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Experimental and computational study of oscillating turbine cascade and influence of part-span shrouds / Q. X. Huang in Transactions of the ASME . Journal of fluids engineering, Vol. 131 N° 5 (Mai 2009) 

Public ISBD [article]  in Transactions of the ASME . Journal of fluids engineering > Vol. 131 N° 5 (Mai 2009) . - 11 p. Titre : Experimental and computational study of oscillating turbine cascade and influence of part-span shrouds Type de document : texte imprimé Auteurs : Q. X. Huang, Auteur ; L. He, Auteur ; David L. Bell, Auteur Année de publication : 2009 Article en page(s) : 11 p. Note générale : fluids engineering Langues : Anglais (eng) Mots-clés : unsteady  flows;  linear  turbine  cascade  oscillating;  part-span  shrouds Résumé : This paper presents a combined experimental and computational study of unsteady flows in a linear turbine cascade oscillating in a three-dimensional bending/flapping mode. Detailed experimental data are obtained on a seven-bladed turbine cascade rig. The middle blade is driven to oscillate and oscillating cascade data are obtained using an influence coefficient method. The numerical simulations are performed by using a 3D nonlinear time-marching Navier–Stokes flow solver. Single-passage domain computations for arbitrary interblade phase angles are achieved by using the Fourier shape correction method. Both measurements and predictions demonstrate a fully 3D behavior of the unsteady flows. The influence of the aerodynamic blockage introduced by part-span shrouds on turbine flutter has been investigated by introducing flat plate shaped shrouds at 75% span. In contrast to practical applications, in the present test configuration, the mode of vibration of the blades remains unchanged by the introduction of the part-span shroud. This allows the influence of the aerodynamic blockage introduced by the part-span shroud to be assessed in isolation from the change in mode shape. A simple shroud model has been developed in the computational solver. The computed unsteady pressures around the shrouds are in good agreement with the experimental data, demonstrating the validity of the simple shroud model. Despite of notable variations in local unsteady pressures around the shrouds, the present results show that the blade aerodynamic damping is largely unaffected by the aerodynamic blockage introduced by part-span shrouds. En ligne : http://fluidsengineering.asmedigitalcollection.asme.org/issue.aspx?journalid=122 [...] [article] Experimental and computational study of oscillating turbine cascade and influence of part-span shrouds [texte imprimé] / Q. X. Huang, Auteur ; L. He, Auteur ; David L. Bell, Auteur . - 2009 . - 11 p. fluids engineering Langues : Anglais (eng) in Transactions of the ASME . Journal of fluids engineering > Vol. 131 N° 5 (Mai 2009) . - 11 p. Mots-clés : unsteady  flows;  linear  turbine  cascade  oscillating;  part-span  shrouds Résumé : This paper presents a combined experimental and computational study of unsteady flows in a linear turbine cascade oscillating in a three-dimensional bending/flapping mode. Detailed experimental data are obtained on a seven-bladed turbine cascade rig. The middle blade is driven to oscillate and oscillating cascade data are obtained using an influence coefficient method. The numerical simulations are performed by using a 3D nonlinear time-marching Navier–Stokes flow solver. Single-passage domain computations for arbitrary interblade phase angles are achieved by using the Fourier shape correction method. Both measurements and predictions demonstrate a fully 3D behavior of the unsteady flows. The influence of the aerodynamic blockage introduced by part-span shrouds on turbine flutter has been investigated by introducing flat plate shaped shrouds at 75% span. In contrast to practical applications, in the present test configuration, the mode of vibration of the blades remains unchanged by the introduction of the part-span shroud. This allows the influence of the aerodynamic blockage introduced by the part-span shroud to be assessed in isolation from the change in mode shape. A simple shroud model has been developed in the computational solver. The computed unsteady pressures around the shrouds are in good agreement with the experimental data, demonstrating the validity of the simple shroud model. Despite of notable variations in local unsteady pressures around the shrouds, the present results show that the blade aerodynamic damping is largely unaffected by the aerodynamic blockage introduced by part-span shrouds. En ligne : http://fluidsengineering.asmedigitalcollection.asme.org/issue.aspx?journalid=122 [...]

