Experimental studies and modeling of temporal evolution of chain formation in magnetorheological fluids

Chain formation in a magnetorheological (MR) fluid consisting of iron particles was investigated experimentally and by simulations. The iron particles had an approximate radius of 50 µm. Four volume fractions of 0.06%, 0.12%, 0.27%, and 0.41% in a carrier fluid of corn syrup and four applied magnetic fields of 1.2 kA/m, 2.4 kA/m, 6.4 kA/m, and 10.3 kA/m were studied. The geometry of the chains was found to be approximately independent of magnetic field strength and to increase with the volume fraction of particles. The chain lengths were shown to grow as an exponential function of time. A simple model explains the exponential growth of the chain lengths as a function of time. The experimental and simulation results were in agreement.