AMS Tracker Thermal Control System TTCS

1
AMS Tracker Thermal Control System (TTCS) Phase
II Safety Presentation TIM-meeting, 22 April
2007, CERN NLR-team J. van Es, P. Dieleman, B.
Verlaat (NIKHEF), A. Pauw, G. van Donk, T.
Zwartbol, SM. Bardet, M. BsibsiSun Yat-Sen
University team ZH. He, KH. Guo, JQ. Ni, SS. Lu,
XZ. Wang, XM. Qi, TX. Li, YH Huang, X. Huang, Mo
et al INFN-AMS-team R. Batiston, M.
Menichelli, A. Alvino, E. Laudi, et
al.CAST-team M. Jianyin, J. Cao, G. Lin et
al. MIT-team V. Koutsenko, Cai, A.
Lebedev AIDC-team B. Hong, B.C.Y. Hsu, W.M. Hsu,
A.J.M. Shue, Chun-Ching Yeh et al.

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Contents

• TTCS System Overview
• Equipment locations
• Components overview
• Thermal Safety Approach TTCS Pressurised CO2
  system
• Safety approach
• Supporting analyses
• Mechanical safety approach
• Box analyses
• Component analyses
• Safety of components
• Condensers
• Accumulator Heat Pipe (NH3-system)
• Documentation

3
TTCS System Overview

• Objective TTCS
• Provide accurate temperature control of AMS
  Tracker front-end electronics

4
TTCS Overview

• Two redundant CO2 two-phase pumped loops
• Primary loop
• TTCB Box on Port side
• Condenser at Wake and RAM radiator (also port
  side)
• Secondary Loop
• TTCB Box on Starboard side
• Condenser at Wake and RAM radiator (also
  starboard side)
• TTCE Tracker Thermal Control Electronics located
  at the wake radiator bottom next to PDS

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TTCS System Overview

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Tracker radiators TTCS Condensers are attached to
the Tracker radiators
Tracker
TTCS box envelopes (locations)
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Evaporator (overview)
Tracker Thermal Control System
192 Hybrids each producing 0.75 Watts of heat
(144 W total)
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Evaporator (overview)
Tracker Thermal Control System
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Evaporator tubing upper inner and outer ring
Tracker Thermal Control System
Connection to transport tubing
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FM evaporator
Tracker Thermal Control System
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Welding close to TTCS boxes
Tracker Thermal Control System
TTCS Boxes
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TTCS Primary Box location (wake port side)
weld locations indocated with arrows
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TTCS Condenser locations
Tracker Thermal Control System
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• Condenser location
• TTCS Tracker Radiator Integration jig (WAKE side)
  indicated are the condenser attachment brackets
  (locations)

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• TTCS Primary loop Wake Condenser (WAKE port
  side)
• Each system has two condensers one on Wake side
  and one on RAM side

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• Location of transport tubing Primary tubes on
  Port side Secondary tubes on Starboard side

Primary loop tubes
Secondary loop tubes
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Box components

• All components except the evaporator and the
  condenser are located in the TTCS-box
• one primary box (port side)
• one secondary box (starboard side)
• Containing
• Pumps (2x)
• Accumulator with Peltier heat exchanger
• Heat Exchanger with start-up heaters
• Absolute pressure sensors (2x)
• Differential pressure sensors (2x)
• Cold orbit heater (1 unit)
• Pre-heaters (2x)
• Thermal switches (20x)
• Pt1000 temperature sensors (30x)
• Dallas temperature sensors (22x)

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TTCS System summary box components

• Each loop includes the following components in
  the box
• 2 redundant pumps
• 1 Accumulator to
• accommodate liquid in case of two-phase operation
  and to allow for temperature-volume changes
• control the evaporation temperature in the
  evaporator by control heaters, Peltier elements
  and emergency heaters
• Heat Exchanger to use the evaporator heat to
  pre-heat the subcooled CO2 fluid (saves power)
• 2 Pre-heaters to heat both evaporator branches to
  Tsaturation

