Characterization of Deterministic Correlations for a Turbine Stage: Part 2 — Unsteady Flow Analysis

Bardoux, Fabien; Leboeuf, Francis; Dano, Cédric; Toussaint, Clément

doi:10.1115/99-gt-101

Cited by 6 publications

(8 citation statements)

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“…However, it has recently been demonstrated that purely spatial correlations are weaker than purely temporal ones for a transonic single-stage turbine [6,7]. The aim of this paper is to con rm this observation through an estimation of their in uence.…”

Section: …5 †mentioning

confidence: 83%

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Impact of deterministic correlations on the steady flow field

Bardoux

Leboeuf

2001

Proceedings of the Institution of Mechanical Engineers, Part A:

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A time-dependent numerical simulation of a single-stage transonic turbine is used as a direct simulation of stator-rotor interactions. The different parts of the deterministic correlations are computed and compared. The present work aims to provide insight into the in uence of these correlations on the steady ow eld of the average-passage equation system. This is related to the deterministic models of the literature. Several steady computations are performed with the various correlations. These results are compared with the time-averaged ow eld. The impact of boundary conditions is also studied to highlight the importance of the non-uniform circumferential distribution at the so-called 'mixing plane'. This work establishes that a non-uniform circumferential distribution is a key to ensure the success of steady computation. Furthermore, it demonstrates that full deterministic correlations are necessary to reproduce the time-averaged ow eld. Spatial correlations are thus insuf cient to model the stator wakes that interact with the rotor. Steady computations using only spatial correlations give less accurate results than those obtained without any correlation. This is a serious aw of most of the literature's models.

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Section: …5 †mentioning

confidence: 83%

“…The test case is the transonic turbine stage VEGA2. Because the unsteadinesses of the stage occur mainly in the rotor domain [6,7], the impact of the deterministic correlations is only studied on this blade row.…”

Section: Numerical Simulationsmentioning

confidence: 99%

Impact of deterministic correlations on the steady flow field

Bardoux

Leboeuf

2001

Proceedings of the Institution of Mechanical Engineers, Part A:

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“…The simulations were run without tip clearance and with an algebraic turbulence model. A complete analysis of the simulations is available in [7], [8]. The main particularity of this testcase is recalled hereafter.…”

Section: Transonic Turbine Stagementioning

confidence: 99%

“…Bardoux et al [7,8] showed that including the deterministic stresses in the 3-D simulation of the VEGA2 rotor allows to capture the mean effect of the unsteadiness on the mean steady flow. They also showed that the purely temporal part of the deterministic stresses cannot be neglected, contrary to the assumptions of the closure proposed by Adamczyk [3].…”

Section: Relative Importance Of the Deterministic And Circumferentialmentioning

confidence: 99%

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On the Role of the Deterministic and Circumferential Stresses in Throughflow Calculations

Simon

Thomas

Léonard

2009

Journal of Turbomachinery

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This paper presents a throughflow analysis tool developed in the context of the average-passage flow model elaborated by Adamczyk. The Adamczyk's flow model describes the 3-D timeaveraged flow field within a blade row passage. The set of equations that governs this flow field is obtained by performing a Reynolds averaging, a time averaging and a passage-to-passage averaging on the Navier-Stokes equations. The throughflow level of approximation is obtained by performing an additional circumferential averaging on the 3-D average-passage flow.The resulting set of equations is similar to the 2-D axisymmetric Navier-Stokes equations but additional terms resulting from the averages show up : blade forces, blade blockage factor, Reynolds stresses, deterministic stresses, passage-to-passage stresses and circumferential stresses. This set of equations represents the ultimate throughflow model provided that all stresses and blade forces can be modeled. The relative importance of these additional terms is studied in the present contribution.The stresses and the blade forces are determined from 3-D steady and unsteady databases (a low speed compressor stage and a transonic turbine stage) and incorporated in a throughflow model based on the axisymmetric Navier-Stokes equations. A good agreement between the throughflow solution and the averaged 3-D results is obtained. These results are also compared to those obtained with a more "classical" throughflow approach based on a Navier-Stokes formulation for the endwall losses, correlations for profile losses and a simple radial mixing model assuming turbulent diffusion. INTRODUCTIONThe throughflow level of approximation still remains an important tool for designing turbomachines [10] even though 3-D calculations are used more and more early in the design process. Throughflow codes are mainly used at the preliminary design stage for specifying the target aerodynamic performances to be achieved by the blading. They can be used either in the design mode, where the angular momentum and/or the total conditions are prescribed and the flow angles are sought, either in the analysis mode, where a known machine geometry is analyzed for its performance. The throughflow models are also used to exploit experimental results or to couple single blade row calculations in order to compute the flow field inside a multistage machine [4].Unfortunately, these models heavily rely on empirical inputs, such as profile losses correlations or end-wall loss models. They can accurately predict the flow field inside a turbomachine provided that the design parameters are not too far from those of the reference machines that were used to calibrate the throughflow model. This approach has shown to be efficient but lacks of generality.The most widespread throughflow method is certainly the streamline curvature method (SLC). In 1980, Spuur has proposed another approach based on the Euler equations. This approach has only started to retain attention in the 1990. Recent works using this approach can be foun...

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Unsteady rotor-stator interaction in high speed compressor and turbine stages

2005

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The blade row interaction can alter the time-mean flow and therefore be of interest for aerodynamic design analysis. Whereas results within low subsonic turbomachines are quite numerous in the literature, there have been far fewer works which give results of blade row interaction within high speed cases. Two cases are related in this paper. First, the effects of an incoming wake on the rotor flow field of a transonic compressor are analyzed. The blade row interaction proved to be positive regarding the total pressure ratio, but negative regarding the losses.The second case concerns a transonic turbine. Particular emphasis is placed on the assessment of the deterministic correlations included in the Averaged Passage Equation System.

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Characterization of Deterministic Correlations for a Turbine Stage: Part 2 — Unsteady Flow Analysis

Cited by 6 publications

References 0 publications

Impact of deterministic correlations on the steady flow field

Impact of deterministic correlations on the steady flow field

On the Role of the Deterministic and Circumferential Stresses in Throughflow Calculations

Unsteady rotor-stator interaction in high speed compressor and turbine stages

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