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Variable Conductance Heat Pipe for a Variable Thermal Link C. J
Variable Conductance Heat Pipe for a Variable Thermal Link C. J
Presentation Outline
Presentation Outline
International Lunar Network Trade Study
International Lunar Network Trade Study
Design Targets
Design Targets
Design Targets
Design Targets
Variable Thermal Link
Variable Thermal Link
LHP Shut-Down
LHP Shut-Down
VCHP Design Constraints
VCHP Design Constraints
VCHP Design
VCHP Design
ILN Anchor Node – Hybrid Wick
ILN Anchor Node – Hybrid Wick
Overall Design – NCG Reservoir Adjacent to Evaporator
Overall Design – NCG Reservoir Adjacent to Evaporator
VCHP Design – NCG Reservoir Adjacent to Evaporator
VCHP Design – NCG Reservoir Adjacent to Evaporator
Standard condenser location gives much higher mass
Standard condenser location gives much higher mass
VCHP with Internal Reservoir
VCHP with Internal Reservoir
VCHP with Internal Reservoir
VCHP with Internal Reservoir
VCHP Testing – Objectives
VCHP Testing – Objectives
VCHP Testing – Instrumentation
VCHP Testing – Instrumentation
Task 3. VCHP Testing – Lunar Freeze/Thaw
Task 3. VCHP Testing – Lunar Freeze/Thaw
Task 3. VCHP Testing – Lunar Freeze/Thaw Results
Task 3. VCHP Testing – Lunar Freeze/Thaw Results
Task 3. VCHP Testing – Lunar Freeze/Thaw Results
Task 3. VCHP Testing – Lunar Freeze/Thaw Results
Task 3. VCHP Testing – Lunar Freeze/Thaw Results
Task 3. VCHP Testing – Lunar Freeze/Thaw Results
Task 3. VCHP Testing – Lunar Freeze/Thaw Results
Task 3. VCHP Testing – Lunar Freeze/Thaw Results
Task 3. VCHP Testing – Lunar Freeze/Thaw Results
Task 3. VCHP Testing – Lunar Freeze/Thaw Results
Task 3. VCHP Testing – Lunar Performance
Task 3. VCHP Testing – Lunar Performance
Task 3. VCHP Testing – Lunar Performance Results
Task 3. VCHP Testing – Lunar Performance Results
Task 3. VCHP Testing – Lunar Performance Results
Task 3. VCHP Testing – Lunar Performance Results
Task 3. VCHP Testing – Space
Task 3. VCHP Testing – Space
Task 3. VCHP Testing – Space Thermal Diode
Task 3. VCHP Testing – Space Thermal Diode
Task 3. VCHP Testing – Space Thermal Diode Results
Task 3. VCHP Testing – Space Thermal Diode Results
Task 3. VCHP Testing – Space Thermal Diode Results
Task 3. VCHP Testing – Space Thermal Diode Results
Task 3. VCHP Testing – Space
Task 3. VCHP Testing – Space
Task 3. VCHP Testing – Space Performance Results
Task 3. VCHP Testing – Space Performance Results
Task 3. VCHP Testing – Space Performance Results
Task 3. VCHP Testing – Space Performance Results
Conclusions and Recommendations
Conclusions and Recommendations
Conclusions and Recommendations
Conclusions and Recommendations
Acknowledgements
Acknowledgements
Variable Conductance Heat Pipe for a Variable Thermal Link C. J
Variable Conductance Heat Pipe for a Variable Thermal Link C. J

Презентация на тему: «По изо весенние цветы фриз 2 класс». Автор: Bill Anderson. Файл: «По изо весенние цветы фриз 2 класс.ppt». Размер zip-архива: 1854 КБ.

