Design and Numerical Analysis of Flow Characteristics in a Scaled Volute and Vaned Nozzle of Radial Turbocharger Turbines

[EN] Over the past few decades, the aerodynamic improvements of turbocharger turbines contributed significantly to the overall efficiency augmentation and the advancements in downsizing of internal combustion engines. Due to the compact size of automotive turbochargers, the experimental measurement of the complex internal aerodynamics has been insufficiently studied. Hence, turbine designs mostly rely on the results of numerical simulations and the validation of zero-dimensional parameters as efficiency and reduced mass flow. To push the aerodynamic development even further, a precise validation of three-dimensional flow patterns predicted by applied computational fluid dynamics (CFD) methods is in need. This paper presents the design of an up-scaled volute-stator model, which allows optical experimental measurement techniques. In a preliminary step, numerical results indicate that the enlarged geometry will be representative of the flow patterns and characteristic non-dimensional numbers at defined flow sections of the real size turbine. Limitations due to rotor-stator interactions are highlighted. Measurement sections of interest for available measurement techniques are predefined.The authors disclose receipt of the following financial support for the research, authorship, and/or publication of this article: This work was partly sponsored by the program "Ayuda a Primeros Proyectos de Investigacion (PAID-06-18), Vicerrectorado de Investigacion, Innovacion y Transferencia de la Universitat Politecnica de Valencia (UPV), Spain". The support given to Ms. N.H.G. by Universitat Politecnica de Valencia through the "FPI-Subprograma 2" (No.FPI-2018-S2-1368) grant within the "Programa de Apoyo para la Investigacion y Desarrollo (PAID-01-18)" is gratefully acknowledgedTiseira, A.; Navarro, R.; Inhestern, LB.; Hervás-Gómez, N. (2020). Design and Numerical Analysis of Flow Characteristics in a Scaled Volute and Vaned Nozzle of Radial Turbocharger Turbines. Energies. 13(11):1-19. https://doi.org/10.3390/en13112930S1191311Praveena, V., & Martin, M. L. J. (2018). A review on various after treatment techniques to reduce NOx emissions in a CI engine. Journal of the Energy Institute, 91(5), 704-720. doi:10.1016/j.joei.2017.05.010Sindhu, R., Amba Prasad Rao, G., & Madhu Murthy, K. (2018). Effective reduction of NOx emissions from diesel engine using split injections. Alexandria Engineering Journal, 57(3), 1379-1392. doi:10.1016/j.aej.2017.06.009Gil, A., Tiseira, A. O., García-Cuevas, L. M., Usaquén, T. R., & Mijotte, G. (2018). Fast three-dimensional heat transfer model for computing internal temperatures in the bearing housing of automotive turbochargers. International Journal of Engine Research, 21(8), 1286-1297. doi:10.1177/1468087418804949Suhrmann, J. F., Peitsch, D., Gugau, M., & Heuer, T. (2012). On the Effect of Volute Tongue Design on Radial Turbine Performance. Volume 8: Turbomachinery, Parts A, B, and C. doi:10.1115/gt2012-69525Roumeas, M., & Cros, S. (2012). Aerodynamic Investigation of a Nozzle Clearance Effect on Radial Turbine Performance. Volume 8: Turbomachinery, Parts A, B, and C. doi:10.1115/gt2012-68835Liu, Y., Yang, C., Qi, M., Zhang, H., & Zhao, B. (2014). Shock, Leakage Flow and Wake Interactions in a Radial Turbine With Variable Guide Vanes. Volume 2D: Turbomachinery. doi:10.1115/gt2014-25888Cornolti, L., Onorati, A., Cerri, T., Montenegro, G., & Piscaglia, F. (2013). 1D simulation of a turbocharged Diesel engine with comparison of short and long EGR route solutions. Applied Energy, 111, 1-15. doi:10.1016/j.apenergy.2013.04.016Bohbot, J., Chryssakis, C., & Miche, M. (2006). Simulation of a 4-Cylinder Turbocharged Gasoline Direct Injection Engine Using a Direct Temporal Coupling Between a 1D Simulation Software and a 3D Combustion Code. SAE Technical Paper Series. doi:10.4271/2006-01-3263Inhestern, L. B. (s. f.). Measurement, Simulation, and 1D-Modeling of Turbocharger Radial Turbines at Design and Extreme Off-Design Conditions. doi:10.4995/thesis/10251/119989Tamaki, H., & Unno, M. (2008). Study on Flow Fields in Variable Area Nozzles for Radial