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Measuring multiphase impinging liquid jets for particle bed re-suspension with ultrasonic profilers

Academic lead
Dr Tim Hunter, School of Chemical & Process Engineering
Industrial lead
Geoff Randall, Sellafield
Prof Mike Fairweather, School of Chemical & Process Engineering, Prof Jeff Peakall, School of Earth & Environment
Project themes
Particulate flows, sediments & rheology

Impinging jets are used in a wide range of process engineering application e.g. tunnelling operations, paint spraying and cavitation drilling. Liquid jets are also used to estimate sediment strength in natural environment studies; from predicting attrition in waste reservoir outlets to measuring long term bed-slip in estuaries. Related is the use of liquid jets in mixing operations to mobilise and homogenise sedimented particulate beds. This is important in the nuclear waste industry for mixing of radioactive sludges, as they are preferred over mechanical mixers due to the lack of moving parts. Despite the wide relevance of multiphase impinging jet mixing systems, quantitative studies of the flow-profiles, turbulence and recirculation currents in sediment beds are lacking. This is due to the difficulty of measuring multiphase particulate jets, as traditional laser or image tracking techniques cannot be used at high solids loads. This problem is compounded when the jets are used to mobilise sediments, often creating completely opaque environments. Acoustics however, offer a possibility of observing simultaneous velocity and depth information using combined Doppler and backscatter at high particle concentrations. The aim is to investigate the application of these instruments for these complex flows.