Experimental assessment of the fuel heating and the validity of the assumption of adiabatic flow through the internal orifices of a diesel injector

[EN] In this paper an experimental investigation on the heating experienced by the fuel when it expands through the calibrated orifices of a diesel injector is carried out. Five different geometries corresponding to the control orifices of two different commercial common-rail solenoid injectors were tested. An experimental facility was used to impose a continuous flow through the orifices by controlling the pressures both upstream and downstream of the restriction. Fuel temperature was controlled prior to the orifice inlet and measured after the outlet at a location where the flow is already slowed down. Results were compared to the theoretical temperature increase under the assumption of adiabatic flow (i.e. isenthalpic process). The comparison points out that this assumption allows to predict the fuel temperature change in a reasonable way for four of the five geometries as long as the pressure difference across the orifice is high enough. The deviations for low imposed pressure differences and the remaining orifice are explained due to the low Reynolds numbers (i.e. flow velocities) induced in these cases, which significantly increase the residence time of a fuel particle in the duct, thus enabling heat transfer with the surrounding atmosphere. A dimensionless parameter to quantify the proneness of the flow through an orifice to exchange heat with the surroundings has been theoretically derived and calculated for the different geometries tested, allowing to establish a boundary that defines beforehand the conditions from which heat losses to the ambient can be neglected when dealing with the internal flow along a diesel injector.This work was partly sponsored by “Ministerio de Economía y Competitividad”, of the Spanish government, in the frame of the project “Estudio de la interacción chorro-pared en condiciones realistas de motor”, reference TRA2015-67679-c2-1-R. This support is gratefully acknowledged by the authors.Salvador, F.; 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. https://doi.org/10.1016/j.fuel.2016.10.061S44245118

Thermal effects on the diesel injector performance through adiabatic 1D modelling. Part I: Model description and assessment of the adiabatic flow hypothesis

