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 Rig Commissioning, RAL, Dec 2008 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)

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 Batch Powder Process 1. Load Hopper 2. Pressurise Hopper 3. Powder Ejection and Observation 4. Suction / Recirculation Control System User Interface (MATLAB) 1 2 3 4

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) Low pressure ejection schematic V jet = 3.7 m/s V air ~30 m/s 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 From hopper load-cell data log: 63 kg in 8 sec = 7.875 kg/sec h ID Nozzle ID = 21.45 mm Jet height = 14.6 mm Jet Area = 262 mm 2 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 m 3 /s Mass flowrate = 7.875 kg/s (from loadcell) Jet Density = Mass flowrate / Vol flowrate = 8139 kg/m 3 Jet Density = 42% Solid tungsten density Uncertainty is of the order ± 5% density

8. Summary Rig commissioning complete in 1 st (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 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? Suction Gravity Next Configuration (vertical powder lift)