Study On Bubble Characteristics Of Pressurized Soluble Air Micro-bubble Generator

With the development of micro-bubble method in the field of water environment restoration,more and more scholars begin to study the formation of micro-bubbles and the mechanism of applying water body restoration.It is found that micro-bubbles have many advantages over ordinary bubbles,such as large specific surface area,self-pressurized dissolution,high interfacial potential,high mass transfer efficiency and long residence time.This paper mainly studies the application of pressurized dissolved air micro-bubble generator in water phase.According to the occurrence mechanism of related devices,a set of pressurized dissolved air micro-bubble generator was designed.The optimization conditions of the micro-bubble generator are mainly studied.The changes of bubble size and bubble concentration were measured by image method and turbidimetry respectively.The results showed that:The effects of operating pressure,air-water volume ratio,water flow rate and temperature on bubble size distribution and concentration were measured by single factor variable method,and the optimum operating pressure,air-water volume ratio,water flow rate and temperature were obtained.It was found that the optimum air-water volume ratio was1.5:1,the optimum water flow rate was Q_L=20L·min^-1,and the optimum operating pressure was P=0.4MPa,the temperature at 10³0?measure micro-bubble diameter changed little.It was found that the liquid level,surfactant and nozzle pore size all affect the diameter of micro-bubbles.When the liquid level was above 1/2 of the pressure dissolved air tank,the size of the bubbles was stable and the diameter was small.The comparison experiment of two nozzles with different orifices showed that compared with the nozzle with 0.4mm,the micro-bubble generated by the nozzle with 1mm has smaller diameter and higher concentration.When SDS was used as the surface activity and the optimal concentration was0.025g·L^-1,the median diameter of micro-bubbles decreased from 34.65?m to 26.68?m,and the concentration of micro-bubbles nearly doubled,indicating that the surfactant had a great influence on the bubble size distribution and concentration.At 15?,the experimental measured,the additive group?median diameter of 34.65?m?of dissolved oxygen a value of10.2mg·L^-1,adding the SDS group?median diameter of 26.68?m?of micro-bubble water dissolved oxygen a value of 11.1mg·L^-1,show that the smaller the diameter of the micro bubble their aerobic capacity.