Research On Technology Of Rounded Door Type Air Curtain Dust Control And Dust Removal System In Fully Mechanized Excavation Face

With the wide application of fully mechanized mining equipment in the mine,the tunneling efficiency has been improved.At the same time,the dust content of fully mechanized mining flour seriously exceeds the standard.The high concentration of dust poses a serious threat to the health and safety of underground workers.Therefore,the dust control of a fully mechanized mining face has become one of the critical technologies to ensure the safe production of the coal mine.Based on the engineering background of a fully mechanized mining face in the Yuhua mine,the airflow and dust transport law under the mode of pressure pumping mixed ventilation and dust removal was studied by using the methods of theoretical analysis,numerical simulation and experimental test.In order to further improve the effect of dust control,a "rounded door" air curtain dust control combined with pressure extraction ventilation and dust removal system was proposed.The influence of various working conditions on the dust control and dust removal effect of the system was studied,and the optimal configuration parameters of the system were obtained.The effectiveness of the rounded door type air curtain dust control and dust removal system was verified by the experimental platform.The specific research contents are as follows:(1)Through the undercover investigation,the dust generation mechanism and dust source of the fully mechanized mining face were analyzed,and the particle size and dispersion of the dust were measured,which provide modelling parameters for the later research.(2)The physical model of a fully mechanized excavation face was established by using SolidWorks.Then,Fluent is used to simulate the airflow and dust migration and distribution,and the dust diffusion process under the dynamic change of dust source was analyzed.The validity of the model was verified by comparing the dust concentration with the measured point.(3)Under the mixed ventilation mode of pressure and extraction,the influence of the change of parameters such as the position of the air outlet and the pressure-to-extraction ratio on the airflow field and dust field in the fully mechanized mining face was studied.The reasonable configuration parameters under this model were obtained.However,the dust concentration in the test area still far exceeds the coal mine safety standard.(4)Based on the analysis of the structure and dust control effect of the right-angle door and rounded door air curtain,a dust control system of rounded door air curtain combined with pressure-extraction mixed ventilation was put forward.The simulation results of the airflow field and dust field of the fully mechanized mining face under this system show that the rounded door type air curtain device forms a unique spatial complex curved air wall,which can effectively control the dust generated by the working face in the front area of the air curtain,and be pumped and filtered by the dust removal fan under the negative pressure of the exhaust duct,so as to achieve the purpose of dust control and dust reduction.The dust concentration in the test area decreased significantly.(5)In order to further improve the effect of dust control and dust removal,the influence of the position of the air outlet(pressure and extraction),the pressure air volume,the pressure-extraction ratio,and the air curtain parameters(initial jet velocity,outlet width,jet angle)on the system airflow field and dust field were studied,and the optimal configuration parameters of the system are obtained.The research shows that the dust concentration in the test area is significantly reduced in the rounded door type air curtain dust control and dust removal system after parameter optimization compared with the pressure-extraction hybrid type.Finally,the experimental platform verified the effectiveness of the dust control system with a rounded corner door air curtain.