Abstract: In order to improve the dust reduction efficiency of wet dust collector in coal mine and improve the working environment of operators,a dust reduction method of installing internal mixing air atomization nozzle in wet dust collector is put forward. Firstly,based on the laser Doppler spray atomization characteristic test platform,the atomization angle and droplet average diameter D[3,2] of three air cap air atomization nozzles are compared,and the nozzle with the best atomization effect is selected. Secondly,based on the wet dust collector and air-water spray dust reduction test platform,the distance between nozzle and fan,nozzle air supply pressure,nozzle water supply pressure and fan air supply pressure are selected for single factor test, and a single optimal level is obtained. Finally,based on the orthogonal test theory,four factors and three levels of orthogonal tests are designed to carry out dust reduction experiments under different working conditions. The results show that under the same working conditions,the nozzle with 2. 0 mm aperture has the largest atomization angle and the smallest droplet size,and D [3,2] ranges from 33. 20 μm to 50. 51 μm,which is more favorable for collecting and settling fine dust. The order of significance level of dust reduction efficiency of 4 factors for total dust and exhaled dust is:distance between nozzle and fan > nozzle water supply pressure > fan air supply pressure > nozzle air supply pressure. The optimum parameters combination of dust suppression system is as follows:the distance between nozzle and fan is 2. 25 m,the air supply pressure of nozzle is 0. 4 MPa,the water supply pressure of nozzle is 0. 4 MPa,and the air supply pressure of fan is 0. 2 MPa. The dust suppression efficiency of total dust and exhaled dust can reach 90. 06% and 75. 91% respectively. This study results can provide theoretical reference for the optimization and application of mine wet dust removal system.

Key words: wet dust collector,air-water spray,atomization characteristics,dust reduction efficiency,orthogonal test