The Comprehensive Evaluation Of Working State And Research Of Multiparameter Non-impact Theory On Drilling Pump Valve

In order to study the failure mechanism of a drilling pump valve and extend its service life, a research has been done on both the impact fatigue wear caused by the valve closure and the erosion wear in flow field of the valve play. (1)A simplified mathematical model describing the closing stage of valve disk is put forward, so the motion characteristic of valve disk is analyzed truly. A FEA dynamic model of impact process is presented based on the working condition of drilling pump valve, and the impact characteristic of the valve is analyzed. A modified structure is presented which can effectively alleviate the stress concentration and extend the service life.The mechanical characteristic and effect degree of the maximum stress concentration spot when the impact of pump valve happens are mainly studied, hence a non-impact working condition of drilling pump valve based on the effects of stress concentration is put forward. (2)The distributed rule of the flow velocity of the slurry at a certain moment is shown with the CFD simulation; with the designed experimental model, PIV technology is employed to measure the flow field distribution of the valve play in the model, and maps of velocity and vorticity of different valve angles and different disc height is obtained, from which the distribution features of flow fields can be concluded, and a general rule of the flow velocity variation with valve angles and disc height is summarized through chart analysis of maximum velocities and mean velocities. Plenty of experiments are conducted respectively with hollow glass beads and fluorescent particles, and especially influence of the optical reflection at the boundary of the channel is weakened significantly by using fluorescent particles, which enriches and completes this PIV experiment. Furthermore, combining tribological theories, an analysis is made on the failure mechanism that erosion and abrasion in the working valve play may induce the valve failure. With all theses studies, completing of valve design and extending of service life can finally be theoretically supported.