Abstract:

The technique of CFD dynamic analysis was used in the simulation of the critical flow velocity at the nozzle of the fluidic in SC71B liquid-jet hammer prototype, the result shows that the critical flow velocity ranges from 20.305 m/s to 22.565 m/s, which is obviously lower than the value of 40 m/s by empirical prediction value. In order to verify the theoretical value by CFD dynamic analysis, a laboratory test was carried out on the machine of SC71B liquid-jet hammer, the laboratory value is 21.83 m/s, which  highly coincides with the theoretical value. CFD dynamic analysis is proved as a validated prediction method, meay while the lowest critical flow velocity is obtained, this value can provide very important reference to develop liquid-jet hammers controlled by fluidic elements with low critical flow velocities for oil and gas drilling.

Key words: liquid-jet hammer, fluidic element, critical flow velocity, CFD dynamic analysis