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

THIESEL 2022. Conference on Thermo-and Fluid Dynamics of Clean Propulsion Powerplants

The THIESEL 2022. Conference on Thermo-and Fluid Dynamic Processes in Direct Injection Engines planned in Valencia (Spain) for 8th to 11th September 2020 has been successfully held in a virtual format, due to the COVID19 pandemic. In spite of the very tough environmental demands, combustion engines will probably remain the main propulsion system in transport for the next 20 to 50 years, at least for as long as alternative solutions cannot provide the flexibility expected by customers of the 21st century. But it needs to adapt to the new times, and so research in combustion engines is nowadays mostly focused on the new challenges posed by hybridization and downsizing. The topics presented in the papers of the conference include traditional ones, such as Injection & Sprays, Combustion, but also Alternative Fuels, as well as papers dedicated specifically to CO2 Reduction and Emissions Abatement.Papers stem from the Academic Research sector as well as from the IndustryXandra Marcelle, M.; Payri Marín, R.; Serrano Cruz, JR. (2022). THIESEL 2022. Conference on Thermo-and Fluid Dynamics of Clean Propulsion Powerplants. Editorial Universitat Politècnica de València. https://doi.org/10.4995/Thiesel.2022.632801EDITORIA

Hydraulic Characterization of Diesel Engine Single-Hole Injectors

Due to world trend on the emission regulations and greater demand of fuel economy, the research on advanced diesel injector designs is a key factor for the next generation diesel engines. For that reason, it is well established that understanding the effects of the nozzle geometry on the spray development, fuel-air mixing, combustion and pollutants formation is of crucial importance to achieve these goals. In the present research, the influence of the injector nozzle geometry on the internal flow characteristics is studied. For this purpose, ten single-hole diesel injectors differing in the orifices degree of conicity (five cylindrical, five conical) but with similar nozzle flow capacity have been characterized geometrically (measurements of nozzle outlet section) and hydraulically. The mass flow and momentum flux rates have been measured for a wide range of experimental conditions. Special attention is given to study the cavitation phenomenon since the cylindrically-shaped nozzle orifices are expected to propitiate cavitation due to abrupt changes in flow direction. The study has been carried out with two different fuels: n-dodecane and commercial diesel, thereby the effect of the fuel properties is also analyzed. The results show that the measured nozzle outlet diameters are higher than the nominal specification for both nozzle types. As expected, the onset of cavitation on the cylindrical nozzles has been identified causing a reduction on the injected mass for all tested conditions. The effective diameter for the cylindrical nozzles have been found to be around 175 mu m (geometrical diameter approximate to 212 mu m) and around 185 mu m (geometrical diameter approximate to 191 mu m) for the conical ones. Finally, the higher density of diesel with respect to n-dodecane have resulted on mass flow rates around 8% over the n-dodecane values for the same test conditions.This work was 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. Additionally, the hardware used for the project was purchased with funding from Ministerio de economia y competitividad FEDER-ICTS-2012-06. Julio Cuisano E. was financed by a postdoctoral fellowship from Fundacion Carolina and Pontifica Universidad Catolica del Peru.Payri Marín, R.; Gimeno García, J.; Cuisano, J.; Arco, J. (2016). Hydraulic Characterization of Diesel Engine Single-Hole Injectors. Fuel. 180:357-366. doi:10.1016/j.fuel.2016.03.083S35736618

