Analysis of the impact of the geometry on the performance of an automotive centrifugal compressor using CFD simulations

[EN] During the latest years, downsizing in internal combustion engines has moved the operating conditions of the compressor closer the surge limit. Surge onset depends on the geometry of the compressor inlet and is difficult to predict. Unfortunately, the determination of the surge line is essential for engine design and calibration, since surge is an oscillating phenomenon that endangers the turbocharger integrity. This work is addressed to study the impact of placing different geometries, namely a tapered duct, a convergent-divergent nozzle and a divergent nozzle in the compressor inlet on different compressor parameters such as stability, efficiency and noise emission. 3D-CFD simulations are performed using the commercial code STAR-CCM+ at both near-surge conditions and high mass flow rate, focusing on the flow structures generated by each configuration. The results are compared with corresponding experimental tests and show a meaningful sensitivity of geometry to the performance, indicating potential benefits of using some of these geometries in turbocharger configurations.Daniel Tarí is partially supported through contract FPI-S2-2015- 1095 of Programa de Apoyo para la Investigación y Desarrollo (PAID) of Universitat Politècnica de València.Galindo, J.; Gil Megías, A.; Navarro, R.; Tarí, D. (2019). Analysis of the impact of the geometry on the performance of an automotive centrifugal compressor using CFD simulations. Applied Thermal Engineering. 148:1324-1333. https://doi.org/10.1016/j.applthermaleng.2018.12.018S1324133314

OMEx-diesel blends as high reactivity fuel for ultra-low NOx and soot emissions in the dual-mode dual-fuel combustion strategy