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TTCS System summary box components

• Absolute pressure sensors to monitor the pressure
• Differential pressure sensors to monitor the mass
  flow
• Cold orbit heater used to increase energy content
  of the CO2 two-phase flow. To avoid too low
  temperatures in cold orbit condition operation
• Start-up heater to heat the liquid flow to the
  evaporator from -40?C to -20?C to keep front-end
  electronics in their temperature window

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TTCS Box
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TTCS Box
accumulator
Abs. P-sensor
Cold orbit heater
Heat exchanger
Diff. P-sensor
Swagelok weld couplings
Cover with ext. connectors
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TTCS Box
Pumps
Cold orbit heater
Pump Electronics box
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Pump

• Pump is an adapted Martian Exploration rover pump
  by PDT
• Centrifugal pump
• Successful CDR in September 2006

Pump Controller
EM Pump
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Accumulator

• Two-phase accumulator by CAST
• Heat pipe to heat the accumulator in the centre
  of the accumulator
• Peltiers to cool the accumulator at the mantle
  the Peltier cold side connected to the liquid
  line from the condensers

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Accumulator
liquid inlet pipe with mesh
HP cross section
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Accumulator

• Mesh Design
• Spoke design to transport the liquid to the HP
• Wick Design Fan Mesh to keep the CO2 around the
  liquid inlet to supply the CO2-loop with liquid

Spoke mesh design
fan mesh design and liquid inlet
HP cross section
Fan mesh detail
Spoke and Fan mesh design
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Heat exchanger Assembly
Heat Exchanger QM/FM
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HX QM/FM Assembly

• Heat Exchanger exists of
• 36 stacked heat exchanger plates (Inconel 625)
• Two container parts (Inconel 625) with machined
  tube ends
• 2 Diff. Pressure Sensor at ones side
• 4 connections to the loop at the other side
• 2 heater wires at the mantle
• 2 brackets to connect to the bottom plate
• 2 clips to connect HX to the brackets
• 6 Thermal Switches (integrated later) to avoid
  overheating the TTCS system

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HX QM/FM Assembly
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Pre-heater
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Absolute Pressure sensor Differential pressure
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Cold-orbit heater
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Thermal Safety Approach TTCS Pressurised CO2
system

• Contents
• Approach and calculation explanation
• Definition of sub T-requirements
• Example of verification of sub T-requirements
• Safety verification

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TTCS Thermal Safety Approach

• TTCS is a pressurised system with
• MDP of 160 bar
• MDT of 65 ?C
• The maximum allowable density is then determined
  from the CO2 Mollier diagram resulting in
• Max Design Pressure 160 Bar
• Max Design Temperature 65 C
• Max Design Density 592.39 kg/m3
  (mass/volume)
• This would apply for a concentrated system with
  uniform temperature

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TTCS Thermal Safety Approach
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TTCS Thermal Safety Approach

• TTCS is a widely distributed one volume system
  therefore a more convenient approach is followed
  to allow for different maximum temperatures per
  sections
• Outline followed approach
• The TTCS is subdivided into sections (volumes)
• Capillary Condenser Lines
• Accumulator
• Heat Exchanger
• .......
• .....
• Unheated components.

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TTCS Thermal Safety Approach

• Based on
• Max Pressure in the loop P 160 Bar
• Maximum TComponents Ti, Tii , Tiii .......,
  Tv
• ?The densities ri...v are known and therefore the
  masses mi...v
• The maximum allowed temperature of the last
  volume Vvi can then be calculated with
• mvi mtot Smi..v
• with mvi/Vvi ? rv and P 160 bar the maximum Tvi
  is known
• Safety is proven when for ki to kvi Tk lt Tmaxk

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TTCS Safety Approach (in a scheme)
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Safety Verification Approach
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Safety Verification Approach
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TTCS Safety verification approach