Simultaneous measurement of three-dimensional soot temperature and volume fraction fields in axisymmetric or asymmetric small unconfined flames with CCD cameras / D. Liu in Journal of heat transfer, Vol. 132 N° 6 (Juin 2010) 

Public ISBD [article]  in Journal of heat transfer > Vol. 132 N° 6 (Juin 2010) . - pp. [061202-1/7] Titre : Simultaneous measurement of three-dimensional soot temperature and volume fraction fields in axisymmetric or asymmetric small unconfined flames with CCD cameras Type de document : texte imprimé Auteurs : D. Liu, Auteur ; Q. X. Huang, Auteur ; F. Wang, Auteur Article en page(s) : pp. [061202-1/7] Note générale : Physique Langues : Anglais (eng) Mots-clés : Soot  temperature  Soot  volume  fraction  Axisymmetric  flame  Asymmetric  flame  CCD  camera Index. décimale : 536 Chaleur. Thermodynamique Résumé : A nonintrusive measurement technique is presented numerically for simultaneous measurement of three-dimensional (3D) soot temperature and volume fraction fields in the axisymmetric or asymmetric flames with charge-coupled device (CCD) cameras. CCD cameras were introduced to capture the flame images for obtaining the line-of-sight radiation intensities. The distributions of local emission source under two wavelengths can be deduced through solving the reconstruction matrix equation by the least-square QR decomposition method from the knowledge of the line-of-sight radiation intensities of the flames. The two-color distributions of the local emission source were used to retrieve the soot temperature and volume fraction distributions. The effects of the discrete ray number of CCD cameras, the number of CCD cameras, and the system signal-to-noise ratio (SNR) on the measurement were investigated. The results show that for accurate measurement of soot volume fraction field, the CCD cameras number should not be less than four and the system SNR can be as low as 54 dB. The proposed technique can be capable for reconstructing the 3D soot temperature and volume fraction fields in both axisymmetric and asymmetric flames well. DEWEY : 536 ISSN : 0022-1481 En ligne : http://asmedl.aip.org/vsearch/servlet/VerityServlet?KEY=JHTRAO&ONLINE=YES&smode= [...] [article] Simultaneous measurement of three-dimensional soot temperature and volume fraction fields in axisymmetric or asymmetric small unconfined flames with CCD cameras [texte imprimé] / D. Liu, Auteur ; Q. X. Huang, Auteur ; F. Wang, Auteur . - pp. [061202-1/7]. Physique Langues : Anglais (eng) in Journal of heat transfer > Vol. 132 N° 6 (Juin 2010) . - pp. [061202-1/7] Mots-clés : Soot  temperature  Soot  volume  fraction  Axisymmetric  flame  Asymmetric  flame  CCD  camera Index. décimale : 536 Chaleur. Thermodynamique Résumé : A nonintrusive measurement technique is presented numerically for simultaneous measurement of three-dimensional (3D) soot temperature and volume fraction fields in the axisymmetric or asymmetric flames with charge-coupled device (CCD) cameras. CCD cameras were introduced to capture the flame images for obtaining the line-of-sight radiation intensities. The distributions of local emission source under two wavelengths can be deduced through solving the reconstruction matrix equation by the least-square QR decomposition method from the knowledge of the line-of-sight radiation intensities of the flames. The two-color distributions of the local emission source were used to retrieve the soot temperature and volume fraction distributions. The effects of the discrete ray number of CCD cameras, the number of CCD cameras, and the system signal-to-noise ratio (SNR) on the measurement were investigated. The results show that for accurate measurement of soot volume fraction field, the CCD cameras number should not be less than four and the system SNR can be as low as 54 dB. The proposed technique can be capable for reconstructing the 3D soot temperature and volume fraction fields in both axisymmetric and asymmetric flames well. DEWEY : 536 ISSN : 0022-1481 En ligne : http://asmedl.aip.org/vsearch/servlet/VerityServlet?KEY=JHTRAO&ONLINE=YES&smode= [...]