A New Methodology to Evaluate Engine Ignition Systems in High Density Conditions

In this research, a new methodology to evaluate the operation of spark ignition systems in high density conditions is presented. New requirements in engines and new combustion modes demand more from these systems. One of the most important new requirements is the increase in density. Thus, a better understanding of the effects of high density and the behavior of the ignition system in these conditions seems necessary. To carry out this work two experimental facilities have been used: a transparent constant volume vessel, and an optical engine to simulate real engine conditions. Thus, the study combines the electrical signals derivate parameters and images obtained with a high speed camera. The methodology has been applied for different cases of pressure, intake temperature, and other parameters that affect the density. Results show that an increase in density causes a decrease in integrated power. Additionally, the dispersion in this integrated power increases too. Finally, the methodology results offer a useful data base for the engineers willing to improve the design of the ignition system. Moreover, it is validated that the results of the ambient transparent constant volume vessel follow the same trends and values as the realistic ones.Payri Marín, R.; Novella Rosa, R.; García Martínez, A.; Domenech Llopis, V. (2014). A New Methodology to Evaluate Engine Ignition Systems in High Density Conditions. Experimental Techniques. 38(3):17-28. doi:10.1111/j.1747-1567.2012.00818.xS1728383Banco , G. An Analysis of the Federal Government's Role in the Research and Development of Clean Diesels in the United States 2004Benajes, J., Novella, R., García, A., & Arthozoul, S. (2009). Partially Premixed Combustion in a Diesel Engine Induced by a Pilot Injection at the Low-pressure Top Dead Center. Energy & Fuels, 23(6), 2891-2902. doi:10.1021/ef900034yBenajes, J. V., López, J. J., Novella, R., & García, A. (2008). ADVANCED METHODOLOGY FOR IMPROVING TESTING EFFICIENCY IN A SINGLE-CYLINDER RESEARCH DIESEL ENGINE. Experimental Techniques, 32(6), 41-47. doi:10.1111/j.1747-1567.2007.00296.xZhao, F., Lai, M.-C., & Harrington, D. . (1999). Automotive spark-ignited direct-injection gasoline engines. Progress in Energy and Combustion Science, 25(5), 437-562. doi:10.1016/s0360-1285(99)00004-0Saitzokoff , A. Reinmann , R. Berglind , T. Glavmo , M. An Ionization Equilibrium Analysis of the Spark Plug an Ionization Sensor 1996Chung , S.S. Ha , J.-Y. Park , W.Y. Lee , M.-J. A Study on a Spark Plug for Charging of Stratified Mixture in a Local Area 2003Kondo , N. Suzuki , T. Sakakura , Y. Yamada , T. Combustion Monitoring by use of the Spark Plug for DI Engine 2001Shimanokami , Y. Matsubara , Y. Suzuki , T. Matsutani , W. Development of High Ignitability with Small Size Spark Plug 2004Lee , M.-J. Hall , M. Ofodike , A.E. Matthews , R. Voltage, and Energy Depositation Characteristics of Spark Ignition SystemsPayri, R., Salvador, F. J., Gimeno, J., & Soare, V. (2005). Determination of diesel sprays characteristics in real engine in-cylinder air density and pressure conditions. Journal of Mechanical Science and Technology, 19(11), 2040-2052. doi:10.1007/bf02916497Lapuerta, M., Armas, O., & Hernández, J. J. (1999). Diagnosis of DI Diesel combustion from in-cylinder pressure signal by estimation of mean thermodynamic properties of the gas. Applied Thermal Engineering, 19(5), 513-529. doi:10.1016/s1359-4311(98)00075-

The effect of nozzle geometry over internal flow and spray formation for three different fuels

The influence of internal nozzle flow characteristics over macroscopic spray development is studied experimentally for two different nozzle geometries and three fuels. The measurements include a complete hydraulic characterization consisting of instantaneous injection rate and spray momentum flux measurements, followed by a high-speed visualization of isothermal liquid spray in combination with cylindrical and conical nozzle configurations. Two of the fuels are pure components n-heptane and n-dodecane while the third fuel consists of a three-component surrogate to better represent the physical and chemical properties of diesel fuel. The cylindrical nozzle with 8.6 % larger diameter, in spite of higher mass flow rate and momentum flux, shows slower spray tip penetration when compared to the conical nozzle. The spreading angle is found to be inversely proportional to the spray tip penetration. The spreading angle is largely influenced by the nozzle geometry and the ambient density. Rail pressure was found to have weak influence on the near-field spreading angle and no influence on the standard deviation of the spreading angle. n-Heptane spray shows slowest penetration rates while n-dodecane and the surrogate fuel mixture show very similar spray behavior for variations in injection pressure and back pressure. However, the surrogate fuel mixture shows higher penetration than n-dodecane when using the conical nozzle and lower penetration than n-dodecane when using cylindrical nozzle.This work was sponsored by Ministerio de Economia y Competitividad of the Spanish Government in the frame of the Project "Estudio de la interaccin chorro-pared en condiciones realistas de motor", Reference TRA2015-67679-c2-1-R. Additionally, the employed nozzles and diesel surrogate were provided and defined by GM R&D.Payri Marín, R.; Viera Sotillo, JP.; Gopalakrishnan, V.; Szymkowicz, PG. (2016). The effect of nozzle geometry over internal flow and spray formation for three different fuels. Fuel. 183:20-33. doi:10.1016/j.fuel.2016.06.041S203318

