海洋温差发电系统中板式换热器换热特性研究

Experimental Study on Heat Transfer Characteristics of Plate Heat Exchanger in OTEC System

对传统可拆式板式换热器进行了改良,以适用于海洋温差能发电系统工况,并对改良后的板式换热器进行了理论数值分析。研建了海洋温差发电系统测试平台,对系统内的换热器换热特性进行测试,在不同工况下对换热器换热特性进行了实验研究,得到了板式换热器瞬态运行特性,同时还得到了换热器换热特性随热流密度的变化曲线及压降随工质流量的变化关系。结合实验数据拟合了换热器换热特性经验关联式和压降随工质流量关联式,预测值和实验值偏差均在20%以内。结果表明:在实验系统运行工况范围内,换热器的换热系数随着热流密度的增加而增大,当热流密度大于3 kW/m2时,换热系数随热流密度变化的曲线斜率变小;换热器压降随着工质流量增大而增加,压降随工质流量变化的曲线斜率变大。

In this study,the traditional detachable plate heat exchanger has been improved to fit the working conditions of the ocean thermal energy conversion(OTEC)system,and performed the theoretical numerical analysis of the improved plate heat exchanger.This study developed an experimental for the platform OTEC system to study the heat transfer characteristics of the heat exchanger.The heat transfer characteristics of the plate heat exchanger were experimentally studied under different operating conditions,and obtained the transient characteristics of the plate heat exchanger.In addition,this study achieved the variations of the exchanger heat transfer characteristics with the heat flux,and built the relationship between the pressure drop and the flow rate of the working fluid.Based on experimental data,this study formed the empirical correlations of heat transfer characteristics and pressure drop,and the errors for both of them are within 20%.The results showed that the heat transfer coefficient of the heat exchanger increases with the rise of heat flux under the operating conditions of the experimental system,and the pressure drop of the heat exchanger increases with the growth of the working fluid flow rate.