吸附式制冷系统吸附床传热传质强化研究现状

Research Status of Heat and Mass Transfer Enhancement of Adsorption Bed in Adsorption Refrigeration System

本文介绍了吸附式制冷系统吸附床传热传质强化的途径,分析比较了多种途径采用的方法。结果表明:吸附式制冷系统吸附床一般通过增加传热面积、加强颗粒间传热和降低接触热阻3种途径,采用翅片式、涂抹式和添加剂法等9种方法来提高吸附床的传热性能,强化传质的方法常用浸渍法;吸附床的传热面积通过增加翅片的方法来增大虽简单有效,但也增加翅片和吸附剂之间的热阻;涂抹式吸附床的传热性能和再生速度能够得到有效提高,但由于涂覆层厚度的局限增加了吸附床金属的质量并降低热容量比;固化法、添加法和化学复合法联合应用效果会更佳,添加硫酸处理过的膨胀石墨并进行固化的吸附剂,其导热率可达到未处理的150倍。

The way to enhance the heat and mass transfer of the adsorbent bed of the adsorption refrigeration system is introduced in this article,and various methods are analyzed and compared.The results show that the heat transfer performance of the adsorbent bed is generally improved by three ways:increasing the heat transfer area,enhancing the heat transfer between particles,and reducing the contact thermal resistance.And nine methods are adopted to improve the heat transfer performance of the adsorption bed such as adding fin type,smearing type and additive method.Immersion methods are commonly used to enhance mass transfer.It is simple and effective to increase the heat transfer area of the adsorbent bed by adding fins,but it will also increase the thermal resistance between the fins and the adsorbent.The heat transfer performance and regeneration speed of the smear type adsorption bed can be effectively improved,but due to the limitation of the thickness of the coating layer,the quality of the bed metal will be increased and the heat capacity ratio will be reduced.And the combined application effect of curing method,additive method and chemical compound method will be better.The thermal conductivity of the adsorbent which is added expanded graphite treated with sulfuric acid and solidified can reach 150 times than that of untreated.