PERFORMANCE OF AN IMPROVED PAN STIRRER AT ISIS SUGAR MILL

A SET OF impeller blades of new design was retrofitted to the stirrer in the Isis No. 4 pan for the 2004 season. The design of the new impeller blade was based on the results obtained from experimental trials and from computational fluid dynamics (CFD) modelling undertaken by SRI over the past few years. During the 2004 season, the performance of the new impeller blades was evaluated for different grades of massecuite in terms of: heat transfer coefficients for the pan; circulation measurements at various locations within the pan; and power consumption of the stirrer at various speeds. The evaluation data collected during the 2004 season are compared with data obtained during the 2001 and 2002 seasons on the same pan when fitted with the original stirrer design. Comparisons of performance for both types of stirrer designs are detailed. CFD studies were also conducted to assess the performance of the new impeller blades under various operating conditions. These results are also discussed.