Study On The Regularity Of Dust Precipitation And Dissipation And Numerical Simulation Of Transpersite In The Coal Conveyer Belt System

This paper concerns a part of"Basic Research on the Law of Dust's Precipitation and Movement and Control Technique in the Coal Conveyer Belt System"funded by national natural science fund (No. 50674052), and is the main research contents of dust comprehensive administering project for Shenhuazhunneng Corporation Coal-dressing Plant.The coal conveyer belt system is the main section of dust generation. Because of having certain drop height, a mass of fugitive dust is created in the transpersite, resulting in tremendous increase of dust density, which composes of main polluting source of the workshop. At present, dust control technology of transpersite is mainly applied to dust removal and dust outlet and so on in domestic and overseas, but there is a lack of the optimum design of overall technology scheme of dust control and prevention and the choice of key shaping equipment, and even more lack of the study on mechanism of dust generation and law of dust dissipation. Therefore it is very difficult to achieve ideal effect of dust government.At present, the study on transpersite of coal conveyer belt system is comparatively weak, and transpersite is regarded as the research object in this paper. By the method of experiment testing, theoretical analysis and numerical simulation, this paper studies coal dust precipitation, subsiding and distribution law of coal dust in the transpersite on different conditions.Applying traction air flow of belt, inducing air flow and shear air flow theories, the mechanism of dust generation is systematically analyzed. We drew the conclusion that dust of transpersite is generated by dusting function of inducing air flow, dusting function of shear air flow and comprehensive dusting function. Based on analyzing the characteristics of dust particle movement, this paper puts forward the dust-cleaning scheme with airtight dust-prevention system and airtight negative pressure dust-control system to control dust of the transpersite,and carries out type selection of dust-cleaning equipments. By the filed test for the airtight dust-prevention system, distribution of dust concentration and granularity is obtained, and distribution characteristics and concentration scope of dust in the transpersite. By calculating the proportion to dust particle volume, we can conclude that the flow field of transpersite is the sparsity gas/solid two-phase turbulence flow field in the coal conveyer belt system.This paper analyzes dust particle's stress in the airtight dust-prevention system with gas-solid two-phase turbulent flow theory, and the rules of the motion and deposition of dust particle and their motion orbits are obtained. Also this paper does research on the dust diffusion law in the flow medium under external force for airtight negative pressure dust-control system.Based on the flow field's characteristic features in airtight dust-prevention system and airtight negative pressure dust-control system, gas-solid two-phase turbulent flow model and convection diffusion model are established, and numerical simulation is carried out by COMSOL Multiphysics, by means of the comparative analysis of two systems'simulation, which results in the flow characteristic features and dust concentration distribution characteristics of every places that are reflected intuitively. Based on the above-mentioned theory research, this paper completes the optimal design of dust-cleaning measures with airtight negative pressure dust-control system in Zhungeer Heidaigou Open-pit Coal Mine coal washery workshop.