4. A pump is required to pump fresh water at a flow rate of 5000 m³/hour against a head of 8 m at a speed of 1500 rev/min. It is planned to test a scale model with a head of 2 m at a flow rate of 100 m³/hour under dynamically similar conditions (but neglecting changes in Reynolds Number). Determine: a) The speed at which the model must be run. b) The scale that must be used for the model. c) The mechanical power required to drive the model pump is found to be 680W at the operating point. Calculate the power required to drive the full scale pump. d) After the full scale pump is fitted into the system it is found that the pump head rise really needs to be increased by 30%. At what speed should the full scale pump now be run at to achieve this head rise and what will be the new ideal flow rate and power consumption in order to match this operating condition? e) Briefly comment on the main advantages and limitations of testing a scale model to prove the performance of a larger prototype.
4. A pump is required to pump fresh water at a flow rate of 5000 m³/hour against a head of 8 m
at a speed of 1500 rev/min. It is planned to test a scale model with a head of 2 m at a flow
rate of 100 m³/hour under dynamically similar conditions (but neglecting changes in Reynolds
Number).
Determine:
a) The speed at which the model must be run.
b) The scale that must be used for the model.
c) The
operating point. Calculate the power required to drive the full scale pump.
d) After the full scale pump is fitted into the system it is found that the pump head rise
really needs to be increased by 30%. At what speed should the full scale pump now be
run at to achieve this head rise and what will be the new ideal flow rate and power
consumption in order to match this operating condition?
e) Briefly comment on the main advantages and limitations of testing a scale model to
prove the performance of a larger prototype.
Step by step
Solved in 3 steps with 4 images
