Engine combustion network: Influence of the gas properties on the spray penetration and spreading angle

In this work, three Engine Combustion Network (ECN) single-hole nozzles with the same nominal characteristics have been tested under a wide range of conditions measuring spray penetration and spreading angle. n-Dodecane has been injected in non-evaporative conditions at different injection pressures ranging from 50 to 150 MPa and several levels of ambient densities from 7.6 to 22.8 kg/m(3). Nitrogen and Sulphur Hexafluoride (SF6) atmospheres have been explored and, in the first case, a temperature sweep from 300 to 550 K at constant gas density has been executed. Mie scattering has been used as the optical technique by employing a fast camera, whereas image processing has been performed through a home-built Mat lab code. Differences in spray penetration related to spray orifice diameter, spreading angle and start of injection transient have been found for the three injectors. Significant differences have been obtained when changing the ambient gas, whereas ambient temperature hardly affects the spray characteristics up to 400 K. However, a reduction in penetration has been observed beyond this point, mainly due to the sensitivity limitation of the technique as fuel evaporation becomes important. The different behavior observed when injecting in different gases could be explained due to the incomplete momentum transfer between spray droplets and entrained gas, together with the fact that there is an important change in speed of sound for the different gases, which affects the initial stage of the injection. (C) 2014 Elsevier Inc. All rights reserved.This work was sponsored by "Ministerio de Economia y Competitividad" of the Spanish Government in the frame of the Project "Comprension de la influencia de combustibles no convencionales en el proceso de injeccion y combustion tipo diesel", Reference TRA2012-36932.Payri González, F.; Payri Marín, R.; Bardi, M.; Carreres Talens, M. (2014). Engine combustion network: Influence of the gas properties on the spray penetration and spreading angle. Experimental Thermal and Fluid Science. 53:236-243. https://doi.org/10.1016/j.expthermflusci.2013.12.014S2362435

Analysis of temperature and altitude effects on the Global Energy Balance during WLTC

This is the author¿s version of a work that was accepted for publication in International Journal of Engine Research. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published as https://doi.org/10.1177/14680874211034292[EN] In this work, the Global Energy Balance (GEB) of a 1.6 L compression ignition engine is analyzed during WLTC using a combination of experimental measurements and simulations, by means of a Virtual Engine. The energy split considers all the relevant energy terms at two starting temperatures (20 degrees C and 7 degrees C) and two altitudes (0 and 1000 m). It is shown that reducing ambient temperature from 20 degrees C to -7 degrees C decreases brake efficiency by 1% and increases fuel consumption by 4%, mainly because of the higher friction due to the higher oil viscosity, while the effect of increasing altitude 1000 m decreases brake efficiency by 0.8% and increases fuel consumption by 2.5% in the WLTC mainly due to the change in pumping. In addition, GEB shows that ambient temperature is affecting exhaust enthalpy by 4.5%, heat rejection to coolant by 2%, and heat accumulated in the block by 2.5%, while altitude does not show any remarkable variations other than pumping and break power.The author(s) disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: This research has been partially funded by the European Union's Horizon 2020 Framework Programme for research, technological development and demonstration under grant agreement 723976 ("DiePeR'') and by the Spanish government under the grant agreement TRA2017-89894-R ("MECOEM'') and Sushma Artham was supported by FPI grant with reference PRE2018-084411. The authors wish to thank Renault SAS, especially P. Mallet and E. Gaiffas, for supporting this research.Payri, F.; Martín, J.; Arnau Martínez, FJ.; Artham, S. (2022). Analysis of temperature and altitude effects on the Global Energy Balance during WLTC. International Journal of Engine Research. 23(11):1831-1849. https://doi.org/10.1177/1468087421103429218311849231

