| To increase the control range of traditional ventilation and dust removal methods,strengthen the dust collection effect,improve the applicability of the site and other issues,the proposed use of rolling suction dust control technology for its management,using a combination of theoretical analysis,numerical simulation,laboratory tests,field testing methods,to carry out research on the cyclonic flow characteristics and dust control mechanism of rolling suction dust control technology,which is of great significance to increase the dust control range of ventilation and dust removal technology,improve the dust removal efficiency of ventilation and dust removal technology.It is important to increase the dust control range and improve the efficiency of ventilation and dust removal technology.The application of this technology to the main dust generating points in coal mines is investigated.Through the analysis of the basic theory of cyclonic flow,the necessary conditions and the formation mechanism of cyclonic flow are grasped.According to the three conservation laws,the fluid micro-element force equilibrium equation is established,the tangential velocity,radial velocity,axial velocity and pressure distribution of the cyclonic flow are obtained,and the mechanism of the cyclonic flow roll suction and dust control is revealed,and the technology is applied to the main dust generating point pairs in coal mines to study its applicability,and the technical solution of roll suction and dust control at the transfer point is designed according to the jet shielding method,and the technical solution of roll suction and dust control at the digging face is designed by using the attraction of high speed airflow to low speed airflow.The technical solution for dust control at the working face was designed using the attraction of high speed airflow to low speed airflow.In the study of the applicability of rolled suction dust control technology at the transfer point,numerical simulations were carried out to obtain the characteristics of the cyclonic flow at the transfer point and the dust distribution in the cyclonic field,and to obtain the optimum dust control parameters for both the down-pipe and wall-in technology solutions.By studying the cyclonic flow characteristics at the transfer point and the dust distribution characteristics in the cyclonic flow at different parameter settings,it was determined that both solutions would form a vertical cyclonic flow in the drop pipe,and the best dust control parameters for both solutions were obtained.The dust concentration at the left and right ends of the guide chute and the inlet and the dispersion of the coal after the transfer was obtained utilizing a simulation test of the wall-in-reel dust control at the transfer point,with a jet angle of 10° and an extraction speed of4m/s(-10Pa).A comparison of the dust concentrations shows that the optimum inlet air speed of8m/s under these conditions reduces the proportion of particles smaller than 50μm by 47.96%and particles smaller than 5μm by 44.62%,resulting in a dust removal efficiency of 97.71% and99.92% at the left and right ends of the guide chute respectively.In the study of the applicability of the dust control technology of the rolled suction at the digging face,numerical simulations were carried out to determine the rationality of the structural design of the split air fork pipe and to obtain the optimum dust control parameters for the dust control technology of the rolled suction at the digging face.Through the study of the characteristics of the cyclonic flow and the dust distribution in the cyclonic field under different structures and parameter settings,it is concluded that the cyclonic flow has the best effect on dust control in the excavation face when the number of side pressure ducts is 6,the jet angle is30°,the jet wind speed is 25m/s and the extraction duct is located above the road header.The dust concentration and dust removal efficiency under the three working conditions of single dust extraction,natural deposition,and reel suction dust control with optimum parameter settings are calculated through simulation tests.A comparison of the dust removal efficiencies shows that the dust removal efficiencies are in the order of reel suction control > single extraction > natural deposition,which verifies the reliability and applicability of the reel suction control technology.On the basis of numerical simulations and experimental test results,the pressure air pipe was connected to the air amplifier via a hose and the air amplifier was used instead of the side pressure blower to carry out a field trial test of the blown suction reel dust control technology at the digging face,comparing the dust concentration at the driver’s position of the digger and 2m behind the digger before and after the application of the dust control technology.The dust concentration at the opening of the downwind side guide chute was measured at the transfer point using the downpipe coiling dust control solution.The field test results show that the dust removal efficiency of this technology is close to 90% for both total dust and respiratory dust,and up to 95% for total dust at the transfer point,which proves that the blowing and sucking type reel suction dust control technology has good dust control effect and application value.The dissertation has 111 figures,12 tables,and 201 references... |
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