Opis: In the paper a new rheological model for an electrostatic ash and water mixture is proposed. The fundamental equation of the rheological model was used to determine the relationship between the shear stress and the shear rate as well as the equation of a velocity profile for the flow through a straight pipe. Experimental results obtained from a capillary viscometer were used as the basis to determine the parameters for the proposed model by the non-linear regression analysis. With the Quadratic law a numerical analysis of a mixture flow through a capillary pipe with the finite volume method was performed. The derived equations for the velocity profile, shear stress and shear rate were validated through a comparison of numerically obtained and theoretical results. Finally, the compariosn between the Quadratic and the Power law is presented. Ključne besede:fluid mechanics, non-Newtonian fluids, mixture of electrofilter ash and water, flow in pipes, capillary pipes, rheological model, velocity profile, shear stress, finite volume method, numerical analysis, quadratic law, power law, mehanika fluidov Objavljeno: 01.06.2012; Ogledov: 1721; Prenosov: 28 Povezava na celotno besedilo

Opis: A boundary element method based solver for particle motion simulation in dilute suspensions under the influence of hydrodynamic and magnetic forces was applied. The Euler-Lagrangian formulation for simulation of dilute two-phase flow was applied. The algorithm solves the incompressible Navier-Stokes equations written in velocity-vorticity formulation. The non uniform magnetic field was defined analytically for the case of a set of long thin wires. The particle trajectories were computed by applying the 4th order Runge-Kutta method. The computed test case consisted of a narrow channel under the influence of a nonuniform magnetic field, where magnetite and aluminium particles were suspended in water. The results of computations show the distributions of particles along the channel and confirms the suitability of the proposed configuration as a separation device under ideal conditions. Ključne besede:boundary element method, laminar flow, magnetic particles, viscous fluids Objavljeno: 01.06.2012; Ogledov: 1981; Prenosov: 34 Povezava na celotno besedilo