基于平行流铝扁管吸附床传热性能的模拟研究

吸附床是吸附式制冷系统的关键部件。吸附床的换热能力对吸附式制冷系统的各项性能有显著影响。文章针对应用于吸附床的传统换热器和扁管换热器的不足之处,设计出一种新型平行流铝扁管吸附床,并建立了该吸附床的二维传热模型,以温度随时间的变化情况为分析指标,分析翅片的间距、高度、厚度,以及吸附剂体积分数等因素对吸附床传热性能的影响,从而优化调整吸附床的结构,提高其换热性能。分析结果表明:当翅片高度约为70 mm时,吸附床的换热能力达到峰值;当翅片厚度大于1.5 mm时,翅片厚度的增加对吸附床传热性能的影响比较微弱;当吸附剂体积分数由0.25逐渐增大至0.45时,吸附剂的等效传热系数约增加了50%。

Heat transfer simulation of adsorbent bed based on parallel flow aluminum flat tube

Adsorbent bed is a crucial component in adsorption refrigeration system, heat transfer capacity of the adsorption bed has a significant impact on the performance of the adsorption refrigeration system. In order to improve the inadequacies of conventional heat exchangers and flat tube heat exchangers in adsorption beds, a new type of parallel flow aluminum flat tube adsorption bed was designed, and a two-dimensional heat transfer model of the adsorbent bed was established.The major parameters(fin space, fin height, fin thickness and volume fraction) which influencing the heat transfer performance were analyzed by the temperature change over time in adsorbent bed,thereby optimizing the structure of the adsorbent bed and improving the heat transfer performance.The following conclusions are obtained through analysis: The heat transfer performance of the adsorbent bed reaches the peak when the height of fin is about 70 mm. When the fin thickness is greater than 1.5 mm, the increase in fin thickness has a weak effect on the heat transfer performance of the adsorption bed. The equivalent heat transfer coefficient of volume fraction θ_p=0.45 is about 50% larger than that of θ_p=0.25.