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Preliminary studies on the closed cycle magneto aerodynamic converter; Etudes preliminaires sur les convertisseurs magnetohydrodynamiques fonctionnant hors d'equilibre thermodynamique

Abstract

Besides the open cycle MHD converters which convert the thermal energy contained in combustion gases, a closed cycle converter which can work with any high temperature heat source and specially with nuclear sources is being very carefully studied. Before proceeding to a practical study of the power station as a whole the performances of the converter itself must be fully investigated. These performances are largely a function of the conductivity of the gas, but this conductivity must not be repaid by a temperature technically unacceptable for the heat exchanger. In the conversion fluid an ionizable seeding vapour such as caesium or potassium is mixed with a carrier gas, helium or argon. Purely thermal ionization is only efficient above 2 500 deg. K, whereas the electric field obtained by Induction in the converter can, under given conditions, increase the electron temperature and produce an ionization rate well above the equilibrium value. This allows the gas to be ionized at moderate temperature. Studies are under way in order to clarify the conditions required to produce extra-thermal ionization in seeded rare gases. Measurements have been performed with a 3-phase 500 kVA plasmatron with potassium-seeded argon. The outgoing gas is fed into a channel  More>>
Authors:
Ricateau, P [1] 
  1. Commissariat a l'Energie Atomique, Saclay (France). Centre d'Etudes Nucleaires
Publication Date:
Jul 01, 1964
Product Type:
Technical Report
Report Number:
CEA-R-2686
Resource Relation:
Other Information: 5 refs
Subject:
30 DIRECT ENERGY CONVERSION; ARGON; CESIUM; CLOSED-CYCLE MHD GENERATORS; CURRENT DENSITY; ELECTRIC CONDUCTIVITY; ELECTRIC FIELDS; ELECTRON TEMPERATURE; FLOW RATE; HALL EFFECT; HELIUM; IMPURITIES; IONIZATION; MAGNETIC FIELDS; PLASMATRONS; POTASSIUM
OSTI ID:
20668380
Research Organizations:
CEA Saclay, 91 - Gif-sur-Yvette (France)
Country of Origin:
France
Language:
French
Other Identifying Numbers:
TRN: FR05R2686107081
Availability:
Available from INIS in electronic form
Submitting Site:
FRN
Size:
20 pages
Announcement Date:
Dec 14, 2005