Turbines. International Journal of Fluid Machinery and Systems, 1(1), 47-56. doi:10.5293/ijfms.2008.1.1.047Eroglu, H., & Tabakoff, W. (1991). LDV Measurements and Investigation of Flow Field Through Radial Turbine Guide Vanes. Journal of Fluids Engineering, 113(4), 660-667. doi:10.1115/1.2926531Karamanis, N., Martinez-Botas, R. F., & Su, C. C. (2000). Mixed Flow Turbines: Inlet and Exit Flow Under Steady and Pulsating Conditions. Volume 1: Aircraft Engine; Marine; Turbomachinery; Microturbines and Small Turbomachinery. doi:10.1115/2000-gt-0470Galindo, J., Tiseira Izaguirre, A. O., García-Cuevas, L. M., & Hervás Gómez, N. (2020). Experimental approach for the analysis of the flow behaviour in the stator of a real centripetal turbine. International Journal of Engine Research, 22(6), 2010-2020. doi:10.1177/1468087420916281Dufour, G., Carbonneau, X., Cazalbou, J.-B., & Chassaing, P. (2006). Practical Use of Similarity and Scaling Laws for Centrifugal Compressor Design. Volume 6: Turbomachinery, Parts A and B. doi:10.1115/gt2006-91227Tancrez, M., Galindo, J., Guardiola, C., Fajardo, P., & Varnier, O. (2011). Turbine adapted maps for turbocharger engine matching. Experimental Thermal and Fluid Science, 35(1), 146-153. doi:10.1016/j.expthermflusci.2010.07.018Menter, F. R. (1994). Two-equation eddy-viscosity turbulence models for engineering applications. AIAA Journal, 32(8), 1598-1605. doi:10.2514/3.12149Broatch, A., Galindo, J., Navarro, R., & García-Tíscar, J. (2014). Methodology for experimental validation of a CFD model for predicting noise generation in centrifugal compressors. International Journal of Heat and Fluid Flow, 50, 134-144. doi:10.1016/j.ijheatfluidflow.2014.06.006Smirnov, P. E., Hansen, T., & Menter, F. R. (2007). Numerical Simulation of Turbulent Flows in Centrifugal Compressor Stages With Different Radial Gaps. Volume 6: Turbo Expo 2007, Parts A and B. doi:10.1115/gt2007-27376Serrano, J. R., Olmeda, P., Arnau, F. J., Dombrovsky, A., & Smith, L. (2014). Analysis and Methodology to Characterize Heat Transfer Phenomena in Automotive Turbochargers. Journal of Engineering for Gas Turbines and Power, 137(2). doi:10.1115/1.4028261Serrano, J. R., Olmeda, P., Arnau, F. J., Dombrovsky, A., & Smith, L. (2015). Turbocharger heat transfer and mechanical losses influence in predicting engines performance by using one-dimensional simulation codes. Energy, 86, 204-218. doi:10.1016/j.energy.2015.03.130Serrano, J. R., Tiseira, A., García-Cuevas, L. M., Inhestern, L. B., & Tartoussi, H. (2017). Radial turbine performance measurement under extreme off-design conditions. Energy, 125, 72-84. doi:10.1016/j.energy.2017.02.118Serrano, J. R., Gil, A., Navarro, R., & Inhestern, L. B. (2017). Extremely Low Mass Flow at High Blade to Jet Speed Ratio in Variable Geometry Radial Turbines and its Influence on the Flow Pattern: A CFD Analysis. Volume 8: Microturbines, Turbochargers and Small Turbomachines; Steam Turbines. doi:10.1115/gt2017-63368Serrano, J. R., Navarro, R., García-Cuevas, L. M., & Inhestern, L. B. (2019). Contribution to tip leakage loss modeling in radial turbines based on 3D flow analysis and 1D characterization. International Journal of Heat and Fluid Flow, 78, 108423. doi:10.1016/j.ijheatfluidflow.2019.108423Choi, M., Baek, J. H., Chung, H. T., Oh, S. H., & Ko, H. Y. (2008). Effects of the low Reynolds number on the loss characteristics in an axial compressor. Proceedings of the Institution of Mechanical Engineers, Part A: Journal of Power and Energy, 222(2), 209-218. doi:10.1243/09576509jpe520Klausner, E., & Gampe, U. (2014). Evaluation and Enhancement of a One-Dimensional Performance Analysis Method for Centrifugal Compressors. Volume 2D: Turbomachinery. doi:10.1115/gt2014-25141Tiainen, J., Jaatinen-Värri, A., Grönman, A., Turunen-Saaresti, T., & Backman, J. (2018). Effect of FreeStream Velocity Definition on Boundary Layer Thickness and Losses in Centrifugal Compressors. Journal of Turbomachinery, 140(5). doi:10.1115/1.4038872Vinuesa, R., Hosseini, S. M., Hanifi, A., Henningson, D. S., & Schlatter, P. (2017). Pressure-Gradient Turbulent Boundary Layers Developing Around a Wing Section. Flow, Turbulence and Combustion, 99(3-4), 613-641. doi:10.1007/s10494-017-9840-

