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AMS Tracker Thermal Control System TTCS Progress

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TIM Meeting Houston, 18-23 October, 2004 ... Sun Yat-Sen University team: Prof. Z. He, ... Condenser Design Details: Thermal calculations for max Trad. Approach ... – PowerPoint PPT presentation

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Title: AMS Tracker Thermal Control System TTCS Progress


1

AMS Tracker Thermal Control System TTCS
Progress Design Issues TIM Meeting Houston,
18-23 October, 2004 NLR-team J. van Es,
M.P.A.M. Brouwer, B. Verlaat (NIKHEF), A. Pauw,
G. van DonkSun Yat-Sen University team Prof. Z.
He, Prof. K. Guo, Prof.J.Q. Ni INFN-AMS-team
Prof. R. Batiston, M. Menichelli
2
Content
  • System Design Issues
  • TTCS Loop lay-out update (no volume enclosure
    possible)
  • TTCS-USS interface temperatures (impact on
    start-up)
  • Condenser design progress
  • Radiator survival heater set-up, lay-out, number
    Pt1000s (TBD)
  • health Control Loops (draft document available)
  • Open safety issues (to be discussed/not presented
    here)
  • TTCS filling procedure (impact on AMS
    Integration)
  • No enclosures possible by the current loop
    lay-out (valves)

3
System Design Issues Loop lay-out update primary
loop
4
Primary Loop
  • Number and location of control sensor locations
    fixed
  • Implementation of a start-up heater to
  • Account for start-up after power down without
    loosing the redundancy

5
System Design Issues Loop lay-out update
secondary loop
6
Secondary Loop
  • Number and location of control sensor locations
    fixed
  • Implementation of a start-up heater to
  • Account for start-up after power down without
    loosing the redundancy
  • Redundancy of the primary and secondary loop is
    made similar (except valves and LFM).

7
System Design Issues TTCS-USS interface
temperatures (impact on start-up)
  • USS Worst case hot temperatures impact the TTCS
    start-up flexibility
  • Old values (BOL USS optical properties)
  • TTCS-P TUSSnearBox 23.6 C
  • TTCS-S TUSSnearBox 42.7 C
  • New values (EOL USS optical properties)
  • TTCS-P TUSSnearBox 59.4 C
  • TTCS-S TUSSnearBox 50.3 C
  • TTCS can start-up with Tbox,max20 C (accumulator
    at 25 C) (even TBC little margin in the box)
  • During operation TTCS cools itself by the loop.
  • TTCS start-up is therefore with current USS
    temperatures not possible in most orbits at EOL.
  • MLI on the USS is proposed (CGS) to solve the
    problem (smaller a solar heat input)

8
Condenser Design Progress
  • Agreed with NASA/LM is high pressure tolerant
    condenser design allowing thawing (up to 3000 bar
    TBC)
  • Derived thermal requirement for the radiator and
    liquid line temperatures. T(enclosed liquid CO2)
    lt 5 ºC This means by analysis Tradiator and
    Tliqlines lt 5 º C

9
(No Transcript)
10
Condenser New Design
  • Situate the connection between the parallel
    condenser tubing outside the freezing area
    (halfway the path to the TTCS-boxes)
  • To cope with high forces/pressures that occur
    during thawing (after freezing) a condenser
    consisting of capillary tubing out of INCONEL 718
    is proposed.
  • Number of parallel tubes will be optimised for
    weight, pressure drop and heat transfer.

11
Mechanical New Condenser Design (schematic)
  • Here 7x7 49 tubes are drawn.
  • Preliminary thermal model calculations show this
    might be reduced to 7x3 or 7x2 tubes.

12
Mechanical New Condenser Design
Material Inconel 718 capillary piping Interface
material cho-term
13
Mechanical New Condenser Design
Flat interface plate
14
Mechanical New Condenser Design
Ribbed interface plate
15
Condenser Design Progress Overall (1/3)
  • Strength-Stress calculations Inconell 718 tubing
  • Pressures up to 3000 bar are feasible with
    acceptable thickness
  • Calculation of optimum number of parallel tubing
  • Required condensing area (Length, diameter,
    passages)
  • Condenser Pressure drop contribution
  • Calculations in progress (will be finalised when
    length is frozen) (see condenser_properties_design
    _20041015.pdf)

16
Condenser Design Progress Pressure drop as
function of number of capillary tubes
  • Pipe ID1mm, L10m
  • Pressure drop decrease
  • With the increasing of
  • Pipe numbers.
  • Increasing the length
  • and the number of tubes
  • will increase the whole
  • condenser mass.
  • The pressure drop mainly
  • depends on the inlet
  • condenser length.
  • From system pressure
  • drop, Npar should be
  • larger than 28 when
  • L10m, which is too long.