[EN] Previous works demonstrated that the use of Oxymethylene ether (OMEx) in advanced combustion modes, as the dual-mode dual-fuel combustion, leads to a notable reduction of the lifecycle CO2 emissions while promoting lower NOx and soot emissions than those from conventional diesel combustion. Nonetheless, the low heating value of OMEx results in a fuel consumption increase. A possible solution to avoid this drawback is by blending OMEx with diesel fuel. This will help to introduce the OMEx in the market with minimum changes in the infrastructure. In this context, this work evaluates the impact of using OMEx-diesel blends in different mass percentages (50% and 70% of OMEx in diesel), compared to the reference net fuels (net diesel and OMEx) in a multi-cylinder compression ignition engine operating under dual-mode dual-fuel combustion at different engine loads (25%, 50%, 80% and 100%) and 1800 rpm. At each condition, an air mass sweep was performed to assess the limiting operating conditions with each fuel due to either excessive pressure gradients and soot production, or low combustion efficiency. The results suggested that the OMEx-diesel blends allow to reduce the soot emissions compared to net diesel for all the conditions tested. In addition, blends having an OMEx mass content greater than 70% allowed to fulfill the EUVI limits for NOx with ultra-low soot levels (.Soler A. Role of e-fuels in the European transport system. Literature review. Concawe, Brussels, January 2020.Benajes, J., García, A., Monsalve-Serrano, J., & Martínez-Boggio, S. (2019). Optimization of the parallel and mild hybrid vehicle platforms operating under conventional and advanced combustion modes. Energy Conversion and Management, 190, 73-90. doi:10.1016/j.enconman.2019.04.010Luján, J. M., García, A., Monsalve-Serrano, J., & Martínez-Boggio, S. (2019). Effectiveness of hybrid powertrains to reduce the fuel consumption and NOx emissions of a Euro 6d-temp diesel engine under real-life driving conditions. Energy Conversion and Management, 199, 111987. doi:10.1016/j.enconman.2019.111987Pastor, J. V., García, A., Micó, C., & Lewiski, F. (2020). An optical investigation of Fischer-Tropsch diesel and Oxymethylene dimethyl ether impact on combustion process for CI engines. Applied Energy, 260, 114238. doi:10.1016/j.apenergy.2019.114238Ershov, M., Potanin, D., Gueseva, A., Abdellatief, T. M. M., & Kapustin, V. (2020). Novel strategy to develop the technology of high-octane alternative fuel based on low-octane gasoline Fischer-Tropsch process. Fuel, 261, 116330. doi:10.1016/j.fuel.2019.116330Verhelst, S., Turner, J. W., Sileghem, L., & Vancoillie, J. (2019). Methanol as a fuel for internal combustion engines. Progress in Energy and Combustion Science, 70, 43-88. doi:10.1016/j.pecs.2018.10.001Deutz, S., Bongartz, D., Heuser, B., Kätelhön, A., Schulze Langenhorst, L., Omari, A., … Bardow, A. (2018). Cleaner production of cleaner fuels: wind-to-wheel – environmental assessment of CO2-based oxymethylene ether as a drop-in fuel. Energy & Environmental Science, 11(2), 331-343. doi:10.1039/c7ee01657cOmari A, Heuser B, Pischinger S. Potential of oxymethylenether-diesel blends for ultra-low emission engines, Fuel, 209, 2017, 232–237, ISSN 0016-2361, doi: 10.1016/j.fuel.2017.07.107.Burre, J., Bongartz, D., & Mitsos, A. (2019). Production of Oxymethylene Dimethyl Ethers from Hydrogen and Carbon Dioxide—Part II: Modeling and Analysis for OME3–5. Industrial & Engineering Chemistry Research, 58(14), 5567-5578. doi:10.1021/acs.iecr.8b05577Burre J, Bongartz D, Mitsos A. Production of oxymethylene dimethyl ethers from hydrogen and carbon dioxide—Part II: Modeling and analysis for OME3–5, Ind Eng Chem Res, March 2019, 58, 5567–5578, doi: 10.1021/acs.iecr.8b05577.García, A., Monsalve-Serrano, J., Villalta, D., Lago Sari, R., Gordillo Zavaleta, V., & Gaillard, P. (2019). Potential of e-Fischer Tropsch diesel and oxymethyl-ether (OMEx) as fuels for the dual-mode dual-fuel concept. Applied Energy, 253, 113622. doi:10.1016/j.apenergy.2019.113622Payri, R., De La Morena, J., Monsalve-Serrano, J., Pesce, F. C., & Vassallo, A. (2018). Impact of counter-bore nozzle on the combustion process and exhaust emissions for light-duty diesel engine application. International Journal of Engine Research, 20(1), 46-57. doi:10.1177/1468087418819250Di Sarli, V., Landi, G., Lisi, L., Saliva, A., & Di Benedetto, A. (2016). Catalytic diesel particulate filters with highly dispersed ceria: Effect of the soot-catalyst contact on the regeneration performance. Applied Catalysis B: Environmental, 197, 116-124. doi:10.1016/j.apcatb.2016.01.073Orihuela, M. P., Gómez-Martín, A., Miceli, P., Becerra, J. A., Chacartegui, R., & Fino, D. (2018). Experimental measurement of the filtration efficiency and pressure drop of wall-flow diesel particulate filters (DPF) made of biomorphic Silicon Carbide using laboratory generated particles. Applied Thermal Engineering, 131, 41-53. doi:10.1016/j.applthermaleng.2017.11.149Pachiannan T, Zhong W, Rajkumar S, He Z, Leng X, Wang Q. A literature review of fuel effects on performance and emission characteristics of low-temperature combustion strategies. Appl Energy, 251,2019,113380.Martins M, Fischer I, Gusberti F, Sari R et al., HCCI of wet ethanol on a dedicated cylinder of a