吸附式制冷装置中吸附床传热传质的研究

本文根据吸附式制冷装置中吸附床的操作特性,建立了吸附床在受热解吸过程中的传热传质数学模型.在这个模型中,假设吸附床是均质的,吸附床的导热系数可用一个当量寻热系数表示,并考虑吸附床中吸附剂与传热片之间的接触热阻.以本文作者所建立的吸附式制冰机为例,对此数学模型进行了计算,计算值与实验结果吻合得较好.

Heat and Mass Transfer in A Fixed Bed of Solid Adsorbent for Adsorptive Refrigeration

A two-dimension numerical model is proposed to describe the heat andmass transfer in a fixed bed of solid adsorbent for adsorptive refrigeration. The fixed bed of dimensions 0.5 × 0.5 × 0.082m3, has internal heat transfer fins 0.075m high and 0.001m thick, 0.49m long, and fin to fin distance 0.03m. In this model the following assumptions are made: the heterogeneous solid adsorbent is treated as equivalent continuous medium ;convective heat transfer in vapour phase is neglected; the pressure is considered as the same at every point inside the fixed bed; and the resistance to heat transfer from fins to solid adsorbent is also taken into account. A set of partial differential equations, based on mass conservation and energy conservation are built up. The equations are solved by using finite difference methods of purely implicit schema. Furthermore, an experiment was conducted to validate the model. In the experiment, 13kg activated carbon was used as adsorbent and methanol as adsorbate. It was found that the experimental results were in agreement with the calculations.