Scaling spray penetration at supersonic conditions through shockwave analysis

[EN] In the current paper, an investigation of the supersonic flow effect on shockwave generation and diesel spray penetration scaling has been performed. For this purpose, spray visualization tests have been carried out in a constant-pressure chamber at room temperature using shadowgraphy technique. Two working gases have been used: nitrogen, with similar thermodynamic characteristics to the engine environment, and sulfur hexafluoride, aimed at producing supersonic conditions at moderate injection pressure values. A total of 60 operating points, including different nozzle geometries, injection pressures and chamber densities have been studied. From the visualization study, two different kinds of shockwaves have been detected: normal or frontal, for moderate spray tip Mach (between 1 and 1.5); and oblique, when the Mach is higher than 1.5. The penetration results show that, for the same injection conditions in terms of injection pressure and chamber density, the spray propagation is equal for SF6 and N-2 when the spray is on subsonic conditions, while penetration is higher for SF6 when supersonic velocity is reached. This behavior has been related to the density gradient appearing across the shockwave. A new methodology to extrapolate supersonic penetration from the well-known subsonic penetration law has been proposed, showing good agreement with the experimental results.This work was partly sponsored by "Ministerio de Ciencia, Innovacion y Universidades", of the Spanish Government, in the frame of the Project "Estudio de la atomizacion primaria mediante simulaciones DNS y tecnicas opticas de muy alta resolucion", Reference RTI2018-099706-B-I00.Salvador, FJ.; De La Morena, J.; Taghavifar, H.; Nemati, A. (2020). Scaling spray penetration at supersonic conditions through shockwave analysis. Fuel. 260:1-7. https://doi.org/10.1016/j.fuel.2019.116308S17260Sazhin, S. S., Feng, G., & Heikal, M. R. (2001). A model for fuel spray penetration. Fuel, 80(15), 2171-2180. doi:10.1016/s0016-2361(01)00098-9Wan, Y., & Peters, N. (1999). SCALING OF SPRAY PENETRATION WITH EVAPORATION. Atomization and Sprays, 9(2), 111-132. doi:10.1615/atomizspr.v9.i2.10Payri, R., Salvador, F. J., Gimeno, J., & Novella, R. (2011). Flow regime effects on non-cavitating injection nozzles over spray behavior. International Journal of Heat and Fluid Flow, 32(1), 273-284. doi:10.1016/j.ijheatfluidflow.2010.10.001Sazhin, S., Crua, C., Kennaird, D., & Heikal, M. (2003). The initial stage of fuel spray penetration☆. Fuel, 82(8), 875-885. doi:10.1016/s0016-2361(02)00405-2Mohan, B., Yang, W., & Chou, S. kiang. (2013). Fuel injection strategies for performance improvement and emissions reduction in compression ignition engines—A review. Renewable and Sustainable Energy Reviews, 28, 664-676. doi:10.1016/j.rser.2013.08.051Choi, W., & Choi, B.-C. (2005). Estimation of the air entrainment characteristics of a transient high-pressure diesel spray. Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering, 219(8), 1025-1036. doi:10.1243/095440705x34630Kostas, J., Honnery, D., Soria, J., Kastengren, A., Liu, Z., Powell, C. F., & Wang, J. (2009). Effect of nozzle transients and compressibility on the penetration of fuel sprays. Applied Physics Letters, 95(2), 024101. doi:10.1063/1.3182821Hillamo, H., Sarjovaara, T., Kaario, O., Vuorinen, V., & Larmi, M. (2010). DIESEL SPRAY VISUALIZATION AND SHOCKWAVES. Atomization and Sprays, 20(3), 177-189. doi:10.1615/atomizspr.v20.i3.10Jia, T.-M., Li, G.-X., Yu, Y.-S., & Xu, Y.-J. (2016). Propagation characteristics of induced shock waves generated by diesel spray under ultra-high injection pressure. Fuel, 180, 521-528. doi:10.1016/j.fuel.2016.04.009Jia, T.-M., Li, G.-X., Yu, Y.-S., & Xu, Y.-J. (2016). Effects of ultra-high injection pressure on penetration characteristics of diesel spray and a two-mode leading edge shock wave. Experimental Thermal and Fluid Science, 79, 126-133. doi:10.1016/j.expthermflusci.2016.07.006Song, E., Li, Y., Dong, Q., Fan, L., Yao, C., & Yang, L. (2018). Experimental research on the effect of shock wave on the evolution of high-pressure diesel spray. Experimental Thermal and Fluid Science, 93, 235-241. doi:10.1016/j.expthermflusci.2018.01.004Payri, R., Salvador, F. J., De la Morena, J., & Pagano, V. (2018). Experimental investigation of the effect of orifices inclination angle in multihole diesel injector nozzles. Part 2 – Spray characteristics. Fuel, 213, 215-221. doi:10.1016/j.fuel.2017.07.076Salvador, F. J., Carreres, M., De la Morena, J., & Martínez-Miracle, E. (2018). Computational assessment of temperature variations through calibrated orifices subjected to high pressure drops: Application to diesel injection nozzles. Energy Conversion and Management, 171, 438-451. doi:10.1016/j.enconman.2018.05.102Payri, R., Salvador, F. J., García, A., & Gil, A. (2012). Combination of Visualization Techniques for the Analysis of Evaporating Diesel Sprays. Energy & Fuels, 26(9), 5481-5490. doi:10.1021/ef3008823Payri, R., Gimeno, J., De la Morena, J., Battiston, P. A., Wadhwa, A., & Straub, R. (2016). Study of new prototype pintle injectors for diesel engine application. Energy Conversion and Management, 122, 419-427. doi:10.1016/j.enconman.2016.06.003Payri, R., Gimeno, J., Viera, J. P., & Plazas, A. H. (2013). Needle lift profile influence on the vapor phase penetration for a prototype diesel direct acting piezoelectric injector. Fuel, 113, 257-265. doi:10.1016/j.fuel.2013.05.057Dhar, A., Tauzia, X., & Maiboom, A. (2016). Phenomenological models for prediction of spray penetration and mixture properties for different injection profiles. Fuel, 171, 136-142. doi:10.1016/j.fuel.2015.12.022Desantes, J. M., Payri, R., Salvador, F. J., & Gil, A. (2006). Development and validation of a theoretical model for diesel spray penetration. Fuel, 85(7-8), 910-917. doi:10.1016/j.fuel.2005.10.023Bermúdez, V., Payri, R., Salvador, F. J., & Plazas, A. H. (2005). Study of the influence of nozzle seat type on injection rate and spray behaviour. Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering, 219(5), 677-689. doi:10.1243/095440705x2830

Serum Inflammatory and Prooxidant Marker Levels in Different Periodontal Disease Stages

