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Licensed Unlicensed Requires Authentication Published by De Gruyter November 15, 2018

Geometry-Based Entropy Generation Minimization in Laminar Internal Convective Micro-Flow

  • Pallavi Rastogi and Shripad P. Mahulikar EMAIL logo


In this theoretical study, fully developed forced convective laminar water flow is considered in circular micro-tubes, for the constant wall heat flux boundary condition. The change in entropy generation rate (ΔS˙gen) for N micro-tubes (each of diameter DN) relative to a reference tube (of 1 mm diameter) was investigated towards the micro-scale, for different tube length (l). A given total heat flow rate is to be removed using a fixed total mass flow rate through N tubes. Hence, the wall heat flux for one of the N tubes decreases towards the micro-scale, which is “thermal under-loading”. For given l, ΔS˙gen due to fluid conduction decreases and ΔS˙gen due to fluid friction increases towards the micro-scale. There exists an optimum DN (=DN,opt) at which the change in sum-total S˙gen (ΔS˙gen,tot) is minimum; where DN,opt decreases with decreasing l. For given l, cooling capacity of the heat sink increases towards the micro-scale. A general criterion for minimization of ΔS˙gen,tot is obtained in terms of Reynolds number, Brinkman number, and dimensionless l.

Award Identifier / Grant number: 154010008

Award Identifier / Grant number: 1104249

Funding statement: The authors thank the Ministry of Human Resource Development, Govt. of India, for the financial support to P. Rastogi (roll no. 154010008 at IIT-Bombay) for pursuing this research. The authors are grateful to the A. von Humboldt Foundation, Germany, for the rich exposure to research methodology through sponsorship no. 1104249 to S. P. Mahulikar.


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Received: 2018-07-16
Revised: 2018-08-27
Accepted: 2018-09-27
Published Online: 2018-11-15
Published in Print: 2019-01-28

© 2019 Walter de Gruyter GmbH, Berlin/Boston

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