Optimized Valve Design to Reduce Cavitation
The main aim of this project is to develop an improved understanding of the cavitation process which may occur within the inlet valve, valve seat and pump chamber of an SPM positive displacement pump through simulation of the pumping cycle using computational fluid dynamics (CFD). Cavitation bubble collapse may result in localized pitting which causes erosion, stress concentration and corrosion damage reducing the pump life. A better understanding of cavitation means improving pump design and life.
CFD Model Achievements
Case 1: Inlet pressure 2 bar, incipient cavitation conditions. Depending on the operative conditions, valve mass, spring preload and stiffness, the minimum pressure barely touches the vapour pressure value for the room temperature (3000 Pa), non-condensable gases expand while the pressure decreases and a negligible quantity of vapour is produced (the sequence on the left). The valve lift history closely follows the plunger displacement history with a small delay due to its inertia and to the spring preload, the mass flow history closely follows the theory
Case 2: Inlet pressure 1 bar, developed cavitation conditions. Decreasing the inlet manifold pressure at 1 bar (room condition) the chamber pressure reaches the vapour pressure value and remains enough to create a high quantity of vapour (up to 100 % in volume fraction, sequence on the left) non-condensable gases expand but insufficiently to stop the vapour production. The valve lift history does not follow the plunger displacement anymore and experiences a remarkable delay due to the time needed to destroy the vapour at the end of the stroke (graphs below).
- Investigating separately each parameter affecting valve dynamics and, therefore, cavitation.
- Design and optimize new valves
For more information about the project contact Dr Matt Stickland (email@example.com), Senior Lecturer at Department of Mechanical and Aerospace Engineering, University of Strathclyde.
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