LH2 Absorber Review

1
LH2 Absorber Review

1. RD Motivation
2. Windows (absorber and vacuum)
3. Absorber manifold designs and flow tests
4. System integration
5. Near term plans
6. Summary

2
Mucool LH2 Absorber Issues
Approx. eq. for emittance

• Minimize scattering
• Nonstandard window designs for absorber and
  vacuum vessel SOLVED

• Maximize heat extraction
• Optimal cryogenic designs IN PROGRESS
• Temperature and density stability LH2
  circulation UNSOLVED

• Safety
• No H2/O2 contact containment, ventilation,
  controls IN PROGRESS
• No ignition sources instrumentation must be
  safe, RF cavities benign

• System Integration
• Confined operation, large B fields system
  integrity and stability IN PROGRESS
• Temperature range from room to Lhe condensation
  issues

3
Measuring the thinnest thickness

1. Two different radii of curvature
2. Possibly not concentric

Modified torispherical design
If not at the center, where?
4
Windows tests

• Non-standard thin window design
• No closed form expression for maximum stress
  vs. volume pressure
• FEA (finite element analysis)
• geometry
  stress
• material
  strain
• volume pressure
  displacement

• Procedure (for manufacture quality control and
  safety performance) Three innovations
• Precision measurement of window photogrammetric
  volume measurements
• FEA predictions inelastic deformation, 3 dim
  included in calcs.
• Performance measurement photogrammetric space
  point measurement

• Progress towards meeting FNAL Safety Guidelines
• Absorber and vacuum window guidelines understood
• Absorber window test completed
• FEA/data agreement established

5
Photogrammetric measurements
Strain gages 20 points
CMM 30 points
Photogrammetry 1000 points
6
Photogrammetry

• Contact vs. non-contact measurements (projected
  light dots)
• Several vs. thousand point measurements
  (using parallax)
• Serial vs. parallel measurements (processor
  inside camera)
• Larger vs. smaller equipment
• Better fit to spherical cap.
• Updating camera and methods to prepare for
  production mode

7
Window shape measurement
D. Kubik, J. Greenwood
Convex
Concave
CMM data points
Whisker z(measured)-z(design)
Given the design radius of curvature of the
concave and convex surfaces, z(design) was
calculated for the (x,y) position of each target
8
Rupture tests
130 m window
340 m window
Burst at 120 psi
1.
3.
Leaking appeared at 31 psi ..outright rupture at
44 psi!
Burst at 152 psi
2.
4.
Burst at 120 psi
350 m window
Cryo test
9
Absorber window test results

• Performance measurement (photogrammetry)
• 1. Room temp test pressurize to burst
  4 X MAWP (25 psi)
• 2. Cryo test
• a) pressure to below elastic limit to confirm
  consistency
• with FEA results
• b) pressure to burst (cryo temp LN2)
  5 X MAWP
• from ASME UG 101 II.C.3.b.(i)
  

Discrepancies between photogrammetry and FEA
predictions are lt 5
10
Vacuum Windows

• FNAL Requirements
• Burst test 5 vacuum windows at room temp. to
  demonstrate a burst pressure of at least 75 psid
  for all samples. (pressure exerted on interior
  side of vacuum volume).
• Non-destructive tests at room temperature
• External pressure to 25 psid to demonstrate no
  failures no creeping, yielding, elastic
  collapse/buckling or rupture
• Other absorber vacuum jacket testing to ensure
  its integrity

Vacuum bellows window (34 cm diam)
No buckling at 1st yield (34 psi)
Internal pressure burst at 83 psi
11
LH2 Window R D

• Immediate future
• Manufacture and test of 21 cm bellows absorber
  window
• Manufacture and test of 34 cm vacuum window
  internal and external pressurization new test
• New aluminum alloy (stronger)
• Optimize seals to manifold
• Stability test in the Lab G magnet

