MTA Cryostat & cooling loop design

Christine Darve

Fermilab/Beams Division/ Cryogenic Department/ Engineering and Design Group

Preparation of the Mucool/MICE review02/11/03

CD MTA Cryostat and cooling loop design February 11 2003

MTA cryo-system - SpecificationsBD/Cryogenic Department

FERMILAB

-5

-4

-3

-2

-1

0

1

2

3

4

5

14 15 16 17 18 19 20 21

Temperature of LH2 (K)

Den

sity

cha

nge

/ den

s. L

H2

@ 1

7 K

(%)

Remove up to 150 Watt of energy loss from LH2

P= 1.2 atm,

T= 17 K

< 5%

T~ 1 K (could be 3 K)

Safety requirements:Safety requirements:

1. “ Guidelines for the Design, Fabrication, Testing, Installation and Operation of LH2 Targets–20 May 1997”, Fermilab by Del Allspach et al.

2. Fermilab ES&H (5032), 3. code/standard ASME, NASA, 4. NEC (art 500)5. CGA

CD MTA Cryostat and cooling loop design February 11 2003

MTA cryo-system - Materials

1.1. Caltech LH2 pump Caltech LH2 pump Max LH2 mass-flow = 450 g/s (0.12 MPa, Tin=17

K) P total < 0.36 psig

References :

1. “A high power liquid hydrogen target for parity violation experiments”, E.J. Beise et al., Research instruments & methods in physics research (1996), 383-391”

2. “ MuCool LH2 pump test report”, C. Darve and B. Norris, (09/02)

BD/Cryogenic DepartmentFERMILAB

2.2. Cryo department refrigeration systemCryo department refrigeration system Max He mass-flow = 27 g/s (0.2 MPa , Tin=14 K)

T=3 K for 450 W (17 K, 0.12 MPa)

Reference :

1. “Results of the MuCool Expander Flow Tests Performed at the Meson Cryogeni Test Facility”, A. Martinez and A. Klebaner, (12/02)

CD MTA Cryostat and cooling loop design February 11 2003

BD/Cryogenic DepartmentFERMILAB Part V – A look at the Hydrogen Proposal

Cryo-system design- Pressure drop calculation

RECALL from Internal review (09/24/02)

If m=450g/s and 32 nozzle dia. = 0.6”

then Maximum allowable P = 0.364 psi

Total P calculated=> 0.203 psi

0.011 psi

0.011 psi

0.031 psi

0.027 psi

0.011 psi

0.036 psi

0.078 psi

Will a velocity at the nozzle equal to 2.5 m/s be enough for ionization cooling?

CD MTA Cryostat and cooling loop design February 11 2003

BD/Cryogenic DepartmentFERMILAB

Flow Simulation by Wing Lau/ Stephanie Yang/ Charles Holding (Oxford)

MTA cryo-system – Cryoloop Design

T

Heat transfer coeff.

Given geometry, Power and

nozzle distribution

mass flow

P

Oxford studies: 1. Simulate the current MTA manifold geometry

2. Simulate beam at 150 W (volume, ø10mm (3 sigma gaussian))

3. Calculate heat transfer coefficients and temperature distribution for MTA conditions (V ~ 0.5 m/s – 4 m/s)

Velocity at nozzle

CD MTA Cryostat and cooling loop design February 11 2003

MTA cryo-system – Cryostat Design

1. Cryostat assembly: Vacuum vessel: MAWP=25

psig; SS, IPS 16 Sch10, IPS 50 Sch10

Dome (SS, 10 mm) Plate (SS, 10 mm)

Thermal shield +MLI (Al, Mylar) Piping (SS, IPS 1, 2) Helium buffer(SS,3) Vacuum window(Al) Safety devices (see internal

review)

BD/Cryogenic DepartmentFERMILAB

2. Heat exchanger assembly

Coil (copper, 0.55in)

Outer shell (SS, IPS6)

3. LH2 pump assembly

LH2 pump and shaft with foam

Motor outer shield

CD MTA Cryostat and cooling loop design February 11 2003

Pressure relief valve – LHPressure relief valve – LH2 2 : II C 4 a (iii): II C 4 a (iii)

Relief pressure (10 psig or 25 psid)Sized for max. heat flux produced by air condensed on the LH2 loop at 1 atm.

2 valves ACGO => 0.502 in2

ASME code RedundantCapacity = 52 g/s

Pressure relief valve – Insulation vacuum Pressure relief valve – Insulation vacuum : II D 3: II D 3MAWP (15 psig internal)Capable of limiting the internal pressure in vacuum vessel to less than 15 psig following the absorber rupture (deposition of 25 liter in the vacuum space)Vapor evaluation q= 20 W/cm2Take into account DP connection piping and entrance/exit losses

3 parallel plates (FNAL design) => 2”ASME code RedundantCapacity = 197 g/s

Relief system must be flow testedRelief system must be flow tested

BD/Cryogenic DepartmentFERMILAB Part V – A look at the Hydrogen Proposal

To meet the standardRECALL from Internal review (09/24/02)

CD MTA Cryostat and cooling loop design February 11 2003

4. Absorber assembly: Ed Black/Wing Lau windows and manifold design Interface of the systems

Bimetallic junction Indium Doubled-seal

5. Supporting system G10 spider

6. Instrumentation P: Penning, P T: Cernox Flowmeter, Heater Valve (elec, pneum, manual..) Turbomolecular pump (N2 guard)

BD/Cryogenic DepartmentFERMILAB

MTA cryo-system – Cryostat Design

Minimum spark energies for ignition of H2 in air is 0.017 mJ at 1 atm, 300 KLower pressure for ignition is ~1 psia (min abs. 0.02 psia // 1.4 mbar)

CD MTA Cryostat and cooling loop design February 11 2003

Cryostat design Focus :Cryostat design Focus :

Final cooling system

Implementation of the vacuum windows

Heater implementation (Helium side)

Supporting system

Instrumentation implementation

BD/Cryogenic DepartmentFERMILAB MTA cryo-system – Conclusions

Cooling loop Focus: Cooling loop Focus:

Thermo-hydraulic behavior inside LH2 absorber for which T=1

K: geometry and nozzle, power distribution, mass flow ==>P

Validation of optimization to T and P as specified

CD MTA Cryostat and cooling loop design February 11 2003

1. Sealing for vacuum window: Teflon O’ring, Indium sealing, copper gasket

(Radiation hardness)

2. Cryopumping (turbo-molecular pump, thermal shield)

3. Distribution of RFs and magnets around cryostat: interface atmosphere or

vacuum behind cryostat vacuum window

4. Supporting system and absorber position in magnet

5. Who design cryostat support in hall?

6. Absorber Instrumentation routing and port

7. …..

BD/Cryogenic DepartmentFERMILAB MTA cryo-system – Questions

CD MTA Cryostat and cooling loop design February 11 2003

BD/Cryogenic DepartmentFERMILAB Part V – A look at the Hydrogen Proposal

Process and Instrumentation DiagramRECALL from Internal review (09/24/02)

CD MTA Cryostat and cooling loop design February 11 2003

BD/Cryogenic DepartmentFERMILAB Part IV – A look at the Windows and Absorber

Vessel

LH2 Manifold absorber (by E. Black)RECALL from Internal review (09/24/02)