83 research outputs found
Evaluation of natural and tracer fluorescent emission methods for droplet size measurements in a diesel spray
The final publication is available at Springer via http://dx.doi.org/10.1007/s12239-012-0070-zSpray sizing that records fluorescent emission and scattered light has been widely applied to spray diagnostics over the last two decades. Different experimental strategies have been developed, but comparing the different solutions offered has remained of interest to experimentalists. In this work, a comparison of two fluorescence strategies for measuring droplet size in the liquid phase of a last-generation DI diesel spray is conducted. The natural fluorescent emission of a commercial diesel fuel and the fluorescence emitted by a tracer (Rhodamine B) are compared using theoretical and experimental approaches. The LIF/Mie ratio commonly called Planar Droplet Sizing (PDS) technique is applied in two different ways to elucidate the possible advantages of using a fluorescent dopant. The sprays were injected under non-evaporative conditions into a constant pressure vessel that simulates densities present at the moment of injection in currently used passenger car diesel engines. Characterization of the signal properties was performed by measuring the absorption coefficient, fluorescence emission spectrum, quantum yield and lifetime of both configurations. The scattered light and fluorescence intensities were calculated to verify the dependencies of the droplet surface and volume. When applying the two techniques to quantify droplet size in dense diesel sprays, the results show that signal weakness and lack of control over the properties of natural fluorescence produce distortion in the shape of the spray and cause measurements to be unreliable. © 2012 The Korean Society of Automotive Engineers and Springer-Verlag Berlin Heidelberg.This research has been funded in the frame of the project PROFUEL reference TRA2011-26293 from Ministerio de Ciencia e Innovacion. The injectors are part of the ECN international project.Pastor Soriano, JV.; Payri, R.; Salavert Fernandez, J.; Manin, J. (2012). Evaluation of natural and tracer fluorescent emission methods for droplet size measurements in a diesel spray. International Journal of Automotive Technology. 13(5):713-724. https://doi.org/10.1007/s12239-012-0070-zS713724135Albrecht, H. E., Damaschke, N., Borys, M. and Tropea, C. (2003). Laser Doppler and Phase Doppler Measurement Techniques. Springer. Berlin.Barnes, M. D., Whitten, W. B. and Ramsey, J. M. (1994). Enhanced fluorescence yields through cavity quantumelectrodynamic effects in microdroplets. J. Optical Society of America B 11,7, 1297â1304.Benajes, J., Molina, S., Novella, R., Amorim, R., Ben Hadj Hamouda, H. and Hardy, J. (2010). Comparison of two injection systems in an HSDI diesel engine using split injection and different injector nozzles. Int. J. Automotive Technology 11,2, 139â146.Charalampous, G. and Hardalupas, Y. (2011). Method to reduce errors of droplet sizing based on the ratio of fluorescent and scattered light intensities (laser-induced fluorescence/Mie technique). Applied Optics, 50, 3622â3637.Chen, G., Mazumder, M., Chang, R. K., Swindal, J. C. and Acker, W. P. (1996). Laser diagnostics for droplet characterization: Application of morphology dependent resonances. Progress in Energy and Combustion Science 22,2, 163â188.Desantes, J. M., Payri, R., Garcia, J. M. and Salvador, F. J. (2007). A contribution to the understanding of isothermal diesel spray dynamics. Fuel 86,7â8, 1093â1101.Domann, R. and Hardalupas, Y. A. (2000). Study of parameters that influence the accuracy of the planar droplet sizing (PDS) technique. Part. Part. Syst. Charact. 3â11.Domann, R. and Hardalupas, Y. A. (2001). Spatial distribution of fluorescence within large doplets and its dependence on dye concentration. Applied Optics 40,21, 3586â3597.Domann, R. and Hardalupas, Y. A. (2002). Quantitative measurement of planar droplet sauter mean diameter in sprays using planar droplet sizing. 11th Int. Symp. Application of Laser Techniques to Fluid Mechanics, Lisbon, Portugal.Eckbreth, A. C. (1988). Laser Diagnostics for Combustion Species and Temperature. Abacus. Cambridge. Mass.Greenhalgh, D. A. (1999). Planar measurements of fuel vapour, liquid fuel, liquid droplet size and soot. Planar Optical Measurement Methods for Gas Turbine Components, 1â7.Im, K., Lin, K., Lai, M. and Chon, M. (2011). Breakup modeling of a liquid jet in cross flow. Int. J. Automotive Technology 12,4, 489â496.Jermy, M. C. and Greenhalgh, D. A. (2000). Planar dropsizing by elastic and fluorescence scattering in sprays too dense for phase doppler measurement. Appl. Phys. B, 71, 703â710.Kim, Y., Kim, K. and Lee, K. (2011). Effect of a 2-stage injection strategy on the combustion and flame characteristics in a PCCI engine. Int. J. Automotive Technology 12,5, 639â644.Ko, F. H., Weng, L. Y., Ko, C. J. and Chu, T. C. (2006). Characterization of imprinting polymeric temperature variation with fluorescent Rhodamine B molecule. Microelectronic Engineering, 83, 864â868.Lakowicz, J. R. (2006). Principles of Fluorescence Spectroscopy. 