Research Papers: Evaporation, Boiling, and Condensation

Experimental Characterization of Capillary-Fed Carbon Nanotube Vapor Chamber Wicks

[+] Author and Article Information
Suresh V. Garimella

e-mail: sureshg@purdue.edu
School of Mechanical Engineering
and Birck Nanotechnology Center,
Purdue University,
585 Purdue Mall,
West Lafayette, IN 47907

1Corresponding author.

Contributed by the Heat Transfer Division of ASME for publication in the Journal of Heat Transfer. Manuscript received August 9, 2011; final manuscript received August 29, 2012; published online December 26, 2012. Assoc. Editor: Bruce L. Drolen.

J. Heat Transfer 135(2), 021501 (Dec 26, 2012) (7 pages) Paper No: HT-11-1388; doi: 10.1115/1.4007680 History: Received August 09, 2011; Revised August 29, 2012

The thermal performance of passive vapor chamber heat spreaders can be improved by enhancing evaporation from the internal wick structure. A wick structure that integrates conventional copper screen mesh and carbon nanotubes (CNTs) is developed and characterized for increased heat transport capability and reduced thermal resistance. The high-permeability mesh provides for a low-resistance liquid flow path while the carbon nanotubes, with their high thermal conductivity and large surface area, help reduce conduction and phase-change resistances. The wicks are fabricated by sintering a copper mesh on a multilayer substrate consisting of copper and molybdenum. CNTs are grown on to this mesh and a submicron layer of copper is evaporated on to the CNTs to improve wettability with water and wicking. Samples grown under varying degrees of positive bias voltage and varying thicknesses of post-CNT-growth copper evaporation are fabricated to investigate the effect of surface morphology variations. The resultant boiling curves indicate that micro/nano-integrated wicks fabricated with higher positive bias voltages during CNT synthesis coupled with thicker copper coatings produce lower wick thermal resistances. Notably, heat fluxes at the heater surface of greater than 500 W/cm2 were supported without a critical heat flux condition being reached.

Copyright © 2013 by ASME
Your Session has timed out. Please sign back in to continue.


