Inverted Meniscus Heat Pipe

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[[Image:HPfig18.png|center|thumb|400px|alt=.|<center>'''Figure 1: .'''</center>]]
 
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Advanced miniature heat pipes are needed to meet the demand for dissipating high heat fluxes (over 100 W/cm<sup>2</sup>) for electronic components <ref name="FR2012">Faghri, A., 2012, "Review and Advances in Heat Pipe Science and Technology," Journal of Heat Transfer, 134(12), 123001. http://dx.doi.org/10.1115/1.4007407</ref><ref name="Faghri1995">Faghri, A., 1995, Heat Pipe Science and Technology, 1st ed., Taylor & Francis, Washington, D.C.</ref>. Several techniques were proposed in this regard, including ivadizing <ref>Khrustalev, D., and Faghri, A., 1996a, "Enhanced Flat Miniature Axially Grooved Heat Pipe," Journal of Heat Transfer, 118(1), 261-264. http://dx.doi.org/10.1115/1.2824057</ref>, which is the deposit of a porous structure on the top of the lands between the grooves or “inverted meniscus scheme” <ref>Khrustalev, D., and Faghri, A., 1995c, "Heat Transfer in the Inverted Meniscus Type Evaporator at High Heat Fluxes," International Journal of Heat and Mass Transfer, 38(16), 3091-3101.  
Advanced miniature heat pipes are needed to meet the demand for dissipating high heat fluxes (over 100 W/cm<sup>2</sup>) for electronic components <ref name="FR2012">Faghri, A., 2012, "Review and Advances in Heat Pipe Science and Technology," Journal of Heat Transfer, 134(12), 123001. http://dx.doi.org/10.1115/1.4007407</ref><ref name="Faghri1995">Faghri, A., 1995, Heat Pipe Science and Technology, 1st ed., Taylor & Francis, Washington, D.C.</ref>. Several techniques were proposed in this regard, including ivadizing <ref>Khrustalev, D., and Faghri, A., 1996a, "Enhanced Flat Miniature Axially Grooved Heat Pipe," Journal of Heat Transfer, 118(1), 261-264. http://dx.doi.org/10.1115/1.2824057</ref>, which is the deposit of a porous structure on the top of the lands between the grooves or “inverted meniscus scheme” <ref>Khrustalev, D., and Faghri, A., 1995c, "Heat Transfer in the Inverted Meniscus Type Evaporator at High Heat Fluxes," International Journal of Heat and Mass Transfer, 38(16), 3091-3101.  
http://dx.doi.org/10.1016/0017-9310(95)00003-R
http://dx.doi.org/10.1016/0017-9310(95)00003-R
</ref><ref name="Kh1996b">Khrustalev, D., and Faghri, A., 1996b, "Estimation of the Maximum Heat Flux in the Inverted Meniscus Type Evaporator of a Flat Miniature Heat Pipe," International Journal of Heat and Mass Transfer, 39(9), 1899-1909. http://dx.doi.org/10.1016/0017-9310(95)00270-7</ref>.
</ref><ref name="Kh1996b">Khrustalev, D., and Faghri, A., 1996b, "Estimation of the Maximum Heat Flux in the Inverted Meniscus Type Evaporator of a Flat Miniature Heat Pipe," International Journal of Heat and Mass Transfer, 39(9), 1899-1909. http://dx.doi.org/10.1016/0017-9310(95)00270-7</ref>.
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[[Image:HPfig18.png|center|thumb|400px|alt=Schematic of an inverted meniscus type evaporator with the triangular fin: (a) with low heat fluxes; (b) with high heat fluxes.|<center>'''Figure 1:Schematic of an inverted meniscus type evaporator with the triangular fin: (a) with low heat fluxes; (b) with high heat fluxes.'''</center>]]
With extremely high heat fluxes, a vapor blanket appears inside the uniform structure in the evaporator along the heated solid surface <ref name="Kh1996b"></ref>, as shown in Figs. 18(a) and 18(b). In this case, evaporation takes place in the dry region of the porous structure at the liquid-vapor interface, the location of which shifts depending on the operational conditions. The heat is conducted to this interface from the heated surface through the dry region of the porous element, and the vapor flows mainly along the solid surface through this porous region towards the triangular vapor channel. The vapor flow is provided by the capillary pressure gradient due to the difference in the curvature of the menisci along the liquid-vapor interface inside the porous structure. Therefore, with high heat fluxes, part of the capillary pressure is spent on the compensation of the pressure drop in the vapor flow through the dry porous region. Hence, the maximum heat flux for this configuration should be calculated with respect to the formation of this vapor blanket and can be less than that estimated from the traditional capillary limit. Numerical results show that miniature copper water heat pipes with an inverted meniscus type evaporator of estimated dimensions of 2x7x120 mm is capable of withstanding high heat fluxes on the evaporator wall, which can be about 200 W/cm2 for horizontal orientation at 120°C <ref name="Kh1996b"></ref>.
With extremely high heat fluxes, a vapor blanket appears inside the uniform structure in the evaporator along the heated solid surface <ref name="Kh1996b"></ref>, as shown in Figs. 18(a) and 18(b). In this case, evaporation takes place in the dry region of the porous structure at the liquid-vapor interface, the location of which shifts depending on the operational conditions. The heat is conducted to this interface from the heated surface through the dry region of the porous element, and the vapor flows mainly along the solid surface through this porous region towards the triangular vapor channel. The vapor flow is provided by the capillary pressure gradient due to the difference in the curvature of the menisci along the liquid-vapor interface inside the porous structure. Therefore, with high heat fluxes, part of the capillary pressure is spent on the compensation of the pressure drop in the vapor flow through the dry porous region. Hence, the maximum heat flux for this configuration should be calculated with respect to the formation of this vapor blanket and can be less than that estimated from the traditional capillary limit. Numerical results show that miniature copper water heat pipes with an inverted meniscus type evaporator of estimated dimensions of 2x7x120 mm is capable of withstanding high heat fluxes on the evaporator wall, which can be about 200 W/cm2 for horizontal orientation at 120°C <ref name="Kh1996b"></ref>.

