Research Papers: Two-Phase Flow and Heat Transfer

Mathematical Modeling of Novel Two-Phase Heat Transfer Device for Thermal Management of Light Emitting Diodes

[+] Author and Article Information
Karthik S. Remella

Microscale Heat Transfer Laboratory,
Department of Mechanical
and Materials Engineering,
College of Engineering and Applied Science,
University of Cincinnati,
565 Rhodes Hall,
Cincinnati, OH 45221
e-mail: sivarara@mail.uc.edu

Frank M. Gerner

Microscale Heat Transfer Laboratory,
Department of Mechanical
and Materials Engineering,
College of Engineering and Applied Science,
University of Cincinnati,
565 Rhodes Hall,
Cincinnati, OH 45221
e-mail: Frank.Gerner@uc.edu

Ahmed Shuja

BritePointe, Inc.,
Hayward, CA 94541
e-mail: ahmed@lvlanalytics.com

1Corresponding author.

2Present address: lvl Analytics LLC, Oakland, CA 94612.

Contributed by the Heat Transfer Division of ASME for publication in the JOURNAL OF HEAT TRANSFER. Manuscript received September 28, 2015; final manuscript received December 15, 2016; published online February 28, 2017. Editor: Portonovo S. Ayyaswamy.

J. Heat Transfer 139(6), 062901 (Feb 28, 2017) (13 pages) Paper No: HT-15-1623; doi: 10.1115/1.4035649 History: Received September 28, 2015; Revised December 15, 2016

The paper introduces a novel two-phase heat transfer device (TPHTD) which is employed in the thermal management of light emitting diodes (LEDs). The heat transfer device structurally resembles a conventional loop heat pipe (LHP) without a compensation chamber, but operates very differently from it. The device is comprised of a central evaporator package and a circular coil that acts as a heat exchanger loop. The working fluid leaving the evaporator has a two-phase mixture quality of approximately 0.2. Having introduced the device, the paper delineates a mathematical model for predicting its thermal performance. The primary objective of the model is to provide a fundamental understanding of the operation of the device. A one-dimensional thermal resistance model (TRM) is utilized in modeling the evaporator. The paper presents a detailed discussion on obtaining these resistances from experiments conducted on the device. A correlation for the external heat transfer coefficient of the heat exchanger loop is proposed based on experiments and is found to be in good agreement with literature. The model predicts performance parameters such as board temperature, two-phase mixture quality, and saturation and subcooled temperatures (Tsat and Tsc) of the working fluid for different input thermal powers (Qtot). Based on experimental evidence, it is concluded that the majority of Qtot (∼75%) is utilized in phase change of the working fluid, and the rest reheats the working fluid from a lower subcooled temperature (Tsc) to the saturation temperature (Tsat) of the evaporator.

Copyright © 2017 by ASME
Your Session has timed out. Please sign back in to continue.


