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Unstable fluid flow in a water-cooled heating channel; Instabilites d'ecoulement du fluide dans un canal chauffant refroidi a l'eau

Abstract

Experimental investigations of the instable behavior of a pressurized water flow in forced convection in a heating channel, with subcooled or bulk boiling have been carried. Tests were conducted at 1140, 850 and 570 psi. The test section was 35 in. high, surmounted by a 25.4 in. riser, these sections were by-passed by a pipe where the flow was between 1 and 4 times the flow in the test section. The water velocity (in the test section) was between 1.6 and 6.6 ft/s. Under certain conditions oscillations with a period of several seconds and perfectly stable have been observed. A mathematical model has been defined and a good agreement obtained for the main characteristics of the oscillations. It seems that the dimensions of the riser have a determining effect: the inception of bulk boiling gives an important variation of the driving head which can generate oscillations due to the non-zero delay for the system to reach its equilibrium. (author) [French] Une investigation experimentale des risques d'instabilite d'ecoulement d'eau sous pression dans un canal chauffant, avec ebullition sous refroidie ou en masse a ete faite. Les essais ont ete effectues a des pressions de 40, 60 et 80 kg/cm{sup 2}. La  More>>
Authors:
Delayre, R; Saunier, J P [1] 
  1. Commissariat a l'Energie Atomique, Saclay (France).Centre d'Etudes Nucleaires
Publication Date:
Jul 01, 1961
Product Type:
Technical Report
Report Number:
CEA-R-1825
Subject:
42 ENGINEERING; BOILING; BYPASSES; CIRCULATING SYSTEMS; COOLANT LOOPS; COOLANTS; CYLINDRICAL CONFIGURATION; FLOW MODELS; FLOW RATE; FORCED CONVECTION; INCOMPRESSIBLE FLOW; PITOT TUBES; PRESSURE DEPENDENCE; PRESSURE DROP; STEAM; TEMPERATURE MEASUREMENT; THERMAL HYDRAULICS; THERMOSYPHON EFFECT; UNSTEADY FLOW; WATER
OSTI ID:
20972172
Research Organizations:
CEA Saclay, 91 - Gif-sur-Yvette (France)
Country of Origin:
France
Language:
French
Other Identifying Numbers:
TRN: FR07R1825001492
Availability:
Available from INIS in electronic form
Submitting Site:
FRN
Size:
60 pages
Announcement Date:
Jan 17, 2008

Citation Formats

Delayre, R, and Saunier, J P. Unstable fluid flow in a water-cooled heating channel; Instabilites d'ecoulement du fluide dans un canal chauffant refroidi a l'eau. France: N. p., 1961. Web.
Delayre, R, & Saunier, J P. Unstable fluid flow in a water-cooled heating channel; Instabilites d'ecoulement du fluide dans un canal chauffant refroidi a l'eau. France.
Delayre, R, and Saunier, J P. 1961. "Unstable fluid flow in a water-cooled heating channel; Instabilites d'ecoulement du fluide dans un canal chauffant refroidi a l'eau." France.
@misc{etde_20972172,
title = {Unstable fluid flow in a water-cooled heating channel; Instabilites d'ecoulement du fluide dans un canal chauffant refroidi a l'eau}
author = {Delayre, R, and Saunier, J P}
abstractNote = {Experimental investigations of the instable behavior of a pressurized water flow in forced convection in a heating channel, with subcooled or bulk boiling have been carried. Tests were conducted at 1140, 850 and 570 psi. The test section was 35 in. high, surmounted by a 25.4 in. riser, these sections were by-passed by a pipe where the flow was between 1 and 4 times the flow in the test section. The water velocity (in the test section) was between 1.6 and 6.6 ft/s. Under certain conditions oscillations with a period of several seconds and perfectly stable have been observed. A mathematical model has been defined and a good agreement obtained for the main characteristics of the oscillations. It seems that the dimensions of the riser have a determining effect: the inception of bulk boiling gives an important variation of the driving head which can generate oscillations due to the non-zero delay for the system to reach its equilibrium. (author) [French] Une investigation experimentale des risques d'instabilite d'ecoulement d'eau sous pression dans un canal chauffant, avec ebullition sous refroidie ou en masse a ete faite. Les essais ont ete effectues a des pressions de 40, 60 et 80 kg/cm{sup 2}. La section d'essais d'une hauteur de 1,37m etait surmontee d'une cheminee de 1 m, le tout by-passe par une conduite ou le debit pouvait varier entre 1 et 4 fois le debit dans la section d'essais. La vitesse dans la section variait entre 0,5 et 2 m/s. Dans certaines conditions, des oscillations de periode de l'ordre de quelques secondes et parfaitement stables sont apparues. Un modele mathematique a permis de retrouver les principales caracteristiques de ces oscillations. Il semble que l'influence des dimensions de la cheminee soit determinante: en effet, l'apparition de l'ebullition de masse entraine une importante variation de la hauteur motrice qui peut engendrer des oscillations entretenues a cause du retard non nul a la mise en equilibre du systeme. (auteur)}
place = {France}
year = {1961}
month = {Jul}
}