[EN] The fuel flow along common-rail injectors is usually treated as isothermal, although the expansions across the injector orifices lead to variations in the fuel temperature that in turn modify the fuel properties influencing injector dynamics. This investigation introduces the hypothesis of adiabatic flow to account for local temperature variations in the computational model of a solenoid injector previously introduced by the authors in its isothermal variant. The main contribution of the study consists on the assessment of the validity of this hypothesis by qualitatively estimating the relative importance of the heat transfer processes during the injection event and in the time lapse among injections. Results of this tentative assessment for engine-like conditions imply that heat transfer is usually still occurring by the time of a new injection, meaning any initial temperature difference among the fuel and the injector wall is not expected to be completely mitigated before each injection event. The magnitude of reduction of this temperature difference depends on the injection frequency through engine speed and load. Anyway, the assumption of adiabatic flow seems to hold once the steady conditions of the injection are reached, meaning that any temperature change predictions considered with the adiabatic hypothesis may be valid as long as a certain temperature change is accounted for at the injector inlet. In a second part of the paper, the capabilities of this new model are validated against experimental data, allowing the use of the model to explore the influence of the thermal effects on the injection event.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. The support of General Motors Global Research and Development (US) concerning the experimental measurements in the engine is gratefully acknowledged by the authors. The authors would also like to thank Jose Enrique del Rey, Leo Thiercelin and Mariano Sanchez for their technical help.Salvador, FJ.; Gimeno, J.; Martín, J.; Carreres, M. (2020). Thermal effects on the diesel injector performance through adiabatic 1D modelling. Part I: Model description and assessment of the adiabatic flow hypothesis. Fuel. 260:1-13. https://doi.org/10.1016/j.fuel.2019.116348S113260Heywood JB. Internal Combustion Engine Fundamentals. vol. 21. 1988.Payri, R., Salvador, F. J., Gimeno, J., & De la Morena, J. (2011). Influence of injector technology on injection and combustion development – Part 1: Hydraulic characterization. Applied Energy, 88(4), 1068-1074. doi:10.1016/j.apenergy.2010.10.012Payri, R., Salvador, F. J., Gimeno, J., & De la Morena, J. (2011). Influence of injector technology on injection and combustion development – Part 2: Combustion analysis. Applied Energy, 88(4), 1130-1139. doi:10.1016/j.apenergy.2010.10.004Gavaises, M. (2008). Flow in valve covered orifice nozzles with cylindrical and tapered holes and link to cavitation erosion and engine exhaust emissions. International Journal of Engine Research, 9(6), 435-447. doi:10.1243/14680874jer01708Som, S., Ramirez, A. I., Longman, D. E., & Aggarwal, S. K. (2011). Effect of nozzle orifice geometry on spray, combustion, and emission characteristics under diesel engine conditions. Fuel, 90(3), 1267-1276. doi:10.1016/j.fuel.2010.10.048Salvador, F. J., Carreres, M., Jaramillo, D., & Martínez-López, J. (2015). Analysis of the combined effect of hydrogrinding process and inclination angle on hydraulic performance of diesel injection nozzles. Energy Conversion and Management, 105, 1352-1365. doi:10.1016/j.enconman.2015.08.035Nguyen, D., Duke, D., Kastengren, A., Matusik, K., Swantek, A., Powell, C. F., & Honnery, D. (2017). Spray flow structure from twin-hole diesel injector nozzles. Experimental Thermal and Fluid Science, 86, 235-247. doi:10.1016/j.expthermflusci.2017.04.020Salvador, F. J., de la Morena, J., Carreres, M., & Jaramillo, D. (2017). Numerical analysis of flow characteristics in diesel injector nozzles with convergent-divergent orifices. Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering, 231(14), 1935-1944. doi:10.1177/0954407017692220Lee, C. S., Lee, K. H., Reitz, R. D., & Park, S. W. (2006). EFFECT OF SPLIT INJECTION ON THE MACROSCOPIC DEVELOPMENT AND ATOMIZATION CHARACTERISTICS OF A DIESEL SPRAY INJECTED THROUGH A COMMON-RAIL SYSTEM. Atomization and Sprays, 16(5), 543-562. doi:10.1615/atomizspr.v16.i5.50Wang, 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.2010.11.035Gumus, 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.2011.11.020Bianchi GM, Falfari S, Pelloni P, Kong S-C, Reitz RD. Numerical Analysis of High-Pressure Fast-Response Common Rail Injector Dynamics. SAE Tech Pap 2002-01-0213 2002. doi:10.4271/2002-01-0213.Marcer R, Audiffren C, Viel A, Bouvier B, Walbott A, Argueyrolles B. Coupling 1D System AMESim and 3D CFD EOLE models for Diesel Injection Simulation Renault. ILASS - Eur. 2010, 23rd Annu. Conf. Liq. At. Spray Syst., 2010, p. 1–10.Plamondon, E., & Seers, P. (2014). Development of a simplified dynamic model for a piezoelectric injector using multiple injection strategies with biodiesel/diesel-fuel blends. Applied Energy, 131, 411-424. doi:10.1016/j.apenergy.2014.06.039Salvador, 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.2011.10.007Salvador, F. J., Plazas, A. H., Gimeno, J., & Carreres, M. (2012). Complete modelling of a piezo actuator last-generation injector for diesel injection systems. International Journal of Engine Research, 15(1), 3-19. doi:10.1177/1468087412455373Payri, 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.2016.02.043Wang, X., Huang, Z., Kuti, O. A., Zhang, W., & Nishida, K. (2010). Experimental and analytical study on biodiesel and diesel spray characteristics under ultra-high injection pressure. International Journal of Heat and Fluid Flow, 31(4), 659-666. doi:10.1016/j.ijheatfluidflow.2010.03.006Theodorakakos, 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.2018.05.102Desantes, 