Laminar heat transfer enhancement downstream of a backward facing step by using a pulsating flow

Velázquez López, Ángel Gerardo and Arias Pérez, Juan Ramón and Mendez, B. (2008). Laminar heat transfer enhancement downstream of a backward facing step by using a pulsating flow. "International Journal of Heat and Mass Transfer", v. 51 (n. 7-8); pp. 2075-2089. ISSN 0017-9310. https://doi.org/10.1016/j.ijheatmasstransfer.2007.06.009.

Description

Title: Laminar heat transfer enhancement downstream of a backward facing step by using a pulsating flow
Author/s:
  • Velázquez López, Ángel Gerardo
  • Arias Pérez, Juan Ramón
  • Mendez, B.
Item Type: Article
Título de Revista/Publicación: International Journal of Heat and Mass Transfer
Date: January 2008
ISSN: 0017-9310
Volume: 51
Subjects:
Freetext Keywords: Back; step; unsteady; laminar; pulsatin
Faculty: E.T.S.I. Aeronáuticos (UPM)
Department: Motopropulsión y Termofluidodinámica [hasta 2014]
Creative Commons Licenses: Recognition - No derivative works - Non commercial

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Abstract

This study is motivated by the need to devise means to enhance heat transfer in configurations, like the back step, that appear in certain types of MEMS that involve fluid flow and that are not very efficient from the thermal transfer point of view. In particular, the work described in this paper studies the effect that a prescribed flow pulsation (defined by two control parameters: velocity pulsation frequency and pressure gradient amplitude at the inlet section) has on the heat transfer rate behind a backward facing step in the unsteady laminar 2-D regime. The working fluid that we have considered is water with temperature dependent viscosity and thermal conductivity. We have found that, for inlet pressure gradients that avoid flow reversal at both the upstream and downstream boundary conditions, the timeaveraged Nusselt number behind the step depends on the two above mentioned control parameters and is always larger than in the steady-state case. At Reynolds 100 and pulsating at the resonance frequency, the maximum time-averaged Nusselt number in the horizontal wall region located behind the step whose length is four times the step height is 55% larger than in the steady-case. Away from the resonant pulsation frequency, the time-averaged Nusselt number smoothly decreases and approaches its steady-state value.

More information

Item ID: 2246
DC Identifier: http://oa.upm.es/2246/
OAI Identifier: oai:oa.upm.es:2246
DOI: 10.1016/j.ijheatmasstransfer.2007.06.009
Official URL: http://www.elsevier.com/wps/find/journaldescription.cws_home/210/description#description
Deposited by: Memoria Investigacion
Deposited on: 19 May 2010 08:12
Last Modified: 20 Apr 2016 11:59
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