Fan Performance Lab Report

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4.2 FAN PERFORMANCE Figure 2 Performance curve of change of pressure against flow rate

The grey curve corresponding to high fan speed (100%) lies above the orange curve corresponding to medium fan speed (50%). The orange curve lies above the blue curve corresponding to low fan speed (30%). This is due to the increase of fan speed, the amount of medium flows through the fan in a direction parallel to the pump shaft increases; impeller pushes the liquid and adds momentum to the fluid flow through the unit by transfer of energy between the fluid and the rotating propeller blades. It results in a pressure, flow rate increase.

The best fit curves for three fan speed present quadratic relationships; it is due to the loss of energy during the transportation of the fluid in the duct tube. “Viscosity and turbulence are present and act to convert kinetic flow energy into heat.” (Frank 2003)The losses increase quadratic ally with increasing flow.

4.2 NON-DIMENSIONAL CURVE Figure 3 Non-dimensional curve of head coefficient against flow coefficient

The performance of ∆P against Q is converted into a non-dimensional head coefficient vs flow coefficient by the use of Dimensional analysis.

“Dimensional analysis is a method for reducing the number and complexity of experimental variables that effect a given physical phenomenon.” (Frank, 2009) “Provided that the mechanical efficiency is the same, the performance of a
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