Characteristics and mechanism of multistage fluctuation of coal-breaking caused by high-pressure gas-liquid two-phase jet
LIN Baiquan
WANG Rui
QIAO Shihe
Abstract：In order to improve the coal rock-breaking capacity of water jet and pressure-relief and permeability effect,by establishing the impact dynamic pressure model of high pressure gas-liquid two-phase jet,the key parameters were obtained which affected the capacity of coal rock-breaking.Experimental tests about the characteristics of impacting coal rocks were conducted by self-designing rock breaking test system of high pressure gas-liquid two-phase jet.The results showed that the rock breaking threshold pressure was reduced by 50％,the breaking depth increased 25％,the diameter was 2 times and the efficiency increased about 80％ by comparing with pure water jet.The coupling between the gas-liquid-solid three phases resulted in breaking coal:the structure of jet was changed and formed local impulse by mixing gas,which strengthened coal rock-breaking ability;cracks were motivated under high pressure liquid pulsation,which promoted by multilevel collapsing of tiny gas phase.By the multilevel alternation of liquid pulsation and gas phase,the coal rock was broken finally when the original cracks were connected.
Keywords：water jetgas-liquid two-phasecoal rock-breakingmultilevel collapsepulsating impact
Publication Date：2018-01-01