On the rate of injection modeling applied to direct injection compression ignition engines

Modern engine design has challenging requirements towards maximum power output, fuel consumption and emissions. For engine combustion development programs, the injection system has to be able to operate reliable under a variety of operating conditions. Today s legislations for quieter and cleaner engines require multiple injection strategies, where it is important to understand the behavior of the system and to measure the effect of one injection on subsequent injections. This study presents a methodology for 0D modeling the mass flow rate and the rail pressure of a common rail system, constructed from a set of experimental measurements in engine-like operating conditions, for single and multiple injection strategies. The model is based in mathematical expressions and correlations that can simulate the mass flow rate obtained with the Bosch tube experiment, focusing on the shape and the injected mass, using few inputs: rail pressure, back pressure, energizing time, etc. The model target is to satisfy two conditions: lowest computational cost and to reproduce the realistic injected quantity. Also, the influence of the rail pressure level on the start of injection is determined, especially for multiple injection strategies on the rate shape and injected mass. Good accuracy was obtained in the simulations. Results showed that the model error is within the 5%, which corresponds at the same time to the natural error of the injector and to the accuracy of the measures which had been done. The benefits of the model are that simulations can be performed quickly and easily for any operation points, and on the other hand that the model can be used in real-time on the engine test bench for mass estimations when doing additional experiments or calibration activities.The author(s) disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: This work was sponsored by "Ministerio de Economia y Competitividad'' in the frame of the project "Estudio de la interaccion chorropared en condiciones realistas de motor (SPRAY WALL)'' reference TRA2015-67679-c2-1-R.Payri Marín, R.; Gimeno García, J.; Novella Rosa, R.; Bracho León, GC. (2016). On the rate of injection modeling applied to direct injection compression ignition engines. International Journal of Engine Research. 17(10):1015-1030. doi:10.1177/1468087416636281S10151030171

Using one-dimensional modeling to analyse the influence of the use of biodiesels on the dynamic behavior of solenoid-operated injectors in common rail systems: Detailed injection system model

A combined experimental and computational investigation has been performed in order to evaluate the influence of physical properties of biodiesel on the injection process in a common-direct injection system with second generation solenoid injectors. For that purpose, after a complete characterization of the system, which involved mechanical and hydraulic characterization, a one-dimensional model has been obtained and extensively validated. Simulations have then been performed with a standard diesel and a 100% rape methyl ester (RME) biodiesel which allowed a comparison and analysis of the dynamic response of the injector to be done. Different injection strategies involving main injection and main plus post-injection have been used to explore the impact of the use of biodiesel on the performance and stability of solenoid injectors. As far as the dynamic response of the injector is concerned, the results obtained have clearly shown that the use of biodiesel affects the dynamic response of the needle, especially at low injection pressures. The behavior of the system under multi-injection strategies (main plus post-injection) has been also evaluated determining for different operating conditions (injection pressures and backpressures) the minimum dwell time between injections to assure a stable behavior in the injection process (mass flow rate). Important differences have been found between biodiesel and standard diesel in this critical parameter at low injection pressures, becoming less important at high injection pressure. Finally, a modification on the injector hardware has been proposed in order to compensate these differences.This research has been funded by "Ministerio de Ciencia e Innovacion" in the frame of the project "Estudio teorico experimental de la influencia del combustible sobre la cavitacion y el desarrollo del chorro evaporative (FlexiFuel)", Reference TRA2010-17564.Payri Marín, R.; Salvador Rubio, FJ.; Marti Aldaravi, P.; Martínez López, J. (2012). Using one-dimensional modeling to analyse the influence of the use of biodiesels on the dynamic behavior of solenoid-operated injectors in common rail systems: Detailed injection system model. Energy Conversion and Management. 54(1):90-99. https://doi.org/10.1016/j.enconman.2011.10.004S909954

Effect of turbulent model closure and type of inlet boundary condition on a Large Eddy Simulation of a non-reacting jet with co-flow stream

