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Study and development of an optical method for the measurement of convection coefficients; Etude et developpement d'une methode optique pour la mesure du coefficient de convection

Thesis/Dissertation:

Abstract

This research thesis addresses the field of fluid-wall thermal exchanges in which the notion of exchange coefficient is notably useful to design, size and optimise devices. A first part reports a bibliographical study which gives an overview of solutions envisaged to determine the convection coefficient in permanent regime with the use of flow sensors, as well as in transient regime. Then, the author reports the development of an unsteady method which is based on the analysis of the cooling kinetics of the front face of a convecting wall, after a unique energetic perturbation (an infinitely brief pulse, or a finite duration energy step). This method is applied to the general case (wall with finite thickness) and to the case of a semi-infinite wall which is typical of materials which are weak thermal conductors. This is extended to the case of good thermal conductors by considering a thermally thin wall. After a detailed description of the experimental bench, above-mentioned solutions are applied to insulating and good thermal conducting materials. In order to validate results of an analysis in transient regime, they are compared with measurements performed in permanent regime with a flow-metering technique. The study of the principle of the dissipation-based  More>>
Publication Date:
Mar 06, 1990
Product Type:
Thesis/Dissertation
Report Number:
FRNC-TH-9777
Resource Relation:
Other Information: 52 refs.; Available from the INIS Liaison Officer for France, see the 'INIS contacts' section of the INIS-NKM website for current contact and E-mail addresses: http://www.iaea.org/inis/Contacts/; Also available from Bibliotheque Universitaire, Universite de Reims Champagne-Ardenne, 9 Boulevard de la Paix, 51100 Reims (France); Sciences - Energetique
Subject:
42 ENGINEERING; CONVECTION; FLOWMETERS; FLUID FLOW; FLUXMETERS; HEAT EXCHANGERS; HEAT FLUX; OPTICAL SYSTEMS; PULSATIONS; THERMAL CONDUCTION; THERMAL CONDUCTIVITY; THERMAL HYDRAULICS; THERMAL INSULATION; THERMODYNAMICS; THERMOGRAPHY
OSTI ID:
22645979
Research Organizations:
Universite de Reims Champagne-Ardenne, 9 Boulevard de la Paix, 51100 Reims (France)
Country of Origin:
France
Language:
French
Other Identifying Numbers:
TRN: FR1702449094576
Availability:
Available from INIS in electronic form
Submitting Site:
INIS
Size:
183 page(s)
Announcement Date:
Dec 14, 2017

Thesis/Dissertation:

Citation Formats

Crowther, David J. Study and development of an optical method for the measurement of convection coefficients; Etude et developpement d'une methode optique pour la mesure du coefficient de convection. France: N. p., 1990. Web.
Crowther, David J. Study and development of an optical method for the measurement of convection coefficients; Etude et developpement d'une methode optique pour la mesure du coefficient de convection. France.
Crowther, David J. 1990. "Study and development of an optical method for the measurement of convection coefficients; Etude et developpement d'une methode optique pour la mesure du coefficient de convection." France.
@misc{etde_22645979,
title = {Study and development of an optical method for the measurement of convection coefficients; Etude et developpement d'une methode optique pour la mesure du coefficient de convection}
author = {Crowther, David J.}
abstractNote = {This research thesis addresses the field of fluid-wall thermal exchanges in which the notion of exchange coefficient is notably useful to design, size and optimise devices. A first part reports a bibliographical study which gives an overview of solutions envisaged to determine the convection coefficient in permanent regime with the use of flow sensors, as well as in transient regime. Then, the author reports the development of an unsteady method which is based on the analysis of the cooling kinetics of the front face of a convecting wall, after a unique energetic perturbation (an infinitely brief pulse, or a finite duration energy step). This method is applied to the general case (wall with finite thickness) and to the case of a semi-infinite wall which is typical of materials which are weak thermal conductors. This is extended to the case of good thermal conductors by considering a thermally thin wall. After a detailed description of the experimental bench, above-mentioned solutions are applied to insulating and good thermal conducting materials. In order to validate results of an analysis in transient regime, they are compared with measurements performed in permanent regime with a flow-metering technique. The study of the principle of the dissipation-based flow sensor, and its operation are reported. Experimental results are presented for both methods (pulse and flow sensor), and compared in order to highlight the interest of the unsteady method [French] Difficile a mesurer, le coefficient de convection reste cependant une grandeur necessaire au calcul et a l'optimisation de tout systeme thermique. L'amelioration des capteurs thermiques permet aujourd'hui de concevoir une methode optique, utilisable a distance, et non destructive. Nous proposons dans ce but, un procede de mesure en regime transitoire base sur la radiometrie photothermique impulsionnelle. L'analyse du regime de relaxation d'une paroi, apres une brusque elevation de temperature, permet de remonter a la valeur du coefficient de convection. Sa determination est principalement basee sur l'utilisation des moments temporels d'ordre zero. Les resultats experimentaux obtenus par cette methode, sont compares a ceux donnes par un fluxmetre en regime permanent. L'etude montre que le coefficient de convection n'est pas constant pendant l'experience impulsionnelle, mais passe par un extremum avant de tendre vers une asymptote.}
place = {France}
year = {1990}
month = {Mar}
}