[Abstract] Background: Periodontitis has been associated to systemic diseases and this association could be due to an increase in circulating inflammatory and oxidative stress biomarkers in the periodontal disease. This study aimed to evaluate the relationship between inflammatory and pro-oxidant markers according to different stages of periodontitis. Methods: This cross-sectional study included 70 subjects who were divided into three groups according to periodontitis stage: stage II (n = 22), stage III (n = 30), and stage IV (n = 18). We evaluated periodontal parameters and levels of high-sensitivity C-reactive protein (hsCRP), fibrinogen, and malondialdehyde (MDA) in serum, and 8-hydroxy-2′-deoxyguanosine (8-OHdG) in urine. Results: Serum hsCRP and fibrinogen levels were associated with periodontitis severity, which were higher in stage IV than in stages III and II of periodontitis (p = 0.003 and p = 0.025, respectively). We observed a slight yet insignificant increase in MDA levels related to periodontitis severity. Probing depth and clinical attachment loss were associated with serum fibrinogen and hsCRP levels. However, there were no significant associations between periodontal variables and MDA and 8-OHdG levels. Conclusion: Our data support an association between periodontitis and systemic inflammation, which increases with periodontal disease severity. This indicates the importance of the early diagnosis and treatment of periodontal disease to avoid the development or worsening of systemic inflammatory diseases

Effects of varying the liquid fuel type and air co-flow conditions on the microscopic spray characteristics in an atmospheric annular co-flow spray burner

[EN] The atomization process is critical for combustion systems since it directly influences emissions and perfor-mance. Thus injection system should provide the spray required structure and characteristics, e.g., angle and droplet size distribution. Therefore, this work investigates the effects of varying the fuel type, air co-flow rates, fuel mass flow rate and air co-flow temperature on the spray characteristics (e.g., droplet size distribution and droplet velocity) in an annular co-flow spray burner. These effects were investigated by measuring droplet sizes and velocities at different radial and axial positions of n-Heptane, n-Decane and n-Dodecane sprays under non-reacting conditions at a room pressure of 1 atm and temperature of 298 K and using the Microscopic Diffused Back-illumination (MDBI) technique. In addition, the Sauter mean diameter (SMD) for different flow conditions were predicted using three well-known correlations and compared to experimental measurements. The outcomes of this research provided a fair understanding of the influence of varying these parameters on the droplet sizes and velocity through a wide test matrix. Finally, the findings reported here will support future research into the function of phase change in flame stability.This research was funded by the Spanish Ministerio de Ciencias e Innovacion through project reference PID2021-125812OB-C21. Part of the experimental equipment was purchased with support from Conselleria de Innovacion, Universidades, Ciencia y Sociedad Digital of Generalitat Valenciana through grant CIPPC/2021/49. Finally, the support of Omar Huerta Cornejo, Jose E. del Rey and Carlos Gil in conducting the experiments and laboratory work is greatly appreciated.Cardona, S.; Payri, R.; Salvador, FJ.; Gimeno, J. (2023). Effects of varying the liquid fuel type and air co-flow conditions on the microscopic spray characteristics in an atmospheric annular co-flow spray burner. Fuel. 335:1-16. https://doi.org/10.1016/j.fuel.2022.12701811633

ECN Spray G External Spray Visualization and Spray Collapse Description through Penetration and Morphology Analysis

[EN] Inside a DISI engine, a wide range of pressure and temperature conditions are possible, and with the current evolution of the systems, many of the conditions are subject to be encountered at the moment of injection. Given the great differences between Diesel injectors and GDi fuel injectors, the effects of such conditions on the development of the fuel injected can cause phenomena like flash boiling and spray collapse that fundamentally change the behavior of sprays. In this work, the Spray G injector developed by Delphi for the Engine Combustion Network (ECN) group has been tested in a High Pressure High Temperature Constant Pressure Flow Rig (HPHT - CPFR) in a wide range of experimental conditions capturing the liquid and vapor phases of the spray by means of DBI and Schlieren imaging. The work presents the results obtained by spray visualization through comparisons of parametric variations with special focus on the collapse of the spray that occurs under high ambient temperature and density conditions. Spray collapse has been described by showing the direct increase that can cause in spray penetration and the great closing effect that can produce to the aperture of the spray (spray angle). Several contour comparisons using the raw images and the detected contours have been discussed in order to support and further explain the observed trends. (C) 2016 Elsevier Ltd. All rights reserved.This work was sponsored by "Ministerio de Economia y Competitividad" in the frame of the project "Estudio de la interaccion chorro-pared en condiciones realistas de motor (SPRAY WALL)" reference TRA2015-67679-C2-1-R. Daniel Vaquerizo is partially supported through contract FPI-S2-2015-1069 of "Programa de Apoyo para la Investigacion y Desarrollo (PAID)" of Universitat Politecnica de Valencia.Payri, R.; Salvador, FJ.; Marti-Aldaravi, P.; Vaquerizo, D. (2017). ECN Spray G External Spray Visualization and Spray Collapse Description through Penetration and Morphology Analysis. Applied Thermal Engineering. 112:304-316. https://doi.org/10.1016/j.applthermaleng.2016.10.023S30431611

Thermal effects on the diesel injector performance through adiabatic 1D modelling. Part II: Model validation, results of the simulations and discussion