17
Condenser Design Progress Overall (2/3)
  • Condenser modelling and attached to detailed
    radiator model (model ready, implementation
    pending)
  • Radiator temperatures will be calculated to check
    5 C maximum temperature during thawing (all
    orbits including transport to ISS)
  • Investigate maximum position freezing front
  • (calculate the radiator survival heater
    positions, thermostats, etc)

18
Condenser Design Progress Overall (3/3)
  • Update mechanical interface Condenser-Tracker
    radiator with 7 HPs (see Condenser update OHB)
  • Investigation on manufacturing options connection
    tube-interface plate
  • Possible options (stainless steel, Inconell 718,
    aluminium (preferred))
  • Possible options are explosion welding between
    Inconell 718 and interface material (tubes are
    then connected to Inconell 718)

19
Condenser design details Location of condenser
connection
  • Location is defined by the maximum position of
    freezing front in the condenser tubing
  • Approach
  • Definition of number parallel tubes for heat
    transfer
  • Modelling of the condenser tubing and incorporate
    in current TTCS Sinda model.
  • Assumptions
  • a. Tubes wrapped in MLI
  • b. Free convection in tubing is neglected
  • c. Detailed radiator model is used and
    incorporated in the TTCS-model
  • Freezing front is defined in worst case cold
  • Assumption
  • A worst case estimate of the background
    temperature viewed by the MLI around the tubing
    is taken
  • Check if the freezing front is at an acceptable
    location.
  • If acceptable to NASA the location of the
    condenser connection can be frozen.
  • If not a VF calculation between the MLI around
    the tubing and the AMS ISS surroundings is
    required.(will be a combined CGS-NLR analysis)

20
Condenser Design Details Thermal calculations
for max Trad
  • Approach
  • Define the maximum temperature above freezing
    enclosed in the freezing parts of the condenser
    and frozen part of the condenser lines
  • Gather information on maximum radiator
    temperature in power-down (already available at
    CGS) including
  • transfer shuttle to final destination on truss
  • on truss
  • Make a worst case assumption of local solar input
    on the liquid lines (wrapped in MLI) and show
    TltTradmax
  • Prove by analysis Tradmax --gt PltPmax
  • Prove condenser and liquid line design is Pmax
    resistant
  • mechanical analysis
  • test
  • focus on condenser exit

21
  • Radiator survival heater set-up, lay-out
  • See Loop Lay-out for electrical (parallel)
    connection
  • See ComponentsList21_09_04_V11.xls
  • Due to HP-freezing (radiator temps lt 78 C)
    heaters should must cover (almost) complete
    HP-length
  • Discussion with OHB of acceptable open areas
    between heaters on pipes.

22
Survival heater details Pt1000s at radiator
  • Needed for TTCS Electronics design
  • Define the final number and location of Pt1000s
    on radiator (OHB)
  • Pt1000s are required as Dallas sensors are out
    of temperature range on the radiator
  • TTCS Electronics team proposes to read them by a
    the microprocessor, not to overload the FPGA

23
Survival heater details Liquid line heaters
  • Sizing approach (similar to freezing front
    calculation)
  • Modelling of the condenser tubing and incorporate
    in current TTCS Sinda model.
  • Assumptions
  • a. Tubes wrapped in MLI
  • b. Free convection in tubing is neglected
  • c. Detailed radiator model is used and
    incorporated in the TTCS-model
  • Heater power to heat up is defined in worst case
    cold
  • Assumptions
  • A worst case estimate of the background
    temperature viewed by the MLI around the tubing
    is taken
  • Heating should be faster than radiator/condenser
    heating
  • Heater is wrapped around the parallel tubing
    liquid lines (less dense at condenser connection)
  • Heater power small (low heat capactity) and no
    heat loss to surroundings

24
Health Monitoring Control Loops (proposed set-up)
  • General
  • On-board health controls will be limited to
    detection unsafe situations
  • On-board will not comprise failure detection
    (will be performed on-ground)
  • health controls may require action from
  • TTCE (Thermal Tracker Control Electronics)
  • JMDC
  • PDS (via JMDC)
  • Implementation of the health controls in TTCE or
    JMDC
  • Implementation in TTCE is preferred as
  • Fast response is required (limited thermal
    capacity in Tracker)
  • health control must protect TTCS during short
    periods of unattended operation during JMDC-TTCE
    communication failures