Numerical Evaluation in a Scaled Rotor-Less Nozzle Vaned Radial Turbine Model under Variable Geometry Conditions

[EN] The widespread trend of pursuing higher efficiencies in radial turbochargers led to the prompting of this work. A 3D-printed model of the static parts of a radial variable geometry turbine, the vaned nozzle, and the volute, was developed. This model was up-scaled from the actual reference turbine to place sensors and characterize the flow around the nozzle vanes, including the tip gap. In this study, a computational model of the scaled-up turbine was carried out to verify the results in two ways. For this model, firstly compared with an already validated CFD turbine model of the real device (which includes a rotor), its operating range was extended to different nozzle positions, and we checked the issues with rotor-stator interactions as well as the influence of elements such as the screws of the turbine stator. After showing results for different nozzle openings, another purpose of the study was to check the effect of varying the clearance over the tip of the stator vanes on the tip leakage flow since the 3D-printed model has variable gap height configurations.This research work was supported by Grant PDC2021-120821-I00, funded by MCIN/AEI/10.13039/501100011033 and by European Union NextGeneration EI/PRTR.Serrano, J.; Tiseira, A.; López-Carrillo, JA.; Hervás-Gómez, N. (2022). Numerical Evaluation in a Scaled Rotor-Less Nozzle Vaned Radial Turbine Model under Variable Geometry Conditions. Applied Sciences. 12(14):1-17. https://doi.org/10.3390/app12147254117121

Experimental approach for the analysis of the flow behaviour in the stator of a real centripetal turbine