[EN] In this paper, a one-dimensional computational model of the flow in a common-rail injector is used to compute local variations of fuel temperature (including the temperature change produced upon expansion across the nozzle) and analyse their effect on injector dynamics. These variations are accounted through the adiabatic flow hypothesis, assessed in a first part of the paper where the model features are also described. They imply variations in the fuel properties and the flow regime established across the injector internal restrictions driving the solenoid valve. An extensive validation of the model against experimental results is presented for a wide range of conditions. Multiple injection strategies are also explored, analysing the influence of the inlet fuel temperature and its variations on the mass injected by successive injections and the critical dwell time below which they cannot be separated. Results show significant changes in fuel temperature across some injector restrictions. These changes are greater the higher the rail pressure and lower the fuel temperature at the injector inlet. In the case of the flow across nozzle orifices, the fuel can be either heated or subcooled depending on the operating conditions, the heating being especially relevant for cold-start-like fuel temperatures at the inlet. Thermal effects also influence the injection rate and duration. This influence on injector dynamics is particularly accused in the injector of study due to its ballistic nature. In this regard, the time needed to effectively separate two successive injections is greater the higher the fuel temperature and the injection pressure.This work was partly sponsored by FEDER and the Spanish "Ministerio de Economia y Competitividad" in the frame of the project "Desarrollo de modelos de combustion y emisiones HPC para el analisis de plantas propulsivas de transporte sostenible (CHEST)", reference TRA2017-89139-C2-1-R-AR. On the other hand, the support given to Mr Mario Belmar by "Universitat Politecnica de Valencia" through the "FPI-Subprograma 2" grant within the "Programa de Apoyo para la Investigacion y Desarrollo (PAID-01-18)" is gratefully acknowledged by the authors.Payri, R.; Salvador, FJ.; Carreres, M.; Belmar-Gil, M. (2020). Thermal effects on the diesel injector performance through adiabatic 1D modelling. Part II: Model validation, results of the simulations and discussion. Fuel. 260:1-17. https://doi.org/10.1016/j.fuel.2019.115663S117260Gumus, M., Sayin, C., & Canakci, M. (2012). The impact of fuel injection pressure on the exhaust emissions of a direct injection diesel engine fueled with biodiesel–diesel fuel blends. Fuel, 95, 486-494. doi:10.1016/j.fuel.2011.11.020Agarwal, A. K., Dhar, A., Gupta, J. G., Kim, W. I., Choi, K., Lee, C. S., & Park, S. (2015). Effect of fuel injection pressure and injection timing of Karanja biodiesel blends on fuel spray, engine performance, emissions and combustion characteristics. Energy Conversion and Management, 91, 302-314. doi:10.1016/j.enconman.2014.12.004Zecca, A., & Chiari, L. (2010). Fossil-fuel constraints on global warming. Energy Policy, 38(1), 1-3. doi:10.1016/j.enpol.2009.06.068Wang, J., Feng, L., Tang, X., Bentley, Y., & Höök, M. (2017). The implications of fossil fuel supply constraints on climate change projections: A supply-side analysis. Futures, 86, 58-72. doi:10.1016/j.futures.2016.04.007Wang, X., Huang, Z., Zhang, W., Kuti, O. A., & Nishida, K. (2011). Effects of ultra-high injection pressure and micro-hole nozzle on flame structure and soot formation of impinging diesel spray. Applied Energy, 88(5), 1620-1628. doi:10.1016/j.apenergy.2010.11.035Boccardo, G., Millo, F., Piano, A., Arnone, L., Manelli, S., Fagg, S., … Weber, J. (2019). Experimental investigation on a 3000 bar fuel injection system for a SCR-free non-road diesel engine. Fuel, 243, 342-351. doi:10.1016/j.fuel.2019.01.122Mancaruso, E., Sequino, L., & Vaglieco, B. M. (2016). Analysis of the pilot injection running Common Rail strategies in a research diesel engine by means of infrared diagnostics and 1d model. Fuel, 178, 188-201. doi:10.1016/j.fuel.2016.03.066Breda, S., D’Orrico, F., Berni, F., d’ Adamo, A., Fontanesi, S., Irimescu, A., & Merola, S. S. (2019). Experimental and numerical study on the adoption of split injection strategies to improve air-butanol mixture formation in a DISI optical engine. Fuel, 243, 104-124. doi:10.1016/j.fuel.2019.01.111Wang, B., Pamminger, M., Vojtech, R., & Wallner, T. (2018). Impact of injection strategies on combustion characteristics, efficiency and emissions of gasoline compression ignition operation in a heavy-duty multi-cylinder engine. International Journal of Engine Research, 21(8), 1426-1440. doi:10.1177/1468087418801660Sun, Z.-Y., Li, G.-X., Chen, C., Yu, Y.-S., & Gao, G.-X. (2015). Numerical investigation on effects of nozzle’s geometric parameters on the flow and the cavitation characteristics within injector’s nozzle for a high-pressure common-rail DI diesel engine. Energy Conversion and Management, 89, 843-861. doi:10.1016/j.enconman.2014.10.047Torelli, R., Som, S., Pei, Y., Zhang, Y., & Traver, M. (2017). Influence of fuel properties on internal nozzle flow development in a multi-hole diesel injector. Fuel, 204, 171-184. doi:10.1016/j.fuel.2017.04.123Salvador, F., De la Morena, J., Crialesi-Esposito, M., & Martínez-López, J. (2017). Comparative study of the internal flow in diesel injection nozzles at cavitating conditions at different needle lifts with steady and transient simulations approaches. Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering, 232(8), 1060-1078. doi:10.1177/0954407017725672Ihme, M., Ma, P. C., & Bravo, L. (2018). Large eddy simulations of diesel-fuel injection and auto-ignition at transcritical conditions. International Journal of Engine Research, 20(1), 58-68. doi:10.1177/1468087418819546Desantes, J. M., Salvador, F. J., Carreres, M., & Martínez-López, J. (2014). Large-eddy simulation analysis of the influence of the needle lift on the cavitation in diesel injector nozzles. Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering, 229(4), 407-423. doi:10.1177/0954407014542627Payri, R., Salvador, F. J., 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 Conversion and Management, 114, 376-391. doi:10.1016/j.enconman.2016.02.043Salvador, F. J., Carreres, M., Crialesi-Esposito, M., & Plazas, A. H. (2017). Determination of critical operating and geometrical parameters in diesel injectors through one dimensional modelling, design of experiments and an analysis of variance. Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering, 232(13), 1762-1781. doi:10.1177/0954407017735262Desantes, J., Salvador, F., Carreres, M., & Jaramillo, D. (2015). Experimental Characterization of the Thermodynamic Properties of Diesel Fuels Over a Wide Range of Pressures and Temperatures. SAE International Journal of Fuels and Lubricants, 8(1), 190-199. doi:10.4271/2015-01-0951Dernotte, J., Hespel, C., Houille, S., Foucher, F., & Mounaim-Rousselle, C. (2012). INFLUENCE OF FUEL PROPERTIES ON THE DIESEL INJECTION PROCESS IN NONVAPORIZING CONDITIONS. Atomization and Sprays, 22(6), 461-492. doi:10.1615/atomizspr.2012004401Park, Y., Hwang, J., Bae, C., Kim, K., Lee, J., & Pyo, S. (2015). Effects of diesel fuel temperature on fuel flow and spray characteristics. Fuel, 162, 1-7. doi:10.1016/j.fuel.2015.09.008Wang, Z., Ding, H., Wyszynski, M. L., Tian, J., & Xu, H. (2015). Experimental study on diesel fuel injection characteristics under cold start conditions with single and split injection strategies. Fuel Processing Technology, 131, 213-222. doi:10.1016/j.fuproc.2014.10.003Salvador, F. J., Gimeno, J., Carreres, M., & Crialesi-Esposito, M. (2017). Experimental assessment of the fuel heating and the validity of the assumption of adiabatic flow through the internal orifices of a diesel injector. Fuel, 188, 442-451. doi:10.1016/j.fuel.2016.10.061Nurick, W. H. (1976). Orifice Cavitation and Its Effect on Spray Mixing. Journal of Fluids Engineering, 98(4), 681-687. doi:10.1115/1.3448452Soteriou C, Andrews R, Smith M. Direct injection diesel sprays and the effect of cavitation and hydraulic flip on atomization. SAE Pap 950080 1995. doi: 10.4271/950080.Lichtarowicz, A., Duggins, R. K., & Markland, E. (1965). Discharge Coefficients for Incompressible Non-Cavitating Flow through Long Orifices. Journal of Mechanical Engineering Science, 7(2), 210-219. doi:10.1243/jmes_jour_1965_007_029_02Franc J-P. The Rayleigh-Plesset equation: a simple and powerful tool to understand various aspects of cavitation. Fluid Dyn. Cavitation Cavitating Turbopumps, vol. 496, Vienna: Springer; 2007, p. 1–41. doi: 10.1007/978-3-211-76669-9_1.PAYRI, R., GARCIA, J., SALVADOR, F., & GIMENO, J. (2005). Using spray momentum flux measurements to understand the influence of diesel nozzle geometry on spray characteristics. Fuel, 84(5), 551-561. doi:10.1016/j.fuel.2004.10.009Salvador, F. J., Gimeno, J., Carreres, M., & Crialesi-Esposito, M. (2016). Fuel temperature influence on the performance of a last generation common-rail diesel ballistic injector. Part I: Experimental mass flow rate measurements and discussion. Energy Conversion and Management, 114, 364-375. doi:10.1016/j.enconman.2016.02.042Payri, R., Salvador, F. J., Gimeno, J., & Bracho, G. (2008). A NEW METHODOLOGY FOR CORRECTING THE SIGNAL CUMULATIVE PHENOMENON ON INJECTION RATE MEASUREMENTS. Experimental Techniques, 32(1), 46-49. doi:10.1111/j.1747-1567.2007.00188.xTheodorakakos, A., Strotos, G., Mitroglou, N., Atkin, C., & Gavaises, M. (2014). Friction-induced heating in nozzle hole micro-channels under extreme fuel pressurisation. Fuel, 123, 143-150. doi:10.1016/j.fuel.2014.01.050Strotos, G., Koukouvinis, P., Theodorakakos, A., Gavaises, M., & Bergeles, G. (2015). Transient heating effects in high pressure Diesel injector nozzles. International Journal of Heat and Fluid Flow, 51, 257-267. doi:10.1016/j.ijheatfluidflow.2014.10.010Salvador, F. J., Carreres, M., De la Morena, J., & Martínez-Miracle, E. (2018). Computational assessment of temperature variations through calibrated orifices subjected to high pressure drops: Application to diesel injection nozzles. Energy Conversion and Management, 171, 438-451. doi:10.1016/j.enconman.2018.05.102Payri, R., Salvador, F. J., Gimeno, J., & Bracho, G. (2008). Effect of fuel properties on diesel spray development in extreme cold conditions. Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering, 222(9), 1743-1753. doi:10.1243/09544070jauto844Salvador, F. J., Gimeno, J., De la Morena, J., & Carreres, M. (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: Results of the simulations and discussion. Energy Conversion and Management, 54(1), 122-132. doi:10.1016/j.enconman.2011.10.007Moon, S., Gao, Y., Park, S., Wang, J., Kurimoto, N., & Nishijima, Y. (2015). Effect of the number and position of nozzle holes on in- and near-nozzle dynamic characteristics of diesel injection. Fuel, 150, 112-122. doi:10.1016/j.fuel.2015.01.09

