Measurement of velocity distribution in the Brabender Farinograph as a model mixer, using Laser-Doppler Anemometry

The nonintrusive technique of Laser-Doppler Anemometry was used to characte rize flow velocity distribution in the Brabender Farinograph, which is ofte n used to mix theologically diverse food materials. A two-dimensional Argon -ion laser Doppler system was used to obtain local velocity data at selecte d locations in this complex mixer. Three components of velocity were obtain ed as a function of time and spatial location for model fluids with charact eristic rheological properties. The results revealed that the velocity dist ribution in the Farinograph changes with the time-relative motion of the bi ases and with fluid rheology. Velocity values at locations close to the bla des were much higher for the non-Newtonian fluids than for the Newtonian fl uid studied. The prevalence of static zones at regions away from the blades was noticeable, particularly in the non-Newtonian fluids. These findings i ndicate that Laser Doppler Anemometry is a valuable tool in the design and analysis of complex mixing processes.