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/10.1177/1468087420916281[EN] During normal operation, radial turbines may work in off-design conditions. Off-design conditions may be characterised by very low expansion ratios, very high expansion ratios, very low rotational speeds or very high rotational speeds. All of these cases are difficult to characterise experimentally due to high experimental uncertainties or a lack of capabilities in the system feeding pressurised air to the turbine. Also, there are two- and three-dimensional computational fluid dynamics simulations at these operating points but could not be accurate enough due to high turbulence effects, flow detachment and shock wave generation. With a lack of high-quality data, experimental or computational, to fit the reduced-order turbine models used in zero- and one-dimensional engine simulations, there are large uncertainties associated to their results in off-design conditions. This work develops an experimental facility able to characterise the internal flow of radial turbine stators in terms of pressure and velocity fields at off-design and regular working conditions. The facility consists of an upscaled model of a radial turbine volute and stator fed with air in pressure- and temperature-controlled conditions, so different sensors can be used inside it with the least amount of flow disturbance. The different restrictions considered in the design of the upscaled model are presented, and their effects in the final experimental apparatus capabilities are discussed. A preliminary comparison between computational fluid dynamics simulations and experimental data shows encouraging results.The author(s) disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: This work was partly sponsored by the programme 'Ayuda a Primeros Proyectos de Investigacion (PAID-06-18), Vicerrectorado de Investigacion, Innovacion y Transferencia de la Universitat Politecnica de Valencia (UPV), Spain'. The support given to Ms N.H.G. by Universitat Politecnica de Valencia through the 'FPI-Subprograma 2' (No. FPI-2018-S2-1368) grant within the 'Programa de Apoyo para la Investigacion y Desarrollo (PAID-0118)' is gratefully acknowledged.Galindo, J.; Tiseira, A.; García-Cuevas González, LM.; Hervás-Gómez, N. (2021). Experimental approach for the analysis of the flow behaviour in the stator of a real centripetal turbine. International Journal of Engine Research. 22(6):2010-2020. https://doi.org/10.1177/1468087420916281S20102020226Tang, H., Pennycott, A., Akehurst, S., & Brace, C. J. (2014). A review of the application of variable geometry turbines to the downsized gasoline engine. International Journal of Engine Research, 16(6), 810-825. doi:10.1177/1468087414552289Payri, F., Serrano, J. R., Fajardo, P., Reyes-Belmonte, M. A., & Gozalbo-Belles, R. (2012). A physically based methodology to extrapolate performance maps of radial turbines. Energy Conversion and Management, 55, 149-163. doi:10.1016/j.enconman.2011.11.003Serrano, J. R., Olmeda, P., Páez, A., & Vidal, F. (2010). An experimental procedure to determine heat transfer properties of turbochargers. Measurement Science and Technology, 21(3), 035109. doi:10.1088/0957-0233/21/3/035109Olmeda, P., Dolz, V., Arnau, F. J., & Reyes-Belmonte, M. A. (2013). Determination of heat flows inside turbochargers by means of a one dimensional lumped model. Mathematical and Computer Modelling, 57(7-8), 1847-1852. doi:10.1016/j.mcm.2011.11.078Serrano, J., Olmeda, P., Arnau, F., Reyes-Belmonte, M., & Lefebvre, A. (2013). Importance of Heat Transfer Phenomena in Small Turbochargers for Passenger Car Applications. SAE International Journal of Engines, 6(2), 716-728. doi:10.4271/2013-01-0576Serrano, J. R., Olmeda, P., Tiseira, A., García-Cuevas, L. M., & Lefebvre, A. (2013). Theoretical and experimental study of mechanical losses in automotive turbochargers. Energy, 55, 888-898. doi:10.1016/j.energy.2013.04.042Serrano, J. R., Olmeda, P., Tiseira, A., García-Cuevas, L. M., & Lefebvre, A. (2013). Importance of Mechanical Losses Modeling in the Performance Prediction of Radial Turbochargers under Pulsating Flow Conditions. SAE International Journal of Engines, 6(2), 729-738. doi:10.4271/2013-01-0577Galindo, J., Fajardo, P., Navarro, R., & García-Cuevas, L. M. (2013). Characterization of a radial turbocharger turbine in pulsating flow by means of CFD and its application to engine modeling. Applied Energy, 103, 116-127. doi:10.1016/j.apenergy.2012.09.013Zhang, Y., Zhang, Y., & Wu, Y. (2016). A review of rotating stall in reversible pump turbine. Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science, 231(7), 1181-1204. doi:10.1177/0954406216640579Galindo, J., Navarro, R., García-Cuevas, L. M., Tarí, D., Tartoussi, H., & Guilain, S. (2018). A zonal approach for estimating pressure ratio at compressor extreme off-design conditions. International Journal of Engine Research, 20(4), 393-404. doi:10.1177/1468087418754899Serrano, J. R., Arnau, F. J., García-Cuevas, L. M., Dombrovsky, A., & Tartoussi, H. (2016). Development and validation of a radial turbine efficiency and mass flow model at design and off-design conditions. Energy Conversion and Management, 128, 281-293. doi:10.1016/j.enconman.2016.09.032Navarro García, R. (s. f.). A numerical approach for predicting flow-induced acoustics at near-stall conditions in an automotive turbocharger compressor. doi:10.4995/thesis/10251/44114Inhestern, L. B. (s. f.). Measurement, Simulation, and 1D-Modeling of Turbocharger Radial Turbines at Design and Extreme Off-Design Conditions. doi:10.4995/thesis/10251/119989Menter, F. R. (1994). Two-equation eddy-viscosity turbulence models for engineering applications. AIAA Journal, 32(8), 1598-1605. doi:10.2514/3.12149Menter, F. R. (1992). Influence of freestream values on k-omega turbulence model predictions. AIAA Journal, 30(6), 1657-1659. doi:10.2514/3.11115Wilcox, D. C. (1988). Reassessment of the scale-determining equation for advanced turbulence models. AIAA Journal, 26(11), 1299-1310. doi:10.2514/3.10041Simpson, A. T., Spence, S. W. T., & Watterson, J. K. (2009). A Comparison of the Flow Structures and Losses Within Vaned and Vaneless Stators for Radial Turbines. Journal of Turbomachinery, 131(3). doi:10.1115/1.298849