Experimental investigation of the effect of orifices inclination angle in multihole diesel injector nozzles. Part 2-Spray characteristics

[EN] Diesel spray development is a key research topic due to its impact on the combustion characteristics. On the current paper, the effect of the orifices inclination angle on the spray penetration characteristics is evaluated. For this purpose, three nozzles with included angles of 90, 140 and 155 degrees are selected. Visualization tests are performed on a room-temperature constant-pressure vessel pressurized with a high-density gas (SF6), in order to reproduce the density conditions inside the combustion chamber at the start of the injection event. Both frontal and lateral Mie-scattering visualization are used, depending on the particular nozzle configuration. Results show how the spray penetration is slower as the inclination angle increases, which is linked to its lower nozzle outlet velocity. A statistical correlation of the spray penetration as a function of the area and velocity coefficients is obtained and discussed.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.Payri, R.; Salvador, FJ.; De La Morena, J.; Pagano, V. (2018). Experimental investigation of the effect of orifices inclination angle in multihole diesel injector nozzles. Part 2-Spray characteristics. Fuel. 213:215-221. https://doi.org/10.1016/j.fuel.2017.07.076S21522121

Experimental study of the injection conditions influence over n-dodecane and diesel sprays with two ECN single-hole nozzles. Part II: Reactive atmosphere

The second part of this experimental analysis, presented in this paper, seeks to go deep on the characterization of the Spray C and Spray D nozzles from the Engine Combustion Network, investigating the penetration of fuel spray at reacting conditions alongside characteristic parameters of combustion such as ignition delay and lift-off length. Both ECN mono-orifice injectors have similar nozzle flow capacity but different conicity degrees and corner sharpness, being Spray C more susceptible to cavitate. Schlieren imaging technique was employed to quantitatively measure reactive penetration and ignition delay, while lift-off length was identified through OH* chemiluminescence. As in the inert part of this research, n-dodecane and commercial diesel were selected for the tests, thereby the effect of the fuel properties in the measured parameters was analyzed. Also, once again the concept of R-parameter, defined as the penetration derivative respect to the square root of time was calculated to delve into the penetration behavior. The experiments were performed in a constant pressure-flow facility able to reproduce engine-like thermodynamic conditions. Results revealed that R-parameter evolution can be divided in four stages: an inert zone, a 'bump', a 'valley' part and a quasi-steady one that overlaps the previous inert part. Those stages are highly governed by ambient temperature and oxygen concentration. Nozzle geometry and fuel properties demonstrated to have a noteworthy influence on all measured parameters.This work was supported by "Ministerio de Economia y Cornpetitividad" of the Spanish Government in the frame of the projects "Estudio de la interaccion chorro-pared en condiciones realistas de motor", Ref. TRA2015-67679-c2-1-R. Moreover, the optical equipment employed in the project was purchased with investment from "Ministerio de Economia y Competitividad" FEDER-ICTS-2012-06.Payri, R.; Salvador Rubio, FJ.; Gimeno, J.; Peraza, JE. (2016). Experimental study of the injection conditions influence over n-dodecane and diesel sprays with two ECN single-hole nozzles. Part II: Reactive atmosphere. Energy Conversion and Management. 126:1157-1167. doi:10.1016/j.enconman.2016.07.079S1157116712

