Migration Characteristics Of Hydrochloric Droplets Accompanying Evaporation And Volatilization In Human Microenvironment

In the industrial building interior,a large amount of hydrochloric droplets will be generated during the process of pickling and electroplating.hydrochloric droplets escape into the indoor environment and migrate into the human micro-environment,which will endanger the health of workers.hydrochloric droplets and the HCl gas produced by their volatilization can cause inflammation of the respiratory system and tooth erosion.Due to the evaporation of water vapor and HCl volatilization,the movement characteristics of hydrochloric droplets in the human microenvironment are constantly changing,which in turn affects the human exposure characteristics of HCl gas and hydrochloric droplets.Therefore,the study of the migration characteristics of hydrochloric droplets accompanying evaporation and volatilization in the human microenvironment has important guiding significance for the development of targeted personalized protective equipment,ventilation methods,and prediction of the degree of hazards of pollutants.In this paper,the numerical simulation method is used to study the migration and distribution characteristics of hydrochloric droplets and their volatile HCl gas in human microenvironment under different influencing factors.The research first determined the numerical simulation method of hydrochloric droplets accompanied by evaporation and volatilization,and selected the DPM model of Euler-Lagrange method to track the trajectory of hydrochloric droplets.Since the hydrochloric droplets contain HCl solutes,the multicomponent droplet model(Multicomponent)was selected for the DPM model droplet type,which can simultaneously consider the evaporation of water in the hydrochloric droplets and the volatilization of the HCl component.In addition,in order to verify the reliability of the numerical model and calculation method,the numerical simulation results are compared with the experimental results in the literature,and the results are found to be in good agreement.Subsequently,the numerical simulation analysis of the human body’s heat dissipation,breathing mode,environmental parameters(particle size,relative humidity)on the indoor uniform flow(air flow rate 0.25 m / s)of hydrochloric droplets and their volatile HCl gas in the human body The influence of environmental migration laws and individual exposure characteristics.Firstly,the influence of human plume and breathing mode on the migration characteristics of hydrochloric droplets with an initial particle size of 50 μm was clarified.The study found that the interaction between the uniform incoming flow and the thermal plume of the human body increased the exposure of hydrochloric droplets deposited on the surface of the human body.The hot plume reduces the exposure of HCl gas in the human respiratory zone.When the breathing method is different,the inhalation exposure of HCl gas in human body is also different,for example: relative humidity is 30%,the concentration of HCl gas in mouth breathing is 18.8% higher than that in nose breathing,so try to avoid breathing with mouth.Secondly,the effects of droplet size and environmental relative humidity on the migration characteristics of hydrochloric droplets and their volatile HCl gas in the human microenvironment were studied.It was found that with the increase of particle size,the exposure of hydrochloric acid droplet deposition on the surface of the human body increased,but the inhalation of hydrochloric droplets and the exposure of HCl gas increased first and then decreased.With the increase of relative humidity in the environment,the deposition exposure of hydrochloric droplets on the surface of the human body increases,and the exposure of human body inhaled HCl gas decreases.Finally,the numerical simulation was carried out to analyze the effect of different initial particle size,indoor lateral airflow velocity and the distance between the human body and the droplet distribution groove surface on the surface of the hydrochloric droplets and HCl gas in the human microenvironment at a relative humidity of 50%.The influence of migration laws and individual exposure characteristics.Studies have shown that:(1)When the initial particle size of hydrochloric droplets is 50 μm,the human body has the largest exposure to inhalation and deposition of hydrochloric droplets.When the particle size is different,the concentration of HCl gas inhaled by the human body is basically the same with time under different working conditions;(2)The effect of indoor horizontal airflow velocity on human exposure is significant.The greater the lateral airflow velocity in the room,the greater the exposure of human body to inhaled HCl gas and the surface deposited hydrochloric droplets,increasing the risk of human exposure;(3)As the distance between the human body and the groove surface(0.5～1.5m)increases,the human body inhales And the exposure of the deposited hydrochloric droplets is reduced.However,the inhalation exposure of HCl gas showed a trend of decreasing first and then increasing as the distance increased.This is because when the distance between the human body and the groove surface is increased from1.0m to 1.5m,the effect of the vortex zone between the human body and the groove surface is enhanced,which causes HCl to diffuse into the human microenvironment,which causes the human body to inhale HCl exposure.Therefore,the vortex area between the human body and the groove surface should be eliminated as much as possible,so as to reduce the human body’s exposure to HCl gas.