Analysis on Fluid-Solid-Thermal Coupling Field in Rock Breaking Under Composite Impact Loads Based on Simulation Model
In order to reveal the rock-breaking mechanism of full-size PDC bit under composite impact loads,from the perspective of temperature,a simulation model of fluid-solid-thermal coupling in rock breaking of PDC bit under composite impact loads was built using iterative algorithm,and verified by taking the temperature of cutter of PDC bit as the evaluation indicator.Moreover,the rock-breaking performances of full-size PDC bit under composite impact loads were analyzed from 4 aspects(dynamic rock-breaking process,mechanical change behavior,temper-ature evolution law,and flow field distribution).The analysis results show that the error of the simulation model is below 10%,meeting the required accuracy in engineering analysis.The rock-breaking process of PDC bit is divid-ed into 3 stages:rock breaking of single cutter,rock breaking on plane and rock breaking in depth.After having increased the composite impact loads,the maximum torque of PDC bit is increased by 66.3%,and the average torque is increased by 27.5% .The high-temperature area of PDC bit is distributed on the surface of the cutter at the bottom of the bit,with a maximum temperature coming to 166.9℃.The drilling fluid creates a high-pressure area on the cutter on the outer side of blade of the PDC bit,with a maximum pressure coming to 107.9 kPa.The drill-ing fluid has the highest flow rate at the nozzle exit,reaching 6.1 m/s.The research results provide theoretical guidance and technical support for revealing the mechanism of composite percussive rock breaking and developing efficient PDC bits.
万方数据
维普
