Study On The Method Of Calculating Flow Field Node Pressure In Goaf Based On Network Solution

Goaf is one of the main sites for disasters in coal mines and has always been the focus of relevant scholars.The leakage of goafs is closely related to the occurrence of goaf disasters.Therefore,the leakage of goafs has always been the focus of research.The study on the law of air leakage in goafs is mainly referred to as the "flow field".Through the numerical solution to find out the law of air leakage,the measures to prevent the occurrence of goaf disasters are proposed.Based on the investigation of the current research methods of goaf flow field,the paper finds that the simulation of goaf flow field is mostly based on the commercial version of CFD software.When CFD is used to simulate the goaf flow field,it is necessary to know the boundary conditions of flow field.For goaf air leakage boundary conditions,some of these conditions can get the solution through the network,but some conditions cannot obtain accurately,using CFD software simulation of goaf flow field and some difficulties.In this paper,the wind tunnel,goaf flow field and surface crack leakage airway are regarded as a physical model,and a network model of the flow field in the goaf under external leakage is established.The network solution method is used to solve it and establish the collaborative solution model.At the same time,after the study of the method for solving the network of goaf flow field,the network solution method of node pressure method is used to solve the goaf flow field based on the characteristics of nodes and network branches after the network partitioning of gob area.After the deeply analysis of the nodal pressure method solution,LDLT decomposition method is proposed based on the characteristics of the Jacobian matrix in the process of its superior symmetry in order to avoid the tedious calculation of the inconsistencies,improve the solution performance of network solution.Object ARX technology is used to complete the development of the corresponding software and simulation of the adjacent gob area filter flow field in the 15207 working face of the Hongliulin coal mine in order to verify the correctness of the model and method.The best surface leakage from the 15207 goaf of the Hongliulin coal mine was simulated and the effect of the maximum surface air leakage at the surface of the gob area on the ventilation system of the working face was reproduced.Through the simulation of the flow field at different surface air leakage and the air volume at the working face and return airway,the distribution status of the spontaneous combustion zone in the goaf is obtained when there is a surface air leakage,and a reasonable amount of surface air leakage is finally determined to ensure the effectiveness of conventional fire fighting measures in the working face.