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Numerical Study on the Flow Characteristics of a Throttle with a Movable Seat in Water Hydraulics

Hydraulic control valve, which plays an important role in hydraulic system, exerts great effects on the control precision of hydraulically actuated equipment. A novel throttle valve with a two-stage movable seat is presented, a computational fluid dynamics (CFD) model is developed with tap water as working medium, and numerical studies have been carried out to investigated its flow characteristics including flow-pressure drop characteristics, flow impacted force acting on the movable seat, anti-cavitation performance etc.. The results show that: (1) the two-stage throttle can reduce the pressure drop of each throttle, thus improving the anti-cavitation performance; (2) under the same total pressure drops, the vapor volume fraction decreases with the increased of valve opening. (3) the maximum velocity occurs at the area behind each throttles and decreases with the increased of valve openings; (4) the umbrella shaped rod can reduce the flow impact force acting on the movable seat effectively; (5) the flow rate increased with the increased of valve opening and pressure drop; (6) cone angle ratio r exerts great effects on the force acting on the seat and cavitation performance and both of the two phenomenon shows best when r = 1 : 2.5. The research provides a basis for the analysis and design of water hydraulic pressure control valve with a movable seat.