3rd Edn. Springer.Lee, S. H., Teong, J., Lee, J. T., Ryou, H. S. and Hong, K. (2005). Investigation on spray characteristics under ultrahigh injection pressure conditions. Int. J. Automotive Technology 6,2, 125â131.Lee, B., Song, J., Chang, Y. and Jeon, C. (2010). Effect of the number of fuel injector holes on characteristics of combustion and emissions in a diesel engine. Int. J. Automotive Technology 11,6, 783â791.LeGal, P., Farrugia, N. and Greenhalgh, D. A. (1999). Laser sheet dropsizing of dense sprays. Optics and Laser Techn., 31, 75â83.Lockett, R. D., Richter, J. and Greenhalgh, D. A. (1998). The characterisation of a diesel spray using combined laser induced fluorescence and laser sheet dropsizing. Conf. Lasers and Electro-Optics Europe.Magde, D., Rojas, G. E. and Seybold, P. (1999). Solvent dependence of the fluorescence lifetimes of xanthene dyes. Photochem. Photobiol., 70, 737.Naber, J. and Siebers, D. (1996). Effects of gas density and vaporization on penetration and dispersion of diesel sprays. SAE Paper No. 960034.Pastor, J. V., LĂłpez, J. J., JuliĂĄ, J. E. and Benajes, J. V. (2002). Planar laser-induced fluorescence fuel concentration measurements in isothermal diesel sprays. Opt. Express 10,7, 309â323.Pastor, J. V., Payri, R., Araneo, L. and Manin, J. (2009). Correction method for droplet sizing by laser-induced fluorescence in a controlled test situation. Optical Engineering 48,1, 013601.Payri, R., Garcia, J. M., Salvador, F. J. and Gimeno, J. (2005a). Using spray momentum flux measurements to understand the influence of diesel nozzle geometry on spray characteristics. Fuel, 84, 551â561.Payri, R., Salvador, F. J., Gimeno, J. and Soare, V. (2005b). Determination of diesel sprays characteristics in real engine in-cylinder air density and pressure conditions. J. Mech. Sci. Technol., 19, 2040â2052.Payri, R., Tormos, B., Salvador, F. J. and Araneo, L. (2008). Spray droplet velocity characterization for convergent nozzles with three different diameters. Fuel 87,15, 3176â3182.Payri, F., Pastor, J., Payri, R. and Manin, J. (2011). Determination of the optical depth of a DI diesel spray. J. Mech. Sci. Technol., 25, 209â219.Potz, D., Chirst, W. and Dittus, B. (2000). Diesel nozzle: The determining interface between injection system and combustion chamber. Conf. Thermo and Fluid-dynamic Processes in Diesel Engines, Valencia, Spain.RamĂrez, A. I., Som, S., Aggarwal, S. K., Kastengren, A. L., El-Hannouny, E. M., Longman, D. E. and Powell, C. F. (2009). Quantitative X-ray measurements of highpressure fuel sprays from a production heavy duty diesel injector. Experiments in Fluids 47,1, 119â134.Schulz, C. and Sick, V. (2005). Tracer-LIF diagnostics: quantitative measurement of fuel concentration, temperature and fuel/air ratio in practical combustion systems. Progress in Energy and Combustion Science, 31, 75â121.Sjoback, R. and Nygren, J. and Kubista, M. (1998). Characterization of fluoresceinâoligonucleotide conjugates and measurement of local electrostatic potential. Biopolymers, 46, 445â453.Soare, V. (2007). Phase Doppler Measurement in Diesel Dense Sprays: Optimisation of Measurements and Study of the Orifice Geometry Influence Over the Spray at Microscopic Level. Ph.D. Dissertion. E.T.S. Ingenieros Industriales. Universidad PolitĂ©cnica de Valencia. Spain.Williams, A. T. R., Winfield, S. A. and Miller, J. N. (1983). Relative fluorescence quantum yields using a computer controlled luminescence spectrometer. Analyst., 108, 1067.Yeh, C. N., Kosaka, H. and Kamimoto, T. A. (1993). Fluorescence/scattering imaging technique for instantaneous 2-D measurements of particle size distribution in a transient spray. Proc. 3rd Cong. Opt. Part. Sizing, Yokohama, Japan, 335â361
Computational investigation of diesel nozzle internal flow during the complete injection event
