HANDLING AND SPREADING OF FERTILIZERS .5. THE SPINNING DISC TYPE FERTILIZER SPREADER

The motion of particles is discussed as affected by physical propertie s, such as coefficient of friction, and the design of the disc includi ng the vane type, pitch angle of the vane and surface of the vane. The influence of factors that may have an effect are studied theoreticall y by means of simulations as well as experimentally. When the simulati on and measurement results were compared, large differences were found between them. The simulation results showed a clear effect of the coe fficient of friction. This effect was, however, hardly visible in the measurements despite differences in vane surfaces that gave large diff erences in coefficient of friction (0.25 to 0.35 for a nylon surface v ersus 0.40 to 0.45 for a stainless steel surface). The measurements sh owed that an increase of the mass flow by a factor of two in the range tested (between 0.3 and 1.0 kg/s) resulted in an increase in the dist ance projected by the particles of about 1 m. The influence of vane ty pe and pitch angle have been analysed in simulation studies and the ef fect proved to be dependent on the coefficient of friction. (C) 1995 S ilsoe Research Institute