| The natural wind pressure is part of the mine ventilation power.In order to ensure the safe production of the mine and reduce the production cost,the natural wind pressure needs to be in an ideal state.Metal mines are affected by mining processes and often use multiPle-ret urn wellbore arrangements and multi-level mining processes.The ventilation system is complex and varied.Natural wind pressure generated by closed loops at various levels and wellbore can affect the flow of wind in the mine;The natural wind pressure generated by the horizontal closed loop of the local wind area due to the elevation and the temperature difference in the wind path will also affect the stability of the regional ventilation:At the same time,even when the season changes,it may even cause disturbances in the wind.For the above ventilation problems,the main work of this paper is as follows:A ventilation system model with different inlet and outlet modes and multiple levels was established to analyze and deduce the local natural wind pressure characteristics and mechanism of action in mines.And the study of the influence of natural wind pressure on the adjacent wind:The influence of the natural wind pressure between the return air shafts on the adjacent wind roads will decrease with the increase of distance,and it will be similar between multiple levels.This rule is similar to parallel wind roads;The turbulence conditions of the wellbore and the horizontal air path were deduced,and the diseriminants of normal,stagnation and reversal were presented.A number of axes method was used to describe and determine the wind flow conditions between the wellbore and the level under the influence of local natural wind pressure.Combining with the current situation of ventilation in Huibaoling iron ore mine,based on the determination of ventilation resistance in the winter,summer and spring of the mine,this paper calculates and analyzes the change law of the intake and return air volume of mines in each season under the influence of natural wind pressure.With the increase of temperature,the total air intake decreased gradually due to natural wind pressure during the three seasons.The air flow rate of the air intake fell the most,from 214.5 m3/s mn winter to 164.9 m3/s in summer,and the amount of return air decreased.However,the return volume of the main well has increased.However,the return air volume of the main well increased from 29.7 m3/s in winter to 61.7 m3/s in summer,and the air volume increased significantly.Calculate and analyze the natural wind pressure of each line of the mine in spring,winter and summer,and obtain the area where the local ventilation of the mine is hindered by natural wind pressure.Combined with the previous chapter,the analysis of wind flow disturbances shows that natural wind pressure is insufficient for each wellbore And the wind in the level caused a reversal.Using Ventsim software to simulate the mine's natural wind pressure alone to obtain an area within the mine that is blocked by natural wind pressure;Calculate the required amount of wind in the mine and compare it with the mine supply air volume under the sole action of natural wind pressure and the natural wind pressure and the wind turbine.The natural wind pressure in the winter,spring and summer seasons and the air supply of the wind turbines together are It can meet the required air volume of the mine,and the supply air volume under the effect of natural wind pressure cannot meet the required air volume of the mine.According to the sensitivity of the branch air volume to natural wind pressure,the branch areas with high sensitivity are obtained.To avoid the change of wind flow in the surrounding roadway branches due to the large change of air volume during the season replacement,some measures are proposed. |
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