[EN] Currently, diesel engines are calibrated using more and more complex multiple injection strategies. Under these conditions, the characteristics of the flow exiting the fuel injector are strongly affected by the transient interaction between the needle, the sac volume and the orifices, which are not yet clear. In the current paper, a methodology combining a 1D injector model and 3D-CFD simulations is proposed. First, the characteristics of the nozzle flow have been experimentally assessed in transient conditions by means of injection rate and momentum flux measurements. Later, the 3D-CFD modeling approach has been validated at steady-state fixed lift conditions. Finally, a previously developed 1D injector model has been used to extract the needle lift profiles and transient pressure boundary conditions used for the full-transient 3D-CFD simulations, using adaptive mesh refinement (AMR) strategies to be able to simulate the complete injection rate starting from 1 mu m lift.This work was partly sponsored by "Ministerio de Economia y Competitividad'', of the Spanish Government, in the frame of the Project "Estudio de la interaccion chorro-pared en condiciones realistas de motor'', Reference TRA2015-67679-c2-1-R. The authors would like also to thank the computer resources, technical expertise and assistance provided by Universidad de Valencia in the use of the supercomputer "Tirant''. Mr. Jaramillo's Thesis is funded by "Conselleria d'Educacio, Cultura i Esports'' of Generalitat Valenciana in the frame of the program "Programa VALI + D para investigadores en formacion, Reference ACIF/2015/040.Salvador, FJ.; De La Morena, J.; Bracho Leon, G.; Jaramillo-CĂscar, D. (2018). Computational investigation of diesel nozzle internal flow during the complete injection event. Journal of the Brazilian Society of Mechanical Sciences and Engineering. 40(3):153-167. https://doi.org/10.1007/s40430-018-1074-zS153167403Hall CAS, Lambert JG, Balogh SB (2014) EROI of different fuels and the implications for society. Energy Policy 64:141â152. https://doi.org/10.1016/j.enpol.2013.05.049Lujan JM, Tormos B, Salvador FJ, Gargar K (2009) Comparative analysis of a DI diesel engine fuelled with biodiesel blends during the European MVEG-A cycle: preliminary study (I). Biomass Bioenergy 33:941â947. https://doi.org/10.1016/j.biombioe.2009.02.004Pickett LM, Siebers DL (2004) Soot in diesel fuel jets: effects of ambient temperature, ambient density, and injection pressure. Combust Flame 138:114â135. https://doi.org/10.1016/j.combustflame.2004.04.006Dec JE (1997) A Conceptual Model of DI Diesel Combustion Based on Laser-Sheet Imaging. SAE Tech. Pap. 970873Wang X, Huang Z, Zhang W et al (2011) Effects of ultra-high injection pressure and micro-hole nozzle on flame structure and soot formation of impinging diesel spray. Appl Energy 88:1620â1628. https://doi.org/10.1016/j.apenergy.2010.11.035Sayin C, Gumus M, Canakci M (2013) Influence of injector hole number on the performance and emissions of a di diesel engine fueled with biodiesel-diesel fuel blends. Appl Therm Eng 61:121â128. https://doi.org/10.1016/j.applthermaleng.2013.07.038Mohan B, Yang W, Chou SK (2013) Fuel injection strategies for performance improvement and emissions reduction in compression ignition enginesâA review. Renew Sustain Energy Rev 28:664â676. https://doi.org/10.1016/j.rser.2013.08.051Payri R, Salvador FJ, Gimeno J, De la Morena J (2011) Influence of injector technology on injection and combustion development, Part 1: hydraulic characterization. Appl Energy 88:1068â1074. https://doi.org/10.1016/j.apenergy.2010.10.012Park SW, Kim JW, Lee CS (2006) Effect of injector type on fuel-air mixture formation of high-speed diesel sprays. Proc Inst Mech Eng D 220:647â659. https://doi.org/10.1243/09544070D20304Moon S, Komada K, Sato K et al (2015) Ultrafast X-ray study of multi-hole GDI injector sprays: effects of nozzle hole length and number on initial spray formation. Exp Therm Fluid Sci 68:68â81. https://doi.org/10.1016/j.expthermflusci.2015.03.027Powell CF, Kastengren AL, Liu Z, Fezzaa K (2010) The effects of diesel injector needle motion on spray structure. J Eng Gas Turbines Power 133:12802. https://doi.org/10.1115/1.4001073Huang W, Moon S, Ohsawa K (2016) Near-nozzle dynamics of diesel spray under varied needle lifts and its prediction using analytical model. Fuel 180:292â300. https://doi.org/10.1016/j.fuel.2016.04.042Sun Z-Y, Li G-X, Chen C et al (2015) Numerical investigation on effects of nozzleâs geometric parameters on the flow and the cavitation characteristics within injectorâs nozzle for a high-pressure common-rail DI diesel engine. Energy Convers Manag 89:843â861. https://doi.org/10.1016/j.enconman.2014.10.047Devassy BM, Habchi C, Daniel E (2015) Atomization modelling of liquid jets using a two-surface density approach. At Sprays 25:47â80Moon S, Gao Y, Park S et al (2015) Effect of the number and position of nozzle holes on in- and near-nozzle dynamic characteristics of diesel injection. Fuel 150:112â122. https://doi.org/10.1016/j.fuel.2015.01.097Payri R, Salvador FJ, Carreres M, De la Morena J (2016) Fuel temperature influence on the performance of a last generation common-rail diesel ballistic injector. Part II: 1D model development, validation and analysis. Energy Convers Manag 