采用新制冷剂R134a和混合制冷剂R410A的板式蒸发器性能研究

采用分布参数法对波纹型通道板式蒸发器建立数学模型,并进行了数值模拟.通过计算板内局部蒸发传热系数和压降可以简化板式蒸发器内复杂三维网状流动的传热特性.针对应用较广的R134a和R410A制冷剂来比较和分析板式蒸发器在小的温差下的传热性能.在3种不同的计算工况下简要分析了各种热力参数的变化对蒸发器整体传热性能的影响.不同的制冷剂,其传热系数和压降差别较大,相同工况下采用R410A替代R22,板式蒸发器的传热性能可提高8.5%～10.0%,且压降可大幅降低.

A STUDY ON THE PERFORMANCE OF PLATE HEAT EXCHANGER USING R134a AND R410A AS WORK FLUIDS

A mathematic model of distributed parameter for plate heat exchanger (PHE) with a corrugated sinusoidal shape of chevron angle was derived.The model is used to analyze the performance of PHE.Heat transfer characteristic of three-dimensional complex turbulent flow was simplified and analyzed by calculating local evaporation heat transfer coefficient and pressure drop. Heat transfer performance with little heat transfer temperature difference was compared and analyzed using refrigerant R134a and refrigerant mixtures R410A. Under three different operating conditions, the effects of the changes of thermodynamic parameters on the performance of PHE were formulated. Adopting different refrigerants in PHE could result in different heat transfer coefficient and pressure drop. R410A substituting for R22 at the same operating condition, the performance of PHE is increased 8.5%~10.0% and the pressure drop is enormously decreased.