1D Simulation and Experimental Analysis of a Turbocharger Compressor for Automotive Engines under Unsteady Flow Conditions

Bozza, Fabio; Bellis, Vincenzo De; Marelli, Silvia; Capobianco, Massimo

doi:10.4271/2011-01-1147

Cited by 52 publications

(29 citation statements)

References 20 publications

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“…Compared to the results presented in previous works [11], a better agreement is here obtained only acting on friction and volute diffusion loss multipliers (fixed to 2.6 and 0.67, respectively). An improved agreement was also found for the efficiency map.…”

Section: Model Tuning and Extended Steady Map Computationsupporting

confidence: 56%

“…In [11] the compressor behavior in the intake system of an internal combustion engine was analyzed. In that case, pulse propagation due to valve opening induced unsteady operation of the device.…”

Section: Results Discussionmentioning

confidence: 99%

“…Following the approach developed in [11], in the present work, an innovative procedure is proposed to investigate a centrifugal compressor behaviour, both for reverse and direct flow conditions. Starting from a reduced set of data, compressor geometry is firstly reconstructed; the performance of the device are then evaluated solving the steady 1D equations in rotating and stationary pipes.…”

Section: Introductionmentioning

confidence: 99%

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Map-Based and 1D Simulation of a Turbocharger Compressor in Surging Operation

Bozza¹,

Bellis²

2011

SAE Int. J. Engines

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One-dimensional (1D) models are commonly employed to study the performances of turbocharged engine. Manufacturers' provided steady turbomachinery maps are usually utilized, although they operate in unsteady conditions as a consequence of pressure pulses propagating into the intake and exhaust systems. This may lead to some inaccuracies in the engine-turbocharger matching calculations, which may be solved through the introduction of proper time-delays (virtual pipe corrections). These drawbacks, however, became more relevant when engine operates under low speed and high load conditions, or during a transient maneuver, because of possibilities of compressor surging. This phenomenon can't be opportunely described employing classical manufacturers' maps: first of all, the flow through the compressor is strongly unsteady in these conditions; moreover, the information about both the unstable and reverse flow regions of compressor map is unavailable, and a somewhat arbitrary map's extrapolation technique must be utilized.In this paper two numerical procedures have been presented to predict automotive turbocharger compressor performance in surging operation. Firstly, a recently proposed approach is utilized to directly compute the stationary map of the compressor for direct and reverse flow conditions. The detailed 3D geometry of the compressor is reconstructed starting from a reduced set of geometrical data measured on the compressor wheel. Then, the 1D meanline evolution of blade angles, cross section and equivalent diameter are deduced from the 3D geometrical model. The steady 1D flow equations are finally solved along the meanline of stationary and rotating channels constituting the compressor device. Proper flow loss correlation holding for direct or reverse flow conditions are included in the model, which is applied to predict the extended steady maps of a turbocharger compressor. With reference to stable operating regions, the theoretically derived maps are compared to available manufacturer data and, after a limited loss coefficients tuning, a good agreement has been obtained.The steady procedure, however, can be utilized under unsteady flow conditions, too. Unsteady terms in flow equations are now accounted for, and mass and energy storages are allowed to occur within each stationary and rotating channel. In this way, compressor operation can be described with a quasi-steady method employing the extended map, or in a fully unsteady approach, as well. In the quasi-steady case, a proper virtual pipe correction is introduced, too. The two methodologies are tested to analyze their potential in characterizing compressor operation under surging conditions. To this aim, a reference compressor is connected to a outlet duct and a plenum. Compressor speed and downstream circuit are managed in order to promote deep surging conditions. Results obtained through the applications of the two methods are discussed in terms of pressure and temperature waves, mass flow rate evolution at compressor inlet and outlet, and Surging loo...