114:376â391. https://doi.org/10.1016/j.enconman.2016.02.043Plamondon E, Seers P (2014) Development of a simplified dynamic model for a piezoelectric injector using multiple injection strategies with biodiesel/diesel-fuel blends. Appl Energy 131:411â424. https://doi.org/10.1016/j.apenergy.2014.06.039Postrioti L, Malaguti S, Bosi M et al (2014) Experimental and numerical characterization of a direct solenoid actuation injector for diesel engine applications. Fuel 118:316â328. https://doi.org/10.1016/j.fuel.2013.11.001Desantes JM, Salvador FJ, Lopez JJ, De la Morena J (2011) Study of mass and momentum transfer in diesel sprays based on X-ray mass distribution measurements and on a theoretical derivation. Exp Fluids 50:233â246. https://doi.org/10.1007/s00348-010-0919-8De la Morena J, Neroorkar K, Plazas AH et al (2013) Numerical analysis of the influence of diesel nozzle design on internal flow characteristics for 2-valve diesel engine application. At Sprays 23:97â118. https://doi.org/10.1615/AtomizSpr.2013006361Duke DJ, Schmidt DP, Neroorkar K et al (2013) High-resolution large eddy simulations of cavitating gasoline-ethanol blends. Int J Engine Res 14:578â589. https://doi.org/10.1177/1468087413501824Mitroglou N, McLorn M, Gavaises M et al (2014) Instantaneous and ensemble average cavitation structures in diesel micro-channel flow orifices. Fuel 116:736â742. https://doi.org/10.1016/j.fuel.2013.08.060Wang X, Li K, Su W (2012) Experimental and numerical investigations on internal flow characteristics of diesel nozzle under real fuel injection conditions. Exp Therm Fluid Sci 42:204â211. https://doi.org/10.1016/j.expthermflusci.2012.04.022Sou A, Pratama RH (2016) Effects of asymmetric inflow on cavitation in fuel injector and discharged liquid jet. At Sprays 26:939â959. https://doi.org/10.1615/AtomizSpr.2015013501Xue Q, Battistoni M, Powell CF et al (2015) An Eulerian CFD model and X-ray radiography for coupled nozzle flow and spray in internal combustion engines. Int J Multiph Flow 70:77â88. https://doi.org/10.1016/j.ijmultiphaseflow.2014.11.012Castilla R, Gamez-Montero PJ, Ertrk N et al (2010) Numerical simulation of turbulent flow in the suction chamber of a gearpump using deforming mesh and mesh replacement. Int J Mech Sci 52:1334â1342. https://doi.org/10.1016/j.ijmecsci.2010.06.009Parlak Z, Engin T (2012) Time-dependent CFD and quasi-static analysis of magnetorheological fluid dampers with experimental validation. Int J Mech Sci 64:22â31. https://doi.org/10.1016/j.ijmecsci.2012.08.006Chiatti G, Chiavola O, Palmieri F (2009) Spray modeling for diesel engine performance analysis. SAE Tech Pap 2009-01-0835. https://doi.org/10.4271/2009-01-0835Marcer R, Audiffren C, Viel A, et al (2010) Coupling 1D system AMESim and 3D CFD EOLE models for diesel injection simulation Renault. In: ILASSâEur. 2010, 23rd Annu. Conf. Liq. At. Spray Syst., pp 1â10Desantes JM, Salvador FJ, Carreres M, MartĂnez-LĂłpez J (2014) Large-eddy simulation analysis of the influence of the needle lift on the cavitation in diesel injector nozzles. Proc Inst Mech Eng D 229:407â423. https://doi.org/10.1177/0954407014542627Battistoni M, Xue Q, Som S (2016) Large-eddy simulation (LES) of spray transients: start and end of injection phenomena. Oil Gas Sci Technol 71:24. https://doi.org/10.2516/ogst/2015024CONVERGE is a trade mark of convergent science. https://convergecfd.comMacian V, BermĂșdez V, Payri R, Gimeno J (2003) New technique for determination of internal geometry of a diesel nozzle with the use of silicone methodology. Exp Tech 27:39â43. https://doi.org/10.1111/j.1747-1567.2003.tb00107.xDabiri S, Sirignano WA, Joseph DD (2007) Cavitation in an orifice flow. Phys Fluids 19:72112. https://doi.org/10.1063/1.2750655Mohan B, Yang W, Chou SK (2014) Cavitation in injector nozzle holesâa parametric study. Eng Appl Comput Fluid Mech 8:70â81Salvador FJ, Hoyas S, Novella R, Martinez-Lopez J (2011) Numerical simulation and extended validation of two-phase compressible flow in diesel injector nozzles. Proc Inst Mech Eng D 225:545â563. https://doi.org/10.1177/09544070JAUTO1569Som S, Longman DE, Ramirez AI, Aggarwal S (2012) Influence of nozzle orifice geometry and fuel properties on flow and cavitation characteristics of a diesel injector. In: Fuel Inject. Automot. Eng., pp 112â126Desantes JM, Salvador FJ, Carreres M, Jaramillo D (2015) Experimental characterization of the thermodynamic properties of diesel fuels over a wide range of pressures and temperatures. SAE Int J Fuels Lubr 8:2015-01-0951. https://doi.org/10.4271/2015-01-0951Bosch W (1966) The fuel rate indicator: a new measuring instrument for display of the characteristics of individual injection. SAE Pap. 660749Payri R, Salvador FJ, Gimeno J, Bracho G (2008) A new methodology for correcting