# Factors affecting Friction Loss

Settling slurries comprise a Newtonian "carrier fluid" conveying solid particles. The carrier fluid is sometimes called the 'vehicle'. Friction loss is a complex function of: ▪Carrier fluid characteristics ▪Flowrate ▪Solids characteristics ▪Pipe inclination Carrier fluid characteristics The carrier fluid is often water but may be another pure Newtonian liquid. However, if there is a fraction of fines in the solids, say of size less than 0.4mm, then these fines may form a homogeneous non-settling mixture with the carrier fluid. The carrier fluid friction loss then becomes proportional to that of the pure fluid. Flowrate At known flow input boundaries flowrate may be defined as: ▪Desired solids (mass) flowrate ▪Carrier fluid flowrate ▪Mixture (total) flowrate Solids characteristics The solids characteristics comprise: ▪Density ▪Bulk density ▪Specific heat ▪Thermal conductivity ▪Shape factor ▪Sliding bed coefficient ▪Particle size distribution ▪Solids concentration The first 6 solid properties above are stored in a Solids database, and the last 3 are entered via the input editor at appropriate boundary elements. Pipe inclination Pipes with an inclination of less than 30 deg are assumed horizontal; pipes with an inclination greater than 30 deg are assumed vertical.