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This basic version of the experiment involves a
centrifugal pump and a gear pump.
Each pump is driven by a DC motor at a
selectable speed, while the motor torque is measured. The flow of water is
controlled by a manually adjustable metering valve, and a pressure sensor
measures the pump discharge pressure. Water leaving the pump passes in series through an orifice meter,
a turbine meter, and a rotameter, and then returns to the 20 liter polycarbonate feed
tanks. The flow rate is measured by
timing the collection of a fixed volume of water.
For each pump, the students measure the pump torque, discharge pressure, and flow
rate as functions of RPM. Power consumption and efficiency can then be plotted under
various conditions. Subsequent precise comparisons can be made between
the series connected flow meters by calibrating them against volumetrically determined
flow rates.
Additional meters such as Venturi, vortex, magnetic, or ultrasound may be selected as options
to the basic experiment. Alternative pumps, for example a piston pump, a flexible impeller pump,
or a multistage centrifugal pump can also be selected as options.
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