По изо весенние цветы фриз 2 класс

содержание презентации «По изо весенние цветы фриз 2 класс.ppt»
СлайдТекст
1 Variable Conductance Heat Pipe for a Variable Thermal Link C. J

Variable Conductance Heat Pipe for a Variable Thermal Link C. J

Peters, J. R. Hartenstine, C. Tarau, & W. G. Anderson Advanced Cooling Technologies, Inc. Bill.Anderson@1-act.com

TFAWS Paper Session

Presented By Calin Tarau

Thermal & Fluids Analysis Workshop TFAWS 2011 August 15-19, 2011 NASA Langley Research Center Newport News, VA

2 Presentation Outline

Presentation Outline

Design Targets Variable Thermal Links Variable Conductance Heat Pipe Design Testing Conclusions and Recommendations

ISO:9001-2000 / AS9100-B Certified

3 International Lunar Network Trade Study

International Lunar Network Trade Study

Objective: Develop Variable Thermal Link designs to be used for Thermal Management of the Warm Electronics Box (WEB) on the International Lunar Network (ILN) Anchor Node mission Remove ~ 60 W during the lunar day Conserve heat to keep the electronics and battery warm during the lunar night

ISO:9001-2000 / AS9100-B Certified

4 Design Targets

Design Targets

Minimum Electronics Temperature

-10°C (263 K)

Maximum Electronics Temperature

50°C (303 K)

Min. Radiator Load (Moon)

73 W at lunar noon (30 % margin: 94.9 W)

Max. Radiator Load (Moon)

90 W during cruise (30 % margin: 117 W)

Power During Transit

Assume Full Power

Trip Length

5 Days, or Several Months

Duration

~ 6 years

Warm Electronics Box Geometry Will be Larger for Solar Option

24” x 41” x 14” (height)

Radiator Dimensions

21” (tall) x 25” (wide)

Solar power controls, Maximum Day and Minimum Night

ISO:9001-2000 / AS9100-B Certified

5 Design Targets

Design Targets

Minimizing power usage at night is extremely important 1 W power = 5 kg Batteries! 20° tilt means that conventional grooved aluminum/ammonia CCHPs can not be used in the WEB to isothermalize the system Maximum Adverse Elevation: 13.3 inch

Maximum Tilt

20° (10° slope, 10° hole)

Maximum Radiator Sink Temperature (Landing)

263 K

Minimum Radiator Temperature

141 K

Minimum Soil Temperature

-173°C (100 K)

Maximum Soil Temperature

116°C (390 K)

ISO:9001-2000 / AS9100-B Certified

6 Variable Thermal Link

Variable Thermal Link

Three basic elements to the WEB thermal control system A method to isothermalize the electronics and battery during the lunar night, and to remove heat to a second, variable conductance thermal link during the day (Constant Conductance Heat Pipes (CCHPs)). A variable thermal link between the WEB and the Radiator A radiator to reject heat Possible Thermal Links Variable Conductance Heat Pipes (VCHPs) Loop Heat Pipes (LHPs) LHPs with a Thermal Control Valve

ISO:9001-2000 / AS9100-B Certified

7 LHP Shut-Down

LHP Shut-Down

Need to shut down LHP during the Lunar night Minimize Heat Losses from the WEB Standard method uses a heater on the compensation chamber During normal operation, the Compensation Chamber runs at a lower temperature than the LHP evaporator Activate heater to shut down Increase saturation temperature and pressure of LHP Cancels the pressure difference required to circulate the sub-cooled liquid from the condenser to the evaporator Standard method validated in spacecraft 1 W = 5 kg Develop variable thermal links with no power requirement LHP with Thermal Control Valve – discussed in separate presentation VCHP

ISO:9001-2000 / AS9100-B Certified

8 VCHP Design Constraints

VCHP Design Constraints

VCHP differs from normal VCHP in 5 different ways Need to operate in space, and on the Lunar surface Need to operate with fairly large tilts in the evaporator Slope can vary from -20° to +20° ~13 inch adverse elevation across the WEB Grooved CCHPs operate with 0.1 inch adverse tilt Requires non-standard wick Tight temperature control not required Have a ~40°C range versus ±1°C for conventional VCHPs No power available for reservoir temperature control 1 W = 5 kg External reservoir will cool down to ~140 K Need to minimize heat leak when shut down

ISO:9001-2000 / AS9100-B Certified

9 VCHP Design

VCHP Design

Develop a VCHP design with three novel features Hybrid-Wick Screen wick in evaporator, grooved wick in condenser Allows operation on the Lunar surface, and during transit Reservoir Near Evaporator Keeps the reservoir warm at night Minimizes the reservoir size Bimetallic Adiabatic Section Grooved stainless steel section in the adiabatic section acts as a thermal dam to minimize heat leak during shutdown

