| Since the Coronavirus disease-2019（COVID-19）burst in global,the pollution of the indoor environment and the spread of microbial aerosols have been specialy attracted attention.Ozone water as an efficient,versatile,green and environmentally friendly disinfectant,it has widely application value in the field of controlling microbial aerosol polltuion.Due to the imperfection of ozone water preparation technology and equipment,it is difficult to obtain high-concentration of ozone water,which greatly affects the sterilization effect.This current study designs a novel equipment for preparation ozone water in high-concentration for air sterilization.The performance of different ozone-water mixing and strengthening devices for enhances ozone mass transfe were investigated,and the sterilization effect of it on indoor microorganisms were also investigated.The main research content is as follows:（1）A rig for high-concentration of ozone preparation and air sterilization was designed and manufactured,and the internal flow field was then simulated.Two types of the ozone-water mixing and dispersed device of orifice plate cavitator and static spiral cutter were investigated in detail.A 20 G·H-1 ozone generator and 2 m3·h-1 stainless steel multi-stage centrifugal pump were chosen in experimental.The effects of numbers,angle and height of inlets,on the flow field were studied using the Fluent simulation.The simulation results show that the best gas distribution unevenness index is 0.576 m·s-1 in the tower with 3 inlets,10°inlet angle and 100mm inlet height.（2）The effects of different structures of orifice plate cavitators and static spiral cutters for enhances ozone mass transfer were investigatedusing equilibrium concentration of ozone water,concentration of hydroxyl radical,ozone mass transfer coefficient and energy consumption cost as evaluation indexes,and the effects of different process parameters for enhaning ozone mass transfer were investigated,and effects between orifice plate cavitator and static spiral cutter were also compared,the effects of The results showed that,for orifice plate cavitator,the equilibrium concentration of ozone water and concentration of hydroxyl radical increased with the increase of orifice number（N）and orifice plate thickness（T）,but decreased with the increase of orifice diameter（d）.When N=4,d=2 mm,T=4 mm,the concentration of ozone water and concentration of hydroxyl radical were 10.68 mg·L-1 and 110.75μmol·L-1,respectively.For static spiral cutters,the equilibrium concentration of ozone water and concentration of hydroxyl radical increased with the increase of the number of channels（F）and the relative angle（φ）,and first increased and then decreased with the increase of pitch（m）.When F=5,φ=720°,m=0.5,the concentration of ozone water and concentration of hydroxyl radical were 14.12 mg·L-1 and95.85μmol·L-1,respectively.Therefore,the static spiral cutter was finally used as strengthening device for ozone-water mixing.For process parameters,the concentration of ozone water decreased with the increase of initial temperature and p H,and increased with the increase of ozone inlet flow.The concentration of hydroxyl radical increased with initial temperature and then decreased,and increased with initial p H and ozone inlet flow.When the initial temperature was 25℃,p H was 7,and the ozone inlet flow was 3 L·min-1,the concentration of ozone water and concentration of hydroxyl radical were 14.12 mg·L-1 and 95.85μmol·L-1,respectively.（3）Temperature,initial concentration of ozone water,wind speed and spray flow rate were used as single factors to explore the effects of process parameters on the sterilization efficiency,and the response surface analysis model and response surface regression equation were then established with bactericidal efficiency as the response value to obtain the optimal process parameters.The results showed that the order of influences was initial concentration of ozone water>temperature>wind speed>spray flow rate.The optimal process parameters were obtained as following:temperature 24℃,initial ozone water concentration 11 mg?L-1,wind speed 2.6 m·s-1,and spray flow 510 L·h-1.The average bactericidal efficiency was 98.15%.In this study,the machine for air sterilization with high-concentration of ozone water was designed and studied by strengthening gas-liquid transfer.The response surface analysis method was used to determine air sterilization effect and optimize process parameters.The current study can provide a better choice for solving the problem of microbial contamination in indoor air. |
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