Experimental and numerical study on the flow topology of finned heat sinks with tip clearance

Sastre Matesanz, Francisco and Valeije Varona, Alejandro and Martin, E. and Velázquez, Angel (2018). Experimental and numerical study on the flow topology of finned heat sinks with tip clearance. "International Journal of Thermal Sciences" (n. 132); pp. 146-160. ISSN 1290-0729. https://doi.org/10.1016/j.ijthermalsci.2018.05.036.

Description

Title: Experimental and numerical study on the flow topology of finned heat sinks with tip clearance
Author/s:
  • Sastre Matesanz, Francisco
  • Valeije Varona, Alejandro
  • Martin, E.
  • Velázquez, Angel
Item Type: Article
Título de Revista/Publicación: International Journal of Thermal Sciences
Date: October 2018
ISSN: 1290-0729
Subjects:
Freetext Keywords: Heat sink; Tip clearance; Heat transfer versus pressure drop
Faculty: E.T.S. de Ingeniería Aeronáutica y del Espacio (UPM)
Department: Mecánica de Fluidos y Propulsión Aeroespacial
Creative Commons Licenses: Recognition - No derivative works - Non commercial

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Abstract

An experimental and numerical study is presented that focuses on the flow topology in finned heat sinks with tip clearances. As it is well known, the use of tip clearances has, normally, a global beneficial effect. Typically, heat transfer may degrade (a negative effect) by a somewhat small percentage while pressure drop may decrease (a positive effect) by a substantial amount. In this context, the important question from an R&D standpoint is to understand the flow topology so that the actual design of the tip clearance optimizes the balance between heat transfer and pressure drop. In this study, a 3D numerical method is validated, first, comparing with the Particle Image Velocimetry based experimental results obtained in the actual setup in isothermal conditions. Then, the flow solver thus validated is used in a series of thermal cases in which both the tip clearance height and Reynolds number are varied so as to clarify the flow topology. In particular, it has been found that the behavior of both heat transfer and pressure drop cannot be explained in view, only, of flow development and thermal development aspects. This is so because the Nusselt versus Graetz curves that have been generated do not collapse into a single fit; instead, they collapse into several families that are governed by the tip clearance parameter. Distinct heat transfer rates have been observed for the different fin walls. The transfer rate of the side walls is nearly three times larger than that of the bottom walls, and this suggests the optimum place to locate the heat sources in a practical engineering application.

Funding Projects

TypeCodeAcronymLeaderTitle
Government of SpainDPI2016-75296-PUnspecifiedUnspecifiedDeformación y rotura de gotas con y sin sobreenfriamiento en flujos de interés aeronáutico

More information

Item ID: 53475
DC Identifier: http://oa.upm.es/53475/
OAI Identifier: oai:oa.upm.es:53475
DOI: 10.1016/j.ijthermalsci.2018.05.036
Official URL: https://www.sciencedirect.com/science/article/pii/S1290072918301364#!
Deposited by: Memoria Investigacion
Deposited on: 04 Feb 2019 11:30
Last Modified: 01 Nov 2019 23:30
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