Numerical simulation research on hydro-pulsed jet swirl fluid flow field

In order to investigate the varying characteristics of swirl flow field within hydro-pulsed jet flow field, the numerical simulation research was conducted on the pulsed jet swirl flow field by building a physical model of single-nozzle pulsed jet impact flow field under bottom hole boundary condition. The result shows that the unstable swirl flow is a significant feature of pulsed jet flow field and plays an important part in accelerating pulsed jet drilling. The swirl flow rate and range change periodically and do not change with the pulse frequency. Within single cycle, the swirl flow is consistent with the change of pulsed jet rate, and range of influence of swirl flow changes from rapid expansion to later slow expansion, maintaining an expansion trend all the time. The swirl flow effect is superior to the jet energy, which is the main reason for local pulse negative pressure generated by pulsed jet. This helps reduce the chip hold-down effect. The swirl flow field changes the pressure distribution on bit surface and helps clean the bit. The research findings are of some reference value to guidance of pulsed jet accelerating technique.