A quasi-one-dimensional CFD model for multistage turbomachines

Léonard, Olivier; Adam, Olivier

doi:10.1007/s11630-008-0007-z

Cited by 31 publications

(14 citation statements)

References 26 publications

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“…The system (1) is solved for the inlet pipe, the volute and the outlet duct, while, within the impeller, the following balance equations apply [18]:…”

Section: Impeller Flow Modelmentioning

confidence: 99%

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

Bozza¹,

Bellis²,

Marelli³

et al. 2011

SAE Int. J. Engines

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Turbocharging technique will play a fundamental role in the near future not only to improve automotive engine performance, but also to reduce fuel consumption and exhaust emissions both in Spark Ignition and diesel automotive applications. To achieve excellent engine performance for road application, it is necessary to overcome some typical turbocharging drawbacks i.e., low end torque level and transient response. Experimental studies, developed on dedicated test facilities, can supply a lot of information to optimize the engine-turbocharger matching, especially if tests can be extended to the typical engine operating conditions (unsteady flow). Different numerical procedures have been developed at the University of Naples to predict automotive turbocharger compressor performance both under steady and unsteady flow conditions. A classical 1D approach, based on the employment of compressor characteristic maps, was firstly followed. A different and more refined procedure has been recently proposed. The new approach is based on the solution of the 1D unsteady flow within the stationary and rotating channels constituting the compressor device, starting from a reduced set of geometrical data. The refined methodology can be utilized to directly compute the stationary map of the compressor but also to reproduce the unsteady flow behavior of the device. A specialized components test rig (particularly suited to study automotive turbochargers) has been operating since several years at the University of Genoa. The test facility also allows to develop studies under unsteady flow conditions both on single components and subassemblies of engine intake and exhaust circuit. In the paper the results of a preliminary experimental study developed on a turbocharger compressor for gasoline engine application under unsteady flow conditions are presented. Instantaneous inlet and outlet static pressure and mass flow rate are compared with the corresponding numerical data supplied by simulation codes. The numerical results showed a good agreement with experimental data. In addition, the comparison between the classical and the refined procedure results highlighted the potential of the performed unsteady 1D calculation, especially in specific compressor operating conditions. The integration of the experimental activity with the numerical analysis represents a methodology that can be helpfully employed during the design process of internal combustion engine intake systems

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“…The system (1) is solved for the inlet pipe, the volute and the outlet duct, while, within the impeller, the following balance equations apply [18]:…”

Section: Impeller Flow Modelmentioning

confidence: 99%

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

Bozza¹,

Bellis²,

Marelli³

et al. 2011

SAE Int. J. Engines

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“…The model contains two momentum equations: the axial momentum conservation and a circumferential momentum equation accounting for angular momentum variations. 13 A generic conservative law governing one dimensional unsteady flow through the compressor can be expressed as,…”

Section: B Governing Equationsmentioning

confidence: 99%

Modeling and Analysis of Ice Shed in Multistage Compressor of Jet Engines

Kundu

Prasad

Singh

et al. 2014

6th AIAA Atmospheric and Space Environments Conference

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Simulation of ice shed into a multistage axial compressor involves a coupled two phase flow of a continuous phase comprising of air and water vapor and a discrete phase with ice crystals and water droplets. A first principles based discrete phase model is formulated to capture the heat and mass transfer processes of ice flow in air. A quasi one-dimensional model is used to represent the continuous phase. An exchange of information at every time step between the two models leads to a coupled response that alters characteristics like temperature and pressure distributions across the compressor. However, an understanding of the impact of various assumptions used for modeling of the icing physics is imperative in order to establish the fidelity of the developed icing model, before its use in gas turbine engine ice ingestion studies. This paper describes the assumptions and semi-numerical models used in the coupled discrete-continuous phase flow numerical models. The input characteristics of the discrete phase related to the size and distribution of ice crystals, the assumed percentage of ice particles escaping through compressor bleed ports, simplifications associated with ice and droplet breakup on impact with compressor blades, moisture content affecting the dry air properties, are some of the factors that are variables in the icing study. The impact of these factors on the compressor flow dynamics is estimated through a parametric analysis.

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“…The model contains two momentum equations: the axial momentum conservation and a circumferential momentum equation accounting for angular momentum variations. 16 A quasi-one-dimensional unsteady mathematical model of the continuous phase that includes blade forcing terms and source terms from the discrete phase, is expressed in Eq. (1).…”

Section: B Governing Equations For Air-vapor Mixturementioning

confidence: 99%

Analysis of Stall Onset in a Multistage Axial Flow Compressor in Response to Engine Icing

Kundu¹,

Prasad²,

Saxena³

et al. 2014

50th AIAA/ASME/SAE/ASEE Joint Propulsion Conference

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Propulsion system instabilities such as compressor surge and stall can arise due to ice ingested by an aircraft engine flying through high ice water content regions. Performance and operability are affected by ice ingestion into a gas turbine engine compression system. Since the 1980's ingestion of ice particles into engines have caused over one hundred engine power loss events. This paper presents an analysis of a multistage compressor system response to ice ingestion. Towards this, an aero-thermodynamic model of the discrete particles that captures mass and heat balances with air, is constructed. The computational methodology integrates it with a quasi-one-dimensional unsteady flow model with additional source terms from the discrete phase. From numerical simulations of the coupled continuous-discrete phase flow model, it is observed that a re-matching of the stages across the compressor occurs with increasing ice flow rates to accommodate loss of energy to the ice flow. The axial flow and pressure oscillations with increasing ice flow rates results in an eventual irretrievable unsteady compressor operating point excursion to stall side. The flow solver simulates the onset of a surge-stall event and identifies the stalling stage of the compressor. The numerical simulations correlate the magnitude of ice flow rates to pressure disturbances ultimately causing compressor instability.

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A quasi-one-dimensional CFD model for multistage turbomachines

Cited by 31 publications

References 26 publications

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

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

Modeling and Analysis of Ice Shed in Multistage Compressor of Jet Engines

Analysis of Stall Onset in a Multistage Axial Flow Compressor in Response to Engine Icing

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