Predicting High-Lift Low-Pressure Turbine Cascades Flow Using Transition-Sensitive Turbulence Closures

Pacciani, Roberto; Marconcini, Michele; Arnone, Andrea; Bertini, Francesco

doi:10.1115/1.4025224

Cited by 28 publications

(21 citation statements)

References 25 publications

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“…We report on one test on wake-induced transition by Pacciani et al [91] on the suction side of the T106A blade and two tests on wake-induced transition by Piotrowski et al [122,145] on the suction side of the N3-60 blade. Later, we illustrate the predictive qualities of four transition models for wake-induced transition on the suction side of the N3-60 blade.…”

Section: Tests Of Transition Models For Wake-perturbed Inflowmentioning

confidence: 99%

“…This parameter is used in the laminar fluctuation kinetic energy models of Pacciani et al [90,91]. However, they do not formulate a strict justification for this use.…”

Section: Onset Of Transition In Separated Boundary Layer Statementioning

confidence: 99%

“…This model is a four-equation model proposed by Pacciani et al [91] for simulation of wake-induced transition. The model uses transport equations for turbulent and laminar kinetic energy and dissipation rate, supplemented with an equation for an indicator function.…”

Section: The K-k L -ω-I Model Of Pacciani Et Almentioning

confidence: 99%

“…[91] tested the γ-Re θ model by Langtry and Menter [77] and their own k-k L -ω-I model for transition in separated state on the suction side of blades in a very-high-lift front-loaded (T108) and a very-high-lift aft-loaded (T106C) low-pressure turbine cascade. They tested the γ-Re θ model with several closure functions from the literature.…”

Section: Tests Of Transition Models For Steady Inflowmentioning

confidence: 99%

“…[91] tested the γ-Re θ model by Langtry and Menter [77] and their own k-k L -ω-I model for wake-induced transition on the suction side of the T106A low-pressure turbine blade for background turbulence level Tu = 4%. In between wake impacts, the boundary layer at the suction side is prone to separation, but not separated.…”

Section: Tests Of Transition Models For Wake-perturbed Inflowmentioning

confidence: 99%

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Transition Models for Turbomachinery Boundary Layer Flows: A Review

Dick

Kubacki

2017

IJTPP

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Current models for transition in turbomachinery boundary layer flows are reviewed. The basic physical mechanisms of transition processes and the way these processes are expressed by model ingredients are discussed. The fundamentals of models are described as far as possible, with a common structure of the equations and with emphasis on the similarities between the models. Tests of models reported in the literature are summarized and our own test is added. A conclusion on the performance of models is formulated.Keywords: turbomachinery flows; transition models; boundary layers; bypass transition; separationinduced transition; wake-induced transition; Reynolds-averaged Navier-Stokes; intermittency; laminar kinetic energy Transition MechanismsWith the objective of modelling with Reynolds-averaged Navier-Stokes (RANS) or URANS (unsteady or time-accurate RANS) description of a flow, generally, four types of transition from laminar state to turbulent state in turbomachinery boundary layer flows are distinguished [1,2]. These are: natural transition in attached boundary layer state, bypass transition in attached boundary layer state under a statistically steady mean flow, separation-induced transition in the free shear layer formed by separation of a boundary layer under a statistically steady mean flow, and wake-induced transition due to periodically unsteady impact of wakes on boundary layers in attached or separated state. Despite the vast amount of studies on these transition types during the last 4 or 5 decades, understanding of the mechanisms is still not complete, although large progress has been made in the last decade thanks to direct numerical simulation (DNS) and large-eddy simulation (LES). Hereafter, we summarise the mean mechanisms, taking into account the inherent limitations of modelling with Reynolds-averaged Navier-Stokes description of a flow. This means that secondary effects, which mostly are the least understood and sometimes still are a matter of controversy, are not discussed, because, anyhow these features cannot be represented by RANS or URANS. Natural TransitionUnder a statistically steady mean flow of low turbulence level, transition in an attached boundary layer is initiated by 2D viscosity-dependent Tollmien-Schlichting instability waves, followed by a 3D instability, leading to formation of spanwise periodic hairpin vortices, which, farther downstream, cause breakdown of the laminar layer with generation of turbulent spots. These spots finally merge resulting in the formation of a turbulent boundary layer [1,2]. This type of transition is called natural transition. It is a rather slow process and, under a very low mean-flow turbulence level, as in external Int.

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Section: Tests Of Transition Models For Wake-perturbed Inflowmentioning

confidence: 99%

“…This parameter is used in the laminar fluctuation kinetic energy models of Pacciani et al [90,91]. However, they do not formulate a strict justification for this use.…”

Section: Onset Of Transition In Separated Boundary Layer Statementioning

confidence: 99%

Section: The K-k L -ω-I Model Of Pacciani Et Almentioning

confidence: 99%

Section: Tests Of Transition Models For Steady Inflowmentioning

confidence: 99%

Section: Tests Of Transition Models For Wake-perturbed Inflowmentioning

confidence: 99%

See 3 more Smart Citations

Transition Models for Turbomachinery Boundary Layer Flows: A Review

Dick

Kubacki

2017

IJTPP

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Introduction

Juntasaro

2022

Intermittency Equation for Transitional Flow

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The Current State of High-Fidelity Simulations for Main Gas Path Turbomachinery Components and Their Industrial Impact

Sandberg

Michelassi²

2019

Flow Turbulence Combust

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Over the past two decades high-fidelity simulations have become feasible for most main gas path turbomachinery components. This paper introduces the key challenges of simulating and modelling turbomachinery flows and presents an overview of possible simulation strategies. A comprehensive overview is given of which particular design challenges have to date been addressed by high-fidelity simulations, with a particular focus on high-pressure and centrifugal compressors, and high-pressure and low-pressure turbines. Recommendations are provided for how quality and accuracy can be ensured for high-fidelity simulations, using direct numerical simulations of a low-pressure turbine as a case study. It is argued that industrial impact from high-fidelity simulations can be achieved in two ways, either by conducting design-of-experiment-like studies that can provide designers with insight into certain physical mechanisms and phenomena, or by helping mature and improve lower-order models. The latter is discussed with particular emphasis on recent advances in machine learning for model assessment and improvement, and the potential of one selected data-driven approach is demonstrated on predictions of wake mixing for low-pressure and high-pressure turbines.

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Predicting High-Lift Low-Pressure Turbine Cascades Flow Using Transition-Sensitive Turbulence Closures

Cited by 28 publications

References 25 publications

Transition Models for Turbomachinery Boundary Layer Flows: A Review

Transition Models for Turbomachinery Boundary Layer Flows: A Review

Introduction

The Current State of High-Fidelity Simulations for Main Gas Path Turbomachinery Components and Their Industrial Impact

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