Improvement of sonic vibration simulation device for gas desorption and seepage under cavitation water jets.

In order to improve the desorption of coal methane by the sonic vibration of cavitation water jets, aiming at overcoming the weakness of originally developed simulation test platform, an experimental cavitation chamber and its coal shaping device have been improved and redesigned. Using the technologies of omnidirectional sealing,such as ring direction and surface sealing,etc.,a good sealing result of triaxial pressure chamber and cavitation chamber for a long time under confining pressure and 5 MPa gas pressure is obtained. Using Venturi nozzle and high-pressure jet device in the cavitation chamber, the cavitation bubble cloud formed in the cavitation chamber enhances the desorption of coal methane. With the installation of pressure sensor at water inlet and outlet, the cavitation effect is monitored in real time. Depending on the temperature and methane pressure sensor, extensometer and the supporting test control software, the permeability characteristics of methane desorption of coal sample under gas pressure and the evolution laws of stress-strain process of coal sample during sonic vibration process can be simulated. The temperature in the cavitation chamber and the variation of gas seepage during sonic vibration process can be monitored in real time. In addition, three-phase separator is designed in the recycle system, and the test maneuverability is improved. The feasibility of separating gas-liquid-solid matters via this separator is realistically proved. The simulation experiments using the improved experimental device show that the sonic vibration of cavitation water jets improves the desorption of coal methane, gas desorption quantity and desorption speed. The variation of temperature in the cavitation chamber and the deformation laws of coal sample verify the thermal effects of sonic vibration, the effects of mechanical vibration and crack damage. [ABSTRACT FROM AUTHOR]