ISO:9001-2000 / AS9100-B Certified

10 ILN Anchor Node – Hybrid Wick

ILN Anchor Node – Hybrid Wick

Standard VCHPs use grooved wick - not suitable for Moon 0.1 inch against gravity Tilt range for lunar surface: ±14° VCHP evaporator needs to operate against gravity Maximum adverse elevation: (9 inch) ? sin(14°) = 2.2 inch Screen wick in evaporator; Grooved wick in condenser Grooves and screen pump in space Screen pumps on lunar surface

+14°, Evaporator Gravity Aided

-14°, Evaporator Works Against Gravity

0°, Puddle Flow in Evaporator

ISO9001-2008 & AS9100-B Certified

11 Overall Design – NCG Reservoir Adjacent to Evaporator

Overall Design – NCG Reservoir Adjacent to Evaporator

NCG Tube

Radiator

Condenser

NCG Tube

NCG Reservoir

Condenser

Al

SS

Al

NCG Reservoir

Bimetallic Transition

Evaporator

Adiabatic

Evaporator

Reservoir is located near evaporator instead of condenser Placing near condenser is standard for most spacecraft VCHPs with electric heaters Condenser is too cold Would require oversized reservoir Location of reservoir inside WEB ensures that its temperature will be regulated NCG tube connects reservoir to condenser

ISO9001-2008 & AS9100-B Certified

12 VCHP Design – NCG Reservoir Adjacent to Evaporator

VCHP Design – NCG Reservoir Adjacent to Evaporator

Radiator

WEB Enclosure

Condenser (Grooves)

Adiabatic (Grooves)

NCG Reservoir

Evaporator (Screen)

ISO9001-2008 & AS9100-B Certified

13 Standard condenser location gives much higher mass

Standard condenser location gives much higher mass

ILN Anchor Node – NCG Reservoir Adjacent to Evaporator

Vertical Asymptotes Reservoir Near Evaporator: 0 K Reservoir Near Condenser: ?29.78 K

ISO9001-2008 & AS9100-B Certified

14 VCHP with Internal Reservoir

VCHP with Internal Reservoir

Adiabatic Section

Condenser

NCG Reservoir

Evaporator

ISO:9001-2000 / AS9100-B Certified

15 VCHP with Internal Reservoir

VCHP with Internal Reservoir

NCG Reservoir

Evaporator

Condenser

Adiabatic Section

Heating Block

Cooling Block

ISO:9001-2000 / AS9100-B Certified

16 VCHP Testing – Objectives

VCHP Testing – Objectives

Lunar Surface Operations (1/6 g) Freeze tolerance; conductance of “on” versus “off” states Performance in adverse gravity orientations Space Operations Thermal diode behavior Thermal Performance

ISO9001-2008 & AS9100-B Certified

17 VCHP Testing – Instrumentation

VCHP Testing – Instrumentation

TC Locations

ISO9001-2008 & AS9100-B Certified

18 Task 3. VCHP Testing – Lunar Freeze/Thaw

Task 3. VCHP Testing – Lunar Freeze/Thaw

Purpose Demonstrate ability to shut down Demonstrate ability to startup and operate for brief periods of time when cold Determine overall thermal conductance Procedure Vary sink conditions to simulate lunar cycle -60?C (liquid) and -177?C (frozen) Several orientations -2.3? & +2.3? Condenser nearly vertical Adiabatic and condenser sections gravity aided 25?C initial evaporator temperature Measure performance Evaluate temperature gradients across heat pipe; conductances; input power

ISO9001-2008 & AS9100-B Certified

19 Task 3. VCHP Testing – Lunar Freeze/Thaw Results

Task 3. VCHP Testing – Lunar Freeze/Thaw Results

TC27 (Cond)

TC1 (Gas)

TC26 (Cond)

TC10 (Evap)

TC30 (Cond)

TC23 (Cond)

