Flow boiling in an in line set of short narrow gap channels

D. D. Janssen, J. M. Dixon, S. J. Young, F. A. Kulacki

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

Heat transfer coefficients in a set of three symmetrically heated narrow gap channels arranged in line are reported at watt densities of 1 kW/cm 3. This experimental configuration emulates an electronics system wherein power dissipation can vary across an array of processors, memory chips, or other components. Three pairs of parallel ceramic resistance heaters in a nearly adiabatic housing form the flow passage, and lengthto- gap ratios for each pair of heaters is 34.1 at a gap of 0.36 mm. Novec™ 7200 and 7300 are used as the heat transfer fluids. Non-uniform longitudinal power distributions are designed with the center heater pair at 1.5X and 2X the level of the first and third heater pairs. At all levels of inlet subcooling, single-phase heat transfer dominates heat transfer over the first two heater pairs, while the third pair exhibits significant increases because of the presence of flow boiling. Reynolds numbers range from 250 to 1200, Weber numbers from 2 to 15, and boiling numbers from O(10-4) to O(10-3). Exit quality can reach 30 percent in some cases. Overall heat transfer coefficients of 40 kW/m2K are obtained. Pressure drops for both NovecTM heat transfer fluids are approximately equal at a given mass flux, and a high coefficient of performance is obtained. With a mass flux of 250 kg/m2s, heater temperatures can exceed 95 °C, which is the acceptable limit of steady operation for contemporary high performance electronics. Thus, an optimal operating point involving power density, power distribution, mass flux, and inlet sub-cooling is suggested by the data set for this benchmark multi-heater configuration.

Original languageEnglish (US)
Title of host publicationHeat Transfer and Thermal Engineering
PublisherAmerican Society of Mechanical Engineers (ASME)
ISBN (Print)9780791856352
DOIs
StatePublished - Jan 1 2013
EventASME 2013 International Mechanical Engineering Congress and Exposition, IMECE 2013 - San Diego, CA, United States
Duration: Nov 15 2013Nov 21 2013

Publication series

NameASME International Mechanical Engineering Congress and Exposition, Proceedings (IMECE)
Volume8 B

Other

OtherASME 2013 International Mechanical Engineering Congress and Exposition, IMECE 2013
CountryUnited States
CitySan Diego, CA
Period11/15/1311/21/13

Keywords

  • Coefficient of performance
  • Flow boiling
  • Heat transfer coefficient
  • In line heater array
  • Narrow gap channel
  • Novectm heat transfer fluid

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  • Cite this

    Janssen, D. D., Dixon, J. M., Young, S. J., & Kulacki, F. A. (2013). Flow boiling in an in line set of short narrow gap channels. In Heat Transfer and Thermal Engineering (ASME International Mechanical Engineering Congress and Exposition, Proceedings (IMECE); Vol. 8 B). American Society of Mechanical Engineers (ASME). https://doi.org/10.1115/IMECE2013-63676