http://www.dspace.cam.ac.uk:80/handle/1810/217875 Fri, 24 May 2013 21:55:02 GMT 2013-05-24T21:55:02Z http://www.dspace.cam.ac.uk:80/handle/1810/243895 Title: Experiments on flame blow-off Authors: Kariuki, James; Cavaliere, Davide Emiglio; Dawson, James; Mastorakos, Epaminondas Description: The extinction behaviour of flames has been extensively studied from an empirical perspective in the past. Recently, with the advent of fast-response laser diagnostics, the temporal evolution of the blow-off process has been visualised and analyzed. The movies below are taken at 5kHz and monitor the OH* chemiluminescence and OH-PLIF of stable and extinguishing flames of various types (premixed, non-premixed, spray). The work has been published in: (1) Dawson, J. R., Gordon, R. L., Kariuki, J., Mastorakos, E., Masri, A. R. and Juddoo, M. (2011) Visualization of blow-off events in bluff-body stabilized turbulent premixed flames. Proceedings of the Combustion Institute 33, 1559-1566. doi:10.1016/j.proci.2010.05.044. (2) Kariuki, J., Dawson, J. R. & Mastorakos, E. (2012) Measurements in turbulent premixed bluff body flames close to blow-off. Combustion and Flame 159, 2589-2607. doi:10.1016/j.combustflame.2012.01.005. (3) Kariuki, J., Cavaliere, D. E., Letty, C. & Mastorakos, E. (2012) A comparison of the blow-off behaviour of swirl-stabilised premixed and spray flames. Presented at the 50th Aerospace Sciences Meeting, AIAA, Nashville, 4-7 January 2012.. (4) Cavaliere, D.E., Kariuki, J. & Mastorakos, E. (2012) A comparison of the blow-off behaviour of swirl-stablized premixed, non-premixed and spray flames. Submitted to Flow, Turbulence and Combustion. Sun, 01 Jan 2012 00:00:00 GMT http://www.dspace.cam.ac.uk:80/handle/1810/243895 2012-01-01T00:00:00Z http://www.dspace.cam.ac.uk:80/handle/1810/243652 Title: Large Eddy Simulations of extinction Authors: Ayache, S; Garmory, A; Tyliszczak, A; Mastorakos, E Description: Large Eddy Simulations, with the Conditional Moment Closure as the combustion sub-model, have been used to capture localised extinction, flame lift-off, and whole flame blow-off for simple geometries like jet flames (Movies 1 and 2 below), swirl-stabilised recirculating flames of natural gas (Movies 3-6), and spray flames (Paper "Spray_LESCMC_PalermoSept2012.pdf". The work is described fully in the following papers: (i) Garmory, A. and Mastorakos, E. (2011) Capturing localised extinction in Sandia Flame F with LES-CMC. Proceedings of the Combustion Institute 33, 1673-1680. doi:10.1016/j.proci.2010.06.065; (ii) Ayache, S. & Mastorakos, E. (2012) Conditional Moment Closure / Large Eddy Simulation of the Delft-III natural gas non-premixed jet flame. Flow, Turbulence and Combustion 88, 207-231. doi: 10.1007/s10494-011-9368-6; (iii) Tyliszczak, A. & Mastorakos, E. (2012) LES/CMC of blow-off in a liquid fuelled swirl burner. To be presented at the THMT7, Palermo, 24-27 September 2012; (iv) Ayache, S. & Mastorakos, E. (2012) Investigation of the “TECFLAM” non-premixed flame using Large Eddy Simulation and Proper Orthogonal Decomposition. Submitted to Flow, Turbulence and Combustion; (iv) S. Ayache, PhD thesis, University of Cambridge, 2012. Tue, 28 Aug 2012 23:00:00 GMT http://www.dspace.cam.ac.uk:80/handle/1810/243652 2012-08-28T23:00:00Z http://www.dspace.cam.ac.uk:80/handle/1810/243651 Title: SPINTHIR: An ignition model for gas turbines Authors: Neophytou, A; Mastorakos, E Description: Modelling ignition in gas turbines is very important from a practical perspective. A new ignition model has been developed, which is fully described in: Neophytou, A., Richardson, E. S. & Mastorakos, E. (2012) Spark ignition of turbulent recirculating non-premixed gas and spray flames: a model for predicting ignition probability. Combustion and Flame. 