Experimental Study On Ultrasonic Comprehensive Dust Reduction In Underground Pipe Network Type Space

The mine dust has always affected the safety production of the mine,and its harm is mainly coal dust explosion and workers suffering from pneumoconiosis.In order to effectively reduce the inhalable dust particles in the mine,this paper attempts to intro-duce the ultrasonic dust reduction technology into the mine pipe network space envi-ronment.A comprehensive experiment was carried out to reduce the concentration of inhalable dust particles by ultrasonic agglomeration and ultrasonic atomization,and the influencing factors of the efficiency of ultrasonic agglomeration and ultrasonic com-bined dust reduction were systematically analyzed.The main achievements are as fol-lows:(1)The basic characteristics of underground dust and ultrasonic are described,and the mechanism of pipe network space ultrasonic agglomeration and combined dust re-duction is revealed.Ultrasonic agglomeration dust reduction is mainly caused by the same direction agglomeration and hydrodynamics.Compared with agglomeration dust reduction,ultrasonic combined dust reduction increases the relative motion,attraction and collision probability between particles.It is clear that the factors affecting the effi-ciency of ultrasonic dust reduction are frequency,sound intensity,working time and initial dust concentration.(2)Combined with the underground dust environment and experimental require-ments,the ultrasonic dust reduction experimental system is designed and built.The composition and parameters of the experimental system are introduced.A total of 48groups of experimental schemes of ultrasonic agglomeration and ultrasonic combined dust reduction are designed by using the method of control variables.It is proposed to reflect the effect of ultrasonic dust reduction experiment by analyzing the change rate of dust particle size volume fraction and dust reduction efficiency.Talc powder is se-lected as the experimental material to simulate underground dust,and the error analysis of experimental data is carried out by using Grubbs criterion.(3)The experiment of dust reduction by ultrasonic agglomeration was carried out around four factors:frequency,sound intensity,working time and initial dust concen-tration.The experimental results show that the effect of ultrasonic agglomeration dust reduction is better on the smaller inhalable dust particles,and the dust reduction effi-ciency is the best when the ultrasonic frequency is 20 kHz.With the increase of sound intensity,working time and initial dust concentration,the dust reduction efficiency of ultrasonic wave increases.When the sound intensity is 158.1 dB,working time t=4 s and the initial concentration of inhalable dust is 100 mg/m~3,the dust reduction effi-ciency reaches the maximum,which is 28.1%,26.1%and 26.9%respectively.(4)The influence of various factors on the dust reduction efficiency in the ultra-sonic"agglomeration atomization"combined dust reduction experiment was studied.The effect of various factors on the combined dust reduction efficiency is reduced,and the better dust reduction efficiency can be obtained with lower energy consumption.When the sound intensity of ultrasonic is 158.1 dB,the dust reduction efficiency is46.2%,34.2%higher than that of ultrasonic atomization,and 39.2%higher than that of ultrasonic agglomeration.(5)The linear correlation coefficient R~2=0.969 of the factors influencing the dust reduction efficiency and the combined ultrasonic dust reduction efficiency is obtained by fitting the experimental data by the multiple linear regression analysis method.The results show that the correlation degree of the efficiency of ultrasonic agglomeration and the combined dust reduction efficiency of ultrasonic is the same as that of the in-fluencing factors,which is frequency>working time>sound intensity.There are 62 papers,22 tables and 123 references.