PREDICTION OF AIR-CORE DIAMETERS FOR HYDROCYCLONES

The flow split between the products of a hydrocyclone is one of the le ast understood aspects of hydrocyclone operation. This split is greatl y influenced by the air core diameter, so an understanding of the air core behaviour would greatly assist in predicting flow splits. A progr am of combined theoretical and experimental investigation of the facto rs that control the air core in a hydrocyclone is being undertaken. Ri etema type simplifications of the Navier Stokes equations have been ex tended to include the prediction of air core diameter. The equations w hich are indirect in their original form have been converted to give a direct solution for the dimensionless pressure and air core diameter ratio. An experimental program using simplified test units has been un dertaken. This has obtained pressure drop, air core diameter and veloc ity profile data over a considerable range of operating conditions. Th is data is being used to identify and correct deficiencies in the theo retical analysis, and to investigate the range of validity of the resu lting relations. The aim is to produce simple relations that can be us ed to improve the accuracy of typical simulations of hydrocyclone perf ormance, and also to provide some guidance in the design of hydrocyclo nes.