Dimensional Analysis and Scaling Rules

Abstract

One might ask, here at the outset, “Why bother with’ scaling rules’ when one can simulate practically any size and type cyclone of interest with a good model?” While the latter is generally true, scaling—when based on the performance of a sufficiently large, geometrically similar laboratory model—can predict the performance of an industrial cyclone installation considerably more accurately than the models. It is also the writers’ experience that scaling rules are important for two additional reasons:

• Certain simplified scaling rules and dimensionless quantities allow the designer or practitioner to make quick, ‘back-of-the-envelope’ type calculations and decisions pertaining to cyclone design and performance.

• The scaling formulae allow one to better’ see’ the effects of changes in one variable upon another—both qualitatively and quantitatively.