Print Email Facebook Twitter Capillary rheometer for magnetic fluids Title Capillary rheometer for magnetic fluids Author Allebrandi, Sander (Student TU Delft) Lampaert, S.G.E. (TU Delft Mechatronic Systems Design) van Ostayen, R.A.J. (TU Delft Mechatronic Systems Design) Date 2020 Abstract Magnetic fluids have been around since the 1940s. They come in different forms: magnetorheological fluids (MR fluids) and ferrofluids. MR fluids characterise themselves by having a large change in viscosity under the influence of a magnetic field. Ferrofluids have a significantly smaller change in viscosity, however ferrofluids are colloidal suspensions. After their discovery many applications followed, such as the MR clutch, magnetic damper and bearing applications, in which the fluids are subjected to ultra high shear rates. Little information is available on what happens to the rheological properties under these conditions. In general, the characteristics determined at lower shear rates are extrapolated and used to design new devices. Magnetic fluids have potential in the high tech and high precision applications and their properties need to be known in particular at shear rates around 10 6 s -1. Commercially available magnetorheometers are not able to measure these fluids at ultra high shear rates and are limited to 10 5 s -1. Therefore a new magnetorheometer is required to measure ultra high shear rates. In this paper the physical limitations of current measuring principles are analysed and a concept is designed for ultra high shear rate rheometry in combination with a magnetic field. A prototype is fabricated and the techniques used are described. The prototype is tested and compared to a state of the art commercial rheometer. The test results of the prototype rheometer for magnetic fluids show its capability to measure fluids to a range of 10 4 s -1 s -1 and the capability to measure the magnetorheological effect of magnetic fluids. Subject RheometerMagnetic fluidsFerrofluidsMagnetorheological fluidsHigh shear To reference this document use: http://resolver.tudelft.nl/uuid:b4fec7af-1166-42d5-9b3e-acd1d2a4ef34 DOI https://doi.org/10.1088/1361-6439/ab3f4c ISSN 0960-1317 Source Journal of Micromechanics and Microengineering, 30 (1) Part of collection Institutional Repository Document type journal article Rights © 2020 Sander Allebrandi, S.G.E. Lampaert, R.A.J. van Ostayen Files PDF Allebrandi_2020_J._Microm ... 015002.pdf 4.4 MB Close viewer /islandora/object/uuid:b4fec7af-1166-42d5-9b3e-acd1d2a4ef34/datastream/OBJ/view