[EN] In this paper, the behavior and turbulence structure of a non-reacting jet with a co-flow stream is described by means of Large Eddy Simulations (LES) carried out with the computational tool OpenFoam. In order to study the influence of the sub-grid scale (SGS) model on the main flow statistics, Smagorinsky (SMAG) and One Equation Eddy (OEE) approaches are used to model the smallest scales involved in the turbulence of the jet. The impact of cell size and turbulent inlet boundary condition in resulting velocity profiles is analyzed as well. Four different tasks have been performed to accomplish these objectives. Firstly, the simulation of a turbulent pipe, which is necessary to generate and map coherent turbulence structure into the inlet of the non-reacting jet domain. Secondly, a structured mesh based on hexahedrons has been built for the jet and its co-flow. The third task consists on performing four different simulations. In those, mapping statistics from the turbulent pipe is compared with the use of fluctuating inlet boundary condition available in OpenFoam; OEE and SMAG approaches are contrasted; and the effect of changing cell size is investigated. Finally, as forth task, the obtained results are compared with experimental data. As main conclusions of this comparison, it has been proved that the fluctuating boundary condition requires much less computational cost, but some inaccuracies were found close to the nozzle. Also, both SGS models are capable to simulate this kind of jets with a co-flow stream with exactitude.This research was performed in the frame of the project "Estudio de la interaccion chorro-pared en condiciones realistas de motor" reference TRA2015-67679-c2-1-R from Ministerio de Economia y Competitividad (Spanish Ministry of Economy). The equipment used in this work has been partially supported by FEDER Project funds "Dotacion de infraestructuras cientifico tectinas para el Centro Integral de Mejora Energetica y Medioambiental de Sistemas de Transporte (CiMeT), (FEDER-ICTS-2012-06)", framed in the operation program of unique scientific and technical infrastructure of the Ministry of Science and Innovation of Spain. Jhoan S. Giraldo was supported by a research grant from Generalitat Valenciana (Programa Santiago Grisolia, GRISOLIA/2013/007).Payri Marín, R.; López Sánchez, JJ.; Marti-Aldaravi, P.; Giraldo Valderrama, JS. (2016). Effect of turbulent model closure and type of inlet boundary condition on a Large Eddy Simulation of a non-reacting jet with co-flow stream. International Journal of Heat and Fluid Flow. 61:545-552. https://doi.org/10.1016/j.ijheatfluidflow.2016.06.016S5455526

Ilass Europe. 28th european conference on liquid atomization and spray systems

ILASS 2017 is the 28th European Conference on Liquid Atomization and Spray Systems.Following the successful 26th ILASS 2014 (Bremen) and 27th ILASS 2016 conferences,we will continue this tradition by providing a venue for industrial and academic researchers and students to engage in the scientific development and practice of Atomization and Spray Systems and to meet and share recent developments in these fields. ILASS is the Institute for liquid atomization and spray systems. ILASS Europe has its roots in an initiative of the late Paul Eisenklam,who established the institute in 1982Payri Marín, R.; Xandra Marcelle, M. (2017). Ilass Europe. 28th european conference on liquid atomization and spray systems. Editorial Universitat Politècnica de València. http://hdl.handle.net/10251/86907EDITORIA

Development of a methodology to learn the characteristics and performances of common rail injection systems based on simulations with AMESim

An injector model built with the platform LMS Imagine.Lab AMESim has been introduced as a useful tool used in one of the practical lessons taught in the Mixing formation and combustion systems in the Reciprocating Internal CombustionEngines course. This course carries 6 ECTS and is a first year course in the second semester of the Master s in Reciprocating Internal Combustion Engines . Using a standard model that has been previously implemented and validated, the students have to carry out an analysis of the injection process from the point of view of the operation of a modern solenoid-valve operated injector. The goal pursued in the lesson described here is, on the one hand, to help the students to understand how injectors work from the moment when they receive the current from the ECU of the engine up to when the fuel is delivered to the combustion chamber as a diesel spray. The different mechanisms involved will be analyzed by the students by exploring important internal variables, such as pressure variations, moving part displacement and, in overall terms, all the variables involved in the injection phenomenon. On the other hand, the students will be able to identify the critical parameters that play a major role, affecting the mass flow rate to a greater extent, by analyzing the response of the system under different geometrical configurations and different operating conditions. There is some evidence that the new teaching approach significantly improves the learning process when compared with the previous teaching methodology.Payri Marín, R.; López Sánchez, JJ.; Salvador Rubio, FJ.; Martí Aldaraví, P. (2013). Development of a methodology to learn the characteristics and performances of common rail injection systems based on simulations with AMESim. International Journal of Engineering Education. 29(2):533-547. http://hdl.handle.net/10251/63629S53354729