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Section: Model Tuning and Extended Steady Map Computationsupporting

confidence: 56%

Section: Results Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Map-Based and 1D Simulation of a Turbocharger Compressor in Surging Operation

Bozza¹,

Bellis²

2011

SAE Int. J. Engines

Self Cite

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show abstract

“…and substituted in equations (22)- (24). The final form of the governing equations is given by a system of nonlinear ODEs in time…”

Section: Roms With Spatial Basis Functions (Sbfs)mentioning

confidence: 99%

Modeling wave action effects in internal combustion engine air path systems: comparison of numerical and system dynamics approaches

Stockar

Canova

Guezennec

et al. 2012

International Journal of Engine Research

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The challenge of continuously improving engine fuel economy and emissions has pushed the automotive industry to adopt more efficient procedures for modeling, system simulation and model-based control. Such procedures require accurate and computationally efficient engine system simulation models that are able to predict the cylinder charge composition and the thermodynamic conditions. To this extent, reduced-order models for unsteady compressible flow systems, namely models derived from the fundamental conservation laws without over-simplifying the topology of the engine air path, are receiving considerable interest for performance simulation and control design.This paper presents a comparative study on modeling approaches for the prediction of one-dimensional unsteady compressible flow in the internal combustion engine air path system. Specifically, the paper compares a well-known second-order, shock-capturing finite-difference scheme with two novel solution methods, namely a finite-volume method and a model-order reduction method. The study aims at evaluating the ability of each method to trade-off the prediction accuracy and robustness with the computation time, in light of potential applications to real-time simulation. This is achieved by increasing the discretization length of each method, and evaluating the accuracy of the predicted response in the time and frequency domain.The characterization of the intake and exhaust flows in the manifolds of a single-cylinder engine is considered as a case study. The results are compared for the three solution methods at different discretization lengths to evaluate the ability of each model to retain accuracy and robustness. The computation times of the different methods are also evaluated.The results presented in this paper establish a clear trade-off between accuracy, stability and computation time for each solution method. This allows one to formulate considerations on the advantages and disadvantages of each method in light of potential applications to engine performance prediction, optimization and control design.

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“…This could be done with a quasi-2D model of the volute, in which the tangential and radial components are calculated by imposing conservation of angular momentum, similar to the work presented by Bozza et al [24] for a centrifugal compressor. In the special case of the volute, where a lateral window permits the air to flow outside of it, the flow mainly moves along the azimuthal coordinate except near the window, where an important radial component appears.…”

Section: Model Descriptionmentioning

confidence: 99%

Development and validation of a radial variable geometry turbine model for transient pulsating flow applications

Galindo

Tiseira

Fajardo

et al. 2014

Energy Conversion and Management

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Elsevier Galindo, J.; Tiseira Izaguirre, AO.; Fajardo, P.; García-Cuevas González, LM. (2014). Development and validation of a radial variable geometry turbine model for transient pulsating flow applications. Energy AbstractThis paper presents the development and validation of a one-dimensional radial turbine model able to be used in automotive turbocharger simulations. The model has been validated using results from a numerical 3D CFD simulation of stationary and pulsating flow in a variable geometry radial turbine. As the CFD analysis showed, the main non-quasi-steady behavior of the turbine is due to the volute geometry, so special care was taken in order to properly model it while maintaining low computational costs. The flow in the volute has been decomposed in its radial and azimuthal direction. The azimuthal flow corresponds to the flow moving along the volute, while the radial flow is computed by coupling its flow with a stator model. Although the stator caused fewer accumulation effects than the volute, a small accumulation model has been used for it, which also allows to compute the evolution of the flow inside the turbine with lower costs. The flow in the moving rotor can be considered quasi-steady, so a zero-dimensional model for the rotor has been developed. Several losses models where implemented for both the stator and the rotor. The results show good agreement with the CFD computations.

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1D Simulation and Experimental Analysis of a Turbocharger Compressor for Automotive Engines under Unsteady Flow Conditions

Cited by 52 publications

References 20 publications

Map-Based and 1D Simulation of a Turbocharger Compressor in Surging Operation

Map-Based and 1D Simulation of a Turbocharger Compressor in Surging Operation

Modeling wave action effects in internal combustion engine air path systems: comparison of numerical and system dynamics approaches

Development and validation of a radial variable geometry turbine model for transient pulsating flow applications

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