• Maximum temperature of non-TS-protected heated
  volumes
• Maximum Temperature TS-protected heated volumes

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TTCS Safety verification approach

• Worst case calculation is performed with
• Condensers Tlt -5 C
• Heat exchanger is thermostat protected Tlt 100C
• Accumulator is thermostat protected T lt 55 C
• Heated components options for calculation ease
• All heated components Tlt300 C.
• All heated components Tlt300 C except pumps and
  the evaporator Tlt100 C.
• All heated components Tlt450 C except the pumps
  and the evaporator Tlt100 C
• Calculation will determine the Tmax unheated
  components

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TTCS Safety verification approach
T 95 C
T 65 C
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TTCS Safety verification approach

• Conclusion option 1
• If in worst case conditions
• Taccult 55 C
• THXlt 100C
• Tcondenser lt -5 C
• Theated parts lt 300 C
• Tunheated parts lt 65 C
• If all conditions are met ? MDP lt 160 bar ? safe
  design
• The above temperature safety requirement should
  be verified by supporting analyses

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TTCS Safety verification supporting analyses HX

• Heat Exchanger protected by thermostats T lt 80
  Cfor material property reasons

Analyses ?THX Tbracket
HX QM Design
HX Thermal Model
HX TS Schematic
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TTCS Safety verification supporting analyses
Condenser

• Condenser and Tracker radiator are equipped with
  120 V heaters. These are protected by thermostats
  (TTS lt -17.8 C)

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TTCS Safety verification supporting analyses
Condenser

• Maximum T is occurs at hot environmental
  conditions
• Condenser max. hot environmental conditions T lt
  -5C

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TTCS Safety verification supporting analyses
Accu

• Accumulator TS protected Taccu lt 55 C

Accumulator control and emergency heaters
thermostat schematic
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TTCS Safety verification supporting analyses Accu

• Accumulator TS protected Taccu lt 55 C
• Flight heater protection
• Three TS one in each feed line two in combined
  return line ? two-fault tolerant with all
  heaters switched on
• Ground test heaters protection
• Not connected during flight
• Protected with one TS per heater
• Peltier elements protection
• Three TS per control loop (Taccult 55 C)

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TTCS Safety verification supporting analyses Accu
Accumulator TS Locations overview
Accu Control heater and emergency heater TS
Locations
Peltier TS Locations
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TTCS Safety verification supporting analyses Accu
Case 1 AB heaters on 75 W Peltiers on 100 W HP
Failure
Accumulator T ltlt 55 C All TS switch well
before accumulator is heated
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TTCS Safety verification supporting analyses Accu

• Accumulator Control and Emergency heaters
• Protected well by TS design on accumulator heat
  pipe
• HP safety is more critical/interesting (will be
  discussed separately)
• Peltier elements
• need only protection when accumulator becomes in
  supercritical condition (see next sheet)
• TS are located on the same copper saddle (so good
  thermal contact)

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TTCS Safety verification supporting analyses Accu
Case 3 AB heaters on 75 W Peltiers on 100
W TAccugt Tcrit? assumed no heat transfer to CO2
Heat switch Peltier TTS lt 45 C Therefore
TAccu lt 55C
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TTCS Safety verification supporting analyses
Pre-heater (example for other components)

• Safety cases
• Non-running loop
• Heaters A B on maximum power
• All Tlt 162 C (435 K)? T lt 300 C

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TTCS Safety verification supporting analyses
unheated parts

• Unheated parts i.e. transport tubing lt 65 C
• TEvaporatorlt 50C
• TVC lt 40 C
• Tsupport beam lt 52 C (TBC)
• TUSS lt 52 C (secondary box)
• TUSS lt 27.2 C (Primary box)

Secondary box maximum temperatures (source CGS
calculation for start-up)
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TTCS Safety approach verification

