High Temperature Titanium/Water and Monel/Water Heat Pipes

Anderson, William G.; Dussinger, Peter M.; Bonner, Richard; Sarraf, David B.

doi:10.2514/6.2006-4113

Cited by 17 publications

(10 citation statements)

References 5 publications

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“…[39][40][41] With the development of alternative processes to CVD on a polymer template, these and other applications may also benefit from the porous structure. Electrodeposition, for example, has unique capabilities for nanoscale control.…”

Section: Discussionmentioning

confidence: 99%

Solid State Foaming of Nickel, Monel, and Copper by the Reduction and Expansion of NiO and CuO Dispersions

et al. 2018

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Nickel and its alloys are useful in a range of applications, and nickel foams have increased in popularity for functional applications, such as electrodes. Despite their versatility and interest for burgeoning technologies, there is only one well-developed method for producing porous nickel commercially. This work introduces a simple method for creating porosity in nickel and Monel (70% Ni, 30% Cu) that results in sub-micron to micron-scale pores and grains. This is accomplished by creating oxide dispersions in the metallic matrix and then reducing those oxides at elevated temperature to form pores. It is found that nickel and Monel reach maximum porosity at 800 C withMonel reaching a higher overall porosity (33% vs. 25% for Ni), whereas Cu exhibited 40% porosity under the same conditions. Varied matrix and oxide pairings are examined microstructurally, and the effects of matrix strength, oxide chemistry, and other factors are considered to determine factors in pore development. Uniquely, this method produces pores within individual metallic particles, so this porosity can be added to other powder methods of solid state foaming to enhance the performance in functional applications.

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Section: Discussionmentioning

confidence: 99%

Solid State Foaming of Nickel, Monel, and Copper by the Reduction and Expansion of NiO and CuO Dispersions

et al. 2018

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“…Figure 3 shows the key internal features of the evaporator and condenser, as well as the circulation path of the water. For material compatibility with water, both components were constructed using copper or Monel 400 [18][19][20][21].…”

Section: Evaporator and Condenser Designmentioning

confidence: 99%

Development and Characterization of an Air-Cooled Loop Heat Pipe With a Wick in the Condenser

Kariya¹,

Peters²,

Cleary³

et al. 2013

Journal of Thermal Science and Engineering Applications

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Thermal management of modern electronics is rapidly becoming a critical bottleneck of their computational performance. Air-cooled heat sinks offer ease and flexibility in installation and are currently the most widely used solution for cooling electronics. We report the characterization of a novel loop heat pipe (LHP) with a wick in the condenser, developed for the integration into an air-cooled heat sink. The evaporator and condenser are planar (102 mm Â 102 mm footprint) and allow for potential integration of multiple, stacked condensers. The condenser wick is used to separate the liquid and vapor phases during condensation by capillary menisci and enables the use of multiple condensers with equal condensation behavior and performance. In this paper, the thermal-fluidic cycle is outlined, and the requirements to generate capillary pressure in the condenser are discussed. The LHP design to fulfill the requirements is then described, and the experimental characterization of a single-condenser version of the LHP is reported. The thermal performance was dependent on the fan speed and the volume of the working fluid; a thermal resistance of 0.177 C/W was demonstrated at a heat load of 200 W, fan speed of 5000 rpm and fluid volume of 67 mL. When the LHP was filled with the working fluid to the proper volume, capillary pressure in the condenser was confirmed for all heat loads tested, with a maximum of 3.5 kPa at 200 W. When overfilled with the working fluid, the condenser was flooded with liquid, preventing the formation of capillary pressure and significantly increasing the LHP thermal resistance. This study provides the detailed thermal-fluidic considerations needed to generate capillary pressure in the condenser for controlling the condensation behavior and serves as the basis of developing multiplecondenser LHPs with low thermal resistance.

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“…The titanium-water LHP configuration was selected for hightemperature electronics applications as given by Anderson et al [10]. Transient temperature distributions, the evaporative heat transfer coefficient, the thermal resistance, and the evaporator wall superheat have been found in terms of the heat input at the evaporator, heat input at the compensation chamber, and radial acceleration field.…”

mentioning

confidence: 99%

Titanium-Water Loop Heat Pipe Operating Characteristics Under Standard and Elevated Acceleration Fields

Fleming

Thomas

Yerkes

2010

Journal of Thermophysics and Heat Transfer

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An experiment has been developed to examine the behavior of a titanium-water loop heat pipe under standard and elevated acceleration fields. The loop heat pipe was mounted on a 2.44 meter-diameter centrifuge table on edge with heat applied to the evaporator via a mica heater and heat rejected using a high-temperature polyalphaolefin oil coolant loop. The loop heat pipe was tested under the following parametric ranges: heat load at the evaporator 100 Q in 600 W, heat load at the compensation chamber 0 Q cc 50 W, radial acceleration 0 a r 10 g. For stationary operation, the evaporative heat transfer coefficient decreased monotonically with heat load whereas the thermal resistance decreased to a minimum then increased. Heat input to the compensation chamber was found to increase the evaporative heat transfer coefficient and decrease the thermal resistance for Q in 500 W. Transient periodic flow reversal in the loop heat pipe was found for some cases, which was likely due to vapor bubble formation in the primary wick. Operation in an elevated acceleration environment revealed that dry out was dependent on both Q in and a r , and the ability for the loop heat pipe to reprime after an acceleration event that induced dry out was influenced by the evaporator temperature. The evaporative heat transfer coefficient and thermal resistance were found not to be significantly dependent on radial acceleration. However, the evaporator wall superheat was found to increase slightly with radial acceleration at high heat loads. Nomenclature a = acceleration, m=s 2 C p = specific heat, J=kg-K D = diameter, m f = frequency, Hz g = standard acceleration, 9:81 m=s 2 h = heat transfer coefficient, W=m 2 -K k = thermal conductivity, W=m-K L = length, m m = mass, kg Nu = Nusselt number, hD=k Q = heat transfer rate, W R = thermal resistance, K=W Ra = Rayleigh number, gT s T 1 D 3 = r = radial coordinate, m T = temperature, K T = average temperature, K t = time, s V = volume, m 3 , voltage, volt = thermal diffusivity, m 2 =s = volumetric thermal expansion coefficient, K 1 = ratio of specific heats T = temperature difference, K T sh = evaporator wall superheat, T e T e=cc , K " = emissivity = resultant acceleration vector angle, arc degrees = absolute viscosity, N-s=m 2 = kinematic viscosity, m 2 =s = density, kg=m 3 = Stefan-Boltzmann constant, 5:67 10 8 W=m 2 -K 4 ' = fluid phase Subscripts amb = ambient b = bayonet inlet c = condenser cc = compensation chamber cl = centerline conv = convection cp = cold plate D = diameter e = evaporator eg = ethylene glycol e=cc = evaporator/compensation chamber junction ie = loop heat pipe inner edge in = in max = maximum oe = loop heat pipe outer edge out = out PAO = polyalphaolefin r = radial rad = radiation sh = superheat tot = total v = vapor z = axial 1 = primary 2 = secondary

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High Temperature Titanium/Water and Monel/Water Heat Pipes

Cited by 17 publications

References 5 publications

Solid State Foaming of Nickel, Monel, and Copper by the Reduction and Expansion of NiO and CuO Dispersions

Solid State Foaming of Nickel, Monel, and Copper by the Reduction and Expansion of NiO and CuO Dispersions

Development and Characterization of an Air-Cooled Loop Heat Pipe With a Wick in the Condenser

Titanium-Water Loop Heat Pipe Operating Characteristics Under Standard and Elevated Acceleration Fields

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