Flat Miniature Heat Pipes With Micro Capillary Grooves
01 Feb 1999-Journal of Heat Transfer-transactions of The Asme (American Society of Mechanical Engineers)-Vol. 121, Iss: 1, pp 102-109
TL;DR: In this article, a detailed experimental and theoretical analysis on maximum heat transfer capabilities of two copper-water FMHP's with diagonal trapezoidal micro capillary grooves and one copper water FMHP with axial rectangular micro-capillary grasps is presented.
Abstract: Flat miniature heat pipes (FMHP's) are shown to be very promising in the cooling of electronic component systems. This investigation presents a detailed experimental and theoretical analysis on maximum heat transfer capabilities of two copper-water FMHP's with diagonal trapezoidal micro capillary grooves and one copper-water FMHP with axial rectangular micro capillary grooves. Maximum heat flux on the evaporator wall of the 120-mm long axial grooved heat pipe, with a vapor channel cross-sectional area of approximately 1.5 x 12 mm 2 and rectangular grooves of dimensions 0.20 mm wide by 0.42 mm deep, exceeded 90 W/cm 2 in the horizontal orientation and 150 W/cm 2 in the vertical orientation. Theoretical prediction of the capillary limitation in the horizontal orientation agreed reasonably well with the experimental data.
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TL;DR: In this article, a review is presented concerning the types of heat pipes, heat pipe analysis, and simulations, as well as advances in computational and experimental methodologies for heat pipes.
Abstract: Over the last several decades, several factors have contributed to a major transformation in heat pipe science and technology applications The first major contribution was the development and advances of new heat pipes, such as loop heat pipes (LHPs), micro and miniature heat pipes, and pulsating heat pipes (PHPs) In addition, there are now many commercial applications that have helped contribute to the recent interest in heat pipes For example, several million heat pipes are manufactured each month for applications in CPU cooling and laptop computers Numerical modeling, analysis, and experimental simulation of heat pipes have significantly progressed due to a much greater understanding of various physical phenomena in heat pipes as well as advances in computational and experimental methodologies A review is presented hereafter concerning the types of heat pipes, heat pipe analysis, and simulations
334 citations
20 Apr 2014
TL;DR: A detailed overview of heat pipes is presented in this paper, including a historical perspective, principles of operations, types of heat pipe, heat pipe performance characteristics, heatpipe limitations, heat pipeline frozen startup and shutdown, heat manifold analysis and simulations, and various applications of heat manifolds.
Abstract: A detailed overview of heat pipes is presented in this paper, including a historical perspective, principles of operations, types of heat pipes, heat pipe performance characteristics, heat pipe limitations, heat pipe frozen startup and shutdown, heat pipe analysis and simulations, and various applications of heat pipes. Over the last several decades, several factors have contributed to a major transformation in heat pipe science and technology . The first major contribution was the development and advances of new heat pipes, such as loop heat pipes, micro and miniature heat pipes, and pulsating heat pipes. In addition, there are now many new commercial applications that have helped contribute to the recent interest in heat pipes, especially related to the fields of electronic cooling and energy. For example, several million heat pipes are now manufactured each month since all modern laptops use heat pipes for CPU cooling. Numerical modeling, analysis, and experimental simulation of heat pipes have also significantly progressed due to a much greater understanding of various physical phenomena in heat pipes, as well as advances in computational and experimental methodologies.
273 citations
Cites background from "Flat Miniature Heat Pipes With Micr..."
...Fabrication and experimental data on the performance characteristics of the flat watercopper heat pipe with external dimensions 2x7x120 mm have been reported by Hopkins et al. (1999) with radial heat fluxes of 90 W/cm2 and 150 W/cm2 for horizontal and vertical applications, respectively....
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...Miniature heat pipe is defined as a heat pipe with a hydraulic diameter in the range of 0.5 to 5 mm (Hopkins et al., 1999)....
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TL;DR: A short review on the micro and miniature heat pipes is presented in this paper, where the authors present a short review of the heat pipe design, definition and prediction of most simple cases, but even today heat pipes are not completely understood and solution strategies still contain significant simplifications.
202 citations
Cites background from "Flat Miniature Heat Pipes With Micr..."
...The shear stresses τ are determined according to [6-8]....
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...In the design of MHPs a number of heat transfer limitations should be taken in consideration [7, 8]....
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TL;DR: In this paper, an experimental study was performed to understand the nucleate boiling heat transfer of water-CuO nanoparticles suspension (nanofluids) at different operating pressures and different nanoparticle mass concentrations.
193 citations
TL;DR: In this article, the effect of water-based Al2O3 nanofluids as working fluid on the thermal performance of a flat micro-heat pipe with a rectangular grooved wick is investigated.
164 citations
References
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TL;DR: In this paper, a detailed mathematical model of low-temperature axially grooved heat pipes (AGHP) is developed in which fluid circulation is considered along with the heat and mass transfer processes during evaporation and condensation.
Abstract: A detailed mathematical model of low-temperature axially grooved heat pipes (AGHP) is developed in which the fluid circulation is considered along with the heat and mass transfer processes during evaporation and condensation. The results obtained are compared to existing experimental data. Both capillary and boiling limitations are found to be important for the flat miniature copper-water heat pipe, which is capable of withstanding heat fluxes on the order of 40 W/cm 2 applied to the evaporator wall in the vertical position. The influence of the geometry of the grooved surface on the maximum heat transfer capacity of the miniature AGHP is demonstrated.
76 citations
66 citations
14 Jan 1980
66 citations
TL;DR: In this article, an experimental study was conducted to demonstrate the ability of heat pipes to simultaneously dissipate high heat fluxes and high total power at low surface temperatures, and the two designs studied incorporate air or liquid cooling in the condenser sections, one of which is a manifold base plate with a series of holes drilled in it each of which was lined with sintered copper powder which served as the wick.
Abstract: Results of an experimental study are reported which demonstrate the ability of heat pipes to simultaneously dissipate high heat fluxes and high total power at low surface temperatures. The application is to cooling high power density (and high total power) semiconductor chip modules. The two designs studied incorporate air or liquid cooling in the condenser sections. The air-cooled design consisted of a manifold base plate with a series of holes drilled in it each of which was lined with sintered copper powder which served as the wick. An array of wick lined tubes was attached normal to the plate and served as the condenser section. The other heat pipe was disk shaped and also had a sintered wick structure. Cooling water channels were placed over the entire periphery of the housing except in the region of heat input. Reported steady heat fluxes are up to 31 W/cm2 corresponding to total power dissipation of up to 1400 W for the water cooled heat pipe and up to 47 W/cm2 (900 W total power) for the air cooled heat pipe with surface temperatures under 100°C.
29 citations
TL;DR: In this article, a physical and mathematical model of the evaporating thick liquid film, attached to the liquid-vapor meniscus in a circular micropore, has been developed.
Abstract: A physical and mathematical model of the evaporating thick liquid film, attached to the liquid-vapor meniscus in a circular micropore, has been developed. The liquid flow has been coupled with the vapor flow along the liquid-vapor interface. The model includes quasi-one-dimensional compressible steady-state momentum conservation for the vapor and also a simplified description of the microfilm at the end of the thick film. The numerical results, obtained for water, demonstrate that formation of extended thick liquid films in micropores can take place due to high-velocity vapor flow under high rates of vaporization. The model has also predicted that the available capillary pressure significantly changes with the wall-vapor superheat and other operational conditions.
18 citations