Experimental study on sonic vibrating effects of cavitation water jets and its promotion effects on coalbed methane desorption

Abstract

To enhance the desorption of coalbed methane and increase the efficiency of gas extraction, a technique method based on the sonic vibrating effects of cavitation water jets to promote methane desorption is proposed. With proper devices, we conduct an experiment of using sonic vibrating effects of cavitation water jets to accelerate methane desorption. This is based on experiment tests on the mechanical vibration and thermal effects caused by the sonic vibrating effects. During the collapse phase of cavitation bubbles, the strong sonic vibrating effects may cause intense mechanical vibration and thermal effects. The vibration acceleration root-mean-square value presents an approximate positive linear correlation with the total volume of methane desorption. The mechanical vibration effect plays a dominant role in promoting the methane desorption, while the facilitation of thermal effect is relatively weaker. There is an obvious accelerating impact of sonic vibrating effects on coalbed methane desorption and the ultimate methane desorption volume increases by from 13.4 to 42.1% respectively, while desorption time shortens by between 12.5 and 21.5%. The study results bear an important significance on revealing the mechanism of promoting the methane desorption by sonic vibrating effects and field application of the technique method to CBM development.