Experimental investigation of magneto-rheological droplet impact on a smooth surface

Abstract We present an experimental investigation of the impact of magneto-rheological droplets on a smooth surface. The experimental setup consists of a syringe pump with capillary tube of 1.6 mm diameter located perpendicularly above a dry smooth quartz surface assembled above an electromagnetic module, which enables magnetic flux density control up to 7.8 G. Free surface flow patterns generated during the impact of droplets of 2.2 mm diameter, Reynolds number in the range 15–125 were recorded using a digital high-speed camera. The materials used in this study were commercial ferro-fluids, (hydrocarbon-based fluid containing micron-sized magnetizable particles). These fluids were characterized using a rotational rheometer modified by an electromagnetic module. The results show an up to 40% reduction in maximum spread diameters as well as reductions in spread velocities for droplets subjected to a magnetic field.