Faghri, A., 1995, Heat Pipe Science and Technology, Taylor & Francis, Washington, DC.
Reay, D., and Kew, P., 2006, Heat Pipes, 5th ed., Butterwoth-Heinemann, Oxford, UK.
Chu, R. C., 2004, “The Challenges of Electronic Cooling: Past, Current and Future,” ASME J. Electron. Packag., 126, pp. 491–500. [CrossRef]
Garimella, S. V., Fleischer, A. S., Murthy, J. Y., Keshavarzi, A., Prasher, R., Patel, C., Bhavnani, S. H., Venkatasubramanian, R., Mahajan, R., Joshi, Y., Sammakia, B., Myers, B. A., Chorosinski, L., Baelmans, M., Sathyamurthy, P., and Raad, P. E., 2008, “Thermal Challenges in Next-Generation Electronic Systems,” IEEE Trans. Compon. Packag. Technol., 31, pp. 801–815. [CrossRef]
Iverson, B. D., Davis, T. W., Garimella, S. V., North, M. T., and Kang, S. S., 2007, “Heat and Mass Transport in Heat Pipe Wick Structures,” J. Thermophys. Heat Transfer, 21, pp. 392–404. [CrossRef]
Cao, X. L., Cheng, P., and Zhao, T. S., 2002, “Experimental Study of Evaporative Heat Transfer in Sintered Copper Bidispersed Wick Structures,” J. Thermophys. Heat Transfer, 16, pp. 547–552. [CrossRef]
Mwaba, M. G., Huang, X., and Gu, J., 2006, “Influence of Wick Characteristics on Heat Pipe Performance,” Int. J. Energy Res., 30, pp. 489–499. [CrossRef]
Ranjan, R., Murthy, J. Y., and Garimella, S. V., 2009, “Analysis of the Wicking and Thin-Film Evaporation Characteristics of Microstructures,” ASME J. Heat Transfer, 131, p. 101001. [CrossRef]
Vadakkan, U., Chrysler, G. M., Maveety, J., and Tirumala, M., 2007, “A Novel Carbon Nano Tube Based Wick Structure for Heat Pipes/Vapor Chambers,” Proceedings of Semiconductor Thermal Measurement and Management Symposium, (SEMI-THERM 2007), San Jose, CA, pp. 102–104. [CrossRef]
Ahn, H. S., Sinha, N., Zhang, M., Banerjee, D., Fang, S., and Baughman, R. H., 2006, “Pool Boiling Experiments on Multiwalled Carbon Nanotube (MWCNT) Forests,” ASME J. Heat Transfer, 128, pp. 1335–1342. [CrossRef]
Ujereh, S., Fisher, T., and Mudawar, I., 2006, “Effects of Carbon Nanotube Arrays on Nucleate Pool Boiling,” Int. J. Heat Mass Transfer, 50, pp. 4023–4038. [CrossRef]
Zhao, Y., and Chen, C.-L., 2006, “An Investigation of Evaporation Heat Transfer in Sintered Copper Wicks With Microgrooves,” Proceedings of 2006 ASME International Mechanical Engineering Congress and Exposition, (IMECE 2006), Chicago, IL, pp. 177–181. [CrossRef]
Semenic, T., and Catton, I., 2009, “Experimental Study of Biporous Wicks for High Heat Flux Applications,” Int. J. Heat Mass Transfer, 52, pp. 5113–5121. [CrossRef]
Davis, W., and Garimella, S. V., 2008, “Thermal Resistance Measurement Across a Wick Structure Using a Novel Thermosyphon Test Chamber,” Exp. Heat Transfer, 21, pp. 143–154. [CrossRef]
Weibel, J. A., Garimella, S. V., Murthy, J. Y., and Altman, D. H., 2011, “Design of Integrated Nanostructured Wicks for High-Performance Vapor Chambers,” IEEE Trans. Compon., Packag., Manuf. Technol., 1, pp. 859–867. [CrossRef]
Cai, Q., and Chen, C.-L., 2010, “Design and Test of a Carbon Nanotube Biwick Structure for High-Heat-Flux Phase Change Heat Transfer,” ASME J. Heat Transfer, 132, p. 052403. [CrossRef]
Cai, Q., and Chen, Y.-C., 2012, “Investigations of Biporous Wick Structure Dryout,” ASME J. Heat Transfer, 134, p. 021503. [CrossRef]
Coso, D., Srinivasan, V., Lu, M.-C., Chang, J.-Y., and Majumdar, A., 2012, “Enhanced Heat Transfer in Biporous Wicks in the Thin Liquid Film Evaporation and Boiling Regimes,” ASME J. Heat Transfer, 134, p. 101501. [CrossRef]
Garg, R. K., Kim, S. S., Hash, D. B., Fisher, T. S., and Gore, J. P., 2008, “Effects of Feed Gas Composition and Catalyst Thickness on Carbon Nanotube and Nanofiber Synthesis by Plasma Enhanced Chemical Vapor Deposition,” J. Nanosci. Nanotechnol., 8, pp. 3068–3076. [CrossRef] [PubMed]
Kim, S. S., Amama, P. B., and Fisher, T. S., 2010, “Preferential Biofunctionalization of Carbon Nanotubes Grown by Microwave Plasma-Enhanced CVD,” J. Phys. Chem. C, 114, pp. 9596–9602. [CrossRef]
Amama, P. B., Lan, C., Cola, B. A., Xu, X., Reifenberger, R. G., and Fisher, T. S., 2008, “Electrical and Thermal Interface Conductance of Carbon Nanotubes Grown Under Direct Current Bias Voltage,” J. Phys. Chem. C, 112, pp. 19727–19733. [CrossRef]
Weibel, J. A., Garimella, S. V., and North, M. T., 2010, “Characterization of Evaporation and Boiling From Sintered Powder Wicks Fed by Capillary Action,” Int. J. Heat Mass Transfer, 53, pp. 4204–4215. [CrossRef]
Coleman, H. W., and Steele, W. G., 1999, Experimentation and Uncertainty Analysis for Engineers, John Wiley & Sons, New York.
Weibel, J. A., and Garimella, S. V., 2012, “Visualization of Vapor Formation Regimes During Capillary-Fed Boiling in Sintered-Powder Heat Pipe Wicks,” Int. J. Heat Mass Transfer, 55, pp. 3498–3510. [CrossRef]
Maschmann, M. R., Amama, P. B., Goyal, A., Iqbal, Z., and Fisher, T. S., 2006, “Freestanding Vertically Oriented Single-Walled Carbon Nanotubes Synthesized Using Microwave Plasma-Enhanced CVD,” Carbon, 44, pp. 2758–2763. [CrossRef]


Grahic Jump Location
Fig. 1

Schematic diagram of a vapor chamber featuring a CNT array in the evaporator section

Grahic Jump Location
Fig. 2

Photograph of a sample after (a) mesh sintering on substrate, (b) deposition of trilayer catalyst, (c) CNT growth in MPCVD system, and (d) post CNT growth coating with copper

Grahic Jump Location
Fig. 3

SEM images at different magnifications of (a) mesh region and (b) central evaporation region of copper mesh/substrate integrated sample

Grahic Jump Location
Fig. 4

(a) Test facility heater block, chamber, and sample assembly. (b) Copper heater block temperature measurement locations and nomenclature.

Grahic Jump Location
Fig. 5

Schematic diagram of the sealed interface between the vertically aligned test sample and chamber wall

Grahic Jump Location
Fig. 6

Steady-state thermal performance data for the set of copper-coated CNT samples presented as (a) boiling curves and (b) thermal resistance curves. The maximum heat flux test points shown do not correspond to observed dryout or critical heat flux conditions.

Grahic Jump Location
Fig. 7

Plot of the minimum thermal resistance, Rmin, achieved along the boiling curve versus the approximate CNT density of each sample tested. The minimum occurs at a heat flux above 450 W/cm2 for all instances.

Grahic Jump Location
Fig. 8

Post-testing image and representative sketch of test sample highlighting a distinct ring formed in the CNT evaporator region



Some tools below are only available to our subscribers or users with an online account.

Related Content

Customize your page view by dragging and repositioning the boxes below.

Related Journal Articles
Related eBook Content
Topic Collections

Sorry! You do not have access to this content. For assistance or to subscribe, please contact us:

  • TELEPHONE: 1-800-843-2763 (Toll-free in the USA)
  • EMAIL: asmedigitalcollection@asme.org
Sign In