Solids Transport Correlations in a Horizontal Rotary Drum with Segmented Lifters
This paper reports a study of axial solid transport in a horizontal rotary drum with segmented lifters in terms of solid inventory, mean residence time and average axial velocity of the solid. Dimension analysis of the system was firstly performed to identify a set of key dimensionless numbers relevant to the problem domain. These important dimensionless parameters are derived in order to discuss the importance of the basic processes that govern the axial solid transport.A series of experiments were then carried out to produce a sufficient databank for the development of empirical correlations amongst the dimensionless numbers. Such experiments were conducted using a pilot-scale rotary drum, considering granular solids of a range of properties under various drum operation conditions. Global power-law correlations, as functions of static angle of repose, solid diameter to kiln diameter ratio, rotational Reynolds number and rotational Froude number, were found to be adequate in representing the experimental data obtained from the pilot-scale rotary drum with segmented lifters. Detailed parameters of these correlations were derived from our experimental data using 16 materials through 339 measurement points under various operation conditions, with fairly good statistical qualities. The correlations developed were also tested against published data available in the literature. The applicability of the correlations appears to strongly depend on the configuration of drum lifters, indicating that these correlations are largely specific to the current lifter designs and configurations and lifters play an important role in solid transport.