Experimental investigation of bendable heat pipes using sintered copper felt wick

Odhekar, Dhananjay; Harris, Daniel K.

doi:10.1109/itherm.2006.1645396

Cited by 14 publications

(17 citation statements)

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“…Research has shown that the effect of bending an originally straight heat pipe up to 90 • has a negligible effect on the vapor-pressure loss and little effect on the temperature difference between the evaporator and the condenser. It was found out that bending of compressible wicking structures may however obstruct the liquid flow to the evaporator and decrease the capillary limit and, consequently, the maximum heat-transport ability of the device [27].…”

Section: B Fabrication Of Pfhpmentioning

confidence: 99%

The Development of Polymer-Based Flat Heat Pipes

Oshman

Shi

et al. 2011

J. Microelectromech. Syst.

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In this paper, polymer-based flat heat pipes (PFHPs) with a thickness on the order of 1 mm have been successfully developed and tested. Liquid-crystal polymer (LCP) films with copper-filled thermal vias are employed as the case material. A copper micropillar/woven mesh hybrid wicking structure was designed and fabricated to promote evaporation/condensation heat transfer and the liquid supply to the evaporator of the PFHP. Water was selected as the working fluid because of its superior thermophysical properties. An experimental study was conducted to examine the PFHP performance. The test data demonstrated that the PFHP can operate with a heat flux of 11.94 W/cm 2 and results in effective thermal conductivity ranging from 650 to 830 W/m · K, with the value varying with the input heat flux and the tilt angle. With the employment of flexible LCP as casing material, the PFHP could potentially be directly integrated into a printed circuit board or flexible circuits for thermal management of heat-generating components.[ 2010-0280]Index Terms-Cooling, flat heat pipe (FHP), hybrid wick, polymer.

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Section: B Fabrication Of Pfhpmentioning

confidence: 99%

The Development of Polymer-Based Flat Heat Pipes

Oshman

Shi

et al. 2011

J. Microelectromech. Syst.

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“…But, it was in 1984 that Cotter first introduced the idea of "micro" heat pipes [1]. Transportation of heat is one of the most difficult and inefficient tasks in thermal management [2]. It often results in costly heat transfer losses and reduced overall efficiency [3].…”

Section: Introductionmentioning

confidence: 99%

“…It often results in costly heat transfer losses and reduced overall efficiency [3]. The performance of various mechanical and electrical components depends on the performance of the cooling system, because during operation they generate heat and dissipation of this heat is necessary for their optimum and reliable operation [2]. Many of today's electronic devices require cooling beyond the capabilities of standard metallic heat sinks.…”

Section: Introductionmentioning

confidence: 99%

Performance Analysis of a Heat Pipe with Stainless Steel Wick

Haque

Hossain

Mashud

2020

JEA

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In this study, the influences of different parameters on performance of a heat pipe with stainless steel net as wick have been presented. Experiments have been carried out for an input power range from 80 W to 160 W, constant cooling water mass flow rate of 0.0515 liter/s, and constant temperature at the inlet to condenser of 11°C. The temperatures were recorded at different power level by using a laser thermometer of the heater block, evaporator and condenser end at 50 second interval. Variation in the input power was done by varying the input voltage. It was done by a variack. Considering all criteria the copper is selected as the material of the container, water is selected as the working fluid of the heat pipe, stainless steel net is used as wick material. As copper/water heat pipes are able to tolerate storage temperatures between -65°C and 250°C, and can effectively operate between 10°C and 250°C. So a .9144 m copper tube is used to construct the heat pipe. Inside this tube stainless steel net is used as wick material to aid the flow of fluid. In the observation it is observed that the temperature of the evaporator end increases at a greater rate of the copper pipe than the heat pipe at different power level. It has been shown the variation of temperature of the heater block and the evaporator section at 80V, 100V, 120V, 140V, 160V respectively of the heat pipe and copper pipe.

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“…We begin by addressing the heat transfer limit that results from the capillarity phenomena active in heat pipes. ________________________________________________________________________ Unfortunately, the standard capillary limit model for even a simple cylindrical system has struggled to predict experimental data [104], [105], [106]. The need for an improved model became apparent as a model-based leading edge design methodology was devised.…”

Section: Discussionmentioning

confidence: 99%

“…Of the few studies which have attempted to experimentally validate the Chi design model, most find that the experimentally determined limit lies well below the predicted values [104], [105], [106]. The model is therefore not ________________________________________________________________________ conservative: its use could lead to unexpected failure under thermal conditions for which a heat pipe design was anticipated to successfully operate.…”

Section: Shortcomings Of the Chi Modelmentioning

confidence: 99%

Thermal Management at Hypersonic Leading Edges

Kasen

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The intense heat flux incident upon the leading edges of hypersonic vehicles traveling through the low earth atmosphere at speeds of Mach 5 and above requires creative thermal management strategies to prevent damage to leading edge components. Conventional thermal protection systems (TPSs) include the ablative coatings of NASA's Mercury, Gemini, and Apollo vehicles and the reusable reinforced carbon-carbon (RCC) system of the Space Shuttle Orbiter. The ablative approach absorbs heat by endothermic transformation (phase and/or chemical change to the polymeric coating). The heat is dissipated from the vehicle as the single-use coating eventually vaporizes. The RCC approach manages the intense heat by operating at high temperatures and radiating heat to its surroundings. The effectiveness of both approaches is predicated on keeping the heat flux that impinges upon the susceptible aluminum airframe below a critical level.ii ________________________________________________________________________ This dissertation has explored an alternative metallic TPS concept which seeks to redistribute the heat from the leading edge, thereby eliminating local hot spots. It makes use of high thermal conductance heat pipes coupled to the leading edge so that the thermal load may be redistributed from a high heat flux location (at the stagnation point) to regions where it can be effectively radiated from the vehicle. The sealed system concept is based upon the evaporation of a fluid near the heat source that sets up a region of elevated vapor pressure inside the pipe. The latent heat is transported down the resulting pressure gradient by the vapor stream where it condenses at cooler regions, releasing the heat for removal.Replenishment of the condensed working fluid to the evaporator region is accomplished through the capillary pumping action of a porous wick which lines the interior surface of the pipe.A design methodology for a wedge-shaped heat pipe is presented which uses a coupled flow-wall temperature model to construct design maps which relate design parameters of the leading edge system (overall length, wall thickness, and alloy) to its operating conditions (isothermal temperature, maximum temperature, maximum thermal stress). Potential bounds on heat transport due to physical phenomena linked to the sound speed within a chamber (sonic limit), capillarity, and boiling nucleation are considered by extending models developed for tube designs to the wedge geometry. A new heat flux limit is proposed which, should it be exceeded, subjects the leading edge to thermally-induced plastic deformation of the TPS. iii ________________________________________________________________________To investigate the validity of the design approach and thermal spreading effectiveness of the proposed concept, a low temperature wedge-shaped leading edge was designed and constructed using stainless steel as the case material and water as the working fluid. Under localized tip heating, the maximum temperatures were significantly reduced compa...

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Experimental investigation of bendable heat pipes using sintered copper felt wick

Cited by 14 publications

References 1 publication

The Development of Polymer-Based Flat Heat Pipes

The Development of Polymer-Based Flat Heat Pipes

Performance Analysis of a Heat Pipe with Stainless Steel Wick

Thermal Management at Hypersonic Leading Edges

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