Estudio experimental del comportamiento dinamico del fluido en turbinas centrípetas

Este trabajo se dedica a comprender el comportamiento del aire en una turbina centrípeta utilizada comunmente en la industria automotriz para la sobrealiemntación de motores diesel o gasolina. Los sistemas de sobrealimentación de motores ayudan a mejorar las prestaciones. El sistema de sobrealimentación mejorado ayuda a ser mas eficientes a los motores. No sólo la industria automotriz se puede beneficiar de la mejora de éste sistema, sino también, la industria de la aviación y la naviera. Para mejorar el sistema de sobrealimentación, comprendido por un compresor y una turbina centrípeta unidos por un eje, puede ser realizado mediante mejoras en el comportamiento dínamico del aire en el interior de los mecanismos tanto moviles como fijos. Éste trabajo trata de mejorar las prestaciones dinámicas del flujo en ambas partes centrando el estudio e el canal de la voluta y los canales de los álabes móviles de estator de una turbina centripeta. Para caracteriar el flujo experimentalemente se utiliza una turbina a escala para poder alvergar todos los sensores de medida posibles. los sensores utilizados son de presión, de temperatura y de dirección del flujo. En este trabajo se presenta un estudio paramétrico para determinar las condiciones de contorno que debe tener la maqueta para ser representativa de un modelo de turbo real.This work is dedicated to understanding the behavior of the air in a centripetal turbine commonly used in the automotive industry for turbocharging diesel or gasoline engines. Engine turbocharging systems help improve performance. The improved this system helps the engines become more efficient. Not only the automotive industry can benefit from the improvement of this system, but also, the aviation industry and the shipping company. To improve the turbocharging system, comprised of a centrifugal compressor and a centripetal turbine connected by an shaft, it can be realized by improvements in the air behavior of the air inside the mobile and fixed mechanisms. This work tries to improve the dynamic performance of the flow in both parts focusing the study of the volute channel and the channels of the stator vanes of a centripetal turbine. To characterize the flow experimentally a scale turbine is used to find all the possible measurement sensors. The sensors used are pressure, temperature and flow direction measurement. In this work a parametric study is presented to determine the boundary conditions that the model must have to be representative of a real turbo model.Hervás Gómez, N. (2018). Estudio experimental del comportamiento dinamico del fluido en turbinas centrípetas. http://hdl.handle.net/10251/111109TFG