the signal cumulative phenomenon on injection rate measurements. Exp Tech 32:46â49. https://doi.org/10.1111/j.1747-1567.2007.00188.xPayri F, Payri R, Salvador FJ, MartĂnez-LĂłpez J (2011) A contribution to the understanding of cavitation effects in diesel injector nozzles through a combined experimental and computational investigation. Comput Fluids 58:88â101. https://doi.org/10.1016/j.compfluid.2012.01.005Lichtarowicz AK, Duggins RK, Markland E (1965) Discharge coefficients for incompressible non-cavitating flow through long orifices. J Mech Eng Sci 7:210â219. https://doi.org/10.1243/JMES_JOUR_1965_007_029_02Lopez JJ, Salvador FJ, De la Garza OA, ArrĂšgle J (2012) Characterization of the pressure losses in a common rail diesel injector. Proc Inst Mech Eng D 226:1697â1706. https://doi.org/10.1177/0954407012447020Salvador FJ, Carreres M, Jaramillo D, MartĂnez-LĂłpez J (2015) Comparison of microsac and VCO diesel injector nozzles in terms of internal nozzle flow characteristics. Energy Convers Manag 103:284â299. https://doi.org/10.1016/j.enconman.2015.05.062LMS (2010) Imagine.Lab AMESim v.10. Userâs manualPayri R, Salvador FJ, MartĂ-AldaravĂ P, MartĂnez-LĂłpez J (2012) Using one-dimensional modeling to analyze the influence of the use of biodiesels on the dynamic behavior of solenoid-operated injectors in common rail systems: detailed injection system model. Energy Convers Manag 54:90â99. https://doi.org/10.1016/j.enconman.2011.10.00
Determination of the optical depth of a DI diesel spray
The optical depth is responsible of limiting the optical diagnostic using visible wavelength in the sprays. This paper proposes to measure the optical depth directly in a real Diesel spray through line-of-sight laser extinction measurements. This easily reproducible method which does not require expensive or complex optical techniques is detailed and the measurement procedure is presented in this paper. As diesel sprays are mostly optically thick, the measurements in the denser region are not reliable and a fuel concentration model has been used to derive the results to the entire spray. This work provides values of SMD at different distance from the nozzle tip depending on the specific parameters like injection pressure or discharge density. The values extracted from a combined experimental/computational approach have been compared to PDPA measurements under the same testing conditions. The results have shown that the maximum optical depth was higher than 10 and that an increase of the injection pressure led to higher Âż values. The SMD values appeared to be below the results measured by the PDPA and the droplet diameter showed to be the main responsible of the optical depth of the jet under the tested conditions. © 2011 The Korean Society of Mechanical Engineers and Springer-Verlag Berlin Heidelberg.Payri GonzĂĄlez, F.; Pastor, JV.; Payri, R.; Manin, JL. (2011). Determination of the optical depth of a DI diesel spray. Journal of Mechanical Science and Technology. 25(1):209-219. https://doi.org/10.1007/s12206-010-1024-xS209219251L. Pickett and D. Siebers, Non-sooting, low flame temperature mixing-controlled DI diesel combustion, SAE Paper, 2004-01-1399 (2004).S. Cheng, A. Upatnieks and C. J. Mueller, Investigation of fuel effects on dilute, mixing-controlled combustion in an optical direct-injection diesel engine, Energy & Fuels, 21 (2007) 1989â2002.S. Park, H. Kim and B. Choi, Emission characteristics of exhaust gases and nanoparticles from a diesel engine with biodiesel-diesel blended fuel (BD20), J. Mech. Sci. Technol., 23(9) (2009) 2555â2564.J. Benajes, S. Molina, K. De Rudder and T. Rente, Influence of injection rate shaping on combustion and emissions for a medium duty diesel engine, J. Mech. Sci. Technol., 20(9) (2006) 1436â1448.S. Som, S. K. Aggarwal, E. M. El-Hannouny, D. E. Longman, Investigation of Nozzle Flow and Cavitation Characteristics in a Diesel Injector, J. of Eng. Gas Turb. and Power, 132(4) (2010).J. Lee and K. Min, Effects of needle response on spray characteristics in high pressure injector driven by piezo actuator for common-rail injection system, J. Mech. Sci. Technol., 19(5) (2005) 1194â1205.R. Payri, F. J. Salvador, J. Gimeno and V. Soare, Determination of diesel sprays characteristics in real engine in-cylinder air density and pressure conditions, J. Mech. Sci. Technol., 19 (2005) 2040â2052.Y. Yue, C. F. Powell, R. Poola and J. Wang, Quantitative measurements of diesel fuel spray characteristics in the near-nozzle region by using x-ray absorption, Atomization Sprays, 11(4) (2001).M. Linne, M. Paciaroni, T. Hall and T. Parker, Ballistic imaging of the near field in a diesel spray, Experiments in Fluid,s 40(6) (2006) 836â846.H. E. Albrecht, N. Damaschke, M. Borys and C. Tropea, Laser