"Detailed Experimental Investigation of the Flow Field During Design and Off-Design Operation of a Squirrel Cage Fan

S. CABITZA;F. NURZIA;C. PALOMBA;PUDDU, PIERPAOLO

2004-01-01

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Abstract

The present paper is concerned with the investigation of the three dimensional flow field in a double-inlet squirrel-cage industrial fan commonly used for handling air. Despite their lower peak efficiencies with respect to other fans, they are widely used due to compactness and low cost representing the largest fan group of all. An open loop facility has been designed and constructed at the Department of Mechanical Engineering at Cagliari University to house, drive and test the fan. This work aims at the determination of the three-dimensional flow-field upstream and downstream of the rotor when the fan is operating in three different conditions: design point, and two off-design conditions one in the low flow regimes where the performance curve presents a dip and the other one in the high flow regimes. The measurements are performed with the aid of a single slanted hot wire and the multirotation techniques for the downstream flow field, while upstream of the rotor the flow field will be measured with a custom designed 5 hole pressure probe. The detailed cinematic description of the flow field will allow a better understanding of the fan behaviour in off-design conditions.