煤矿喷雾降尘雾滴存活时间的数值模拟

为提高煤矿喷雾除尘效率,揭示雾滴蒸发和存活时间的影响因素,基于差分方法,使用MATLAB软件编制雾滴蒸发过程仿真试验程序,研究了雾滴初始半径、雾滴与风流的初始相对速度、雾滴初始温度,以及巷道风流初始温度、湿度、风压共6个关键影响因素与存活时间的关系;采用逐步回归方法构造了包含5因素的雾滴存活时间计算方程。结果表明:在目前煤矿采用的雾化降尘工艺范围内,除雾滴初始温度外的其他5个因素对雾滴存活时间的影响均较为显著;构建的雾滴存活时间综合计算方程能合理计算雾滴的存活时间。

Numerical simulation for the surviving time length of the spray dust-settling droplets in the coal mine

To improve the efficiency of the spray for the dust suppression and clarify the influential factors of the evaporation and the survival time lengths of the droplets in the coal mine,the paper has done a series of numerical simulation experiments.The program of the said experiment series has been compiled by using a software of MATLAB based on the differential method,which is in a position of simulating and analyzing the heat and mass transfer performances in the processes of droplet evaporation.And,in so doing,it would be possible to construct an integrated calculation equation of droplets' survival time in SPSS based on the indexation data transformation by means of the stepwise regression.What is more,an analysis has been done for the relationship between the survival time length and the 6 key influential factors (i.e.the initial radii,the relative velocity,the temperature of the droplets,the initial air pressure,the relative humidity and the temperature of the air flow).Thus,an integrated equation for calculating the droplet survival time has been set up including the said five key factors.The results of our simulated study show that the suitable initial radii are 15-20 μm,whereas the suitable initial relative velocities should be between 80-100 m/s,with the average survival time length of the droplets being 22 s.It can be seen that,except for the initial temperature of droplets,the other 5 key influential factors may all have significant effects on the survival time lengths.According to the results of study,if the initial radii,the air pressure and relative humidity increase,the survival time of the droplets will be prolonging,too.On the contrary,if the temperature of airflow and initial relative velocity of droplets increase,the survival time of the droplets shall be reduced.It can also be inferred that the survival time of the droplets tend to increase or decline exponentially with the above mentioned 5 significant indicators.What is more,as the integrated calculation equation comprises the aforementioned five factors,it should also contain the initial spray velocity of the droplets,too.In addition,we have also worked out that the average relative error between the simulation results and the results of comprehensive calculation formula has been found at about 3.6％,with the survival time length of the droplets being made out via the integrated computation equation,too.