Measurement, Simulation, and 1D-Modeling of Turbocharger Radial Turbines at Design and Extreme Off-Design Conditions

Inhestern, Lukas Benjamin

doi:10.4995/thesis/10251/119989

Cited by 3 publications

(8 citation statements)

References 61 publications

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“…The SST turbulence model is commonly used in many of the turbomachinery applications found in the literature as observed in the literature. 25–27 These examples demonstrate the model’s ability to reproduce the flow separation in a wide range of operating conditions.…”

Section: Computational Studymentioning

confidence: 79%

“…A numerical accuracy study was performed to evaluate the independence of the numerical results with the mesh size and number of layers close to the wall. Thanks to the previous experience of the authors in simulations with small interstices according to the size of the modelled geometry, 21 the independence of the numerical results was considered near the walls, through the channels and upstream and downstream of the blades where the results are more critical. This analysis has been performed considering the average cell size in the VGT and volute.…”

Section: Computational Studymentioning

confidence: 99%

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

Galindo

Tiseira

García-Cuevas

et al. 2020

International Journal of Engine Research

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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.

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Section: Computational Studymentioning

confidence: 79%

Section: Computational Studymentioning

confidence: 99%

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

Galindo

Tiseira

García-Cuevas

et al. 2020

International Journal of Engine Research

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“…To better visualize the data of ETE at different flow admission conditions, twodimensional contour plot is preferred as shown in Figure 3. 21. Inside this type of map, one can interpolate from the experimental data to show how a dependent variable such as efficiency varies with the mass flow ratios and overall blade to speed ratio.…”

Section: Based On Literature Reviewmentioning

confidence: 99%

“…It is undesirable but true since not a physical model can be extracted from Figure 3. 21. But, only interpolating between the efficiency valleys and efficiency peaks as a function of MFR, BSR and maybe also turbine reduced speed.…”

Section: Based On Literature Reviewmentioning

confidence: 99%

“…Dombrovsky [20], further improved the models of Reyes-Belmonte [19] to enhance engine simulation using commercial 1D tools like GT-POWER T M and also studied the effects of external heat transfers in turbochargers. Inhestern [21] focused his study at the extreme off-design working conditions of radial turbines experimentally. Further, CFD analysis was performed to understand better the flow phenomena occurring in this kind of turbine.…”

Section: Introductionmentioning

confidence: 99%

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Experimental characterization and mean line modelling of twin-entry and dual-volute turbines working under different admission conditions with steady flow

Samala¹

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Despite the importance of radial in-flow twin-entry and dual-volute turbines for turbocharged engines, their characteristic maps and fully predictive modelling using 1D gas dynamic codes are not well established yet. The complexity of the un-steady flow and the unequal admission of these turbines, when operating with pulses of engine exhaust gas, make them a challenging system. Mainly due to the unequal flow admission, an additional degree of freedom is introduced to well-known single entry vanned or vaneless turbines. Moreover, the addition of the second inlet to the turbine volute brings extra complexity in determining the steady-state turbine performance parameters under unequal admission conditions. This thesis has a main novelty, which is a simple procedure for characterizing experimentally and elaborating characteristic maps of these turbines with unequal flow conditions. This method of analysis allows easy interpolating within the proposed distinctive maps or simple convincing models for calculating and extrapolating full performance parameters of twin-entry and dual-volute turbines.Finally, the models have been fully validated by coupling them with one-dimensional modelling software and simulated both the gas stand and the whole engine measured points. On the one hand, the validation results from the gas stand simulation show that the model can predict well all steady flow variables. On the other hand, the validation results from the whole engine simulation show that the model is able to produce all the full load engine variables like air mass flow and brake torque in a reasonable degree of agreement with the experimental data.

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

Tiseira¹,

Garcia²,

Inhestern³

et al. 2020

Energies

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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.

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Measurement, Simulation, and 1D-Modeling of Turbocharger Radial Turbines at Design and Extreme Off-Design Conditions

Cited by 3 publications

References 61 publications

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

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

Experimental characterization and mean line modelling of twin-entry and dual-volute turbines working under different admission conditions with steady flow

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

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