Doppler and Phase Doppler Measurement Techniques, Springer Berlin (2003).R. Domann and Y. Hardalupas, Quantitative Measurement of planar Droplet Sauter Mean Diameter in sprays using Planar Droplet Sizing, 11th Int. Symp. on App. of Laser Techniques to Fluid Mechanics (Lisbon Portugal) (2002).M. Van der Mark, M. Van Albada and A. Lagendijk, Light scattering in strongly scattering media: Multiple scattering and weak localization, Physical Review, B 37(7) (1988).L. Araneo and R. Payri, Experimental quantification of the planar droplet sizing technique error for micro-metric monodispersed spherical particles, Proc. of the Inst. for Liquid Atomization and Spray Systems Conf. (Como Italy) (2008).G. Hiromi, Multiple scattering correction in the measurement of particle size and number density by the diffraction method, Applied Optics 25(19) (1986) 3552â3558.C. Dumouchel, P. Yongyingsakthavorn and J. Cousin, Light multiple scattering correction of laser-diffraction spray drop-size distribution measurements, International Journal of Multiphase Flow 35(3) (2009) 277â287.J. V. Pastor, R. Payri, L. Araneo and J. Manin, Correction method for droplet sizing by laser-induced fluorescence in a controlled test situation, Optical Engineering, 48(1) (2009).C. Espey and J. E. Dec, The effect of TDC temperature and density on the liquid-phase fuel penetration in a Di Diesel engine, SAE transactions, 104(4) (1995) 1400â1414.J. M. Desantes, R. Payri, A. GarcĂa and J. Manin, Experimental Study of Biodiesel Blendsâ Effects on Diesel Injection Processes, Energy & Fuels, 23 (2009) 3227â3235.C. R. Kitchin, Stars, Nebulae and the Interstellar Medium: Observational Physics and Astrophysics CRC Press (1987).M. A. Linne, Spectroscopic Measurement: An Introduction to the Fundamentals, Academic Press (London, UK) (2002).J. V. Pastor, J. J. Lopez, J. E. JuliĂĄ and J. V. Benajes, Planar laser-induced fluorescence fuel concentration measurements in isothermal sprays, Opt. Express, 10(7) (2002) 309â323.J. Benajes, R. Payri, S. Molina, A.H. Plazas, Investigation of the influence of injection rate shaping on the spray characteristics in a diesel common rail system equipped with a piston amplifier, Journal of fluids engineering-transactions of the ASME, 127(6) (2005) 1102â1110.V. Bermudez, R. Payri, F. J. Salvador and A. H. Plazas, Study of the influence of nozzle seat type on injection rate and spray behavior, ImechE, Journal of automobile engineering, Part D, 219 (2005) 677â689.R. Payri, J. M. Garcia, F. J. Salvador and J. Gimeno, Using spray momentum flux measurements to understand the influence of diesel nozzle geometry on spray characteristics, Fuel, 84 (2005) 551â561.J. M. Desantes, R. Payri, F. J. Salvador and A. Gil, Development and validation of a theoretical model for diesel spray penetration, Fuel, 85 (2006) 910â917.H. Hattori, K. Narumiya, M. Tsue and T. Kadota, Analysis of initial breakup mechanism of diesel spray injected into high-pressure ambience, SAE Paper, 2004-01-0528 (2004).J. D. J. Ingle and S. R. Crouch, Spectrochemical Analysis, Prentice Hall (New Jersey, USA) (1988).F. V. Tinaut, A. Melgar, F. Castro, M. L. Sanchez and B. A. Gimenez, Method to determine liquid concentration in nonstationary axisymmetric sprays, Experiments in Fluids, 23 (1997) 299â305.P. Laven, Simulation of Rainbows, Coronas and Glories by the use of Mie theory, Applied Optics 43(3) (2003) 436â444.J. M. Desantes, R. Payri, J. M. Garcia and F. J. Salvador, A contribution to the understanding of isothermal diesel spray dynamics, Fuel, 86(7â8) (2007) 1093â1101.R. Payri, L. Araneo, J. Shakal and V. Soare, Phase doppler measurements: system set-up optimization for characterization of a diesel nozzle, J. Mech. Sci. Technol., 22 (2008) 1620â1632.E. Berrocal, D. L. Sedarsky, M. E. Paciaroni, I. V. Meglinski and M. A. Linne, Laser light scattering in turbid media Part I: Experimental and simulated results for the spatial intensity distribution, Optics Express, 15 (2007) 10649â10665.C. Roze, T. Girasole, L. Mevcs, G. Grehan, L. Hespel and A. Delfour, Interaction between ultra short pulses and a dense scattering medium by Monte Carlo simulation: consideration of particle size effect, Optics Communications, 220(4â6) (2003) 237â245.E. Berrocal, D. L. Sedarsky, M. E. Paciaroni, I. V. Meglinski and M. A. Linne, Laser light scattering in turbid media Part II: Spatial and temporal analysis of individual scattering orders via Monte Carlo simulation, Optics Express, 17 (2009) 13792â13809.E. Berrocal, Multiple scattering of light in optical diagnostics of dense sprays and other complex turbid media, PhD Thesis Cranfield University (2006).J. Naber and D. Siebers, Effects of gas density and vaporization on penetration and dispersion of diesel sprays, SAE Paper, 