Pumped Flow with Pump Curve
The purpose of this model is to demonstrate the calculation of flow rate through a pump given a pump operating curve and required head upstream of the pump. The challenge in this type of problem is that the flow through the pump is dependent on the head on the pump, which is not fully known until the flow is determined. This type of problem must be solved through iteration. In this model,
a GoldSim script element is used to do a binary search to converge on the solution of pumped flow. Another way this could be done is using
a looping container but the script element provides a way to view the solver algorithm all in one place and is easier to document.
Description
Often times, it is necessary to use a pump curve to calculate the flow through a pump or pump station. A pump curve is a graphical relationship between flow rate and the total dynamic head on the pump. Below is a typical representation of a pump curve.
The pump curve is developed by the pump manufacturer and usually the pump is delivered to the owner with pump verification specs showing how it performed during tests as compared to the pump curve. If the impeller size is increased, the pump will push more flow at the same head imposed on it. As seen on the curve, if the head is increased, the flow rate must be reduced.
In the GoldSim model, the pump curve is defined using a lookup table element called, "pump_curve". The head is calculated in the model by adding the water level of the reservoir it is pumping to plus the headloss in the pipe that carry the water from the pump to the reservoir. Using the lookup table, GoldSim will calculate the flow rate through the pump based on this calculated head on the pump.
Article on pump curves:
http://www.engineeringtoolbox.com/pump-system-curves-d_635.html
Download the model file
Screen Captures of the Model:
Main model page:
Script element binary search algorithm:
Chart plot of the reservoir storage verses pumped flow:
See Also
