Magnetic resonance imaging for investigating diesel particulate filters

In recent years magnetic resonance imaging (MRI) has been shown to be an attractive method for fluid flow visualisation in chemical engineering research. Here MRI has been used to non-invasively study the flow behaviour of gas in diesel particulate filters (DPF). The study includes an investigation into the effect of particulate matter loading on gas flow, and also the influence of a catalyst coating layer on gas flow dynamics. To date we have used the method to directly measure axial channel velocities and from this calculate through-wall gas flow distributions at a range of Reynolds numbers (Re). The measurements allow us to understand the effect of particulate loading on the flow profile, and also to infer the soot location within the filter channels. Furthermore, we can now measure the effect of catalyst layer location on the gas flow profile along the DPF channels; this is of key importance in optimising catalysed DPFs.