Simulation of flux decline due to particulate fouling in ultrafiltration

The flux decline in thin-channel and tubular ultrafiltration (UF) modules due to fouling by dilute suspensions is presented for a wide range of operating conditions. The dynamics of fouling is simplified by viewing the particle deposition on the membrane surface at discrete time as a steady state event and formulating the problem as an infinite series of successive events, Only inertial effects are considered and it is assumed that for a dilute system, particle-particle interactions and forces of interaction between particles and membrane walls are insignificant. Further, at such low concentration, the motion of fluid and particle may be taken independent of each other. The equations of motion for the particles are solved by Fourthorder Runge-Kutta method, where the fluid flow is obtained from the finite difference solution of Navier-Stokes equation. The present theoretical calculations of flux decline due to particulate fouling at typical UF operating conditions indicate that the inertial effects are important and under positive wall permeation flux conditions, particles are encouraged to migrate to the membrane walls.