Power

ISO9001-2008 & AS9100-B Certified

20 Task 3. VCHP Testing – Lunar Freeze/Thaw Results

Task 3. VCHP Testing – Lunar Freeze/Thaw Results

VCHP Operation (25 °C, 95 W, -2.3°)

ISO9001-2008 & AS9100-B Certified

21 Task 3. VCHP Testing – Lunar Freeze/Thaw Results

Task 3. VCHP Testing – Lunar Freeze/Thaw Results

VCHP Cold Shutoff (-60 °C, 0.2 W, -2.3°)

ISO9001-2008 & AS9100-B Certified

22 Task 3. VCHP Testing – Lunar Freeze/Thaw Results

Task 3. VCHP Testing – Lunar Freeze/Thaw Results

VCHP Very Cold Shutoff (-177 °C, 0.1 W, -2.3°)

Heat Pipe Overall Conductances for Freeze/Thaw (-2.3° Inclination)

Heat Pipe Overall Conductances for Freeze/Thaw (-2.3° Inclination)

Testing Condition

Overall Conductance (W/°C)

25 °C Operation

4.7

-60 °C Shutdown

0.00310

-177 °C Shutdown

0.00057

9 Inch Evaporator; 12 Inch Condenser

9 Inch Evaporator; 12 Inch Condenser

ISO9001-2008 & AS9100-B Certified

23 Task 3. VCHP Testing – Lunar Freeze/Thaw Results

Task 3. VCHP Testing – Lunar Freeze/Thaw Results

VCHP can undergo freeze/thaw cycles without performance degradation Effectively shuts off at cold temperatures and reduces heat transfer VCHP can experience short-duration full-power bursts during -60 °C and -177 °C cold shutdown Evaporator stays within -10 °C to +50 °C temperature range with no power except heat in-leak

ISO9001-2008 & AS9100-B Certified

24 Task 3. VCHP Testing – Lunar Performance

Task 3. VCHP Testing – Lunar Performance

Purpose: Demonstrate thermal performance in a simulated lunar environment Test Procedure – 1 temperature, 3 elevations -2.3?, 0? and +2.3? inclinations Condenser nearly vertical Adiabatic and condenser sections gravity aided 25?C evaporator temperature Test Results Summary 220W @ -2.3? 212W @ 0? 220W @ +2.3? Dryout was not demonstrated, test was terminated based on elevated temperature on TC9 Possible gap between evaporator wall and screen wick resulting in a “hot spot” 2 ? target power

ISO9001-2008 & AS9100-B Certified

25 Task 3. VCHP Testing – Lunar Performance Results

Task 3. VCHP Testing – Lunar Performance Results

Temperature Profile (25 °C, 220 W, -2.3°)

ISO9001-2008 & AS9100-B Certified

26 Task 3. VCHP Testing – Lunar Performance Results

Task 3. VCHP Testing – Lunar Performance Results

Powers demonstrated are twice maximum target power Pipe can operate against lunar gravity Evaporator stays within -10 °C to 50 °C target temperature range

ISO9001-2008 & AS9100-B Certified

27 Task 3. VCHP Testing – Space

Task 3. VCHP Testing – Space

Thermal diode Backward operation (reverse heat input/output & elevation) Measure heat transport in reverse direction Thermal Performance Determine dryout Extrapolate dryout power to 0-g

For All Space Tests Near horizontal Vary adverse elevation of evaporator (0.1 in, 0.2 in, 0.3 in)

ISO9001-2008 & AS9100-B Certified

28 Task 3. VCHP Testing – Space Thermal Diode

Task 3. VCHP Testing – Space Thermal Diode

The purpose of this test is to demonstrate that the pipe can behave as a diode in space Test Procedure – 3 elevations, 1 evaporator temperature 0.1”, 0.2” and 0.3” adverse elevation 25?C evaporator temperature 20?C ?T between evaporator and condenser Determine reverse heat transfer rate required to meet 20?C ?T requirement Conservative NCG charge Test Results 0.1 inch, 4.3 watts, -0.0195 W/°C 0.2 inch, 3.2 watts, -0.0157 W/°C 0.3 inch, 3.2 watts, -0.0160 W/°C

