A flow control device for incompressible fluids

• A mechanical constant flow controller for incompressible fluids called MCOP was designed to simulate the function of critical cavitating flow.
• Lower velocity and pressure loss than critical cavitating flow were achieved.
• The MCOP is insensitive to upstream and downstream pressure changes.
• Both CFD and experiments were conducted, and their results agreed well with each other.

This paper introduces a constant flow method for incompressible fluids using a mechanical choked orifice plate (MCOP), even when changes in differential pressure occur between the upstream and downstream. The MCOP is constructed by inserting a float-spring blockage into an ordinary orifice plate to imitate the function of a critical cavitating flow in a cavitating Venturi. A model MCOP is established and verified by numerical simulation, and a prototype MCOP is designed and tested by experiments. The results show that the numerical simulation is a good guide for the MCOP design. The designed MCOP can keep a constant flow with an error in the flow control of ±4% within the range of the differential pressure between the upstream and downstream of 6–70 kPa. Because the constant flow is obtained without fluid vapourization, the pressure loss is greatly reduced and the noise and erosion are avoided. Additionally, due to the action of the float-spring blockage being based on the differential pressure between upstream and downstream, it is simultaneously insensitive to both upstream and downstream pressure fluctuations. The design idea and the conclusions can be used as a reference in the design of a constant flow control device for incompressible fluids.