SPEME Faculty of Engineering

1. Tim HUNTER, Chetan LAKHANPAL, Bo LIN and Hugh RICE Multiphase flow meeting, 29/06/2010 SPEME Faculty of Engineering Investigation of pipe and jet flows: transport and deposition of particles

2. 1. Background • Nuclear industry legacy waste: • Radioactive sludges and slurries exist on nuclear sites • Waste present in tanks, ponds, drains and other storage and transport vessels • Sludges difficult to characterise: limited accessibility, radioactivity

3. 2. Objectives • To investigate dense, high-concentration, multiphase flows in three regimes of interest: • Characterisation of settled beds • Resuspension of settled beds by impinging jets • Transport and deposition of particles in pipes

4. 3. Characterisation of settled beds Use of readily-available,single-probe ultrasonic (US) systems Aims: • Measure particle settling rates • Bed formation & compaction over time • Dispersion concentration changes Particles Tested: Coagulated Spheriglass

5. 3. Characterisation of settled beds • Ultrasonic Velocity Profiler (UVP) “UVP-DUO” • Measures particle velocity from Doppler shift. • Single 1 MHz Dip Probe. • Distance 5 – 30 cm. • 2L vessel. • Settling rates & bed scan. UVP versus ABS used in Settling • Acoustic Backscatter System (ABS) • “Aquascat” • Measures raw attenuation of scattered ultrasonic signal. • 1 - 5 MHz Dip Probes. • Distance 5 – 20 cm • 5L vessel. • Dispersion Concentration. 30/20 cm 2/5L Mag. Stirrer

6. 3. Characterisation of settled beds UVP- Colour Plot Hindered settling above bed? Spheriglass_5000 pH 7, 5 wt%, 1M KCl Ave vel. ~2-4 mm/s Cloud-front

7. 3. Characterisation of settled beds ABS Settling Beaker base Raw scatter data (highlights cloud-front)

8. 3. Characterisation of settled beds ABS Settling Beaker base Raw scatter data (highlights cloud-front)

9. 3. Characterisation of settled beds ABS Settling Beaker base Raw scatter data (highlights cloud-front)

10. 3. Characterisation of settled beds ABS Settling Beaker base Raw scatter data (highlights cloud-front)

11. 3. Characterisation of settled beds ABS Settling Beaker base Raw scatter data (highlights cloud-front)

12. 3. Characterisation of settled beds Analysis of ABS results Average bulk dispersion concentration increases as settling progresses => Inhomogeneous settling & hindrance effects

13. Experimental Rig Tim and Chetan 4. Resuspension by impinging jets Vertical Jet flow & Bed Erosion

14. 4. Resuspension by impinging jets Measuring impinging jet flow dynamics UVP – HORIZONTAL ARRAY Particle Image Velocimetry (PIV)

15. 4. Resuspension by impinging jets Measuring sand-bed erosion using UVP Equilibrium Profile Scans Erosion Kinetics Traverse 5 UVP Probes Jet Jet UVP Probe bed bed Jet 0.3 L/s Jet 0.6 L/s Jet 1 L/s Images of erosion

16. 5. Transport and deposition in pipes Flow loop 1

17. 5. Transport and deposition in pipes • Aim to understand the effects physical parameters, such as particle size and size distribution, solid concentration as well as solid density, on the properties of solid-liquid system in horizontal pipe flow over the Reynolds number ranger 5200-10400. • Measurements: • UDVP (high solid concentration >5% vol) • PIV (low solid concentration <5% vol) DIAMOND University Research Consortium, funded by the EPSRC

18. 5. Transport and deposition in pipes Material properties Spheriglass 5000 cp03 Mean particle size: 9.8um Particle size distribution: D10=1.3um D50=8.5um D90=17.9um Density: 2.5g/cm3 UDVP frequency: 4 MHz Results from Malvern Mastersizer 2000 DIAMOND University Research Consortium, funded by the EPSRC

19. 5. Transport and deposition in pipes Results with bed formation u: instantaneous velocityU: mean streamwise velocityu’: root-mean square values Turbulence intensity where Ū: depth-average streamwise velocity

20. 5. Transport and deposition in pipes Results with bed formation • Change in turbulence intensity as a function of solids concentration • Higher concentration => higher turbulence intensity? • Near the wall region: very clear • Along pipe centre-line: no difference, maybe within error?

21. 5. Transport and deposition in pipes UVP probe position Flow loop 2 Control boxes Flow meter Mixer Tank Pump

22. 5. Transport and deposition in pipes Flow loop 2 UVP probe assembly

23. 5. Transport and deposition in pipes Objectives (1) • Bimodal suspensions represent simple analogues of those found on nuclear sites • Aim to study fluid-dynamical processes, since they are not well understood, namely: • Deposition of high- vs. low-density particles; stratification of deposits • Fluid-particle interactions; turbulence modulation • Particle-particle interactions, i.e. four-way coupling

24. 5. Transport and deposition in pipes Objectives (2) • Aim to gather data over range of dp, ρp, Re using viscosity equivalence method (VEM) • Two fluids – water/glycerol and water/fine particles – with equivalent viscosities • Comparison of results will be used to quantify interparticle interactions

25. 5. Transport and deposition in pipes Pipe flow experiments – parameters Probe 55° Ub

26. 5. Transport and deposition in pipes Mean velocity profile* * Met-Flow UVP-Duo Eggels JGL et al. (1994), JFM 268 175-209

27. 5. Transport and deposition in pipes RMS velocities* * Met-Flow UVP-Duo Eggels JGL et al. (1994), JFM 268 175-209

28. Acknowledgements Supervisors: Prof. Simon Biggs1, Prof. Mike Fairweather1, Dr. Jeff Peakall2 Lab assistance: Dr. Gareth Keevil2, Russ Dixon2 1 School of Process, Environmental and Materials Engineering 2 School of Earth and Environment * DIAMOND Consortium Questions please!