ANALYSIS OF FULLY DEVELOPED LAMINAR CHANNEL FLOW OF SUSPENSIONS WITH EXTERNAL ELECTRIC FIELD

Deposition of suspensions of solid particles in channel and pipe flows causes serious technical problems due to blockage and contamination of flow passa-ges. Such problems, for instance, occur in the fluidic devices (Laminar Proportional Amplifiers) used for flow control. In this work, the analysis of fully developed laminar channel flow of suspensions with external elect-ric field is presented. The external electric field is obtained by a number of equally spaced parallel cylinders having the same potential and placed at the channel centre line. A mathematical model for the flow of suspensions using the equations of dif-fusion, Poisson, external electric field and rate of deposition along with the proper boundary conditions is given. Numerical solution is obtained by using the finite difference technique. The effects of the external electric field intensity and the number of char-ged cylinders on the rate of deposition of the solid particles are studied.
The analytical results show that an externally applied electric field obta-ined by an array of equally spaced parallel cylinders having the same voltage and placed at the channel centre can appreciably reduce the rate of particle deposition from laminar channel flow of suspensions if the potential of the charged cylinders has an opposite sign with respect to the polarity of the charge on the particles. In addition, increasing the number of cylinders for the same applied voltage results in more reduction in rate of deposition.