Study On Modulation Of Negative Pressure Pulse In Swing Valve Type

With increasing depth of drilling speed will continue to slow, a substantial increase in the cost of drilling. Negative pulse drilling technology can be more effective to reduce the bottom hole pressure to weaken or even to overcome rock debris hold down effect, to avoid duplication of broken rock, increase drilling speed.In this paper, in accordance with actual drilling conditions, designed two models swing valve type negative pressure pulse modulators, No.Ⅰswing valve type negative pressure pulse modulator and No. Ⅱ swing valve type negative pressure pulse modulator. Study numerical simulation of two models swing valve type negative pressure pulse modulators via FLUENT CFD software. Study numerical simulation on No.Ⅰswing valve type negative pressure pulse modulator to obtain: when the same area of the inlet and outlet area this modulator does not work; When the inlet cross-sectional area relative export area decreases, the pressure difference between the first increase after a large decrease, the frequency increases; when the pump displacement is increased, the pressure difference increases, the frequency also increases; when the inlet cross section of 25cm2, when the pump displacement is 510L/min, the pressure difference is 1.543 MPa, a frequency is 16.8Hz. Study numerical simulation on No. Ⅱswing valve type negative pressure pulse modulator to obtain: When the pump displacement increases, the pressure difference is increased, the frequency also increases; when the pump displacement is 510L/min When the pressure difference is 1.288 MPa, a frequency is 26.7Hz.Based on the results of numerical simulations, made two models swing valve type negative pressure pulse modulators prototypes, which No.Ⅰ swing valve type negative pressure pulse modulator prototype’s entrance area is 25cm2, Test and evaluate two models swing valve type negative pressure pulse modulators by B&K sound pressure measurement system. By No. Ⅰ swing valve type negative pressure pulse modulator experimental results: When the pump displacement is increased, the pressure difference increases, the frequency also increases; 510L/min when the pump displacement is, the pressure difference2.10 MPa, frequency of 17.5Hz. By No. Ⅱ swing valve type negative pressure pulse modulator experimental results: When the pump displacement increases, the pressure difference and the frequency is increased; When the pump when the pressure differential displacement 510L/min is 1.50 MPa, the frequency of 32.5Hz. Through to the modulator fixed pin, intensity modulator fixed pin is calculated in accorda nce with design requirements。...