Numerical simulations of magnetorheological fluids flowing between two fixed parallel plates

摘要

In this paper, a study on the motion of a magnetorheological fluid (MRF) under application of a magnetic external field is presented. The magnetic field is perpendicular to two nonconducting flat parallel plates which are stationary. Numerical simulations are provided by an in-house CFD code developed by the authors and adapted to include the magnetohydrodynamics (MHD) field equations. Solutions studied show how these magnetic fields can modify both the velocity profile and the pressure drop along the channel. Numerical solutions are firstly compared with analytical ones in some simple cases in order to verify the computational code. Relative errors remained around 10(-4). A second test was set up where a magnetic field is applied only in a portion of the channel in order to control the flowrate. The results showed that with strong magnetic fields, the flowrate could be reduced up to 90% from a normal state, i.e. B = 0 T. The maximum velocity at the centreline shows a peak at the outlet of the region where the magnetic field is applied due to the acceleration of the fluid when the magnetic forces disappear. When employing the code in a geometry similar to that presented in a previous paper in which the authors used a commercial code, some discrepancies were found, especially at the edges of the zone where the magnetic field was applied. Some speculations about this disagreement are put forward. (C) 2019 Elsevier Inc. All rights reserved.