Influence of nozzle design on flow, mixing, and fluidisation in a bubbling bed fluidised by a single nozzle

In this paper we apply, for the first time, positron emission particle tracking (PEPT) to a fluidised bed in which gas is injected through a nozzle-type distributor. The detailed, three-dimensional data obtained provide direct insight into how the angle of the orifices through which gas is injected affects the fluidisation, mixing, and flow patterns observed within the bed. Our results show that the fastest and most consistent recirculation of material – an indicator of good mixing – as well as the most complete fluidisation may be achieved by using a nozzle with horizontal- or near-horizontal outlets. •The effect of nozzle design on fluidised bed dynamics was explored.•Detailed three-dimensional data were acquired via positron emission particle tracking.•Angle of nozzle outlets has strong influence on both fluidisation and mixing.•Optimal flow pattern and mixing achieved with downward-facing nozzles.