中文摘要：

基于脉冲式井下增压钻井装置的结构和工作原理，建立了其活塞增压模型，进而对其增压特性进行数值模拟研究。研究结果表明，流体增压是活塞运动和高压喷嘴节流共同作用的结果。当其他条件相同时，高压喷嘴出口流速随转速、活塞行程的增大而增大，并且增大幅度较高，增压压力受这3个因素的影响规律相似；高压喷嘴出口流速和增压压力都随高压喷嘴直径的增大而明显降低；随着钻井液密度增大，高压喷嘴出口流速和增压压力稍微增大。高压脉冲射流的脉冲频率只与转速有关，且随转速增大而增大，其他因素对其没有影响。该研究结果为后续的样机设计和现场试验参数的确定提供了依据。

英文摘要：

On the basis of the structure and working princlple drilling device, the piston supercharging model is established, based on which the piston supercharging character- istic is simulated. The results show that pressurized fluid is the result of piston movement and the high-pressure noz- zle choke. Given the same conditions, the high-pressure nozzle exit velocity increases significantly with the incre- ment of revolving speed and the piston stroke. The high-pressure nozzle exit velocity, revolve speed and the piston stroke have similar effects on the supercharging pressure. The high-pressure nozzle exit velocity and the superchar- ging pressure reduce significantly with the increment of the high-pressure nozzle diameter. The increase of the fluid density would result in slightly increased high-pressure nozzle exit velocity and supercharging pressure. The pulse frequency of the high-pressure pulse jet is only influenced by the revolving speed, and the pulse frequency would increase with the increment of the revolving speed. Other factors have no effect on the pulse frequency. The study re- sults could provide references for the follow-up prototype design and field test parameters determination.