diesel engine, SAE Technical Paper 2017-01-0733, 2017, doi: 10.4271/2017-01-0733.Reitz, R. D., & Duraisamy, G. (2015). Review of high efficiency and clean reactivity controlled compression ignition (RCCI) combustion in internal combustion engines. Progress in Energy and Combustion Science, 46, 12-71. doi:10.1016/j.pecs.2014.05.003Olmeda, P., García, A., Monsalve-Serrano, J., & Lago Sari, R. (2018). Experimental investigation on RCCI heat transfer in a light-duty diesel engine with different fuels: Comparison versus conventional diesel combustion. Applied Thermal Engineering, 144, 424-436. doi:10.1016/j.applthermaleng.2018.08.082Benajes, J., García, A., Monsalve-Serrano, J., & Lago Sari, R. (2018). Fuel consumption and engine-out emissions estimations of a light-duty engine running in dual-mode RCCI/CDC with different fuels and driving cycles. Energy, 157, 19-30. doi:10.1016/j.energy.2018.05.144Curran S, Hanson R, Wagner R. Reactivity controlled compression ignition combustion on a multi-cylinder light-duty diesel engine. Int J Engine Res 13 (3), 216–225.Kokjohn SL, Hanson RM, Splitter DA, Reitz RD. Fuel reactivity controlled compression ignition (RCCI): a pathway to controlled high-efficiency clean combustion, Int J Engine Res, 2011. 12, June 2011, 209–226.Benajes, J., Molina, S., García, A., & Monsalve-Serrano, J. (2015). Effects of low reactivity fuel characteristics and blending ratio on low load RCCI (reactivity controlled compression ignition) performance and emissions in a heavy-duty diesel engine. Energy, 90, 1261-1271. doi:10.1016/j.energy.2015.06.088Benajes, J., Molina, S., García, A., & Monsalve-Serrano, J. (2015). Effects of direct injection timing and blending ratio on RCCI combustion with different low reactivity fuels. Energy Conversion and Management, 99, 193-209. doi:10.1016/j.enconman.2015.04.046Benajes, J., García, A., Monsalve-Serrano, J., & Lago Sari, R. (2018). Experimental investigation on the efficiency of a diesel oxidation catalyst in a medium-duty multi-cylinder RCCI engine. Energy Conversion and Management, 176, 1-10. doi:10.1016/j.enconman.2018.09.016García, A., Piqueras, P., Monsalve-Serrano, J., & Lago Sari, R. (2018). Sizing a conventional diesel oxidation catalyst to be used for RCCI combustion under real driving conditions. Applied Thermal Engineering, 140, 62-72. doi:10.1016/j.applthermaleng.2018.05.043Benajes, J., García, A., Monsalve-Serrano, J., & Villalta, D. (2018). Exploring the limits of the reactivity controlled compression ignition combustion concept in a light-duty diesel engine and the influence of the direct-injected fuel properties. Energy Conversion and Management, 157, 277-287. doi:10.1016/j.enconman.2017.12.028Benajes, J., García, A., Monsalve-Serrano, J., Balloul, I., & Pradel, G. (2017). Evaluating the reactivity controlled compression ignition operating range limits in a high-compression ratio medium-duty diesel engine fueled with biodiesel and ethanol. International Journal of Engine Research, 18(1-2), 66-80. doi:10.1177/1468087416678500Molina, S., García, A., Monsalve-Serrano, J., & Estepa, D. (2018). Miller cycle for improved efficiency, load range and emissions in a heavy-duty engine running under reactivity controlled compression ignition combustion. Applied Thermal Engineering, 136, 161-168. doi:10.1016/j.applthermaleng.2018.02.106Pedrozo V, May W, Guan W, Zhao H. High efficiency ethanol-diesel dual-fuel combustion: a comparison against conventional diesel combustion from low to full engine load. Fuel, 230, 2018, 440–451, ISSN 0016-2361, doi: 10.1016/j.fuel.2018.05.034.Benajes, J., García, A., Monsalve-Serrano, J., & Boronat, V. (2017). Achieving clean and efficient engine operation up to full load by combining optimized RCCI and dual-fuel diesel-gasoline combustion strategies. Energy Conversion and Management, 136, 142-151. doi:10.1016/j.enconman.2017.01.010García, A., Monsalve-Serrano, J., Rückert Roso, V., & Santos Martins, M. E. (2017). Evaluating the emissions and performance of two dual-mode RCCI combustion strategies under the World Harmonized Vehicle Cycle (WHVC). Energy Conversion and Management, 149, 263-274. doi:10.1016/j.enconman.2017.07.034Benajes, J., García, A., Pastor, J. M., & Monsalve-Serrano, J. (2016). Effects of piston bowl geometry on Reactivity Controlled Compression Ignition heat transfer and combustion losses at different engine loads. Energy, 98, 64-77. doi:10.1016/j.energy.2016.01.014Luján, J. M., Dolz, V., Monsalve-Serrano, J., & Bernal Maldonado, M. A. (2019). High-pressure exhaust gas recirculation line condensation model of an internal combustion diesel engine operating at cold conditions. International Journal of Engine Research, 22(2), 407-416. doi:10.1177/1468087419868026AVL manufacturer manual. Smoke value measurement with the filter-papermethod. Application notes. June 2005 AT1007E, Rev. 02. Web:.Payri R, Gimeno J, Mata C, Viera A. Rate of injection measurements of a direct-acting piezoelectric injector for different operating temperatures. Energy Convers Manage, 154, 2017, 387-393, ISSN 0196-8904, doi: 10.1016/j.enconman.2017.11.029.Pedrozo, V. B., May, I., & Zhao, H. (2017). Exploring the mid-load potential of ethanol-diesel dual-fuel combustion with and without EGR. Applied Energy, 193, 263-275. doi:10.1016/j.apenergy.2017.02.04