Current revision as of 19:33, 13 March 2014

 Related Topics Catalog
Types of Heat Pipes
  1. Two-Phase Closed Thermosyphon
  1. Capillary-Driven Heat Pipe
  1. Annular Heat Pipe
  1. Vapor Chamber
  1. Rotating Heat Pipe
  1. Gas-Loaded Heat Pipe
  1. Loop Heat Pipe
  1. Capillary Pumped Loop Heat Pipe
  1. Pulsating Heat Pipe
  1. Monogroove Heat Pipe
  1. Micro and Miniature Heat Pipes
  1. Inverted Meniscus Heat Pipe
  1. Nonconventional Heat Pipes

Advanced miniature heat pipes are needed to meet the demand for dissipating high heat fluxes (over 100 W/cm2) for electronic components [1][2]. Several techniques were proposed in this regard, including ivadizing [3], which is the deposit of a porous structure on the top of the lands between the grooves or “inverted meniscus scheme” [4][5].

Schematic of an inverted meniscus type evaporator with the triangular fin: (a) with low heat fluxes; (b) with high heat fluxes.
Figure 1:Schematic of an inverted meniscus type evaporator with the triangular fin: (a) with low heat fluxes; (b) with high heat fluxes.

With extremely high heat fluxes, a vapor blanket appears inside the uniform structure in the evaporator along the heated solid surface [5], as shown in Figs. 18(a) and 18(b). In this case, evaporation takes place in the dry region of the porous structure at the liquid-vapor interface, the location of which shifts depending on the operational conditions. The heat is conducted to this interface from the heated surface through the dry region of the porous element, and the vapor flows mainly along the solid surface through this porous region towards the triangular vapor channel. The vapor flow is provided by the capillary pressure gradient due to the difference in the curvature of the menisci along the liquid-vapor interface inside the porous structure. Therefore, with high heat fluxes, part of the capillary pressure is spent on the compensation of the pressure drop in the vapor flow through the dry porous region. Hence, the maximum heat flux for this configuration should be calculated with respect to the formation of this vapor blanket and can be less than that estimated from the traditional capillary limit. Numerical results show that miniature copper water heat pipes with an inverted meniscus type evaporator of estimated dimensions of 2x7x120 mm is capable of withstanding high heat fluxes on the evaporator wall, which can be about 200 W/cm2 for horizontal orientation at 120°C [5].


References

  1. Faghri, A., 2012, "Review and Advances in Heat Pipe Science and Technology," Journal of Heat Transfer, 134(12), 123001. http://dx.doi.org/10.1115/1.4007407
  2. Faghri, A., 1995, Heat Pipe Science and Technology, 1st ed., Taylor & Francis, Washington, D.C.
  3. Khrustalev, D., and Faghri, A., 1996a, "Enhanced Flat Miniature Axially Grooved Heat Pipe," Journal of Heat Transfer, 118(1), 261-264. http://dx.doi.org/10.1115/1.2824057
  4. Khrustalev, D., and Faghri, A., 1995c, "Heat Transfer in the Inverted Meniscus Type Evaporator at High Heat Fluxes," International Journal of Heat and Mass Transfer, 38(16), 3091-3101. http://dx.doi.org/10.1016/0017-9310(95)00003-R
  5. 5.0 5.1 5.2 Khrustalev, D., and Faghri, A., 1996b, "Estimation of the Maximum Heat Flux in the Inverted Meniscus Type Evaporator of a Flat Miniature Heat Pipe," International Journal of Heat and Mass Transfer, 39(9), 1899-1909. http://dx.doi.org/10.1016/0017-9310(95)00270-7