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Title: Entrance-length dendritic plate heat exchangers

We explore the idea that the highest heat transfer rate between two fluids in a given volume is achieved when plate channel lengths are given by the thermal entrance length, i.e., when the thermal boundary layers meet at the exit of each channel. The overall design can be thought of an elemental construct of a dendritic heat exchanger, which consists of two tree-shaped streams arranged in cross flow. Every channel is as long as the thermal entrance length of the developing flow that resides in that channel. The results indicate that the overall design will change with the total volume and total number of channels. We found that the lengths of the surfaces swept in cross flow would have to decrease sizably as number of channels increases, while exhibiting mild decreases as total volume increases. The aspect ratio of each surface swept by fluid in cross flow should be approximately square, independent of total number of channels and volume. We also found that the minimum pumping power decreases sensibly as the total number of channels and the volume increase. FurtherThe maximized heat transfer rate per unit volume increases sharply as the total volume decreases, in agreement with the natural evolutionmore » toward miniaturization in technology.« less
Authors:
 [1] ;  [2] ; ORCiD logo [3] ;  [4]
  1. Duke Univ., Durham, NC (United States)
  2. Kuwait Univ., Safat (Kuwait)
  3. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
  4. Univ. of Toulouse (France)
Publication Date:
Grant/Contract Number:
AC05-00OR22725
Type:
Accepted Manuscript
Journal Name:
International Journal of Heat and Mass Transfer
Additional Journal Information:
Journal Volume: 114; Journal Issue: C; Journal ID: ISSN 0017-9310
Publisher:
Elsevier
Research Org:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Sponsoring Org:
USDOE Office of Energy Efficiency and Renewable Energy (EERE), Geothermal Technologies Office (EE-4G)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; Constructal; Evolution; Scaling up; Dendritic; Entrance length; Heat exchanger
OSTI Identifier:
1376642

Bejan, A., Alalaimi, M., Sabau, A. S., and Lorente, S.. Entrance-length dendritic plate heat exchangers. United States: N. p., Web. doi:10.1016/j.ijheatmasstransfer.2017.06.094.
Bejan, A., Alalaimi, M., Sabau, A. S., & Lorente, S.. Entrance-length dendritic plate heat exchangers. United States. doi:10.1016/j.ijheatmasstransfer.2017.06.094.
Bejan, A., Alalaimi, M., Sabau, A. S., and Lorente, S.. 2017. "Entrance-length dendritic plate heat exchangers". United States. doi:10.1016/j.ijheatmasstransfer.2017.06.094. https://www.osti.gov/servlets/purl/1376642.
@article{osti_1376642,
title = {Entrance-length dendritic plate heat exchangers},
author = {Bejan, A. and Alalaimi, M. and Sabau, A. S. and Lorente, S.},
abstractNote = {We explore the idea that the highest heat transfer rate between two fluids in a given volume is achieved when plate channel lengths are given by the thermal entrance length, i.e., when the thermal boundary layers meet at the exit of each channel. The overall design can be thought of an elemental construct of a dendritic heat exchanger, which consists of two tree-shaped streams arranged in cross flow. Every channel is as long as the thermal entrance length of the developing flow that resides in that channel. The results indicate that the overall design will change with the total volume and total number of channels. We found that the lengths of the surfaces swept in cross flow would have to decrease sizably as number of channels increases, while exhibiting mild decreases as total volume increases. The aspect ratio of each surface swept by fluid in cross flow should be approximately square, independent of total number of channels and volume. We also found that the minimum pumping power decreases sensibly as the total number of channels and the volume increase. FurtherThe maximized heat transfer rate per unit volume increases sharply as the total volume decreases, in agreement with the natural evolution toward miniaturization in technology.},
doi = {10.1016/j.ijheatmasstransfer.2017.06.094},
journal = {International Journal of Heat and Mass Transfer},
number = C,
volume = 114,
place = {United States},
year = {2017},
month = {7}
}