159, 1503-1522. doi:10.1016/j.combustflame.2011.12.015. In this model, called SPINTHIR (Stochastic Particle INTegrator for HIgh-altitude Relight), a CFD solution of the inert flow is interrogated to provide information on the ignition behaviour. The three movies below (1-3) show trajectories of flame elements following spark ignition in a swirling spray lab-scale flame that has been used for validation of the model. Movies 4 and 5 show particle paths for a favourable (4) and an unfavourable (5) spark ignition event for a surface discharge igniter in a realistic gas turbine that has been simulated by Rolls-Royce. Mon, 27 Aug 2012 23:00:00 GMT http://www.dspace.cam.ac.uk:80/handle/1810/243651 2012-08-27T23:00:00Z http://www.dspace.cam.ac.uk:80/handle/1810/243259 Title: Flow Field Results of the Cambridge Stratified Swirl Burner Using Laser Doppler Anemometer Authors: Zhou, Ruigang; Sweeney, Mark; Hochgreb, Simone Description: A series of flow fields generated by a turbulent methane/air stratified swirl burner are investigated using laser Doppler anemometer (LDA) to obtain the velocities in axial, radial and tangential directions. All mean and RMS of the LDA velocity results are supplied along with a report describing the experimental methodology, data processing routines and the data format. Thu, 07 Jun 2012 23:00:00 GMT http://www.dspace.cam.ac.uk:80/handle/1810/243259 2012-06-07T23:00:00Z http://www.dspace.cam.ac.uk:80/handle/1810/243258 Title: A Tool for the Spectral Analysis of the Laser Doppler Anemometer Data of the Cambridge Stratified Swirl Burner Authors: Zhou, Ruigang; Balusamy, Saravanan; Hochgreb, Simone Abstract: A series of flow fields generated by a turbulent methane/air stratified swirl burner are investigated using laser Doppler anemometer (LDA). The LDA provides flow field measurements with comparatively high temporal resolutions. However, processing of the power spectral energy density (PSD) and autocorrelation functions (ACF) of the flow velocity by LDA is complicated by the random, intermittent nature of the LDA signal caused by random arrival of particles at the measuring volume. A tool is developed to overcome this difficulty and the preliminary results are presented in the present report. Thu, 07 Jun 2012 23:00:00 GMT http://www.dspace.cam.ac.uk:80/handle/1810/243258 2012-06-07T23:00:00Z http://www.dspace.cam.ac.uk:80/handle/1810/241609 Title: Technical Drawings of Cambridge Stratified Swirl Burner (SwB) Authors: Sweeney, Mark; Barlow, Robert; Hochgreb, Simone Description: Technical drawings (plan, elevation etc) of components in the Cambridge Stratified Swirl Burner. All images are to scale Tue, 01 Jan 2008 00:00:00 GMT http://www.dspace.cam.ac.uk:80/handle/1810/241609 2008-01-01T00:00:00Z http://www.dspace.cam.ac.uk:80/handle/1810/226470 Title: Cambridge Stratified Slot Burner Data Authors: Sweeney, Mark; Hochgreb, Simone; Barlow, Rob Description: Experimental datasets from weakly turbulent methane\air v-flames for a premixed case (fs1), moderately stratified case (fs4) and highly stratified case (fs6). Line measurements of temperature and major species concentrations are supplied, along with simultaneous cross planar OH-PLIF images where the axis of intersection is coincident with the line measurement axis. The OH-PLIF images have been corrected for background, laser beam intensity profile, and have been normalized between zero and one. Wed, 22 Sep 2010 23:00:00 GMT http://www.dspace.cam.ac.uk:80/handle/1810/226470 2010-09-22T23:00:00Z http://www.dspace.cam.ac.uk:80/handle/1810/226367 Title: Direct numerical simulations of spray spark ignition Authors: Neophytou, Alexandre; Cant, Stewart R; Mastorakos, Epaminondas Abstract: Direct Numerical Simulations (DNS) of a mono-disperse spray in a turbulent flow have been used to explore the nature of flame kernels when a spark is deposited in the spray. The simulations use complicated chemistry and are done with the code SENGA2, which has been used for a variety of other turbulent flame problems. For details, see: (i) A. Neophytou's PhD thesis; (ii) Neophytou, A, Mastorakos, E. and Cant, R. S. (2010) DNS of spark ignition and edge flame propagation in turbulent droplet-laden mixing layers. Combustion and Flame 157, 1071-1086. doi:10.1016/j.combustflame.2010.01.019; (iii) Neophytou, A., Mastorakos, E. and Cant, R.S. (2011) Complex chemistry simulations of spark ignition in turbulent sprays. Proceedings of the Combustion Institute 33, 2135-2142. doi:10.1016/j.proci.2010.06.022 ; (iv) Neophytou, A., Mastorakos, E. and Cant, R.S. (2012) The internal structure of igniting turbulent sprays as revealed by complex chemistry DNS. Combustion and Flame 159, 641-664. doi: 10.1016/j.combustflame.2011.08.024. Description: The animations show: (i) black regions correspond to stoichiometric mixture, essentially