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., Foucher, F., Houillé, S., & Mounaïm-Rousselle, C. (2012). Influence of physical fuel properties on the injection rate in a Diesel injector. Fuel, 96, 153-160. doi:10.1016/j.fuel.2011.11.073Park, 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.2015.09.008Seykens X, Somers LMT, Baert RSG. Modelling of common rail fuel injection system and influence of fluid properties on process. Proc. VAFSEP, Dublin, Ireland; July 6-9, 2004, p. 6–9.Catania, A. E., Ferrari, A., & Spessa, E. (2008). Temperature variations in the simulation of high-pressure injection-system transient flows under cavitation. International Journal of Heat and Mass Transfer, 51(7-8), 2090-2107. doi:10.1016/j.ijheatmasstransfer.2007.11.032Yu, H., Goldsworthy, L., Brandner, P. A., Li, J., & Garaniya, V. (2018). Modelling thermal effects in cavitating high-pressure diesel sprays using an improved compressible multiphase approach. Fuel, 222, 125-145. doi:10.1016/j.fuel.2018.02.104Salvador, 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.2016.10.061Salvador, F. J., Gimeno, J., De la Morena, J., & Carreres, M. (2018). Comparison of Different Techniques for Characterizing the Diesel Injector Internal Dimensions. Experimental Techniques, 42(5), 467-472. doi:10.1007/s40799-018-0246-1Desantes, J. M., López, J. J., Carreres, M., & López-Pintor, D. (2016). Characterization and prediction of the discharge coefficient of non-cavitating diesel injection nozzles. Fuel, 184, 371-381. doi:10.1016/j.fuel.2016.07.026Leonhard, R., Warga, J., Pauer, T., Rückle, M., & Schnell, M. (2010). Solenoid common-rail injector for 1800 bar. MTZ worldwide, 71(2), 10-15. doi:10.1007/bf03227003PAYRI, 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.2004.10.009Siebers DL. Scaling liquid-phase fuel penetration in diesel sprays based on mixing-limited vaporization. SAE Tech Pap 1999-01-0528 1999. doi:10.4271/1999-01-0528.Desantes, 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:10.1177/0954407014542627Salvador, 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.2016.02.042Chorążewski, M., Dergal, F., Sawaya, T., Mokbel, I., Grolier, J.-P. E., & Jose, J. (2013). Thermophysical properties of Normafluid (ISO 4113) over wide pressure and temperature ranges. Fuel, 105, 440-450. doi:10.1016/j.fuel.2012.05.059Huang, D., Simon, S. L., & McKenna, G. B. (2005). Chain length dependence of the thermodynamic properties of linear and cyclic alkanes and polymers. The Journal of Chemical Physics, 122(8), 084907. doi:10.1063/1.1852453Bell, I. H., Wronski, J., Quoilin, S., & Lemort, V. (2014). Pure and Pseudo-pure Fluid Thermophysical Property Evaluation and the Open-Source Thermophysical Property Library CoolProp. Industrial & Engineering Chemistry Research, 53(6), 2498-2508. doi:10.1021/ie4033999Růžička, V., & Domalski, E. S. (1993). Estimation of the Heat Capacities of Organic Liquids as a Function of Temperature using Group Additivity. I. Hydrocarbon Compounds. Journal of Physical and Chemical Reference Data, 22(3), 597-618. doi:10.1063/1.555923Zábranský, M., Kolská, Z., Růžička, V., & Domalski, E. S. (2010). Heat Capacity of Liquids: Critical Review and Recommended Values. Supplement II. Journal of Physical and Chemical Reference Data, 39(1), 013103. doi:10.1063/1.3182831Winklhofer, E., Ahmadi-Befrui, B., Wiesler, B., & Cresnoverh, G. (1992). The Influence of Injection Rate Shaping on Diesel Fuel Sprays—An Experimental Study. Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering, 206(3), 173-183. doi:10.1243/pime_proc_1992_206_176_02Nishimura T, Satoh K, Takahashi S, Yokota K. Effects of Fuel Injection Rate on Combustion and Emission in a DI Diesel Engine. SAE Tech. Pap. 981929, 1998. doi:10.4271/981929.Benajes, J., Molina, S., De Rudder, K., & Rente, T. (2006). Influence of injection rate shaping on combustion and emissions for a medium duty diesel engine. Journal of Mechanical Science and Technology, 20(9), 1436-1448. doi:10.1007/bf02915967He, Z., Xuan, T., Xue, Y., Wang, Q., & Zhang, L. (2014). A numerical study of the effects of injection rate shape on combustion and emission of diesel engines. Thermal Science, 18(1), 67-78. doi:10.2298/tsci130810013hPayri, F., Payri, R., Bardi, M., & Carreres, 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. doi:10.1016/j.expthermflusci.2013.12.014Sieder, E. N., & Tate, G. E. (1936). Heat Transfer and Pressure Drop of Liquids in Tubes. Industrial & Engineering Chemistry, 28(12), 1429-1435. doi:10.1021/ie50324a027Salvador, 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:10.1177/0954407017735262Matsumoto S, Yamada K, Date K. Concepts and Evolution of Injector for Common Rail System. SAE Tech Pap 2012-01-1753 2012. doi:10.4271/2012-01-1753.Schöppe, D., Zülch, S., Hardy, M., Geurts, D., Jorach, R. W., & Baker, N. (2008). Delphi Common Rail system with direct acting injector. MTZ worldwide, 69(10), 32-38. doi:10.1007/bf03226918Benajes, J., Olmeda, P., Martín, J., Blanco-Cavero, D., & Warey, A. (2017). Evaluation of swirl effect on the Global Energy Balance of a HSDI Diesel engine. Energy, 122, 168-181. doi:10.1016/j.energy.2017.01.082Broatch, A., Olmeda, P., García, A., Salvador-Iborra, J., & Warey, A. (2017). Impact of swirl on in-cylinder heat transfer in a light-duty diesel engine. Energy, 119, 1010-1023. doi:10.1016/j.energy.2016.11.040Bardi, M., Payri, R., Malbec, L. M., Bruneaux, G., Pickett, L. M., Manin, J., … Genzale, C. (2012). ENGINE COMBUSTION NETWORK: COMPARISON OF SPRAY DEVELOPMENT, VAPORIZATION, AND COMBUSTION IN DIFFERENT COMBUSTION VESSELS. Atomization and Sprays, 22(10), 807-842. doi:10.1615/atomizspr.2013005837Gimeno, J., Martí-Aldaraví, P., Carreres, M., & Peraza, J. E. (2018). Effect of the nozzle holder on injected fuel temperature for experimental test rigs and its influence on diesel sprays. International Journal of Engine Research, 19(3), 374-389. doi:10.1177/1468087417751531ECN. Engine Combustion Network. Https://EcnSandiaGov/Diesel-Spray-Combustion/ 2010. www.sandia.gov/ecn/

