The characteristic of a water pump has been determined by experiment (Pump_Char.xls). The result is shown in the graph of pressure difference versus flow.Here, the pressure difference across the pump is given by the height to which water could delivered (pressure head in meters).
a. Create a model of a pump which sets up a constant pressure difference. Now imagine that—in addition to the ideal pump—there is a flow element in the pump which reduces the pressure difference measured from the inlet to the outlet of the pump. Would laminar or turbulent flow be better to explain the shape of the characteristic curve? b. Determine a characteristic function by interpolating the data in the graph. Calculate the parameter(s) of your model for the flow element in the pump, and for the zero-flow pressure difference. c. Use the correlation for turbulent flow for smooth pipes to determine a concrete flow characteristic for a pipe (Efunda.com). Take a smooth pipe having a length of 30 m and a radius of 2 cm. d. Imagine that the pump in this example is used to pump water through the pipe whose characterisitc you just calculated. The pipe is lying on the ground (horizontally). What will be the flow through this pipe? e. Assume that the pump is used to pump water 15 m high through a pipe having a length of 30 m. What should be the minimum radius of the pipe? Assume the pipe to be smooth. Use the correlation for turbulent flow for smooth pipes. | |
Click to obtain graph as pdf.
|
