The Numerical Simulation Of Heat Transfer And Discharge In Multi-dischage Ozonizer

Ozone is widely used in sterilization and bleaching due to its strong oxidation.When compared with other sterilization product, it wouldn’t cause secondarypollution. Since Siemens developed the first ozonizer in1857, ozone was applied invarious fields of industrial production. Ozone has broad application prospects,however, low efficiency of ozone production is a serious problem for a long period oftime. In reality, ozone yield couldn’t reach the theoretical value of1266g/(Kw h).Only10%of total energy is used to generate ozone, while the rest energy is dissipatedin the form of heat. Thus, lots of researches regarding improving the ozoneproduction are investigated. Hyun-Jig SONG proposed the highest ozone productivityof783g/Kw h in the research with a mixed discharged ozonizer (three electrodeand two discharge space). However, although the productivity of ozone is reported,SONG didn’t make research on the ozonizer configuration. Therefore morediscussions regarding the mixed discharge ozonizer are needed. Based on the theoryand experimental structure of SONG, this paper performed numerical simulation ofmixed discharged ozonizer both on heat transfer and discharge. The results ofsimulation were as follows:(1) Modeling and simulation calculation were carried out in FLUENT, the resultswere as follows: after the gas entered the two discharge spaces, the temperature of gasincreased gradually in radial direction, and the average temperature of the threeelectrode were304.8K,309.9K and313.2K, respectively; temperature difference inradial direction of medium and the inside of electrode was very low; about36.14%ofelectric energy was emitted in the form of heat, and the rest electric energy wastotally transformed to reaction heat to generate ozone; considering the averagetemperature of different flow rate, temperature reduction in discharge gap was foundto be the key factor which would influence the ozone productivity; on the condition ofcertain flow rate and discharge volume, changing the location of inner electrode indischarge space could balance the gas speed in the discharge space, and then theretention time of gas in the discharge space was cut down, which would decrease the decomposition rate of ozone and thus to improve the ozone productivity.(2) The mixed discharge experiment was simulated and analyzed utilizingANSYS, the results were as follows: the current intensity of three types of mixeddischarge distributed equally in the no-hole field, but the current intensity fluctuatedviolently in the perorated field, which was caused by point discharge; electron energydistribution of three types of mixed discharge was analyzed using BOLSIG, theresults showed that IESDO mixed discharge ozonizer was favorable to ozonegeneration, which was consistent with Song’s results; when the mixed discharge oftwo electrodes was simulated separately, the results showed that there was noevidence of superposition of electric field strength.