A recent eulerian langrarian CFD methodology for modeling direct injection diesel sprays

[EN] The global objective of this work is to show the capabilities of the Eulerian Lagrangian spray atomization (ELSA) model for the simulation of Diesel sprays in cold starting con- ditions. Our main topic is to focus in the analysis of spray formation and its evolution ◦at low temperature 255 K (−18 C) and nonevaporative conditions. Spray behavior and several macroscopic properties, included the liquid spray penetration, and cone angle are also characterized. This study has been carried out using different ambient temper- ature and chamber pressure conditions. Additionally, the variations of several technical quantities, as the area coefficient and effective diameter are also studied. The results are compared with the latest experimental results in this field obtained in our institute. In the meantime, we also compare with the normal ambient temperature at 298 K (25◦ C) where the numerical validation of the model has shown a good agreement.In this article, KAD did all the simulations, analyze the results coming from them, and wrote the first version of the manuscript under the direct supervision of SH. JMD, AG and FR gave continuous advice during the work and collaborated in the final form of the manuscript. This work was supported in part by the Spanish Government in the frame of the Project `Metodos LES para la simulacion de chorros multifasicos, Ref. ENE2010-18542 and by Renault. Dung Khuong-Anh has been supported in part by the VECOM (Vehicle Concept Modeling), EU FP7 Marie Curie Initial Training Network (ITN) Grant Agreement 213543 and in conjunction with Renault SA, France.Desantes Fernández, JM.; Hoyas Calvo, S.; Gil Megías, A.; Khuong, AD.; Ravet, F. (2014). A recent eulerian langrarian CFD methodology for modeling direct injection diesel sprays. International Journal of Computational Methods. 11(3):1343012-1343029. https://doi.org/10.1142/S0219876213430123S1343012134302911

Development of non-reflecting boundary condition for application in 3D computational fluid dynamics codes

This is an Author's Accepted Manuscript of an article published in [include the complete citation information for the final version of the article as published in the Engineering applications of computational fluid mechanics, 2012 © Taylor & Francis, available online at: http://doi.org/ 10.1080/19942060.2012.11015434[EN] Numerical computations are commonly used for better understanding the unsteady processes in internal combustion engine components and their acoustic behavior. The acoustic characterization of a system requires that reflections from duct terminations are avoided, which is achieved either by using highly dissipative terminations or, when an impulsive excitation is used, by placing long ducts between the system under study and the duct ends. In the latter case, the simulation of such a procedure would require a large computational domain with the associated high computational cost, unless non-reflecting boundary conditions are used. In this paper, first the different non-reflecting boundary conditions available in ANSYS-FLUENT are evaluated. Then, the development and implementation of an anechoic termination in a 3D-CFD code is presented. The performance of the new implementation is first validated in the classic Sod's shock tube problem, and then checked against numerical and experimental results of the flow and acoustic fields in automotive exhaust mufflers. The results obtained compare favorably with those from the conventional CFD approach and experiments, while the computational cost is significantly reduced.This work has been partially supported by Ministerio de Ciencia e Innovacion through grant No. DPI2009-14290. The authors wish to thank Dr. David R. Perry for his kind assistance in manuscript editing.Torregrosa, AJ.; Fajardo, P.; Gil Megías, A.; Navarro García, R. (2012). Development of non-reflecting boundary condition for application in 3D computational fluid dynamics codes. Engineering Applications of Computational Fluid Mechanics. 6(3):447-460. https://doi.org/10.1080/19942060.2012.11015434S44746063ANSYS Inc. (2009). Ansys Fluent 12.0 User’s Guide. Canonsburg, PA: ANSYS Inc.Benson RS (1982).The Thermodynamics and Gas Dynamics of Internal Combustion Engines. Volume 1, Oxford: Oxford University Press.Luján JM, Bermúdez V, Serrano JR, Cervelló C (2002). Test bench for turbocharger groups characterization.SAE Paper2002–01-0163.Munjal ML (1987).Acoustics of Ducts and Mufflers. New York: Willey.Onorati A, Montenegro G, D’Errico G (2006). Prediction of the attenuation characteristics of IC engine silencers by 1-D and multi-D simulation models.SAE Paper2006–01-1541.Patil AR, Sajanpawar PR, Masurekar VV (1996) Acoustic three dimensional finite element analysis of a muffler.SAE Paper960189