25
health Control Loops (proposed set-up)
  • General
  • Health Monitoring
  • TTCE
  • A health-flag (8-16 bit word) is proposed as a
    Health monitor.
  • OK/Not_OK for the several Health limits
  • Health algorithms have an update freq. 1 Hz
  • JMDC
  • JMDC will process health flag and take (to be
    defined) action(s)

26
Health Control Loops (proposed set-up)
  • Overview of Control Loops
  • Overall Tracker electronics temperature Health
    control
  • JMDC-TTCE communication Health control (in JMDC)
  • Subcooling margin Health control
  • Hot_Cold temperature difference Health control
  • High temperature at pump inlet Health control
  • Accumulator temperature Health controls
  • Pre-heaters temperatures too high Health control
  • Tracker too low temperature Health control
  • Condensers temperatures out of limits Health
    control

27
Health Control Loops (proposed set-up)
  • Overall Tracker electronics temperature Health
    control
  • Objective
  • Protect Tracker electronics for too high
    temperatures (25 C)
  • Rule
  • If TTracker gt 25 C
  • Action
  • JMDC will switch-off Tracker electronics

28
Health Control Loops (proposed set-up)
  • JMDC-TTCE communication Health control (in JMDC)
  • Objective
  • Protect of Tracker against incorrect functioning
    of the TTCS, by switching off Tracker electronics
    after TTCE-JMDC communication outage
  • Rule
  • If TTCS_JMDC_Com_out_duration gt 10 (TBC) samples
  • Action
  • JMDC will switch-off Tracker electronics

29
Health Control Loops (proposed set-up)
  • Subcooling margin Health control (1/2)
  • Objective
  • Increase TTCE accumulator set-point to avoid
    vapour at pump inlet
  • Rule
  • If DT_subcool (T_acc-T_pump_inlet) lt Health
    margin 5 C (TBC)
  • Action
  • TTCE increases Taccu_setpointTaccu_setpoint
    TBD C

30
Health Control Loops (proposed set-up)
  • Subcooling margin Health control (2/2)
  • Objective
  • Switch-off pump in case of T_pump inlet
    temperature reaches T_accu
  • Rule
  • If DT_subcool (T_acc-T_pump_inlet) lt Health
    margin 2.5 C (TBC)
  • Action
  • Set pump to 0 RPM

31
Health Control Loops (proposed set-up)
  • Hot_Cold temperature difference Health control
  • Objective
  • Protect pump for cavitation in case of
    unacceptable low accumulator volume
  • Rule
  • If T_accu-T_meanloop gt 45 C (TBC)
  • Action
  • TTCE will set pump to 0 RPM

32
Health Control Loops (proposed set-up)
  • High temperature at pump inlet Health control
  • Objective
  • Protect pump for fluid flow close to critical
    point CO2 (avoid cavitation)
  • Rule
  • If T_pump_inlet gt 25 C
  • Action
  • TTCE will set pump to 0 RPM

33
Health Control Loops (proposed set-up)
  • Accumulator temperature Health control (1/2)
  • Objective
  • Protect Tracker Electronics from overheating
  • Rule
  • If T_accu_upper_operating_range gt 22 C
  • Action
  • JMDC switch-off electronics

34
Health Control Loops (proposed set-up)
  • Accumulator temperature Health control (2/2)
  • Objective
  • Prevent Accumulator to heat above Health limit
    (80 C)
  • Rule
  • If T_accu_temperature gt 79 C
  • Action
  • JMDC switch-off electronics
  • Remark Obsolete as Health analyses will assure
    80 C is not reachable

35
Health Control Loops (proposed set-up)
  • Pre-heaters temperatures too high Health control
  • Objective
  • Prevent too high temperature at pre-heater
    location (in case pump is off)
  • Rule
  • If T_pre_heater gt 40 C
  • Action
  • TTCE switch off pre-heater power

36
Health Control Loops (proposed set-up)
  • Tracker too low temperature Health control
  • Objective
  • Prevent pumping too cold liquid in Tracker. Add
    additional power to stay within survival
    temperature window (-20 C)
  • Rule
  • If T_Tracker lt -16 C
  • Action
  • JMDC switch-on start-up heaters (on/off
    controlled)

37
Health Control Loops (proposed set-up)
  • Condensers temperatures out of limits Health
    control
  • Objective
  • Prevent freezing of condensers when PDS has
    powered off Health heaters. Alert JMDC command to
    command PDS to power-on survival heaters
  • Rule
  • If T_radiators lt -40 C (TBC)
  • Action
  • Alert JMDC to power on PDS survival heaters
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