Title: Transient free convection in parallelogrammic cavities applied to the thermoregulation of avionics

Authors: A. Bairi, E. Zarco Pernia, N. Laraqi, J.M. Garcia De Maria, F. Gutierrez, A. Campo, B. Chanetz, H.F. Oztop

Addresses: Universite Paris Ouest Nanterre La Defense, LTIE-GTE, EA 4415, 50, rue de Sevres, F-92410 Ville d'Avray, France. ' Universite Paris Ouest Nanterre La Defense, LTIE-GTE, EA 4415, 50, rue de Sevres, F-92410 Ville d'Avray, France. ' Universite Paris Ouest Nanterre La Defense, LTIE-GTE, EA 4415, 50, rue de Sevres, F-92410 Ville d'Avray, France. ' Departamento de Fisica Aplicada, Universidad Politecnica de Madrid, Ronda de Valencia, 3, E-28012 Madrid, Espana. ' Departamento de Quimica Industrial y Polimeros, Universidad Politecnica de Madrid, Ronda de Valencia, 3, E-28012 Madrid, Espana. ' Department of Mechanical Engineering, The University of Texas at San Antonio, San Antonio TX 78249, USA. ' Office National d'Etudes et Recherches Aerospatiales ONERA, 8 rue des Vertugadins, F-92190 Meudon, France. ' Department of Mechanical Education, Firat University, 23119 Elazig, Turkey

Abstract: This work addresses momentum and heat transfer phenomena that take place in closed cavities filled with air. The cavities are formed by two vertical active walls, one hot consisting of bands that are alternately insulated and heated at temperature T_h and other cold, isothermal at T_c. The closing upper and lower passive walls can be tilted an angle αeither above or below the horizontal plane. When α is positive (hot wall below the level of the cold one), the air movement is favoured while the opposite occurs for negative angles. These cavities are thus either transferring or insulating, which confers them the quality of a so-called convective diode. Such geometry is applied in this work to the thermoregulation of the on-board aviation electronics. The flows corresponding to different angles and temperature differences ΔT = T_h – T_c are examined both numerically and experimentally. We consider in particular the transient transport phenomena which occur at the very beginning, a critical stage in the operation of the on-board materials.

Keywords: transient natural convection; parallelogrammic cavities; discrete sources; avionics thermoregulation; heat transfer; numerical simulation; experimental measurements; convective diode effect; Rayleigh number; aviation electronics.

DOI: 10.1504/IJESMS.2010.031871

International Journal of Engineering Systems Modelling and Simulation, 2010 Vol.2 No.1/2, pp.58 - 64

Published online: 27 Feb 2010 *

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