Development of An Experimental Small Loop Heat Pipe with PTFE Wick

Nagano, Hosei; Fukuyoshi, Fuyuko; Ogawa, H.; Nagai, Hiroki

doi:10.2514/6.2010-6006

Cited by 3 publications

(5 citation statements)

References 4 publications

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“…The LHP operating temperature adjusts itself such that the condenser generates enough subcooling to match the heat leak and the heat exchange with the environment. SC Q is obtained by the following equation 9) :…”

Section: )mentioning

confidence: 99%

“…By heating or cooling the CC, the overall loop temperature can be controlled. A detailed explanation can be seen in Ref (9). In this study, a thermoelectric converter (TEC) was used for the temperature control.…”

Section: Temperature Controlmentioning

confidence: 99%

“…As a result, the subcooled region increased, and therefore the heat leak increased as expressed by eq. (9). In order to compensate HL Q , much TEC power was required.…”

Section: Power Step-up and Step-downmentioning

confidence: 99%

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Thermal Vacuum Testing of a Small Loop Heat Pipe with a PTFE Wick for Spacecraft Thermal Control

Nagano

Nishikawara

Fukuyoshi

et al. 2012

AEROSPACE TECHNOLOGY JAPAN

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A loop heat pipe (LHP) is a two-phase heat transfer device that utilizes the evaporation and condensation of a working fluid to transfer heat, and the capillary forces developed in fine porous wicks to circulate the fluid. LHPs have been gaining increased acceptance for spacecraft missions, and recently, small LHPs on the order of a few hundred watts have been investigated for this purpose. In this study, a 100W class small LHP with a polytetrafluoroethylene wick as the primary wick was designed and fabricated for thermal vacuum testing. The LHP has a thermoelectric converter (TEC) to control the loop operating temperature. The thermal vacuum test was conducted to evaluate the LHP's thermal performance under a space-simulated environment such as ultra-high-vacuum, and black body radiation, except for a gravitational effect. The loop showed large thermal hysteresis before and after the large and small head loads. The TEC was able to control the loop operating temperature with a small amount of electrical power.

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Section: )mentioning

confidence: 99%

Section: Temperature Controlmentioning

confidence: 99%

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Thermal Vacuum Testing of a Small Loop Heat Pipe with a PTFE Wick for Spacecraft Thermal Control

Nagano

Nishikawara

Fukuyoshi

et al. 2012

AEROSPACE TECHNOLOGY JAPAN

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“…In the study by Nagano et al [26], an experimental miniature LHP was used for heat transfer performance testing using a wick made of PTFE. Multiple PTFE wicks having pore sizes ranging between 0.8 -2.2 µm (porosity ranging 27% -50%) were fabricated and tested for fluid transport capability, as well as effective thermal conductivity.…”

Section: Introductionmentioning

confidence: 99%

“…Standard wick materials used have included fine pore sintered metals such as Nickel [4][5][6]8,9,14,16,20], Titanium [21,22] and Stainless Steel [23,24]. Alternate materials such as Porous Silicon [13], Polystyrene [25], Polyethylene [7,26] and soda lime glass [27, 28,29] have also been used in LHPs as wick structures at a continually increasing rate. For a more complete review of relevant literature the authors recommend Silk and Myre [28,29,30] Wu et al [25] investigated LHP performance when using a polystyrene wick structure with Ammonia as the working fluid.…”

Section: Introductionmentioning

confidence: 99%

Fractal Loop Heat Pipe Performance Comparisons of a Soda Lime Glass and Compressed Carbon Foam Wick

Myre¹,

Silk

2014

52nd Aerospace Sciences Meeting

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This study compares heat flux performance of a Loop Heat Pipe (LHP) wick structure fabricated from compressed carbon foam with that of a wick structure fabricated from sintered soda lime glass. Each wick was used in an LHP containing a fractal based evaporator. The Fractal Loop Heat Pipe (FLHP) was designed and manufactured by Mikros Manufacturing Inc. The compressed carbon foam wick structure was manufactured by ERG Aerospace Inc., and machined to specifications comparable to that of the initial soda lime glass wick structure. Machining of the compressed foam as well as performance testing was conducted at the United States Naval Academy. Performance testing with the sintered soda lime glass wick structures was conducted at NASA Goddard Space Flight Center. Heat input for both wick structures was supplied via cartridge heaters mounted in a copper block. The copper heater block was placed in contact with the FLHP evaporator which had a circular cross-sectional area of 0.88 cm 2 . Twice distilled, deionized water was used as the working fluid in both sets of experiments. Thermal performance data was obtained for three different Condenser/Subcooler temperatures under degassed conditions. Both wicks demonstrated comparable heat flux performance with a maximum of 76 W/cm 2 observed for the soda lime glass wick and 75 W/cm 2 for the compressed Carbon foam wick. Nomenclature Area= area (cm 2 ) P = pressure (kPa) T = temperature (°C) TC = thermocouple TM = thermistor δ = error ∆ = difference k = thermal conductivity (W/m-K) h fg = enthalpy of vaporization (kJ/kg) q ɺ ′ ′ = heat flux per unit area(W/cm 2 ) q ɺ ′ ′ δ = uncertainty (W/cm 2 ) ܴ" = Thermal resistance (°C/W/cm 2 ) x = thermocouple distance (mm) Subscripts cond,avg = condenser average int = heat flux probe/evaporator interface k = conductivity sat = saturation surf = surface 1 Senior Principle Engineer/Scientist, KDM Systems Inc., AIAA Senior Member 2 Branch Head, Cryogenics and Fluids, Code 552.0, AIAA Member Downloaded by CORNELL UNIVERSITY on July 31, 2015 | http://arc.aiaa.org |

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Fractal Loop Heat Pipe performance testing with a compressed carbon foam wick structure

Silk

Myre

2013

Applied Thermal Engineering

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Development of An Experimental Small Loop Heat Pipe with PTFE Wick

Cited by 3 publications

References 4 publications

Thermal Vacuum Testing of a Small Loop Heat Pipe with a PTFE Wick for Spacecraft Thermal Control

Thermal Vacuum Testing of a Small Loop Heat Pipe with a PTFE Wick for Spacecraft Thermal Control

Fractal Loop Heat Pipe Performance Comparisons of a Soda Lime Glass and Compressed Carbon Foam Wick

Fractal Loop Heat Pipe performance testing with a compressed carbon foam wick structure

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