revealing droplet locations. (ii) blue surfaces denote endothermic reaction zones, while (iii) green and red surfaces denote progressively higher exothermic reaction zones. (iv) The gray surface is the region where the temperature equals 1400 K, to denote the spreading of the energy deposited by the spark. Thu, 09 Sep 2010 10:04:46 GMT http://www.dspace.cam.ac.uk:80/handle/1810/226367 2010-09-09T10:04:46Z http://www.dspace.cam.ac.uk:80/handle/1810/226366 Title: Autoignition of droplets in hot air flow Authors: Gordon, Robert; Mastorakos, Epaminondas Abstract: A single-droplet generator has been used to inject fuel droplets of various sizes and chemical composition into a hot turbulent air flow. The ensuing autoignition and flame behaviour has been recorded with a fast camera. The title of the movie contains the fuel and the framing rate (frames per second). The "grid" refers to the size of the holes in the perforated plate used to produce the turbulence, while the frequency refers to the forcing frequency of the droplet generator. The work is described in: Gordon, R.L. and Mastorakos, E. (2012) Autoignition of monodisperse biodiesel and diesel sprays in turbulent flows. Experimental Thermal and Fluid Science 43, 40-46. doi: 10.1016/j.expthermflusci.2012.04.003 Thu, 09 Sep 2010 09:41:46 GMT http://www.dspace.cam.ac.uk:80/handle/1810/226366 2010-09-09T09:41:46Z http://www.dspace.cam.ac.uk:80/handle/1810/218322 Title: Ignition of spray flame with multiple spark Authors: Marchione, Teresa; Ahmed, Samer F; Mastorakos, Epaminondas Abstract: The movies have been taken at 4000 fps. The spark is placed at a distance z from the nozzle and at 5mm from the enclosure. The ignition unit delivers at 100Hz a spark lasting 8ms, followed by 2ms of no activity. The front and side views are shown. The main flow is from top to botton and the swirling flow from right to left (evident in the front view movies). The flame ignites a long time after the spark sequence has begun. The work is described in: T. Marchione, S.F. Ahmed, E. Mastorakos, "Ignition of turbulent swirling n-heptane spray flames using single and multiple sparks", Combustion and Flame 156 (2009) 166–180. Mon, 25 May 2009 09:58:29 GMT http://www.dspace.cam.ac.uk:80/handle/1810/218322 2009-05-25T09:58:29Z http://www.dspace.cam.ac.uk:80/handle/1810/218189 Title: Autoignition of a H2 jet in hot air flow Authors: Markides, Christos N; Mastorakos, Epaminondas Abstract: The movie (taken with a conventional video camera at 30fps) shows the various operation modes of the Cambridge Autoignition experiment, described in: C.N. Markides, E. Mastorakos, An experimental study of hydrogen autoignition in a turbulent co-flow of heated air, Proceedings of the Combustion Institute 30 (2005) 883–891. The movie contains sound. Thu, 21 May 2009 14:14:13 GMT http://www.dspace.cam.ac.uk:80/handle/1810/218189 2009-05-21T14:14:13Z http://www.dspace.cam.ac.uk:80/handle/1810/218188 Title: Ignition of bluff-body methane flames Authors: Ahmed, Samer F; Marchione, Teresa; Balachandran, R; Mastorakos, Epaminondas; Triantafyllidis, A Abstract: The movies show the ignition process following a spark in a bluff-body stabilised methane non-premixed flame. The flow is described in: S.F. Ahmed, R. Balachandran, T. Marchione, E. Mastorakos, Spark ignition of turbulent nonpremixed bluff-body flames, Combustion and Flame 151 (2007) 366–385 doi:10.1016/j.combustflame.2007.06.012. The Large Eddy Simulation movie is due to A. Triantafyllidis; the paper will appear in Combustion and Flame (2009). Thu, 21 May 2009 13:52:51 GMT http://www.dspace.cam.ac.uk:80/handle/1810/218188 2009-05-21T13:52:51Z http://www.dspace.cam.ac.uk:80/handle/1810/218187 Title: Flame in methane jet after spark ignition Authors: Ahmed, Samer F; Mastorakos, Epaminondas Abstract: The video shows the flame motion following spark ignition in a turbulent methane jet. The flow conditions were: 30% air, 70% CH4, jet velocity 12.5m/s & 25m/s, framing rate 4200 fps, spark at r=0, z=40d (40 jet diameters; d=5mm). For details, see: S.F. Ahmed, E. Mastorakos, Spark ignition of lifted turbulent jet flames, Combustion and Flame 146 (2006) 215–231. doi:10.1016/j.combustflame.2006.03.007 Thu, 21 May 2009 12:06:03 GMT http://www.dspace.cam.ac.uk:80/handle/1810/218187 2009-05-21T12:06:03Z