• All temperature requirements are fulfilled
• Taccult 55 C
• THXlt 80 C lt 100C
• Tcondenser lt -5 C
• Theated parts lt 300 C
• Tunheated parts lt 65 C
• ? safe design on thermal aspects

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Mechanical safety approach

• TTCB Box mechanical analyses
• structural analyses
• Combined acceleration loads and pressure loads
  during launch
• Failsafe analysis
• Modal Analysis
• bolt analyses
• Margin of Safety analyses
• Failsafe analysis
• Component mechanical analyses
• structural analyses
• Combined acceleration loads and pressure loads
  during launch
• Modal Analysis
• bolt analyses
• Margin of Safety analyses
• Failsafe analysis
• Design without negative MoS ? safe design

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TTCS Box Mechanical analyses (FEM model)
Pressure Sensor Lumped Mass
USS
Pumps Controller Lumped Mass
Accumulator
Heat Exchange
Top Base Plate
Start up radiator plate
Pressure Sensors Lumped Mass
Vales Lumped Mass
Side plate
Pumps
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TTCS Box Mechanical analyses
Structural Baseplate, sideplate, startup
radiator, Accu. Brackets, pump Brackets, HX
Brackets Bolts MoS USS-Baseplate,
USS-Sideplate, Baseplate-StartupRadiator,
BasePlate-Acc.Brakets,
Baseplate-HX Brackets, PumpBracket-Startup
Radiator Failsafe Structural Baseplate,
Sideplate Failsafe bolts USS-Baseplate,
USS-Sideplate All analyses show positive margins
of safety. All analyses performed documentation
is upto finalisation
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TTCS Box Mechanical analyses
First modal node 79.6 Hz gt 50 Hz
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TTCS Accumulator Mechanical analyses (FEM)

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TTCS Accumulator Mechanical analyses Load cases
Launching/Landing Load Cases
Inorbit Load Cases
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TTCS Accumulator Mechanical analyses
Acceleration loads combined with pressure load
160 bar
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TTCS Accumulator Mechanical analyses
Structural No Negative MoS Bolts MoS No
Negative MoS Failsafe Structural No Negative
MoS Failsafe bolts No Negative MoS All
analyses show positive margins of safety Most
critical point is the stress in the connection
between the Peltier saddle and the
accumulator. The properties of the solder
connection is not specified well a test is
proposed to verify the modelling assumptions.
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TTCS Accumulator Mechanical analyses
First modal node 216 Hz gt 50 Hz
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Safety of components Condenser (freezing)

• Condensers
• The condensers are attached to the Tracker
  radiators and dump the tracker heat into deep
  space
• The condensers are equipped with
• Liquid line health heaters to thaw frozen CO2 in
  the inlet and outlet capillary lines (28 V
  controlled by TTCE)Frozen CO2 can be formed
  during a AMS02 complete power down
• Condenser/radiator heaters to
• keep the Tracker radiators T gt -40 ? C in TTCS
  non-operational conditions
• thaw frozen CO2 above

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Safety of components Condenser (freezing)

• Freezing problem
• TTCS contains CO2 with a freezing point of 55
  C
• In normal operation conditions no freezing can
  occur
• However in a AMS02 power down the Tracker
  radiators can reach T -120 C
• Environmental heating can cause enclosure of
  liquid CO2 in between frozen CO2 in the condenser
  

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Safety of components Condenser (freezing)

• A freeze-proof design is made by the following
  approach
• Locate condenser manifolds at locations T gt -40
  C
• Design freeze proof condenser tubes with
  capillary diameter from high strength material
  (Inconel 718)
• Verify by test the maximum pressure during
  thawing ? MDPcondenser
• Verify by test the proof pressure of the design
  and the burst pressure to the highest maximum
• Verify the condenser manufacturing sequence

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Safety of components Condenser (freezing)

• Locate condenser manifolds at locations T gt -40
  Cupper trunnion bridge

Manifolds
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Safety of components Condenser (freezing)

