Session: 01-04-01 Fluid Machinery Symposium

Paper Number: 87987

87987 - The Impact of Scaling on the Gap Flow Rate of Radial Fans 

Due to the gap between the impeller and the casing of a radial fan a gap flow rate occurs, leading to a higher flow rate through the impeller than through the fan. The gap flow rate has an impact on the performance of the radial fan and must be considered in the design process. There is only little known from the literature about the gap flow rate. Furthermore, as to the knowledge of the authors, no information on the effect of scaling on the gap flow rate is known from the literature.

In this work a systematic study of the effect of scaling on the gap flow rate has been performed. For this first a baseline radial fan has been designed. This model and its full characteristics have been computed with the commercial Navier-Stokes solver Ansys CFX. Then the impeller width, the outer diameter, the inner diameter, the gap width, and the rotational speed were varied. These designs have been simulated with the commercial Navier-Stokes solver Ansys CFX. The effect of these parameters on the performance characteristics of total-to-total and total-to-static pressure and efficiency and its impact on the gap flow rate were evaluated.

Based on these results, a similarity model for the gap flow rate have been developed and evaluated with the full characteristics of all simulated models.  It has been shown that the gap flow rate can be estimated based on the experimental performance characteristics, the main dimensions of the impeller and the gap and the similarity model. These results are presented and discussed in detail.

Presenting Author: Philipp Epple Coburg University of Applied Sciences