and semi-ellipse II ）. The numerical simulation results indicated that the backflow is produced in the corrugate channel when flowing forward from convex surface to concave surface. As a result of the perturbation from geometry structures to the fluid, the corrugate channel enhances heat transfer and in the same time increases resistance. In three kinds of periodic corrugated plates, the semi-circle channel heat transfer＇s performance is best. Nu is 1.4 times as big as semi-ellipse II ; and the resistance is also greatest. The pressure drop is 1.9 times as big as semi-ellipse II.