管内垂直降膜绝热吸收评估方法与实验分析

构建了氨水降膜吸收实验设备，研究垂直管内降膜绝热吸收性能.通过套管换热器调节稀溶液入口过冷度，给予溶液吸收潜力，进行变工况降膜吸收实验.基于传质微分方程推导一种新的舍伍德数计算方法，用于传质性能评估.实验表明,传质速率以及舍伍德数随着雷诺数的增大而增大.增加吸收压力，稀溶液入口过冷度均能强化传质效果.具有过冷度的耦合传热传质过程传质速率及舍伍德数大于单独的过冷绝热吸收或者耦合传热传质吸收.利用实验结果拟合绝热吸收传质舍伍德数方程，可应用于传热传质分离的降膜吸收器热设计.

Evaluation Method and Experimental Performance of Inner Vertical Adiabatic Falling Film Absorption

The performance of NH3-H2O inner vertical adiabatic falling film absorption was studied based on the experimental set-up. The potential of absorption was just given by the inlet sub-cooling of the weak solution. Variable working conditions were performed and tested. A novel evaluation method related to Sherwood number was derived from the conservation and transfer equations, which was used to evaluate the experimental data. The experimental results show that transfer rates and Sherwood numbers increase with the growing of Reynolds numbers. The mass transfer process is enhanced by increasing absorption pressure or inlet sub-cooling. The mass transfer performance of coupled heat and mass transfer combined with inlet sub-cooling is higher than inlet sub-cooling or coupled heat and mass transfer only. Sherwood correlation has been fitted based on the experimental data to evaluate the adiabatic falling film absorption. It could be used in designing falling film absorber whose heat and mass transfer are independent of each other.