Bogue, R. , 2013, “ Recent Developments in MEMS Sensors: A Review of Applications, Markets and Technologies,” Sens. Rev., 33(4), pp. 300–304. [CrossRef]
Lim, S. R. , Kang, D. , Ogunseitan, O. A. , and Schoenung, J. M. , 2013, “ Potential Environmental Impacts From the Metals in Incandescent, Compact Fluorescent Lamp (CFL), and Light-Emitting Diode (LED) Bulbs,” Environ. Sci. Technol., 47(2), pp. 1040–1047. [CrossRef] [PubMed]
Yeh, L. T. , 1995, “ Review of Heat Transfer Technologies in Electronic Equipment,” ASME J. Electron. Packag., 117(4), pp. 333–339. [CrossRef]
Pal, A. , Joshi, Y. K. , Beitelmal, M. H. , Patel, C. D. , and Wenger, T. M. , 2002, “ Design and Performance Evaluation of a Compact Thermosyphon,” IEEE Trans. Compon. Packag. Technol., 25(4), pp. 601–607. [CrossRef]
Zimbeck, W. , Slavik, G. , Cennamo, J. , Kang, S. , Yun, J. , and Kroliczek, E. , 2008, “ Loop Heat Pipe Technology for Cooling Computer Servers,” 11th Intersociety Conference on Thermal and Thermomechanical Phenomena in Electronic Systems, ITHERM, pp. 19–25.
Pastukhov, V. G. , and Maydanik, Y. F. , 2009, “ Active Coolers Based on Copper-Water LHPs for Desktop PC,” Appl. Therm. Eng., 29(14–15), pp. 3140–3143. [CrossRef]
Ku, J. , 1999, “ Operating Characteristics of Loop Heat Pipes,” SAE Technical Paper No. 1999-01-2007.
Maydanik, Y. F. , 2005, “ Loop Heat Pipes,” Appl. Therm. Eng., 25(5–6), pp. 635–657. [CrossRef]
Maydanik, Y. F. , Vershinin, S. V. , Korukov, M. A. , and Ochterbeck, J. M. , 2005, “ Miniature Loop Heat Pipes—A Promising Means for Cooling Electronics,” IEEE Trans. Compon. Packag. Technol., 28(2), pp. 290–296. [CrossRef]
Launay, S. , Sartre, V. , and Bonjour, J. , 2007, “ Parametric Analysis of Loop Heat Pipe Operation: A Literature Review,” Int. J. Therm. Sci., 46(7), pp. 621–636. [CrossRef]
Faghri, A. , and Chen, M.-M. , 1989, “ A Numerical Analysis of the Effects of Conjugate Heat Transfer, Vapor Compressibility, and Viscous Dissipation in Heat Pipes,” Numer. Heat Transfer, Part A, 16(3), pp. 389–405. [CrossRef]
Kaya, T. , and Goldak, J. , 2006, “ Numerical Analysis of Heat and Mass Transfer in the Capillary Structure of a Loop Heat Pipe,” Int. J. Heat Mass Transfer, 49(17–18), pp. 3211–3220. [CrossRef]
Hamdan, M. , and Elnajjar, E. , 2009, “ Loop Heat Pipe: Simple Thermodynamic,” Int. J. Mech. Aerosp. Ind. Mech. Manuf. Eng., 3(4), pp. 367–373.
Hamdan, M. , Cytrynowicz, D. , Medis, P. , Shuja, A. , Gerner, F. M. , Henderson, H. T. , Golliher, E. , Mellott, K. , and Moore, C. , 2002, “ Loop Heat Pipe (LHP) Development by Utilizing Coherent Porous Silicon (CPS) Wicks,” 8th Intersociety Conference on Thermal and Thermomechanical Phenomena in Electronic Systems, ITHERM 2002, pp. 457–465.
Remella, K. S. , Gerner, F. M. , Shuja, A. , and Medis, P. , 2012, “ Steady State Numerical Modeling of Non-Conventional Loop Heat Pipes (LHPs),” ASME Paper No. IMECE2012-88217.
Kandlikar, S. G. , 2004, “ Heat Transfer Mechanisms During Flow Boiling in Microchannels,” ASME J. Heat Transfer, 126(1), pp. 8–16. [CrossRef]
Gorenflo, D. , 1993, “VDI Heat Atlas,” Springer, Berlin.
Tsubouchi, T. , and Masud, H. , 1970, “ Natural Convection Heat Transfer From Horizontal Cylinders With Circular Fins,” 4th International Heat Transfer Conference, Paris, France, Aug. 31–Sept. 5.
Knudsen, J. G. , and Pan, R. B. , 1963, “ Natural Convection Heat Transfer From Transverse Finned Tubes,” Chem. Eng. Prog., 59(7), pp. 45–50.
Kayansayan, N. , 1993, “ Thermal Characteristics of Natural Convection Cooled Fin-Tube Heat Exchanger,” Exp. Therm. Fluid Sci., 7(2), p. 131. [CrossRef]
Hahne, E. , and Zhu, D. , 1994, “ Natural Convection Heat Transfer on Finned Tube in Air,” Int. J. Heat Mass Transfer, 37(93), pp. 59–63. [CrossRef]
Tien, C. L. , and Chung, K. S. , 1979, “ Entrainment Limits in Heat Pipes,” AIAA J., 17(6), pp. 643–646. [CrossRef]
Nguyen-Chi, H. , and Groll, M. , 1981, “ Entrainment or Flooding Limit in a Closed Two-Phase Thermosyphon,” J. Heat Recovery Syst., 1(4), pp. 275–286. [CrossRef]
Hasegawa, S. , Echigo, R. , and Irie, S. , 1975, “ Boiling Characteristics and Burnout Phenomena on Heating Surface Covered With Woven Screens,” J. Nucl. Sci. Technol., 12(11), pp. 722–724. [CrossRef]
Zivi, S. M. , 1964, “ Estimation of Steady-State Steam Void-Fraction by Means of the Principle of Minimum Entropy Production,” ASME J. Heat Transfer, 86(2), pp. 247–251. [CrossRef]
Rice, C. K. , 1987, “ Effect of Void Fraction Correlation and Heat Flux Assumption on Refrigerant Charge Inventory Predictions,” ASHRAE Trans., 93(Pt. 1), pp. 341–367.


Grahic Jump Location
Fig. 1

A detailed schematic of conventional loop heat pipe (LHP) [10]

Grahic Jump Location
Fig. 2

A 2D schematic of the gravity-assisted TPHTD

Grahic Jump Location
Fig. 3

The evaporator package of the two-phase heat transfer device along with its orientation

Grahic Jump Location
Fig. 4

Environmental scanning electron microscope image of wire-mesh screen

Grahic Jump Location
Fig. 5

Thermal resistance model of evaporator package

Grahic Jump Location
Fig. 6

Liquid void fraction versus two-phase mixture quality, comparing two void fraction models

Grahic Jump Location
Fig. 7

Thermocouple locations during experiments on TPHTD

Grahic Jump Location
Fig. 8

Experimental reference heat transfer coefficient (ho-ref) versus saturation temperature (Tsat)

Grahic Jump Location
Fig. 9

Variation of board temperature (Tbrd) with applied thermal power (Qtot)

Grahic Jump Location
Fig. 10

Variation of saturation temperature (Tsat) with applied thermal power (Qtot)

Grahic Jump Location
Fig. 11

Variation of condenser (Lcon) and subcooler (Lsc) lengths with applied thermal energy (Qtot)

Grahic Jump Location
Fig. 12

Variation of subcooler temperature (Tsc) with applied thermal power (Qtot)

Grahic Jump Location
Fig. 13

Variation of two-phase mixture quality (xevp) with applied thermal power (Qtot)

Grahic Jump Location
Fig. 14

Variation of mass flow rate of working fluid with applied thermal energy (Qtot)




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