• Locate condenser manifolds at locations T gt -40
  Cupper trunnion bridge

Manifolds
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Safety of components Condenser (freezing)

• Design freeze proof condenser tubes with
  capillary diameter from high strength material
  (Inconel 718) (7 parallel tubes)

Manifolds
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Safety of components Condenser (freezing)

• Verify by test the maximum pressure during
  thawing ? MDPcondenser
• Freezing test performed successfully
• MDP is determined by the melting line (see
  results)
• ? Environmental induced Tmax - 5 ?C ? MDP
  3000 bar
• ? condenser design feasible for strength (Inconel
  718)

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Safety of components Condenser freezing

• Maximum T is occurs at hot environmental
  conditions
• Condenser max. hot environmental conditions T lt
  -5C

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Safety of components Condenser (freezing)

• Verify by test the maximum pressure during
  thawing ? MDPcondenser
• The pressure build-up during thawing follows the
  melting line
• Maximum environmental Temperature -5 ?C
• ? MDPcondenser 3000 bar.
• It is shown that a tube of 1 mm wall thickness
  needs to sustain a von Mises stress of approx.
  600 MPa.

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Safety of components Condenser (freezing)

• Verify by test the maximum pressure during
  thawing ? MDPcondenser
• The pressure build-up during thawing follows the
  melt line
• Maximum pressure is approx. 3000 bar.
• A condenser comprising small diameter Inconel 718
  tubing (din 1.0mm, dout 3.0mm) is shown to
  withstand this pressure using a safety factor of
  1.5 for yield and 4.0 for burst.

Inconel 718 properties
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Safety of components Condenser (freezing)

• Verify by test the proof pressure of the design
  and the burst pressure to the highest maximum
• Proof pressure 1.5 3000 4500 bar
• Max burst 10,000 bar ? SF 3.3
• Test sample (and test tubes) will follow the same
  heat treatment
• A. Start with Inconel according to 5590E
• B. Soldering at 1040 C
• C. Solution heat treatment at 970 C
• B. Heat treatment according to AMS 5589D
• Pressure test up to 1000 MPa (10,000 bar) will be
  performed
• Tensile test on test tubes will give information
  on Ty, Tu and hardness

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Safety of components Accumulator heat pipe

• The Accumulator heat pipe is attached to
• MDP 50.2 bar based on a 89 C maximum T

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Safety of components Accumulator heat pipe

• The Accumulator heat pipe is attached to
• MDP 50.2 bar based on a 89 C maximum T

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Safety of components Accumulator heat pipe
Manufacturing sample
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Safety of components Accumulator heat pipe

• The accumulator heat pipe is equipped with
  control and emergency heaters (wire heaters
  soldered to the HP)
• The Accumulator heat pipe is equipped with TS
• TS HP switch temperature 55 ?C
• MDP 50.2 bar based on a 89 ?C maximum HP
  temperature
• Modelling shows in all cases THP lt 85 C ? Safe

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Safety of components Accumulator heat pipe

Most Critical case HP-failure
one TS failure
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Safety documentation

• TTCS Box Structural safety analysis (1 week)
• CDR Pump Package (Directly delivered to NASA/JS)
• Design Description Accumulator (incl. Prel.
  Verification Plan)
• HP Safety Analysis (mechanical)
• TTCS Accumulator Thermal safety analysis (accu
  and HP)
• TTCS Accumulator Structural safety analysis (1
  week)
• Evaporator Data Package (including mech.
  verification)
• Condenser Design Description
• Heat Exchanger Design Description
• TTCS Heater specification
• TTCS Safety approach (including thermal model
  results)

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Safety Documentation

• Design drawings
• Evaporator FM
• Pump drawings (on request by PDT ? NASA/JS)
• Heat Exchanger QM
• Design Mechanical Models
• TTCS Box model
• Heat Exchanger QM/FM
• Pump including Electronics box FM
• Accumulator QM/FM
• Pre-heater QM/FM
• Cold-orbit heater QM/FM
• APS/DPS external model only
• Condenser QM/FM