Mecánica de fluidos computacional: reconstrucción de la solución para el cálculo de flujos y métodos multigrid

En este artículo vamos a presentar cómo se puede reconstruir la solución para calcular los flujos entre celdas en el método de volúmenes finitos para la resolución de problemas de mecánica de fluidos computacional. Además, introduciremos los métodos multigrid, con sus ventajas para la resolución de grandes sistemas de ecuaciones linealizados como los encontrados en los problemas de mecánica de fluidos computacional.García-Cuevas González, LM.; Gil Megías, A.; Navarro García, R.; Quintero Igeño, PM. (2020). Mecánica de fluidos computacional: reconstrucción de la solución para el cálculo de flujos y métodos multigrid. http://hdl.handle.net/10251/146096DE

Mecánica de fluidos computacional: tipos de mallas y calidad del mallado

En este artículo vamos a presentar los principales tipos de mallas utilizados en problemas de mecánica de fluidos computacional mediante la aproximación de volúmenes finitos. Se describen las mallas estructuradas y no estructuradas, mallas por bloques, mallas móviles y deformables, mallas quimera o los tipos de celdas utilizados. Además, vamos a dar algunas pinceladas sobre cómo se puede asegurar la calidad de las mismas, incluyendo una descripción de los métodos estándar para definir el índice de convergencia de una malla.García-Cuevas González, LM.; Gil Megías, A.; Navarro García, R.; Quintero Igeño, PM. (2020). Mecánica de fluidos computacional: tipos de mallas y calidad del mallado. http://hdl.handle.net/10251/146219DE

Osmotic stress activates nif and fix genes and induces the Rhizobium tropici CIAT 899 Nod factor production via NodD2 by up-regulation of the nodA2 operon and the nodA3 gene

The symbiosis between rhizobia and legumes is characterized by a complex molecular dialogue in which the bacterial NodD protein plays a major role due to its capacity to activate the expression of the nodulation genes in the presence of appropiate flavonoids. These genes are involved in the synthesis of molecules, the nodulation factors (NF), responsible for launching the nodulation process. Rhizobium tropici CIAT 899, a rhizobial strain that nodulates Phaseolus vulgaris, is characterized by its tolerance to multiple environmental stresses such as high temperatures, acidity or elevated osmolarity. This strain produces nodulation factors under saline stress and the same set of CIAT 899 nodulation genes activated by inducing flavonoids are also up-regulated in a process controlled by the NodD2 protein. In this paper, we have studied the effect of osmotic stress (high mannitol concentrations) on the R. tropici CIAT 899 transcriptomic response. In the same manner as with saline stress, the osmotic stress mediated NF production and export was controlled directly by NodD2. In contrast to previous reports, the nodA2FE operon and the nodA3 and nodD1 genes were up-regulated with mannitol, which correlated with an increase in the production of biologically active NF. Interestingly, in these conditions, this regulatory protein controlled not only the expression of nodulation genes but also the expression of other genes involved in protein folding and synthesis, motility, synthesis of polysaccharides and, surprinsingly, nitrogen fixation. Moreover, the non-metabolizable sugar dulcitol was also able to induce the NF production and the activation of nod genes in CIAT 899.España, MINECO AGL2016-77163-

