Performance analysis of table and pedestal fans

Abstract

Performances of pedestal and table fans were analysed through experimental measurements of the induced flow field (velocity distribution) and the power consumption by three different fan types (makes). A test rig was constructed to facilitate the measurement of axial flow velocities in the three dimensional space. In order to predict the jet pattern produced by the fan, axial velocity distributions on sufficient number of planes were measured. These data were used to calculate the jet diameter, flow rate, kinetic energy and the linear momentum of the flow. The power consumption and the angular speed of the rotor for each regulator setting were also taken. The velocity distributions measured on different planes from the rotor clearly illustrate the general characteristics of the flow generated by free flow fans, including the reverse flow near the rotor plane, jet entrainment and diffusion. As an example, in one situation the maximum flow rate becomes four times the flow rate at the rotor plane, which distance of seven rotor diameters from the fan.