Model test in KHRC cavitation tunnel T-32 in a pump loop set-up to determine pump characteristics. Head rise, flow rate and power are measured, pump efficiency and cavitation performance are obtained. Observation of cavitation pattern is enabled, and the risk of cavitation erosion can be assessed.
A model scale pump with an inlet diameter of 200 mm is installed in the cavitation tunnels’ measuring section. Pump inlet is usually bell mouth shaped, and pump exit connected to a pipe system that enable flow rate to be varied and accurately measured.
A torque meter inside the pump hub eliminate uncertainties from losses in bearings and seals. Head rise is measured as static pressure difference corrected by taking cross sectional data and boundary layer profiles into account.
Cavitating conditions are reached by lowering static pressure in the cavitation tunnel. Cavitation observations are enabled by making pump housing of Perspex material. Normal video or high-speed video can be used for documentation. A special soft paint method is used to assess risk of cavitation erosion. Laser doppler equipment, or more conventional methods, can be used for velocity scanning. Pressure transducers, hydrophones and accelerometers are possible to use for noise and vibration measurements.