The Rhizobium tropici CIAT 899 NodD2 protein regulates the production of Nod factors under salt stress in a flavonoidindependent manner

In the symbiotic associations between rhizobia and legumes, NodD promotes the expression of the nodulation genes in the presence of appropriate flavonoids. This set of genes is implied in the synthesis of Nodulation factors, which are responsible for launching the nodulation process. Rhizobium tropici CIAT 899 is the most successful symbiont of Phaseolus vulgaris and can nodulate a variety of legumes. This strain produces Nodulation factors under abiotic stress such as acidity or high concentration of salt. Genome sequencing of CIAT 899 allowed the identification of five nodD genes. Whereas NodD1 is essential to nodulate Leucaena leucocephala, Lotus japonicus and Macroptilium atropurpureum, symbiosis with P. vulgaris and Lotus burtii decreased the nodule number but did not abolish the symbiotic process when NodD1 is absent. Nodulation factor synthesis under salt stress is not regulated by NodD1. Here we confirmed that NodD2 is responsible for the activation of the CIAT 899 symbiotic genes under salt stress. We have demonstrated that NodD1 and NodD2 control the synthesis of the Nod factor necessary for a successful symbiosis with P. vulgaris and L. burtii. This is the first time that NodD is directly implied in the activation of the symbiotic genes under an abiotic stress

Effect of the presence of the plant growth promoting rhizobacterium (PGPR) Chryseobacterium balustinum Aur9 and salt stress in the pattern of flavonoids exuded by soybean roots

In this work we studied how biotic and abiotic stresses can alter the pattern of flavonoids exuded by Osumi soybean roots. A routine method was developed for the detection and characterization of the flavonoids present in soybean root exudates using HPLC-MS/MS. Then, a systematic screening of the flavonoids exuded under biotic stress, the presence of a plant growth promoting rhizobacterium, and salt stress was carried out. Results obtained indicate that the presence of Chryseobacterium balustinum Aur9 or 50 mM NaCl changes qualitatively the pattern of flavonoids exuded when compared to control conditions. Thus, in the presence of C. balustinum Aur9, soybean roots did not exude quercetin and naringenin and, under salt stress, flavonoids daidzein and naringenin could not be detected. Soybean root exudates obtained under saline conditions showed a diminished capacity to induce the expression of the nodA gene in comparison to the exudates obtained in the absence of salt. Moreover, lipochitooligosaccharides (LCOs) were not detected or weakly detected when Sinorhizobium fredii SMH12 was grown in the exudates obtained under salt stress conditions or under salt stress in the presence of C. balustinum Au9, respectively.Fil: Dardanelli, Marta Susana. Universidad de Sevilla. Facultad de Farmacia; España. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas, Fisicoquímicas y Naturales. Departamento de Biología Molecular. Sección Química Biológica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba; ArgentinaFil: Manyani, Hamid. Universidad de Sevilla. Facultad de Farmacia; EspañaFil: González Barroso, Sergio. Universidad de Sevilla. Facultad de Farmacia; EspañaFil: Rodríguez Carvajal, Miguel A.. Universidad de Sevilla. Facultad de Farmacia; EspañaFil: Gil Serrano, Antonio M.. Universidad de Sevilla. Facultad de Farmacia; EspañaFil: Espuny, Maria R.. Universidad de Sevilla. Facultad de Farmacia; EspañaFil: López Baena, Francisco Javier. Universidad de Sevilla. Facultad de Farmacia; EspañaFil: Bellogín, Ramon A.. Universidad de Sevilla. Facultad de Farmacia; EspañaFil: Megías, Manuel. Universidad de Sevilla. Facultad de Farmacia; EspañaFil: Ollero, Francisco J.. Universidad de Sevilla. Facultad de Farmacia; Españ