| For large and extra large mines,in order to solve the problem of ventilation in the remote mining area,the most direct and effective way is to add a pair of inlet and return air wells,so that the large road connected between the two inlet air wells becomes the inlet angle coupling Branch.The wind volume and wind direction of these angle-connected branches are affected by the changes in the resistance of their adjacent branches,as well as the changes in the wind pressure and natural wind pressure of the mine ventilator.When the structure of the wind network changes,there is often no wind,less wind or even wind.The corner joint roadway between the two inlet air shafts includes the belt main roadway and the auxiliary transport roadway,which undertakes the important task of coal transportation in the whole mine.It is extremely important to ensure the stability of its air volume,so the research on the subject has important practical significance.In this paper,the method of network solution and numerical simulation is used to find out the factors that affect the air volume of the angle connected roadway between the two air intake shafts.By optimizing the mine roadway system,the method to ensure the air volume of the angle connected roadway between the air intake shafts is found.The reliability of the calculation results of the air network is mainly determined by the accuracy of the measurement of each initial condition parameter.As an extremely important initial condition parameter,the natural air pressure of the mine has many problems in practice,such as the measurement process is complicated,the measurement data is not accurate enough,and the external environment has a great impact on the change within one year.At the same time,compared with the air resistance of the underground roadway branches,the branches of the shaft are affected by the There is a lifting device with constantly moving and changing position inside,and its wind resistance is not fixed value,so it is difficult to measure by conventional methods.Therefore,in order to more accurately predict the air volume of the angle air inlet roadway,the paper gives the guarantee method of the air volume of the angle air inlet roadway.Taking Gaohe energy mining area as the engineering background,the paper mainly studies the following contents based on the field measurement data of the mine and fluent numerical simulation.Research on the law of natural wind pressure change:by combining the field measurement data to establish a numerical model of the inlet and return air well and verifying and verifying,the temperature distribution of surrounding rock and the temperature density of the air flow in the well bore under different environmental conditions in summer and winter Conduct numerical simulation studies.When the ambient temperature in winter is 7?,due to the air volume of Xiaozhuang Inlet Shaft is about 2.52 times that of the central auxiliary well,there is a temperature difference of about 3?between the inner walls of the surrounding rocks at the bottom of the two wells.The increments are 8.8?and6.1?respectively;the shallower the depth,the smaller the temperature difference between the inner walls of the two wellbores;when the summer ambient temperature is 29.6?,the temperature of the inner wall of the bottom of the Xiaozhuang intake shaft is higher than that of the central auxiliary well by about 2.66?;Throughout the year,it is less affected by changes in external environmental factors,and the temperature change law of the surrounding rock of the wellbore is only related to the wind volume and the geothermal gradient of the wellbore.At the same time,by studying the law of airflow temperature and density change along the depth of the wellbore at different radius from the center of the wellbore,it is concluded that the temperature and density distribution of the airflow inside the wellbore are not uniformly changed,and the changes in the airflow temperature and density on the axis of the wellbore are surrounded Rock temperature has the weakest influence.Through the comparative study of the numerical simulation method and the wellhead bottom hole average value method to solve the average density of the air flow in the wellbore,it is clear that only the average value of the wellhead bottom hole air density is used to calculate the difference between the gravity of the air column and the natural air pressure in the wellbore.The simulation experiment shows that the actual average density of the air flow in the wellbore in summer or winter is greater than the calculated average value.On this basis,using the average density of all fluid grids,it is calculated that the change range of natural air pressure in the central air shaft area and Xiaozhuang air shaft area is about-80?425pa.When the ambient temperature is 25?,the natural air pressure in the two areas reverses;at the same time,the average change range of natural air pressure between the two air intake shafts is-11.040?10.165pa.Study on the local resistance of shaft hoisting equipment:through the establishment of numerical model of cage,hanging plate and shaft,the parameters of velocity,pressure and turbulence intensity of air flow around the cage and hanging plate are analyzed,and it is concluded that the change of the wind resistance value fluctuates with the difference of the distance between the two cages except that the local wind resistance value generated in the intersection state is relatively large The value is stable near 3.25×10-4N·S2/m8,which is about 1/2 of the maximum local wind resistance when the cage meets;the wind resistance value is the minimum when the hanging plate is located in the center of the shaft,which is 21.854×10-4N·S2/m8.The closer it is to the entrance and exit of the shaft,the greater the local wind resistance value.Study on the calculation of the wind network and the guarantee measures for the air volume of the corner joint roadway:The experimental natural wind pressure value and the shaft branch wind resistance value are substituted into the wind network calculation,and the changes of the main fan operating point before and after the opening of the Jiucun air shaft,The air volume changes of the main corner joint air lanes in each area of the mine are predicted.In view of the problem of local breezes in multiple sections of the main airway between the Xiaozhuang Inlet Vertical Shaft and the Jiucun Inlet Vertical Shaft after the new Jiucun Air Shaft was opened,the installation angle of the main fan blades of the Xiaozhuang Air Shaft was increased from 42.2°to 45°.Put forward the air flow guarantee schemes for the"corner air intake shaft at the same time supply air to Nanjiao and Nanfu main lane","control scheme for connecting lane between Nanjiao and Nanjin main auxiliary lane".According to the air volume guarantee plan,corresponding wind regulation and wind control measures were taken to ensure that the air volume of each section of Nanfu and Nanjiao Daxiang was about 1000 m3/min.After guiding the actual engineering application,through the comparison of the actual measured air volume,it was confirmed that the air volume guarantee measures can solve the on-site problems well,and the gap between the simulated prediction data and the actual measured data is small.Using numerical simulation to solve two important wind network calculation parameters can effectively guarantee the accuracy of the wind network calculation. |
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