| As an efficient and energy-saving separation technology,flash evaporation has important application value in many fields such as desalination,medical treatment,food processing,drying separation,oil and gas exploitation,aerospace cooling,and process chemicals.With the advancement of science and technology,the past flash method can no longer meet the needs of production.Research on the flash characteristics of different flash forms will help improve the flash efficiency and increase the production capacity.Based on the research of static flash evaporation,this paper independently designed and built a circulatory flash evaporation experiment platform to study the Non-equilibrium characteristics of circulatory flash evaporation of different working fluids.The changes of temperature,pressure,Non-equilibrium fraction(NEF),circulatory flash speed(CFS)and volumetric heat transfer coefficient during the circulatory flash evaporation process are given.The experimental fitting correlation formula of the NEF is given,Study the characteristics of circulatory flash evaporation from a macro perspective,It provides a basis for the design and parameter selection of the flash system in practical applications.In order to further reveal the evolution process of circulatory flash evaporation,a visual study of the circulatory flash evaporation process was carried out with the help of a highspeed camera.The expansion height of the foam layer is defined to describe the flashing phenomenon,analyzed the influence of different initial working conditions on the change law of foam layer expansion height,and studied the bubble growth characteristics during the flash evaporation process.Analyzed the different bubble nucleation characteristics in the circulatory flash evaporation process,increase the degree of superheat and reducing the height of the initial liquid film can promote flash evaporation,study the characteristics of circulatory flash evaporation from a microscopic point of view,it has important guiding significance for the design of flash chamber and circulating flash system.In order to analyze the change law of flash evaporation characteristics of different working fluids,Take the offshore Monoethylene Glycol Regeneration Unit(MRU)system as the technical background,take ethylene glycol solution as the research object of circulatory flash evaporation,compare the flash characteristics of pure water,Na Cl solution,and ethylene glycol solution,The flashing law and evolution process of ethylene glycol solutions of different concentrations are also studied.The increase in the concentration of MEG reduces the surface tension and promotes the flash evaporation.It provides data support for the design of the offshore MRU system and is of great significance to the design of the deep-sea combustible ice mining platform. |
