Rock breaking mechanism of supercritical CO2 straight-swirling mixed jet and influences of nozzle structure
Supercritical CO2 straight-swirling mixed jet combines technical advantages of supercritical CO2 jet and straight-swirling mixed jet,it is a new rock breaking tool for oil and gas resource exploration and development.Based on the fluid-solid-thermal coupled theory,a 3-D computational model of rock breaking with supercritical CO2 straight-swirling mixed jet was established to study rock breaking mechanism of supercritical CO2 straight-swirling mixed jet.The results showed that supercritical CO2 straight-swirling mixed jet has multi-action of forward impact,radial tension,circumferential shear force and thermal stress;presence of thermal stress significantly increases Mises stress on rocks,but the increase extent weakens with duration of impact time;taking erosion and overflow actions as important parameters,effects of different nozzle structural parameters on jet flow field characteristics are analyzed,when opening angle of spiral groove is 45°,central hole diameter is 2 mm,spiral groove number is 4 and impeller spiral angle is 60°,jet flow field characteristics are in optimal state;the study results can provide a reference for optimization application of supercritical CO2 straight-swirling mixed jet.
jet rock breakingsupercritical CO2straight-swirling mixed jetnozzle structure
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