13 / 2023-05-12 10:31:17

Deformation and failure analysis of reverse dampers of different materials under coal and gas two-phase flow

Coal and gas outburst; Reverse damper; Deformation and failure analysis; Finite element analysis

In order to ensure the safe functioning of the mining face and prevent the occurrence of extensive injuries after the outburst accident, the reverse dampers on the intake side of the protruding coal seam must be able to function normally under the impact airflow during coal and gas outburst. Since the reverse dampers' structural robustness and material characteristics are major determinants of their risk resistance. The steel reverse damper and the wooden reverse damper are used as the main materials of the reverse damper structure, and the five main feature points of the reverse damper are selected as the main monitoring objects, the evolution characteristics of deformation and failure analysis of reverse dampers are carried out using a self-developed coal and gas outburst roadway simulation test system in order to thoroughly investigate the destructive effect of the impulsive airflow on the different materials' reverse damper when coal and gas outbursts occur. Furthermore，WORKBENCH software is conducted to observe the characteristics of deformation and failure of reverse dampers under the effect of coal and gas two-phase flow through changing the material of the reverse damper structure. When the initial gas pressure is constant, the simulation is carried out by WORKBENCH software, and the experimental results are discussed in depth. The results show that when coal and gas outburst occurred, a large amount of pulverized coal pours into the roadway driven by the gas flow, according to the overpressure curve of the shock wave in front of the reverse damper, it can be seen that the time for the first overpressure peak of the 1 MPa outburst pressure is only 4 s, indicating that the shock wave propagation speed is extremely fast. Under the same initial pressure, the deformation at the bottom of the reverse damper is the largest, indicating that the bottom of the damper is most vulnerable to damage. According to the simulation results, it can be seen intuitively that when the four sides of the reverse damper are fixed, the maximum stress generated by the reverse damper is mainly concentrated in the middle of the four sides of the damper and the central area of the damper after the reverse damper is impacted by the two-phase flow of coal and gas. The area with the largest deformation of the reverse damper is distributed in the center of the reverse damper. The farther away from the center of the damper, the smaller the deformation. It indicates that both the steel structure reverse damper and the wooden structure reverse damper show the same deformation and failure characteristics after being impacted by the two-phase flow of coal and gas outburst. However, When the material of the reverse damper is changed from steel to wood, the micro-strain value of the reverse damper at the same monitoring point during the outburst test is increased by several times without changing the initial pressure. At the same time, the displacement cloud diagram generated by the numerical simulation results can also visually observe that the deformation degree of the wooden structure reverse damper is greater than that of the steel structure reverse damper, indicating that the disaster resistance of the wooden structure reverse damper is weaker than that of the steel structure reverse damper. The damage effect of the shock wave generated by the two-phase flow of coal and gas on the reverse shock absorber is analyzed by experiment and simulation. The damage-prone feature points of the reverse damper structure are determined, and the factors affecting the strength of the reverse damper structure are explored, so as to provide some technical reference for the strength design of the reverse damper structure and improve the anti-disaster ability of the reverse damper.