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Forced heat convection in annular spaces; Convection forcee de la chaleur dans les espaces annulaires

Abstract

This report deals with the experimental study of forced heat convection in annular spaces through which flow of air is passing when a uniform heat flux is dissipated across the inner wall. These observations took place chiefly in the region where thermal equilibrium are not yet established. Amongst other things it became apparent that, both in the region where thermal equilibrium conditions are on the way to establishment and where they are already established, the following relationship held good: the longitudinal temperature gradient, either on the wall or in the fluid stream, is proportional to the heat flux dissipated q, and inversely proportional to the average flow rate V: dT/dx = B (q/V). From this result the next step is to express the variations of the local convection coefficient {alpha} (or of the Margoulis number M) in a relationship of the form: 1/M = {psi}(V) + F(x). If this relationship is compared with the classical empirical relationship {alpha} = KV{sup n} (where n is close to 0.8), the relationship: 1/M = {xi}V{sup 1-n} + F(x) is obtained ({xi} is a constant for a given annular space); from this it was possible to coordinate the whole set of experimental results. (author)  More>>
Authors:
Pelce, J [1] 
  1. Commissariat a l'Energie Atomique, Saclay (France). Centre d'Etudes Nucleaires
Publication Date:
Feb 15, 1960
Product Type:
Thesis/Dissertation
Report Number:
CEA-R-1303
Resource Relation:
Other Information: TH: These ES sciences physiques; 15 refs
Subject:
42 ENGINEERING; AIR FLOW; ANNULAR SPACE; ENERGY LOSSES; FLOW RATE; FLUID-STRUCTURE INTERACTIONS; FORCED CONVECTION; HEAT FLUX; PITOT TUBES; PRESSURE DROP; TEMPERATURE DISTRIBUTION; TEMPERATURE GRADIENTS; TEMPERATURE MEASUREMENT; THERMAL CONDUCTIVITY; THERMAL EQUILIBRIUM; THERMAL HYDRAULICS; THERMOCOUPLES; TURBULENT FLOW; VELOCITY
OSTI ID:
20942957
Research Organizations:
CEA Saclay, 91 - Gif-sur-Yvette (France); Faculte des Sciences de l'Universite de Poitiers, 86 (France)
Country of Origin:
France
Language:
French
Other Identifying Numbers:
TRN: FR07R1303096410
Availability:
Available from INIS in electronic form
Submitting Site:
FRN
Size:
92 pages
Announcement Date:
Dec 13, 2007

Citation Formats

Pelce, J. Forced heat convection in annular spaces; Convection forcee de la chaleur dans les espaces annulaires. France: N. p., 1960. Web.
Pelce, J. Forced heat convection in annular spaces; Convection forcee de la chaleur dans les espaces annulaires. France.
Pelce, J. 1960. "Forced heat convection in annular spaces; Convection forcee de la chaleur dans les espaces annulaires." France.
@misc{etde_20942957,
title = {Forced heat convection in annular spaces; Convection forcee de la chaleur dans les espaces annulaires}
author = {Pelce, J}
abstractNote = {This report deals with the experimental study of forced heat convection in annular spaces through which flow of air is passing when a uniform heat flux is dissipated across the inner wall. These observations took place chiefly in the region where thermal equilibrium are not yet established. Amongst other things it became apparent that, both in the region where thermal equilibrium conditions are on the way to establishment and where they are already established, the following relationship held good: the longitudinal temperature gradient, either on the wall or in the fluid stream, is proportional to the heat flux dissipated q, and inversely proportional to the average flow rate V: dT/dx = B (q/V). From this result the next step is to express the variations of the local convection coefficient {alpha} (or of the Margoulis number M) in a relationship of the form: 1/M = {psi}(V) + F(x). If this relationship is compared with the classical empirical relationship {alpha} = KV{sup n} (where n is close to 0.8), the relationship: 1/M = {xi}V{sup 1-n} + F(x) is obtained ({xi} is a constant for a given annular space); from this it was possible to coordinate the whole set of experimental results. (author) [French] Il s'agit precisement de l'etude experimentale de la convection forcee de la chaleur dans des espaces annulaires parcourus par de l'air en ecoulement turbulent, lorsqu'on dissipe a travers la paroi interieure un flux de chaleur uniforme. Ces observations ont eu lieu principalement dans la region ou le regime thermique n'est pas encore etabli. Il est apparu, entre autre, qu'il existait, tant dans la region ou le regime thermique est en voie d'etablissement qu'en regime etabli, la relation suivante: le gradient longitudinal des temperatures, que ce soit sur la paroi ou dans l'ecoulement fluide, est proportionnel au flux de la chaleur dissipee q, et inversement proportionnel a la vitesse moyenne V de l'ecoulement: dT/dx = B (q/V). Ce resultat a pour consequence de traduire les variations du coefficient local de convection {alpha} (ou du nombre de Margoulis M), dans une relation de la forme: 1/M = {psi}(V) + F(x). Si on rapproche de cette relation, la relation empirique classique, {alpha} = KV{sup n} (ou n est voisin de 0,8), on obtient la relation: 1/M = {xi}V{sup 1-n} + F(x) ({xi} est une constante pour un espace annulaire donne), au moyen de laquelle a pu etre coordonne l'ensemble de tous les resultats experimentaux. (auteur)}
place = {France}
year = {1960}
month = {Feb}
}