Citation Formats

Ricateau, P. Preliminary studies on the closed cycle magneto aerodynamic converter; Etudes preliminaires sur les convertisseurs magnetohydrodynamiques fonctionnant hors d'equilibre thermodynamique. France: N. p., 1964. Web.
Ricateau, P. Preliminary studies on the closed cycle magneto aerodynamic converter; Etudes preliminaires sur les convertisseurs magnetohydrodynamiques fonctionnant hors d'equilibre thermodynamique. France.
Ricateau, P. 1964. "Preliminary studies on the closed cycle magneto aerodynamic converter; Etudes preliminaires sur les convertisseurs magnetohydrodynamiques fonctionnant hors d'equilibre thermodynamique." France.
@misc{etde_20668380,
title = {Preliminary studies on the closed cycle magneto aerodynamic converter; Etudes preliminaires sur les convertisseurs magnetohydrodynamiques fonctionnant hors d'equilibre thermodynamique}
author = {Ricateau, P}
abstractNote = {Besides the open cycle MHD converters which convert the thermal energy contained in combustion gases, a closed cycle converter which can work with any high temperature heat source and specially with nuclear sources is being very carefully studied. Before proceeding to a practical study of the power station as a whole the performances of the converter itself must be fully investigated. These performances are largely a function of the conductivity of the gas, but this conductivity must not be repaid by a temperature technically unacceptable for the heat exchanger. In the conversion fluid an ionizable seeding vapour such as caesium or potassium is mixed with a carrier gas, helium or argon. Purely thermal ionization is only efficient above 2 500 deg. K, whereas the electric field obtained by Induction in the converter can, under given conditions, increase the electron temperature and produce an ionization rate well above the equilibrium value. This allows the gas to be ionized at moderate temperature. Studies are under way in order to clarify the conditions required to produce extra-thermal ionization in seeded rare gases. Measurements have been performed with a 3-phase 500 kVA plasmatron with potassium-seeded argon. The outgoing gas is fed into a channel where the tensor components of conductivity are measured in the presence of a magnetic field. The values found under thermodynamic equilibrium conditions confirm the simple theory. This is not the case when the electrons are heated. Measurements of the same kind have been made by another method in caesium-seeded helium contained in an isothermal vessel at 1 900 deg. K. There also the equilibrium values are in good agreement, but non-equilibrium ionization seems to be lower than expected. The effect of electron heating inside the converter in the case of argon-. potassium mixture has been considered in a theoretical study. It is shown that the electrode set must be carefully subdivided along the channel, and that electron heating in argon-potassium can be achieved by magnetic fields from 1 to 2 Ts. Plans are being made to build an important facility which will work on the principle of hot shots. The gas generator will deliver cesium-seeded helium shots at a temperature of 2100 deg. K. The shot will last 1/ 10 s and the instantaneous thermal power will reach 1 MW. (author) [French] A cote des convertisseurs magnetoaerodynamiques a cycle ouvert qui transforment l'energie thermique contenue dans les gaz de combustion on etudie tres attentivement le convertisseur a cycle ferme qui peut tirer son energie de toute source de chaleur a haute temperature et tout particulierement des sources nucleaires. Avant une etude pratique de l'ensemble de la centrale les performances du convertisseur lui-meme doivent etre bien delimitees. Ces performances sont largement fonction de la conductivite du gaz utilise. Mais cette conductivite ne doit pas etre payee par une temperature techniquement inadmissible pour l'echangeur de chaleur. Dans le fluide de conversion on est amene a associer un gaz porteur, helium ou argon, et une semence facilement ionisable cesium ou potassium. L'ionisation purement thermique n'est efficace qu'a partir de 2500 deg. K, par contre le champ electrique developpe par induction dans le convertisseur peut, sous certaines conditions, accroitre la temperature electronique et developper une ionisation bien superieure a la valeur d'equilibre. Il devient alors possible d'ioniser le gaz a temperature moderee. Des travaux en cours ont pour but de preciser les conditions permettant de creer cette ionisation hors d'equilibre dans les gaz rares ensemenses. Des mesures ont ete faites a l'aide d'un plasmatron triphase do 500 kVA alimente a l'argon ensemence de potassium. On a fait debiter cet appareil dans une cellule permettant de mesurer les composantes tensorielles de la conductivite en presence de champ magnetique. Les valeurs trouvees dans les conditions d'equilibre thermodynamique confirment la theorie simple. Il n'en est pas de meme dans le cas ou le chauffage electronique intervient. Des mesures du meme ordre ont ete effectues par une autre methode dans l'helium ensemence au cesium contenu dans une enceinte isotherme portee a 1900 deg. K. La aussi les valeurs d'equilibres concordent tres correctement mais l'ionisation hors d'equilibre parait etre inferieure aux valeurs previsibles. On a examine dans une etude theorique l'effet du chauffage electronique a l'interieur du convertisseur dans le cas de l'argon et du potassium. Cette etude met en evidence l'importance d'un fractionnement fin des electrodes le long du canal. Elle montre par ailleurs que le chauffage electronique dans l'argon potassium peut etre provoque par des champs magnetiques de 1 a 2 Ts. Il est prevu l'installation d'un vaste banc experimental qui fonctionnera sur un principe analogue aux souffleries a rafales. Le generateur de gaz delivrera des rafales d'helium ensemence au cesium porte a une temperature de 2100 deg. K. La duree de passage du gaz atteindra l/l0 de seconde et la puissance thermique instantanee 1 MW. (auteur)}
place = {France}
year = {1964}
month = {Jul}
}