960034 (1996).V. Soare, Phase Doppler Measurements in Diesel Dense Sprays: Optimisation of Measurements and Study of the Orifice Geometry Influence over the Spray at Microscopic Level PhD Thesis, Universidad PolitĂ©cnica de Valencia, (2007).G. Wigley, Measurement techniques and data analyses for direct injection fuel sprays, in Phase Doppler measurements in Ultra-dense sprays, University of Darmstad (2005).J. Koo and J. Kim, Assessment of a Phase Doppler Anemometry Technique in Dense Droplet Laden Jet, KSME International Journal, 17(7) (2003) 1083â1094.J. S. Kim and J. S. Kim, A characterization of the spray evolution by dual-mode phase doppler anemometry in an injector of liquid-propellant thruster, J. Mech. Sci. Technol., 23(6) (2009) 1637â1649.J. Labs and T.E. Parker, Two-dimensional droplet size and volume fraction distributions from the near-injector region of high-pressure diesel sprays, Atomization & Sprays, 16 (2006) 843â855
Seagrass ecosystem contributions to people's quality of life in the Pacific Island Countries and Territories
Seagrass ecosystems provide critical contributions (goods and perceived benefits or detriments) for the livelihoods
and wellbeing of Pacific Islander peoples. Through in-depth examination of the contributions provided by
seagrass ecosystems across the Pacific Island Countries and Territories (PICTs), we find a greater quantity in the
Near Oceania (New Guinea, the Bismarck Archipelago and the Solomon Islands) and western Micronesian (Palau
and Northern Marianas) regions; indicating a stronger coupling between human society and seagrass ecosystems.
We also find many non-material contributions historically have been overlooked and under-appreciated by
decision-makers. Closer cultural connections likely motivate guardianship of seagrass ecosystems by Pacific
communities to mitigate local anthropogenic pressures. Regional comparisons also shed light on general and
specific aspects of the importance of seagrass ecosystems to Pacific Islanders, which are critical for forming
evidence-based policy and management to ensure the long-term resilience of seagrass ecosystems and the contributions
they provide
Seagrass ecosystems of the Pacific Island countries and territories: a global bright spot
Seagrass ecosystems exist throughout Pacific Island Countries and Territories (PICTs). Despite this area covering nearly 8% of the global ocean, information on seagrass distribution, biogeography, and status remains largely absent from the scientific literature. We confirm 16 seagrass species occur across 17 of the 22 PICTs with the highest number in Melanesia, followed by Micronesia and Polynesia respectively. The greatest diversity of seagrass occurs in Papua New Guinea (13 species), and attenuates eastward across the Pacific to two species in French Polynesia. We conservatively estimate seagrass extent to be 1446.2 km2, with the greatest extent (84%) in Melanesia. We find seagrass condition in 65% of PICTs increasing or displaying no discernible trend since records began. Marine conservation across the region overwhelmingly focuses on coral reefs, with seagrass ecosystems marginalised in conservation legislation and policy. Traditional knowledge is playing a greater role in managing local seagrass resources and these approaches are having greater success than contemporary conservation approaches. In a world where the future of seagrass ecosystems is looking progressively dire, the Pacific Islands appears as a global bright spot, where pressures remain relatively low and seagrass more resilient
Analyse écorégionale marine de Nouvelle-Calédonie : atelier d'identification des aires de conservation prioritaires
Dans le cadre de l'initiative pour les rĂ©cifs coralliens du Pacifique sud (CRISP), le WWF-France a souhaitĂ© dĂ©velopper un projet pour la protection des rĂ©cifs et des lagons nĂ©o-calĂ©doniens. L'atelier, qui s'est dĂ©roulĂ© les 10 et 11 aoĂ»t Ă NoumĂ©a, avait pour objectif de rassembler les scientifiques et les experts du lagon nĂ©ocalĂ©donien pour identifier, sur la base de leur connaissance experte, les zones les plus remarquables du lagon (richesse, endĂ©misme, originalitĂ© des faunes et flores, espĂšces emblĂ©matiques, zones d'intĂ©rĂȘt fonctionnel) sur lesquelles doivent porter en prioritĂ© les efforts de conservation. Il a permis d'identifier 20 aires prioritaires pour la conservation, parmi lesquelles 6 ont un intĂ©rĂȘt mondial, 4 ont un intĂ©rĂȘt sur le plan rĂ©gional, les autres ayant un intĂ©rĂȘt local
Rhodolith Beds Are Major CaCO3 Bio-Factories in the Tropical South West Atlantic
