Abstract:

Based on the preparation of the uniform and stable Al₂O₃ nanofluid，two experimental schemes were developed，which validated that the ammonia bubble absorption effect was enhanced by adding Al₂O₃ nano-particles into the absorption solution.Two main factors which possibly induce the enhancing absorption effect were found：one was the stability of the nanofluid，the other was the pressure difference between the inlet of the absorber and the gas phase surface in the absorber.In the conditions of sodium dodecyl benzene sulfonate（SDBS）additive，the Al₂O₃ nanofluid having good stability and enhancing absorption effect could be obtained，although the experimental results showed that the absorption effect of ammonia was restrained by only adding SDBS additive into the absorption solution.Under the bigger pressure difference the Al₂O₃ nanofluid could represent the enhancing absorption effect at the beginning stage of absorption.With the concentration of ammonia solution increasing，the absorption potential declined，but the enhancing influence induced by the nanofluid was more obvious compared with that with no nanofluid.The possible mechanism of the experimental phenomena was explained.This paper provides a reference for subsequent research on the heat and mass transfer for nanofluid and the thermochemical compressor of the minitype ammonia absorption refrigerator.

摘要：

在试制出了性能稳定的Al₂O₃纳米流体的基础上，通过定氨气流量和定入口压力两种实验方案，验证了Al₂O₃纳米颗粒对氨水吸收过程的强化影响，同时找出了引起强化吸收的两个主要影响因素：纳米流体性能的稳定性和吸收器入口与吸收器内气相界面的压力差。在添加十二烷基苯磺酸钠（SDBS）的情况下，可以获得性能稳定而具有强化吸收效果的Al₂O₃纳米流体，尽管SDBS本身对Al₂O₃纳米流体强化吸收具有抑制作用。较大的压力差下Al₂O₃纳米流体在吸收开始阶段就表现出强化吸收效果。随着氨水浓度的增加，氨水对氨气的吸收潜力减小，而Al₂O₃纳米流体对氨水溶液强化吸收的效果更加明显。对强化现象的可能机理给出了合理解释，为纳米流体对传热传质强化研究提供参考。