Fluidised Powder Rig Developments

1. Fluidised Powder Rig Developments Work by: Chris Densham, Peter Loveridge & Ottone Caretta (RAL) Tom Davies (Exeter University) Richard Woods (Gericke Ltd.) With special thanks to EPSRC Engineering Instrument Pool www.eip.rl.ac.uk Presented by Peter Loveridge P.Loveridge@rl.ac.uk UKNF Meeting, Lancaster April 2009

2. Why a Powder Target? A fluidised powder could be considered for future high power target scenarios: Neutrino Factory target Open (or contained?) jet in solenoid Alternative to liquid Mercury baseline Superbeam Contained flowing powder + horn To go beyond “power limit” in solid graphite targets Tungsten Powder test programme launched Test rig commissioned Dec 2008 at RAL First results Mar 2009 • A fluidised powder has some of the advantages of both solid and liquid targets: • Material already broken (no fear of rupture) • Shock waves constrained within material, i.e. no splashing or cavitation • Flowing, replenishable material • Favourable heat-transfer • Decoupled (offline) cooling • Few moving parts • Powder handling is a mature process technology (ready solutions for most issues) Rig Commissioning, RAL, Dec 2008

3. Rig Operation Overview Powder recirculated in “Batch” mode Rig contains ~130 kg Tungsten Powder Particle size < 250 microns Fully automated control system Valve open/close sequence Blower on/off Blower Frequency Data Logging Hard-wired safety interlocks 4 1 2 3 Batch Powder Process 1. Load Hopper 2. Pressurise Hopper 3. Powder Ejection and Observation 4. Suction / Recirculation Control System User Interface (MATLAB)

4. Summary of Data runs 18 March – 01 April Total ~3,000 kg powder ejected 31 suction/ejection cycles Parameters Varied: Conveying pressure range 2 to 5 bar Coaxial flow geometry Coaxial flow velocity 10 – 30 m/s Powder jet recorded using High-speed camera Vision Research PHANTOM 7.1 5000 fps Rig instrumentation data logged throughout Pressure Flowrate Temperature Mass High speed camera setup

5. Post-processing Underway Data interpretation underway… Preliminary results available Results for a Low Pressure Jet Low pressure ejections look quite promising 2.0 bar ejection hopper pressure Jet “droops” by ~30 mm over a 300 mm length Each particle takes ~0.1 sec to traverse viewport Jet Velocity = 3.7 m/s Nozzle pipe not full! Stable Jet Constant pressure in hopper throughout ejection Velocity (does not vary top/bottom) Velocity (constant over time) Dimensions (constant with distance from nozzle) Dimensions (reasonable stability over time) Vair ~30 m/s Vjet = 3.7 m/s Low pressure ejection schematic Still from video clip (2 bar ejection hopper pressure)

6. Video Clip High-Speed Video Clip (2 bar ejection hopper pressure)

7. Jet Density Calculation ID h Nozzle ID = 21.45 mm Jet height = 14.6 mm Jet Area = 262 mm2 From hopper load-cell data log: 63 kg in 8 sec = 7.875 kg/sec • Recall: Solid Tungsten density = 19,300 kg/m3 • Powder density “at rest” ~ 50% solid Density Calculation for 2 bar ejection Jet area, A= 262 mm2 (from nozzle dimensions and video still measurements) Powder bulk velocity, V = 3.7 m/s (from particle tracking) Vol flowrate = A.V = 0.000968 m3/s Mass flowrate = 7.875 kg/s (from loadcell) Jet Density = Mass flowrate / Vol flowrate = 8139 kg/m3 Jet Density = 42% Solid tungsten density Uncertainty is of the order ± 5% density

8. Summary Rig commissioning complete in 1st (simple) configuration Data runs Mar/Apr 2009 Preliminary results indicate a jet density 42 ± 5 % is feasible 42% Tungsten density is equivalent to 60% Mercury Density Gravity Suction Next Configuration (vertical powder lift) Next Steps • Ongoing evaluation of data runs • Hardware • Reconfigure rig for vertical powder lift (without 90 degree bend in suction line) • Install nozzle pressure sensors • Experiments • Powder flotation, minimise velocity and wear in suction cycle • Nozzle pressure drop • Test minimum flow velocity (for contained powder target) • Next EIP camera slot in June?