Experimental Study Of Phase-transforming Fracturing Of Liquid Carbon Dioxide

Explosive blasting is widely used in engineering field,and the blasting process can produce high temperature flame and release a lot of heat.This process produces harmful gas and will cause environmental pollution due to chemical reaction.In addition,the balsting excavation of the coal mine with mashgas caused a large number of deaths and injuries.Liquid CO₂ phase-transforming fracturing technology not only can avoid accident but also have a lot of advantages as low cost,easy to operate,recycle utilization and no pollution.As a new non-explosive technology,Liquid CO₂ phase-transforming fracturing can alsobe used in boiler cleaning and mine mining.It is of great significance to study the mechanism of phase-transforming fracturing and the optimal design of equipment.In order to improve the power of liquid CO₂ phase-transforming fracturing technology,we carried out several sets of different thickness of the rupture discs,charge quantity and activator to test the pressure changes of tube.At the same time,we concluded the theory of rupture discs thickness and TNT equivalent by security safety performance analysis.In the case of rock breaking,the radius of the rupture zone is calculated,and the numerical results are agreed with the test by LS-DYNA.To find out the influence of CO₂ loading density to peak pressure,based on the high-pressure virial equation of state,the relationship between the pressure,temperature and charge density is analyzed and predicted in the confined space,and the results can be used for the designing and optimizing of the cracked pipe and rupture discs directly.This research will play an important role in equipment safety analysis and equipment improvement.