12
Convection absorber design
Internal heat exchange
Convection is driven by heater and particle
beam.Heat exchange via helium tubes near absorber
wall. Flow is intrinsically transverse.
Output from 2-dim Computational Fluid Dynamics
(CFD) calcs. (K. Cassel, IIT). Lines indicate
greatest flow near beam center.
KEK prototype, S. Ishimoto
13
Force-flow Absorber
External heat exchange
Mucool 100 - 300W (E. Black, IIT)
Large and variable beam width gt
large scale
turbulence
Establish transverse turbulent flow with
nozzles
Mucool design
E158 design
14
LH2 Manifold R D

1. The driving physics issue in Mucool LH2 R D is
   now fluid flow and heat removal
2. Two separate absorber designs
3. Pre-MTA test (2003) convection
4. MTA operation (2004) force flow
5. Flow simulations
6. 3 dim FEA
7. CFD
8. Flow tests
9. Instrumentation

15
LH2 flow issues

• Our Challenge
• Large heat deposition and beam path is through
  entire volume absorber!
• 1. Liquid must move everywhere, particularly in
  window volumes
• 2. Need gauge of temperature and density
  uniformity
• Questions
• What is testable?
• How quickly can simulations be verified by
  experiment?
• What tests will be useful, and how quantitative
  can they be?
• What level of instrumentation will convince us of
  sufficient temperature uniformity?

16
Force flow simulations
3 dimensional FE simulations are possible but CPU
intensive (W. Lau, S. Wang)
3-dim and 2-dim flow simulations are consistent
use 2 dim for design and iteration. Preliminary
results indicate that bellows window has better
flow pattern in window volume.
17
Convection flow simulations
Lau/Wang FE 3-d flow simulation of KEK LH2
absorber
3-d grid
K. Cassel CFD
18
Flow Tests
Schlieren testing of convection flow (water) test
at ANL (more quantitative program to run in 2003)
J. Norem, L. Bandura
19
MTA Prestage with KEK absorber

1. LH2 setup and system integration
2. Absorber manifold and containment will be ready
   before the MTA!
3. Exercise filling and purging of absorber
4. Readout of temperature probes as a first
   verification of temperature maintenance via
   convection
5. Instrumentation readout
6. Can establish heat loading capacity sufficient
   for MICE requirements UNSOLVED

20
MTA LH2 Experiment
Lab G magnet
LH2 Cryostat
RF cells
Beamline C. Johnstone
21
Mucool Test Area LH2 Setup
Lab G magnet
22
MTA Force Flow Cryo System
Red - Hydrogen Blue
Helium Based on E158 LH2 target system

23
Mucool 2003/2004

• Absorber/vacuum windows manufacture and test
• Fluid flow/convection simulations
• Instrumentation and data acq. development
• Flow tests Forced Flow, Convection
• Safety Review
• MTA test design finalization
• MICE design
• Japanese absorber pre-MTA LH2 run
• Absorber/Solenoid Tests
• 2004
• MTA LH2 absorber staging
  

24
Summary Comments On LH2 R D

1. We have an established window design/manufacture/c
   ertification program, for absorber and vacuum
   windows, completed tests on the first window
   prototype, and have made many technical
   improvements on design.
2. We have developed new applications for
   photogrammetry (NIM article(s) in progress!)
3. Several projects have developed from LH2 absorber
   concerns, ideal for university and student
   participation.
4. MICE participation has advanced the Mucool
   program the two absorber designs are
   complementary integration problems are being
   solved possible hybrid absorber for a real
   cooling channel likely.
5. The above four points means that we have survived
   as a program the delay of the FNAL MTA
   construction (KEK in prestage LH2 tests could
   help)
6. LH2 flow and heat conduction has now become the
   dominant physics concern for the absorber. The
   two flow designs will be pursued in parallel.
7. LH2 safety is the dominant engineering concern
   for the cooling cell, but there has not yet been
   any show-stopping problems.