Accurate Prediction of Loss Using High Fidelity Methods

Przytarski, Pawel J.; Wheeler, Andrew P. S.

doi:10.1115/gt2018-77125

Cited by 7 publications

(3 citation statements)

References 26 publications

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“…Second, the entropy transport equation was used to determine the unresolved dissipation. Two sub-volumes of data are extracted from the tip gap and an entropy budget calculation conducted in the same manner as [19]. The subvolumes are shown in Fig.…”

Section: Mesh Resolutionmentioning

confidence: 99%

Unsteady Structure of Compressor Tip Leakage Flows

Maynard

Wheeler

Taylor

et al. 2022

Journal of Turbomachinery

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Direct numerical simulations (DNS) are performed of a cantilevered stator blade to identify the unsteady and turbulent flow structure within compressor tip flows. The simulations were performed with clearances of 1.6 and 3.2 percent of chord. The results show that the flow both within the gap and at the exit on the suction side are highly unsteady phenomena controlled by fine-scale turbulent structures. The signature of the classical tip leakage vortex is a consequence of time-averaging and does not exist in the true unsteady flow. Despite the complexity, we are able to replicate the flow within the tip gap using a validated quasi-three-dimensional model. This enables a wide range of quasi-3D DNS simulations to study the effects of blade tip corner radius and Reynolds number. Tip corner radius is found to radically alter the unsteady flow in the tip; it affects both separation bubble size and shape, as well as transition mechanisms in the tip flow. These effects can lead to variations in tip mass flow of up to 10 percent and a factor of 2 variation in dissipation within the tip gap

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Section: Mesh Resolutionmentioning

confidence: 99%

Unsteady Structure of Compressor Tip Leakage Flows

Maynard

Wheeler

Taylor

et al. 2022

Journal of Turbomachinery

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“…To establish guidelines for what simulation fidelity, in terms of grid resolution and order-of-accuracy, is required to correctly capture entropy losses, Przytarski & Wheeler [109] established that the entropy generation rate based on the entropy flux could be used as a proxy for loss. Using a Taylor-Green vortex problem to represent fully turbulent flow, it was shown that a grid resolution with spacing of 4 and 2 times the Kolmogorov scale for 8th-order and 4th-order accurate schemes, respectively, was required for an accurate prediction of the entropy loss.…”

Section: Entropy Based Simulation Quality Assessmentmentioning

confidence: 99%

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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“…Influence of different numerical schemes of divergence part:Both KEP(kinetic energy preserving) and CR(Chain-Rule) are used for the calculation of divergence part of the flux reconstruction discretization as Eq(7). The computational speed of CR is slightly faster than KEP while the result is nearly the same fromFig.…”

mentioning

confidence: 99%

KEPLER: An Integrated Simulating System for Efficient Industrial Design and Optimization

Lu¹,

Liu²

2019

Proceedings of Global Power &Amp; Propulsion Society

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This paper describes the fundamental numerical schemes, objectives, structure and current capabilities of the KEPLER simulating system. This computational analysis and design software collection is aim to be designed and developed to solve wide range of industrial simulations in analysis and optimization tasks for industrial designers. KEPLER integrates pre-processing(automatic mesh generation), simulation and post-processing by using the "In-memory database" technology, which provide one-step solution for complete simulations without switching between different softwares/tools, also enables real-time reading/editing configurations and extracting results during the simulation by multi-users which could increase the working and collaboration efficiency dramatically. KEPLER provides unsteady solutions for compressible and incompressible flows(CFD) based on innovative high order Kinetic Energy Preserving flux reconstruction method with space-time expansion as time marching method(STE-KEP-FR). FR method is a localized stencil numerical scheme which constructs high order discretization completely in-cell, this method is very efficient for its simple differential formulation. The KEP method preserve the order of accuracy and enhance the nonlinear stability of FR discretization without increasing distinct computing cost. The STE method enables time-accurate local time-stepping, which means each cell use its local optimal time-step instead of the globally smallest time-step during the time-marching process, and the local time-step could be adaptive for stability and any other dynamic process. Because of the locality of STE-FR-FR method on both space and time, time-adaptive non-conformal and overset mesh are using seamless and efficiently on KEPLER, which enable the abilities for simulating complex moving/deforming geometries and wide range of dynamic flow problems. The computing efficiency, accuracy, stability of convection calculations, and overset performance is investigated in this work which are all critical issues for the ability and Competitiveness of Kepler code.

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Accurate Prediction of Loss Using High Fidelity Methods

Cited by 7 publications

References 26 publications

Unsteady Structure of Compressor Tip Leakage Flows

Unsteady Structure of Compressor Tip Leakage Flows

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

KEPLER: An Integrated Simulating System for Efficient Industrial Design and Optimization

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