板式换热器性能的数值模拟

Numerical Simulation on Performance of Plate Heat Exchangers

建立了人字形板式换热器冷热双流道的流体流动与传热计算模型,利用计算流体力学软件对5组不同速度工况下换热器内流体的流动和传热进行了数值模拟,分析了换热器流道内的速度场、温度场和压力场.结果表明:数值模拟得到的板式换热器进、出口温差和压降与试验测量值的误差均小于6%;换热器内流体的流动和传热存在明显的不均匀性,导致其进、出口的另一侧出现明显的传热"死区";换热器的总传热系数和流道阻力均随着流体流速的增大而增大.

A calculation model was built up for fluid flow and heat transfer in cold and hot flow channels of a chevron-type plate heat exchanger.Using CFD software,numerical simulations were carried out for fluid flow and heat transfer inside the heat exchanger under conditions of five different velocities,while the velocity field,temperature field and pressure field in the channels analyzed.Results show that the error of both temperature difference and pressure drop are all less than 6% between simulated and test results at inlet and outlet of heat exchanger.Obvious non-uniformity of flow and heat transfer exists in the heat exchanger,resulting in obvious heat transfer＇dead zone＇ at another side of inlet/outlet.The total heat transfer coefficient and channel resistance increase with rising flow velocity.