9620 TESIS-2012-110 spa 532 Ramírez Vázquez, Juan Antonio A computational fluid dynamics investigation of turbulent swirling burners Zaragoza Universidad de Zaragoza, Prensas de la Universidad 2012 192 Tesis de la Universidad de Zaragoza 2254-7606 2012-24 Presentado: 06 07 2012 Tesis-Univ. Zaragoza, Instituto de Investigación Mixto CIRCE, 2012 Zaragoza, Universidad de Zaragoza 2012 This thesis presents detailed numerical calculations of the Unsteady, Reynolds- Averaged Navier-Stokes (URANS) equations to simulate isothermal, single-phase flow in the geometries of realistic swirl burners at large Reynolds numbers. Simulations are run with two different turbulence closures, viz., the standard k-epsilon and Reynolds stresses (RSM) models. The numerical method is validated concerning convergence, grid density and far-field influence. Results describe a flow that is in any case periodic or pseudo-periodic, and exhibits quite convincing time-dependent features: bubble- and spiral-type vortex breakdowns and vortex core precession. Some simulations are validated by comparison with corresponding experiments. Good agreement with the experiments has been obtained for mean flow, and frequency peaks of the power spectral density of pressure fluctuations. In order to asses the reliability of URANS methods within this context, calculated time-averaged flow and coherent structures are documented via 2D graphs, spectral analysis, 3D isosurfaces and advanced, vortex-related visualization methods and 2D snapshot proper orthogonal decomposition (S-POD). Differences arising from the nature of the turbulence model (k-epsilon vs. RSM) are very relevant indeed, given the cost factor involved and the apparent verisimilitude of the predicted flow; they are thoroughly analyzed. mecánica de fluidos simulación fuentes no convencionales de energía Cortés Gracia, Cristóbal dir. Universidad de Zaragoza Instituto de Investigación Mixto CIRCE zaguan@unizar.es Mecánica de fluidos Instituto de Investigación Mixto CIRCE TESIS oai:zaguan.unizar.es:9620 public driver Tesis tesis http://zaguan.unizar.es/record/9620/files/TESIS-2012-110.pdf Texto completo (spa)