| Titre : | An investigation of the effect of pressure gradient, temperature and temperature ratio on the tagnation point heat transfer | | Type de document : | texte imprimé | | Auteurs : | Gahmousse, Abderrahmane, Auteur ; Robert E. Duffy, Directeur de thèse | | Editeur : | Rensselaer Polytechnic Institute | | Année de publication : | 1982 | | Importance : | 151 f. | | Présentation : | ill. | | Format : | 28 cm | | Note générale : | Thèse de Doctorat : Génique Mécanique : New Yorke, Resselaer Polytechnic Institute : 1982
Bibliogr. [3] f. Annexe f. 155 - 193 | | Langues : | Anglais (eng) | | Mots-clés : | Heat transfer
Heat cage
Temperatture ratio
Aeronautical engineering | | Index. décimale : | D004082 | | Résumé : | This investigation is concerned with the study of the stagnation point heat transfer and is in fact the first part of two part investigation of effects of pressure gradient, temperature and wall temperature ration on the heat transfert over blunt and streamlined bodies.
Specifically here, experiments have been conducted to study the effect of pressure gradient and nigh temperatures on the exernal heat transfer rates over a circular cylinder, simulating in this way the leading edge of turbine vanes and blades.
All the tests were taken utilizing short time duration shock tube facilities.
At R.P.I. two shock tube facilities have been fabricated.
The first, a low pressure tube, is used for testing when the reynolds number (Re)< 3.8x 10⁵.
The second, a high pressure tube, permits an extension of the operating Reynolds up to 2.2x 10⁶.flow temperature is limited to approximately 4000°F in either facility.
Thin film platium heat gages were used to record the heat flux. Five different diameter cylindrical heat gages were selected and tested so as to provided a pressure gradient variation up 50 times. It is evident from the results that there is an appreciable effect due to pressure gradient in roynolds number range tested.
The data for all five gages indicated the same tren; namely the larger, the lower was the geat transfer at a fixed Rynolds number.
Using the shock tube facilities, flow conditions were adjusted to reach temperatures approaching 4000°F.
The data gathered were compared to that taken at low temperatures (280°F) for each of the 5 gages. It was found, in general, that the stagnation point heat transfer coefficient, or Nusselt Number, did not change remarkably for temperatures up to 700°F.
However, in the range of 800°F to 2500°F the Nusselt Number increased.
At flow temperatures of the order of 3500°F the Nusselt Number again decreased and approached the low temperature values.
This Reasearch has shown that the shock tube can be utilized in an effective and effecient facility in wich to gather high temperature heat transfer data.
The results of the investigation show that there is pronounced pressure gradient and temperature scaling effects on stagnation point heat transfer. |
An investigation of the effect of pressure gradient, temperature and temperature ratio on the tagnation point heat transfer [texte imprimé] / Gahmousse, Abderrahmane, Auteur ; Robert E. Duffy, Directeur de thèse . - Troy, New York, USA : Rensselaer Polytechnic Institute, 1982 . - 151 f. : ill. ; 28 cm. Thèse de Doctorat : Génique Mécanique : New Yorke, Resselaer Polytechnic Institute : 1982
Bibliogr. [3] f. Annexe f. 155 - 193 Langues : Anglais ( eng) | Mots-clés : | Heat transfer
Heat cage
Temperatture ratio
Aeronautical engineering | | Index. décimale : | D004082 | | Résumé : | This investigation is concerned with the study of the stagnation point heat transfer and is in fact the first part of two part investigation of effects of pressure gradient, temperature and wall temperature ration on the heat transfert over blunt and streamlined bodies.
Specifically here, experiments have been conducted to study the effect of pressure gradient and nigh temperatures on the exernal heat transfer rates over a circular cylinder, simulating in this way the leading edge of turbine vanes and blades.
All the tests were taken utilizing short time duration shock tube facilities.
At R.P.I. two shock tube facilities have been fabricated.
The first, a low pressure tube, is used for testing when the reynolds number (Re)< 3.8x 10⁵.
The second, a high pressure tube, permits an extension of the operating Reynolds up to 2.2x 10⁶.flow temperature is limited to approximately 4000°F in either facility.
Thin film platium heat gages were used to record the heat flux. Five different diameter cylindrical heat gages were selected and tested so as to provided a pressure gradient variation up 50 times. It is evident from the results that there is an appreciable effect due to pressure gradient in roynolds number range tested.
The data for all five gages indicated the same tren; namely the larger, the lower was the geat transfer at a fixed Rynolds number.
Using the shock tube facilities, flow conditions were adjusted to reach temperatures approaching 4000°F.
The data gathered were compared to that taken at low temperatures (280°F) for each of the 5 gages. It was found, in general, that the stagnation point heat transfer coefficient, or Nusselt Number, did not change remarkably for temperatures up to 700°F.
However, in the range of 800°F to 2500°F the Nusselt Number increased.
At flow temperatures of the order of 3500°F the Nusselt Number again decreased and approached the low temperature values.
This Reasearch has shown that the shock tube can be utilized in an effective and effecient facility in wich to gather high temperature heat transfer data.
The results of the investigation show that there is pronounced pressure gradient and temperature scaling effects on stagnation point heat transfer. |
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