分流孔直径对射流式液动锤性能的影响

摘要

For the purpose of optimizing the flow-dividing structure, the effect of diameter of flow-dividing holes on the performance of liquid-jet hammer and the average flow velocity at the cross-section of the nozzle of the fluidic element is investigated by means of CFD ( computational fluid dynamics) dynamic analysis, and the simulation results are verified by experiments. It is shown that under conditions of different diameters of flowdividing holes the maximum relative error between the calculated blow energy and the tested is not greater than 10％, and the maximum relative error between the calculated blow frequency and the tested is less than 11.5％. The results show that blow energy decreases approximately in the form of parabola and blow frequency and the average flow velocity at the cross-section of the nozzle of the fluidic element decrease approximately linearly as the diameter of flow-dividing holes increases. This investigation solves the problem that there is no method for calculating at the designing stage the performance parameters of liquid-jet hammer and the average flow velocity at the cross-section of the nozzle of the fluidic element when flow-dividing mechanism is involved, which can provide a reference for optimizing the internal flow-dividing mechanism in liquid-jet hammers designed for oil and gas drilling.%为了对射流式液动锤内分流结构进行优化设计,应用CFD(computational fluid dynamics)动态分析技术,研究了分流孔直径对射流式液动锤冲击性能参数和射流元件喷嘴处过流断面平均流速的影响,并进行了实验验证.结果表明:不同分流孔直径条件下,冲击功理论计算值与实测值最大相对误差不大于10%,冲击频率理论计算值与实测值最大相对误差小于11.5%;冲击功随着分流孔直径的增大近似以抛物线形式下降;冲击频率和射流元件喷嘴处过流断面平均流速随着分流孔直径的增大近似呈线性下降趋势.该研究解决了此前在设计阶段无法计算分流条件下液动锤性能参数和射流元件喷嘴处平均流速大小的问题,可为油气钻井用射流式液动锤内分流结构的优化设计提供参考.