Numerical Simulation And Optimization Analysis Of Chlorine Dioxide Gas Mixer Based On CFD

As an efficient,broad-spectrum and environmentally friendly disinfectant,chlorine dioxide has wide application prospect in the field of space disinfection,but the current generating device and detection technology of low-concentration chlorine dioxide gas can not meet the need completely.In this paper,based on the high-concentration chlorine dioxide gas generator designed by our research group,a venturi mixer which can realize high-concentration chlorine dioxide gas and air fast and uniform mixing was designed.The numerical simulation and optimization of the chlorine dioxide gas mixer was conducted in this dissertation,wherein the CFD numerical simulation method,the orthogonal test design and response surface method were employed.Firstly,the structure of the mixer was designed,which is a venturi mixer with a gas distributor in the throat,and then the mixing effect and pressure drop were simulated by Fluent.The effects of different turbulence models on the hybrid simulation results are investigated.The results showed that the different turbulence models had little effect on the hybrid simulation results,and the RNG k-? model was adopted finally.The effects of process parameters and mixer structure parameters on the mixing effect and pressure drop were investigated.In order to improve the mixing effectiveness and reduce the pressure drop,the orthogonal test was used to achieve the initial optimization of the mixer,and the process parameters and the structure parameters of the mixer were selected as the test factors.According to range analysis and variance analysis of the experimental results,the influence degree of the experimental factors for the mixing effects and the pressure drop were analyzed.The results showed that: for the mixing effectiveness,the importance of the test factor from large to small is the throat diameter,the outlet angle,the inlet angle,air flow,chlorine dioxide gas flow,and a more optimum combination of factor levels was obtained.However,the simulation results show that the combination can achieve better mixing effect,but the pressure drop is very large.Meanwhile for the pressure drop,the importance of the experimental factor from large to small is the throat diameter,air flow,the outlet angle,chlorine dioxide gas flow,theinlet angle and a optimum combination of factor levels was obtained.Although the simulation results show that the combination can obtain a small pressure drop,the mixing effect can not meet the requirements.The response surface methodology was adopted to secondly optimize the mixer based on the orthogonal test optimization under the condition of keeping the mixing process parameters unchanged.The optimal solution is throat diameter 18 mm,inlet cone angle 20 degrees,exit cone angle of 4 degrees.The simulation results show that the non-uniformity of the mixer is 0.0058 and the pressure drop is 2.49 KPa.Compared with the results of orthogonal test,mixing effect is the best and the pressure drop is better.Finally,the mixer was manufactured.