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Drawings to be added
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Back-up slides
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TTCS System components
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TTCS Safety verification supporting analyses OHP

• OHP heater
• Tmax loop side lt 100 C lt 300 C

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Safety of components Condenser (freezing)

• Verify by test the maximum pressure during
  thawing ? MDPcondenser

92
CO2 melt line and measurement results
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Condenser Freezing Test Results
Max. Tenv - 5 ?C
Maximum design pressure plotted along CO2 melt
line
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Safety of components Condenser (freezing)
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Safety of components Condenser (freezing)
Test Sample as built
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Safety of components Oscillating Heat Pipe

• OHP-Experiment
• Objective
• To demonstrate OHP operation in m-g conditions
• Main properties
• Undulating capillary pipe OHP tubing L
  3279.15 mm, Din 1.2 mm, Dout 1.5 mm
• Filled with liquid and vapour FC-87
• Wire heater connected on copper saddle on one
  side
• Other side connected to TTCS-loop as heat sink

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Safety of components Oscillating Heat Pipe
TTCS Primary loop
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Safety of components Oscillating Heat Pipe

• Oscillating Heat Pipe Experiment
• The volume of the containing SS tubing is 2.26
  ml FC-87.
• The fill charge will be 70 resulting in a
  total mass of 2.56 gram FC-87 _at_ 290 K.
• FC-87 Properties
• - Critical temperature 423 K (150 C)
• - Critical pressure 21.3 bar
• - Liquid density 1650 kg/m3 _at_ 298 K
• - Liquid specific heat 1100 J/kgK _at_ 298 K

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Safety of components Oscillating Heat Pipe
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Safety of components Oscillating Heat Pipe

• OHP maximum average design temperature of 100 C
  (373.15 K)
• MDP 8.94 bar
• The limiting Von Mises stress is calculatedsVM
  1.987 MPa
• With a safety factor, SF 4.0 syieldlimit SF
  sVM 7.95 MPa
• SS 316L yield strength 234 MPa gtgt 7.95 MPa

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HX Information
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Flow explanation (2-phase)
X1 Top 2-phase flow in
2-phase out through X2
Blocked by top plate ? through package to bottom
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Flow explanation (1-phase)
L1 Top liquid flow in (1)
Blocked by bottom plate ? flow leaves through the
hole in the top plate
Fluid is collected at the bottom plate and leaves
through L2 outlet
Blocked by top plate ? through package to right
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Engineering Model pictures
Vacuum braze test
Destructive inspection
Braze supports top plate
Stack brazed
After all brazing
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Engineering Model pictures
EM Complete
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Pump

• Pump is an adapted Martian Exploration rover pump
  by PDT
• The CO2 circulation pumps that are to be
  installed on the AMS2 each contain the
• following total rotating mass Total 0.0384 lbs
  (0.614 oz)
• 304L stainless steel container housing
• Minimum wall thickness of 0.118 inches
• can withstand a burst pressure of 400 BAR, (5800
  psig).
• The Rotor Assembly, the larger of the rotating
  masses, is also contained within the motor
• stator assembly. The motor stator assembly
  laminations and windings have a thickness of
• 0.195 inches.
• The maximum radius of the rotating mass is 0.250
  inches.
• The maximum rate of rotation is 9000 rpm.

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TTCS Safety verification supporting analyses
Cold-orbit heater

• Case
• Non-running loop
• Heaters A B on maximum power
• All Tlt 281 C (555 K)? T lt 300 C

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TTCS Safety verification supporting analyses
Liquid line health heaters (capillary condenser
feed/return lines)

• Case
• Non-running loop
• Heaters A B on maximum power
• No conduction
• only radiation to environment (through MLI)
• Tmax 301 C