关键词: 异辛醇, 降膜蒸发器, 接触角, 表面活性剂, 吸收式制冷

Abstract: Adding a little bit 2-ethylhexanol additives to lithium bromide-water solution can enhance the absorption dramatically in LiBr-water chiller.As a result,COP of the chiller is improved.But the heat transfer is going bad in falling film evaporator where 2-ethylhexanol water solution is working.To find the reasons,this paper focuses on the contact angle by comparing the 2-ethylhexanol water solution and deionized water on the different metal plates.Experimental results show that adding a little bit 2-ethylhexanol additives to the water makes the contact angle bigger than no additives.Wettability is changed to be lower.Hence,the heat transfer in the falling film evaporator is decreased.It also shows that 40 mg稬^-1 2-ethylhexanol water solution on the zinc coated steel has the smallest contact angle,next is stainless steel and the copper has the biggest contact angle.Concentration of the 2-ethylhexanol water solution has no obvious effect on the contact angle.

Key words: 2-ethylhexanol, falling film evaporator, contact angle, surfactant, absorption refrigeration