Rhodoliths are nodules of non-geniculate coralline algae that occur in shallow waters (<150 m depth) subjected to episodic disturbance. Rhodolith beds stand with kelp beds, seagrass meadows, and coralline algal reefs as one of the world's four largest macrophyte-dominated benthic communities. Geographic distribution of rhodolith beds is discontinuous, with large concentrations off Japan, Australia and the Gulf of California, as well as in the Mediterranean, North Atlantic, eastern Caribbean and Brazil. Although there are major gaps in terms of seabed habitat mapping, the largest rhodolith beds are purported to occur off Brazil, where these communities are recorded across a wide latitudinal range (2°N - 27°S). To quantify their extent, we carried out an inter-reefal seabed habitat survey on the Abrolhos Shelf (16°50âČ - 19°45âČS) off eastern Brazil, and confirmed the most expansive and contiguous rhodolith bed in the world, covering about 20,900 km2. Distribution, extent, composition and structure of this bed were assessed with side scan sonar, remotely operated vehicles, and SCUBA. The mean rate of CaCO3 production was estimated from in situ growth assays at 1.07 kg mâ2 yrâ1, with a total production rate of 0.025 Gt yrâ1, comparable to those of the world's largest biogenic CaCO3 deposits. These gigantic rhodolith beds, of areal extent equivalent to the Great Barrier Reef, Australia, are a critical, yet poorly understood component of the tropical South Atlantic Ocean. Based on the relatively high vulnerability of coralline algae to ocean acidification, these beds are likely to experience a profound restructuring in the coming decades
<i>Pseudocodium mucronatum</i>, a new species from New Caledonia, and an analysis of the evolution of climatic preferences in the genus (Bryopsidales, Chlorophyta)
A new species, Pseudocodium mucronatum, is described from the Chesterfield platform off the west coast of New Caledonia. The species differs from its congeners in having mucronate utricules. A phylogenetic analysis of rbcL and tufA sequences showed that P. mucronatum is most closely associated with P. natalense De Clerck, Coppejans et Verbruggen and P. devriesii Weber Bosse, with which it shares compressed axes, depressed apices, and plastids in the utricles and the medullar siphons. We studied the evolution of climatic and ecological preferences in the genus using an interdisciplinary approach consisting of relaxed molecular clock analysis, extraction of macroecological data from satellite imagery in a geographic information system (GIS) framework, andancestral character state estimation. It was shown that the genus originated in tropical waters during the Early Mesozoic. Whereas the P. floridanum-okinawense lineage remained tropical, the lineage including P. natalense, P. devriesii, and P. mucronatum gradually invaded more temperate waters during Cenozoic times. Except for P. devriesii, which occurs in shallow and intertidal habitats, all Pseudocodium species grow in deep-water habitats, and this ecological preference appears to be ancestral
New records of marine benthic algae from the Lagon Sud-Ouest of New Caledonia, South Pacific
One hundred years later, resurrection of Tydemania gardineri A. Gepp & E. Gepp (Udoteaceae, Chlorophyta) based on molecular and morphological data
Tydemania Weber-van Bosse is a genus belonging to the family Udoteaceae (Bryopsidales, Chlorophyta) and currently thought to be monospecific throughout its distribution range in the Indo-Pacific. We tested the assumption that Tydemania is a single species using species delimitation methods, morphological observations and phylogenetic reconstructions of large datasets. Our molecular and morphological data recovered two distinct groups, which we argue are the type species T. expeditionis Weber-van Bosse and T. gardineri A. Gepp & E. Gepp. The latter is currently considered a synonym of the former and we resurrect this name from synonymy. T. gardineri is distinguished morphologically from T. expeditionis by the complete absence of glomeruli, whereas T. expeditionis can have glomeruli and flabella, glomeruli alone, or flabella alone. The two species can also be distinguished by the shape and length of the stalks at the base of the flabellum, the diameter of the main axis and of the flabella siphons at the apices. In addition, they have different geographic distributions, with T. gardineri restricted to the Western Indian Ocean, and T. expeditionis extending from the Red Sea, throughout the Indian Ocean and into the West Pacific, including the Coral Triangle, the Philippines and Japan. From our dataset and literature search, we hypothesize that its south-western distribution limit is in northern Madagascar. Finally, we confirm the synonymization of T. mabahithae with T. expeditionis based on specimens from the type locality of the former and the lack of flabella in several other specimens of T. expeditionis
- âŠ