Caracterización de flujo interno en régimen continuo y pulsante en un compresor centrífugo y una turbina centrípeta

[ES] En el presente documento se va a mostrar la caracterización del flujo interno continuo y pulsante en un compresor centrífugo y una turbina centrípeta utilizados comúnmente en automoción. Lo que se pretende, de manera un poco más concreta, es obtener los mapas de funcionamiento para validar un modelo predictivo cuasi-bidimensional de compresor y turbina radial en aplicaciones de flujo pulsante transitorio. Dicho modelo ha sido desarrollado previamente por un alumno de doctorado.Hervás Gómez, N. (2014). Caracterización de flujo interno en régimen continuo y pulsante en un compresor centrífugo y una turbina centrípeta. http://hdl.handle.net/10251/177017Archivo delegad

Estudio experimental sobre la influencia de aceite deteriorado usado en turbos de sobrealimentación de MCIA

[ES] La sobrealimentación de motores de automoción diésel o gasolina se lleva a cabo, comúnmente, gracias a un turbogrupo. Esté se encuentra compuesto por una turbina y un compresor unidos por un eje que posee cojinetes. Estas últimas dos piezas se encuentran lubricadas por el aceite del propio motor. Por lo tanto, el correcto funcionamiento del turbo depende del aceite. El aceite debe estar en óptimas condiciones pero el mismo puede ser afectado por diversos factores entre los que se encuentra la trasmisión de calor, el hollín, pequeños metales, etc. Este trabajo tiene por objetivo principal apreciar las consecuencias que puede tener un turbo cuando el aceite se encuentra en diversos estados de deterioro. Para ello se hace un estudio experimental empleando un banco motor donde el aceite contaminado o deteriorado sólo lubrica al turbo. En el proyecto se emplean dos aceites de distintas densidades. Luego, se deterioran con distintos niveles de oxidación y suciedad. A cada uno de los aceites obtenidos se le asigna un turbo. Cada uno de los turbos son iguales y del mismo tipo que emplea el motor usado en los ensayos experimentales ubicado el banco. El ensayo, de cada aceite con su turbo, consiste en repetir varias veces un ciclo de motor especifico, donde alcanza su máxima temperatura de trabajo en estacionario. En el ensayo se miden varios parámetros buscando indicios sobre si el turbo puede estar afectado o no por el uso de aceite deteriorado.[EN] Turbocharging diesel or gasoline is carried out commonly through a turbogenerator. It is is composed of a turbine and a compressor connected by a shaft having bearings. These last two parts are lubricated by the engine oil itself. Therefore, proper operation depends turbo oil. Oil should be in good condition but it can be affected by various factors including the transmission of heat, soot, particulars metals, etc. This work mainly aims appreciate the consequences that can have a turbo when the oil is found in various states of disrepair. An experimental study using an engine bench where oil contaminated or deteriorated only lubricates the turbo is made. In the project two oils of different densities are used. Then they deteriorate with different oxidation and dirt. Each of the oils obtained are assigned a turbo. Each of the turbochargers are equal and the same type employing the motor used in experimental trials located bank. The trial, each with its turbo oil, is repeated several times a cycle of specific engine, where it reaches its maximum operating temperature steady. several parameters are measured for signs on whether the turbo may be affected or impaired by the use of oil in the test.Hervás Gómez, N. (2016). Estudio experimental sobre la influencia de aceite deteriorado usado en turbos de sobrealimentación de MCIA. Universitat Politècnica de València. http://hdl.handle.net/10251/76520TFG