Study of turbulence in atomizing liquid jets

[EN] Among the many unknowns in the study of atomizing sprays, defining an unambiguous way to analyze turbulence is, perhaps, one of the most limiting ones. The lack of proper tools for the analysis of the turbulence field (e.g. specific one/two-point statistics, spectrum, structure functions) limits the understanding of the overall phenomenon occurring, impeding the correct estimation of motion scales (from the Kolmogorov one to the integral one). The present work proposes a methodology to analyze the turbulence in atomizing jets using a pseudo-fluid method. The many challenges presented in these types of flows (such as temporal fluid properties uncertainties, strong anisotropy and lack of a priori chance of determining the motion scales) can be simplified by such a method, as it will be clearly shown by the smooth results obtained. Finally, the method is tested against the one-phase flows turbulent data available in the literature for the Kolmogorov scaling of the one-dimension energy spectra, showing how a pseudo-fluid method could provide a reliable tool to analyze multiphase turbulence, especially in spray's primary atomization.This research has been partially funded by Spanish Ministerio de Economia y Competitividad through project RTI2018-099706-B-100, "Estudio de la atomizacion primaria mediante simulaciones DNS y tecnicas opticas de muy alta resolucion". Additionally, the authors thankfully acknowledge the computer resources at MareNostrum 4 (Barcelona Supercomputing Center) and their technical support provided by FI-2017-2-0035 and TITAN (Oak Ridge Leadership Computing Facility) in the frame of the project TUR124.Torregrosa, AJ.; Payri, R.; Salvador, FJ.; Crialesi-Esposito, M. (2020). Study of turbulence in atomizing liquid jets. International Journal of Multiphase Flow. 129:1-12. https://doi.org/10.1016/j.ijmultiphaseflow.2020.103328S112129Agbaglah, G., Chiodi, R., & Desjardins, O. (2017). Numerical simulation of the initial destabilization of an air-blasted liquid layer. Journal of Fluid Mechanics, 812, 1024-1038. doi:10.1017/jfm.2016.835Aliseda, A., Hopfinger, E. J., Lasheras, J. C., Kremer, D. M., Berchielli, A., & Connolly, E. K. (2008). Atomization of viscous and non-newtonian liquids by a coaxial, high-speed gas jet. Experiments and droplet size modeling. International Journal of Multiphase Flow, 34(2), 161-175. doi:10.1016/j.ijmultiphaseflow.2007.09.003Antonia, R. A., Anselmet, F., & Chambers, A. J. (1986). Assessment of local isotropy using measurements in a turbulent plane jet. Journal of Fluid Mechanics, 163, 365-391. doi:10.1017/s0022112086002331Bassenne, M., Esmaily, M., Livescu, D., Moin, P., & Urzay, J. (2019). A dynamic spectrally enriched subgrid-scale model for preferential concentration in particle-laden turbulence. International Journal of Multiphase Flow, 116, 270-280. doi:10.1016/j.ijmultiphaseflow.2019.04.025Brändle de Motta, J. C., Costa, P., Derksen, J. J., Peng, C., Wang, L.-P., Breugem, W.-P., … Renon, N. (2019). Assessment of numerical methods for fully resolved simulations of particle-laden turbulent flows. Computers & Fluids, 179, 1-14. doi:10.1016/j.compfluid.2018.10.016Chorin, A. J. (1968). Numerical solution of the Navier-Stokes equations. Mathematics of Computation, 22(104), 745-762. doi:10.1090/s0025-5718-1968-0242392-2Comte-Bellot, G., & Corrsin, S. (1971). Simple Eulerian time correlation of full-and narrow-band velocity signals in grid-generated, ‘isotropic’ turbulence. Journal of Fluid Mechanics, 48(2), 273-337. doi:10.1017/s0022112071001599Desantes, J. M., Salvador, F. J., López, J. J., & De la Morena, J. (2010). Study of mass and momentum transfer in diesel sprays based on X-ray mass distribution measurements and on a theoretical derivation. Experiments in Fluids, 50(2), 233-246. doi:10.1007/s00348-010-0919-8Pitsch, H., & Desjardins, O. (2010). DETAILED NUMERICAL INVESTIGATION OF TURBULENT ATOMIZATION OF LIQUID JETS. Atomization and Sprays, 20(4), 311-336. doi:10.1615/atomizspr.v20.i4.40Dodd, M. S., & Ferrante, A. (2016). On the interaction of Taylor length scale size droplets and isotropic turbulence. Journal of Fluid Mechanics, 806, 356-412. doi:10.1017/jfm.2016.550Duret, B., Luret, G., Reveillon, J., Menard, T., Berlemont, A., & Demoulin, F. X. (2012). DNS analysis of turbulent mixing in two-phase flows. International Journal of Multiphase Flow, 40, 93-105. doi:10.1016/j.ijmultiphaseflow.2011.11.014Elghobashi, S. (2019). Direct Numerical Simulation of Turbulent Flows Laden with Droplets or Bubbles. Annual Review of Fluid Mechanics, 51(1), 217-244. doi:10.1146/annurev-fluid-010518-040401Gauding, M., Danaila, L., & Varea, E. (2018). One-point and two-point statistics of homogeneous isotropic decaying turbulence with variable viscosity. International Journal of Heat and Fluid Flow, 72, 143-150. doi:10.1016/j.ijheatfluidflow.2018.05.013Gorokhovski, M., & Herrmann, M. (2008). Modeling Primary Atomization. Annual Review of Fluid Mechanics, 40(1), 343-366. doi:10.1146/annurev.fluid.40.111406.102200Gréa, B.