ISO9001-2008 & AS9100-B Certified

29 Task 3. VCHP Testing – Space Thermal Diode Results

Task 3. VCHP Testing – Space Thermal Diode Results

Thermal Diode Temperatures (Evaporator at 25 °C, 0.1 Inch Adverse)

ISO9001-2008 & AS9100-B Certified

30 Task 3. VCHP Testing – Space Thermal Diode Results

Task 3. VCHP Testing – Space Thermal Diode Results

Pipe is an effective thermal diode Pipe has very low thermal conductance Pipe reduces reverse heat transfer (transports only 4 % of maximum power)

ISO9001-2008 & AS9100-B Certified

31 Task 3. VCHP Testing – Space

Task 3. VCHP Testing – Space

Purpose: Demonstrate thermal performance in a simulated space environment Test Procedure – 3 elevations, 1 temperature 0.1”, 0.2” and 0.3” adverse elevation 25?C evaporator temperature Pipe operation with NCG and without NCG Possible asymmetry Flipped pipe 180? Marked improvement in performance

ISO9001-2008 & AS9100-B Certified

32 Task 3. VCHP Testing – Space Performance Results

Task 3. VCHP Testing – Space Performance Results

(25 °C, No NCG)

Zero-g power extrapolated

ISO9001-2008 & AS9100-B Certified

33 Task 3. VCHP Testing – Space Performance Results

Task 3. VCHP Testing – Space Performance Results

Pipe carries approximately 72 % of the zero-gravity target power Possible contributing factors causing asymmetry and lower than expected thermal performance Screen attachment resulting in a gap between the wall and wick Interface between screen and grooves resulting in a larger than designed hydraulic joint

ISO9001-2008 & AS9100-B Certified

34 Conclusions and Recommendations

Conclusions and Recommendations

Variable Thermal Link can be provided by Loop Heat Pipe LHP with Thermal Control Valve Variable Conductance Heat Pipe VCHP has the following benefits No power to shutdown Least expensive However, lowest TRL level VCHP was developed with the following Hybrid-Wick, to allow the VCHP to operate with a tilt Reservoir Near Evaporator, to minimize the reservoir size Bimetallic Adiabatic Section, to minimize axial heat leak to the cold radiator during shutdown

ISO:9001-2000 / AS9100-B Certified

35 Conclusions and Recommendations

Conclusions and Recommendations

Simulated Lunar performance testing demonstrated Shuts off at cold temperatures and reduces heat transfer Freeze/thaw cycles without performance degradation and accommodated short-duration full-power bursts during -60 °C and -177 °C cold shutdown Design can meet target power at adverse elevations Demonstrated start up with frozen condenser and can operate briefly at low condenser temperatures Simulated 0-g testing demonstrated Effective thermal diode operation Performance shortfalls encountered in testing indicated potential hybrid wick design and fabrication issues Currently examining sintered wick insert Eliminate hot spots Better wick/groove interface

ISO:9001-2000 / AS9100-B Certified

36 Acknowledgements

Acknowledgements

The trade study was sponsored by NASA Marshall Space Flight Center under Purchase Order No. 00072443. The VCHP was sponsored by NASA Marshall Space Flight Center under Purchase Order No. NAS802060. Jeffery Farmer was the Technical Monitor Kara Walker was the engineer on the Variable Thermal Link trade study. Tim Wagner as the technician at ACT. We would like to thank Kyle Van Riper for technical discussions about the VCHP. Any opinions, findings, and conclusions or recommendations expressed in this presentation are those of the authors and do not necessarily reflect the views of the National Aeronautics and Space Administration.

ISO:9001-2000 / AS9100-B Certified

37 Variable Conductance Heat Pipe for a Variable Thermal Link C. J

Variable Conductance Heat Pipe for a Variable Thermal Link C. J

Peters, J. R. Hartenstine, C. Tarau, & W. G. Anderson Advanced Cooling Technologies, Inc. Bill.Anderson@1-act.com

TFAWS Paper Session

Presented By Calin Tarau

Thermal & Fluids Analysis Workshop TFAWS 2011 August 15-19, 2011 NASA Langley Research Center Newport News, VA

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