Evaluation of Butanol–Gasoline Blends in a Port Fuel-injection, Spark-Ignition Engine

This paper assesses different butanol–gasoline blends used in a port fuel-injection, spark-ignition engine to quantify the influence of butanol addition on the emission of unburned hydrocarbons, carbon monoxide, and nitrogen oxide. Furthermore, in-cylinder pressure was measured to quantify combustion stability and to compare the ignition delay and fully developed turbulent combustion phases as given by 0%–10% and 10%–90% Mass Fraction Burned (MFB). The main findings are: 1) a 40% butanol/60% gasoline blend by volume (B40) minimizes HC emissions; 2) no significant change in NOx emissions were observed, with the exception of the 80% butanol/20% gasoline blend; 3) the addition of butanol improves combustion stability as measured by the COV of IMEP; 4) butanol added to gasoline reduces ignition delay (0%–10% MFB); and 5) the specific fuel consumption of B40 blend is within 10% of that of pure gasoline for stoichiometric mixture

Evaluation of Butanol–Gasoline Blends in a Port Fuel-injection, Spark-Ignition Engine Évaluation de mélange butanol-essence dans un moteur à allumage commandé à injection indirecte

This paper assesses different butanol–gasoline blends used in a port fuel-injection, spark-ignition engine to quantify the influence of butanol addition on the emission of unburned hydrocarbons, carbon monoxide, and nitrogen oxide. Furthermore, in-cylinder pressure was measured to quantify combustion stability and to compare the ignition delay and fully developed turbulent combustion phases as given by 0%–10% and 10%–90% Mass Fraction Burned (MFB). The main findings are: 1) a 40% butanol/60% gasoline blend by volume (B40) minimizes HC emissions; 2) no significant change in NOx emissions were observed, with the exception of the 80% butanol/20% gasoline blend; 3) the addition of butanol improves combustion stability as measured by the COV of IMEP; 4) butanol added to gasoline reduces ignition delay (0%–10% MFB); and 5) the specific fuel consumption of B40 blend is within 10% of that of pure gasoline for stoichiometric mixture. Cet article évalue le potentiel de l’utilisation de différents mélanges butanolessence dans un moteur à allumage commandé à injection indirecte afin de quantifier l’influence de l’ajout de butanol sur les émissions des hydrocarbures imbrûlés (HC), le monoxyde de carbone (CO) et les oxydes d’azote (NOx). De plus, l’influence sur la stabilité de combustion, le délai d’inflammation et sur la durée de la phase de combustion turbulente développée y sont également présentés. Les principaux résultats: 1) un mélange de 40% butanol et 60% essence (B40) par volume diminue les émissions de HC; 2) aucun effet significatif sur les émissions de NOx n’a été observé à l’exception du mélange 80% butanol/20% essence; 3) l’ajout de butanol améliore la stabilité de combustion ; 4) l’ajout de butanol réduit le délai d’inflammation, quantifié par la durée pour consommer 10% de masse de gaz frais; et 5) la consommation spécifique de carburant pour un mélange stoechiométrique de B40 est 10% supérieure à celle de l’essence