Documents disponibles écrits par cet auteur

Influence of the Lagrangian integral time scale estimation in the near wall region on particle deposition / Grégory Lecrivain in Transactions of the ASME . Journal of fluids engineering, Vol. 134 N° 7 (Juillet 2012) 

Public ISBD [article]  in Transactions of the ASME . Journal of fluids engineering > Vol. 134 N° 7 (Juillet 2012) . - 06 p. Titre : Influence of the Lagrangian integral time scale estimation in the near wall region on particle deposition Type de document : texte imprimé Auteurs : Grégory Lecrivain, Auteur ; Uwe Hampel, Auteur Année de publication : 2012 Article en page(s) : 06 p. Note générale : fluids engineering Langues : Anglais (eng) Mots-clés : pebble-bed  reactor;  friction;  graphite;  fuel  elements;  Lagrangian  integral  time  scale Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : In a high temperature pebble-bed reactor core where thousands of pebbles are amassed, the friction between the outer graphite layer of the fuel elements triggers the formation of carbonaceous dust. This dust is eventually conveyed by the cooling carrier phase and deposits in the primary circuit of the high temperature reactor. The numerical prediction of carbonaceous dust transport and deposition in turbulent flows is a key safety issue. Most particle tracking procedures make use of the Lagrangian integral time scale to reproduce the turbulent dispersion of the discrete phase. In the present Lagrangian particle tracking procedure, the effect of the Lagrangian integral time scale near the wall is thoroughly investigated. It is found that, in the linear sublayer, a value of the normalized wall normal component of the Lagrangian integral time scale lower that 4 delivers accurate particle deposition velocities. The value worked out here near the wall region is in accordance with Lagrangian integral time scales derived from recent direct numerical simulations. DEWEY : 620.1 ISSN : 0098-2202 En ligne : http://asmedl.org/getabs/servlet/GetabsServlet?prog=normal&id=JFEGA4000134000007 [...] [article] Influence of the Lagrangian integral time scale estimation in the near wall region on particle deposition [texte imprimé] / Grégory Lecrivain, Auteur ; Uwe Hampel, Auteur . - 2012 . - 06 p. fluids engineering Langues : Anglais (eng) in Transactions of the ASME . Journal of fluids engineering > Vol. 134 N° 7 (Juillet 2012) . - 06 p. Mots-clés : pebble-bed  reactor;  friction;  graphite;  fuel  elements;  Lagrangian  integral  time  scale Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : In a high temperature pebble-bed reactor core where thousands of pebbles are amassed, the friction between the outer graphite layer of the fuel elements triggers the formation of carbonaceous dust. This dust is eventually conveyed by the cooling carrier phase and deposits in the primary circuit of the high temperature reactor. The numerical prediction of carbonaceous dust transport and deposition in turbulent flows is a key safety issue. Most particle tracking procedures make use of the Lagrangian integral time scale to reproduce the turbulent dispersion of the discrete phase. In the present Lagrangian particle tracking procedure, the effect of the Lagrangian integral time scale near the wall is thoroughly investigated. It is found that, in the linear sublayer, a value of the normalized wall normal component of the Lagrangian integral time scale lower that 4 delivers accurate particle deposition velocities. The value worked out here near the wall region is in accordance with Lagrangian integral time scales derived from recent direct numerical simulations. DEWEY : 620.1 ISSN : 0098-2202 En ligne : http://asmedl.org/getabs/servlet/GetabsServlet?prog=normal&id=JFEGA4000134000007 [...]

Measurement of dynamic liquid distributions in a fixed bed using electrical capacitance tomography and capacitance wire-mesh sensor / Bartosz Matusiak in Industrial & engineering chemistry research, Vol. 49 N° 5 (Mars 2010) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 49 N° 5 (Mars 2010) . - pp. 2070–2077 Titre : Measurement of dynamic liquid distributions in a fixed bed using electrical capacitance tomography and capacitance wire-mesh sensor Type de document : texte imprimé Auteurs : Bartosz Matusiak, Auteur ; Marco Jose da Silva, Auteur ; Uwe Hampel, Auteur Année de publication : 2010 Article en page(s) : pp. 2070–2077 Note générale : Industrial Chemistry Langues : Anglais (eng) Mots-clés : Measurement  of  Dynamic;  Electrical  Capacitance;  Tomography;  Wire-Mesh  Sensor;  Media  supply;  ECT Résumé : An intricate problem associated with fixed bed operation is liquid maldistribution, which denotes the fact that the liquid does not homogeneously flow through the bed. In a comparative study we evaluated two capacitance imaging methods—capacitance wire-mesh sensor and electrical capacitance tomography (ECT)—with respect to their capability of measuring static and dynamic liquid holdup in a fixed bed. The capacitance wire-mesh sensor as an invasive instrument is able to disclose flow structures at higher spatial resolution and was therefore considered the reference instrument for liquid holdup measurement. We found that both methods predict dynamic liquid holdup in the column in a similar way with only small systematic deviation. The results therefore prove that noninvasive electrical capacitance tomography can reliably measure cross-sectional dynamic liquid holdup in a fixed bed, even with a simple and fast linear back projection reconstruction algorithm. Note de contenu : Bibliogr. ISSN : 0888-5885 En ligne : http://pubs.acs.org/toc/IECRED/49/5 [article] Measurement of dynamic liquid distributions in a fixed bed using electrical capacitance tomography and capacitance wire-mesh sensor [texte imprimé] / Bartosz Matusiak, Auteur ; Marco Jose da Silva, Auteur ; Uwe Hampel, Auteur . - 2010 . - pp. 2070–2077. Industrial Chemistry Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 49 N° 5 (Mars 2010) . - pp. 2070–2077 Mots-clés : Measurement  of  Dynamic;  Electrical  Capacitance;  Tomography;  Wire-Mesh  Sensor;  Media  supply;  ECT Résumé : An intricate problem associated with fixed bed operation is liquid maldistribution, which denotes the fact that the liquid does not homogeneously flow through the bed. In a comparative study we evaluated two capacitance imaging methods—capacitance wire-mesh sensor and electrical capacitance tomography (ECT)—with respect to their capability of measuring static and dynamic liquid holdup in a fixed bed. The capacitance wire-mesh sensor as an invasive instrument is able to disclose flow structures at higher spatial resolution and was therefore considered the reference instrument for liquid holdup measurement. We found that both methods predict dynamic liquid holdup in the column in a similar way with only small systematic deviation. The results therefore prove that noninvasive electrical capacitance tomography can reliably measure cross-sectional dynamic liquid holdup in a fixed bed, even with a simple and fast linear back projection reconstruction algorithm. Note de contenu : Bibliogr. ISSN : 0888-5885 En ligne : http://pubs.acs.org/toc/IECRED/49/5