-J., Griffond, J., & Burlot, A. (2014). The effects of variable viscosity on the decay of homogeneous isotropic turbulence. Physics of Fluids, 26(3), 035104. doi:10.1063/1.4867893Harris, V. G., Graham, J. A. H., & Corrsin, S. (1977). Further experiments in nearly homogeneous turbulent shear flow. Journal of Fluid Mechanics, 81(4), 657-687. doi:10.1017/s0022112077002286Hasslberger, J., Ketterl, S., Klein, M., & Chakraborty, N. (2018). Flow topologies in primary atomization of liquid jets: a direct numerical simulation analysis. Journal of Fluid Mechanics, 859, 819-838. doi:10.1017/jfm.2018.845Hinze, J. O. (1955). Fundamentals of the hydrodynamic mechanism of splitting in dispersion processes. AIChE Journal, 1(3), 289-295. doi:10.1002/aic.690010303Lasheras, J. C., & Hopfinger, E. J. (2000). Liquid Jet Instability and Atomization in a Coaxial Gas Stream. Annual Review of Fluid Mechanics, 32(1), 275-308. doi:10.1146/annurev.fluid.32.1.275Lebas, R., Menard, T., Beau, P. A., Berlemont, A., & Demoulin, F. X. (2009). Numerical simulation of primary break-up and atomization: DNS and modelling study. International Journal of Multiphase Flow, 35(3), 247-260. doi:10.1016/j.ijmultiphaseflow.2008.11.005Lee, K., Girimaji, S. S., & Kerimo, J. (2008). Validity of Taylor’s Dissipation-Viscosity Independence Postulate in Variable-Viscosity Turbulent Fluid Mixtures. Physical Review Letters, 101(7). doi:10.1103/physrevlett.101.074501Ling, Y., Fuster, D., Zaleski, S., & Tryggvason, G. (2017). Spray formation in a quasiplanar gas-liquid mixing layer at moderate density ratios: A numerical closeup. Physical Review Fluids, 2(1). doi:10.1103/physrevfluids.2.014005Ling, Y., Fuster, D., Tryggvason, G., & Zaleski, S. (2018). A two-phase mixing layer between parallel gas and liquid streams: multiphase turbulence statistics and influence of interfacial instability. Journal of Fluid Mechanics, 859, 268-307. doi:10.1017/jfm.2018.825LUCCI, F., FERRANTE, A., & ELGHOBASHI, S. (2010). Modulation of isotropic turbulence by particles of Taylor length-scale size. Journal of Fluid Mechanics, 650, 5-55. doi:10.1017/s0022112009994022Manin, J. (2018). NUMERICAL INVESTIGATION OF THE PRIMARY BREAKUP REGION OF HIGH-PRESSURE SPRAYS. Atomization and Sprays, 28(12), 1081-1100. doi:10.1615/atomizspr.2019026990MARMOTTANT, P., & VILLERMAUX, E. (2004). On spray formation. Journal of Fluid Mechanics, 498, 73-111. doi:10.1017/s0022112003006529Park, G. I., Bassenne, M., Urzay, J., & Moin, P. (2017). A simple dynamic subgrid-scale model for LES of particle-laden turbulence. Physical Review Fluids, 2(4). doi:10.1103/physrevfluids.2.044301Pope, S. B., 2001. Turbulent flows.Popinet, S. (2009). An accurate adaptive solver for surface-tension-driven interfacial flows. Journal of Computational Physics, 228(16), 5838-5866. doi:10.1016/j.jcp.2009.04.042Prakash, V. N., Martínez Mercado, J., van Wijngaarden, L., Mancilla, E., Tagawa, Y., Lohse, D., & Sun, C. (2016). Energy spectra in turbulent bubbly flows. Journal of Fluid Mechanics, 791, 174-190. doi:10.1017/jfm.2016.49Roghair, I., Mercado, J. M., Sint Annaland, M. V., Kuipers, H., Sun, C., & Lohse, D. (2011). Energy spectra and bubble velocity distributions in pseudo-turbulence: Numerical simulations vs. experiments. International Journal of Multiphase Flow, 37(9), 1093-1098. doi:10.1016/j.ijmultiphaseflow.2011.07.004Saddoughi, S. G., & Veeravalli, S. V. (1994). Local isotropy in turbulent boundary layers at high Reynolds number. Journal of Fluid Mechanics, 268, 333-372. doi:10.1017/s0022112094001370Salvador, F. J., S., R., Crialesi-Esposito, M., & Blanquer, I. (2018). Analysis on the effects of turbulent inflow conditions on spray primary atomization in the near-field by direct numerical simulation. International Journal of Multiphase Flow, 102, 49-63. doi:10.1016/j.ijmultiphaseflow.2018.01.019Scardovelli, R., & Zaleski, S. (2003). Interface reconstruction with least-square fit and split Eulerian-Lagrangian advection. International Journal for Numerical Methods in Fluids, 41(3), 251-274. doi:10.1002/fld.431Schmidt, O. T., Towne, A., Rigas, G., Colonius, T., & Brès, G. A. (2018). Spectral analysis of jet turbulence. Journal of Fluid Mechanics, 855, 953-982. doi:10.1017/jfm.2018.675Shinjo, J., & Umemura, A. (2010). Simulation of liquid jet primary breakup: Dynamics of ligament and droplet formation. International Journal of Multiphase Flow, 36(7), 513-532. doi:10.1016/j.ijmultiphaseflow.2010.03.008Uberoi, M. S. (1970). Turbulent Energy Balance and Spectra of the Axisymmetric Wake. Physics of Fluids, 13(9), 2205. doi:10.1063/1.1693225Villermaux, E. (2007). Fragmentation. Annual Review of Fluid Mechanics, 39(1), 419-446. doi:10.1146/annurev.fluid.39.050905.110214Wang, Y., & Bourouiba, L. (2018). Unsteady sheet fragmentation: droplet sizes and speeds. Journal of Fluid Mechanics, 848, 946-967. doi:10.1017/jfm.2018.359Zandian, A., Sirignano, W. A., & Hussain, F. (2018). Understanding liquid-jet atomization cascades via vortex dynamics. Journal of Fluid Mechanics, 843, 293-354. doi:10.1017/jfm.2018.11