| In recent years,with the comprehensive management of air pollution,the air quality has been greatly improved.But the steel,coal-fired power plants,coal and electrolytic aluminum industries,with high-energy and heavy-pollution,still exhaust a large amount of fine particles that are difficult to be reduced effectively.The fine particles from industrial sources significantly harm the atmospheric environment.Under this background,it is urgent to study a new dust removal technology of high efficiency,low emission of fine particles,more energy-saved and without secondary pollution.Cloud-Air-Purifying(CAP)technology is a new type of high-efficiency dust removal technology that is similar to the natural cloud-forming process.CAP uses heterogeneous condensation and super-gravity environment to make fine particles collide and coagulate in the disturbed flow field and grow up.Finally,the particles are efficiently removed by the action of supergravity.Based on CAP technology,this paper studies the influence of inlet atomization characteristics on water vapor distribution and performance in the cyclone.Firstly,the experiment and simulation study the condensation rate and the pressure drop of the cyclone,with selecting different inlet atomization concentration and temperature.The numerical simulation results were compared with the experimental data to verify the reliability of the model,and then the numerical simulation of the flow field of the cyclone under different inlet atomization concentrations and temperatures was carried out.The Reynolds stress(RSM)model and the Euler wall(EWF)model were used to simulate the characteristics of gas-liquid two-phase flow field,such as water vapor distribution,turbulent diffusion coefficient and three-dimensional velocity.The mechanism of inlet atomization concentration and temperature changing flow field was analyzed.Finally,based on the gas-liquid two-phase flow field,the Lagrangian particle tracking(LPT)model and the condensation growth model are used to simulate the growth region and the change of particle size in the cyclone.The separation efficiency and grade efficiency are obtained,clarifying the mechanism of the influence of inlet atomization characteristics on the performance of cyclone in CAP technology.The results show that with the increase of the inlet atomization concentration(0to 50g/m~3),at the same temperature,the particle separation efficiency of the cyclone increases,the pressure drop decreases,the particle separation efficiency can be increased by 12.11%,the pressure drop decreases by up to 10.79%;the particle growth mainly occurs in the cylinder section and the lower end of the vortex finder;the particle diameters of 2.5?m,5?m and 10?m is found to be increased.The growth rate of 2.5?m,5?m and 10?m is increased by 21.31%,18.14%,and 18.82%respectively.The decrease of the inlet atomization temperature(25°C to 5°C)is benefit to the increase of efficiency and grade efficiency of the cyclone at the same atomization concentration.Compared to the cyclone with no-atomization,when the temperature is lowered to 5°C,the particle separation efficiency is improved by 10.42%;and the removal efficiency of 2.5?m,5?m,and 10?m increased by 19.63%,16.96%,11.77%,respectively.In summary,increasing the concentration and reducing the temperature of the atomization can significantly improve the flow field characteristics in the cyclone,and improve efficiency of fine particles.By studying the influence of inlet atomization concentration and temperature on the flow field and particles growth in the cyclone of CAP technology,the mechanism of the influence of atomization characteristics on the performance of cyclone was explained.This is of great significance for further optimization and improvement of CAP technology,which will greatly promote the applications of CAP technology in industrial and contribute to air pollution control.At the same time,this research of the study can also provide reference for the improvement and optimization of wet dust removal technology. |
PDF Full Text Request