An Accelerated 3D Navier-Stokes Solver for Flows in Turbomachines

Brandvik, Tobias; Pullan, Graham

doi:10.1115/gt2009-60052

Cited by 62 publications

(45 citation statements)

References 14 publications

(22 reference statements)

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“…The competing effects of deterministic and stochastic unsteadiness upon compressor performance have been a hotly debated topic ever since the works of Adkins and Smith (1982) and Gallimore and Cumpsty (1986). Furthermore, the phase-locked statistics reported in this paper will enable comparisons against other scale-resolving measurement techniques, such as three-component particle image velocimetry (Bhattacharya et al 2016), and high fidelity numerical simulations (Brandvik and Pullan 2009) to be made. Full details of the theoretical, numerical, and experimental aspects of a new rotated hot-wire method are provided in this paper and include: (1) a complete derivation of the phase-averaged sensor response equations following a triple decomposition of the instantaneous field variables; (2) the numerical solution of the sensor response equations using a weighted non-linear regression algorithm and (3) a demonstration of the technique in a low-speed, single-stage compressor research facility.…”

Section: Discussionmentioning

confidence: 99%

Phase-averaged flow statistics in compressors using a rotated hot-wire technique

2017

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produces a flow field that is inherently unsteady, threedimensional and multi-scale.It is customary to divide the unsteadiness in compressors into two categories: (1) deterministic fluctuations related to the shaft and blade frequencies and (2) broadband stochastic fluctuations related to naturally occurring turbulence. The mean square of (1) and (2) are manifest as deterministic stresses and Reynolds stresses, respectively. Furthermore, statistical moments may exhibit periodicities in both space and time. The space-time dependence of flow statistics significantly complicates the closure of the phase-averaged Navier-Stokes equations, relative to the traditional Reynolds-averaged formulation (Reynolds and Hussain 1972).The numerical prediction of compressor performance and stability rank amongst the greatest achievements of modern computational fluid dynamics (CFD) (Bradshaw 1996). Several frameworks for compressor CFD exist and include: (1) the steady-state mixing-plane method (Denton 1990; Dawes 1991; (2) the unsteady sliding-plane method (Rai 1989); and (3) the average-passage method (Adamczyk 1985). Depending on which method is adopted, the action of deterministic stresses, Reynolds stresses, or their combined effect should be modeled properly to achieve physically meaningful results. However, it is widely acknowledged that contemporary modeling practice can compromise the reliability of CFD results (Denton 2010). Ultimately, modeling uncertainties will only be reduced through improved physical understanding.To improve the understanding of momentum and energy exchange mechanisms in compressor annuli, it is imperative to acquire scale-resolved measurements in realistic, rotating, multi-bladed environments. Steady-state data are of limited value, since statistical moments of fluctuating quantities cannot be evaluated. Useful data must be highly Abstract A technique based on a rotated hot wire has been developed to characterise the unsteady, three-dimensional flow field between compressor blade rows. Data are acquired from a slanted hot wire rotated through a number of orientations at each measurement point. Phase-averaged velocity statistics are obtained by solving a set of sensor response equations using a weighted, non-linear regression algorithm. The accuracy and robustness of the method were verified a priori by conducting a series of tests using synthetic data. The method is demonstrated by acquiring a full set of phase-averaged flow statistics in the wake of a compressor stator blade row. The technique allows three components of phase-averaged velocity, six components of phase-averaged deterministic stress, and six components of phase-averaged Reynolds stress to be recovered using a single rotated hot-wire probe.

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Section: Discussionmentioning

confidence: 99%

Phase-averaged flow statistics in compressors using a rotated hot-wire technique

2017

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“…[11] The code uses the finite volume method to solve for the flow on structured O-H multiblock meshes with hexahedral cells. The temporal discretization used in unsteady mode is based on the second-order Adams-Bashforth scheme.…”

Section: Stall Point Calculationmentioning

confidence: 99%

“…[11] The hardware used to carry out the calculations was a cluster comprising 48 Nvidia K10 GPUs. Each K10 is made up of two GK104 GPUs, each of which has 1536 cores.…”

Section: High Performance Computing Architecturementioning

confidence: 99%

Pathways to Improved Aerodynamic Design

Page¹,

Hield²,

Mantell³

et al. 2016

Proceedings of the VII European Congress on Computational Methods in Applied Sciences and Engineering (ECCOMAS Congress 2016)

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Abstract. Large-scale unsteady graphical processor unit (GPU) based calculations are used to study the flow in realistic transonic fan geometries and shown to produce useful insights into the complex unsteady flow physics in systems of practical engineering relevance. Inlet flow distortion produces complex flow patterns which can significantly reduce stall margin. In order to design efficient, well targeted fan stabilizing technologies, it is essential to gain understanding into which specific features of distorted flow patterns are important in causing instability.In this paper, the use of large-scale, high-fidelity 3D unsteady Reynolds-Averaged Navier Stokes (URANS) calculations with sliding planes is shown to allow the isolation of a wide range of inlet distortion features and a high throughput of calculations is achieved. This facilitates a comprehensive investigation into stall margin loss and the observation of complex instability processes, which is in turn used to support the development of specialized design solutions. The costs of simulations and turnaround times are given. The potential for mixed fidelity simulations, in particular mixing one-dimensional low order models and large eddy type simulations to generate inlet conditions, is discussed. 7544Figure 1: Aerospace airframe and propulsion technology under development.

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“…This trend and its implications are explored in more detail in [21]. One leading example of this trend towards many-core computing is the use of GPUs (graphics processing units) for running CFD such as [22]. The authors present a three-dimensional unsteady RANS turbomachinery code running on GPUs with speeds high enough to enable whole assembly, multi-bladerow calculations to be realistic.…”

Section: (C) Computational Engineeringmentioning

confidence: 99%

Delivering better power: the role of simulation in reducing the environmental impact of aircraft engines

Menzies

2014

Phil. Trans. R. Soc. A.

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The growth in simulation capability over the past 20 years has led to remarkable changes in the design process for gas turbines. The availability of relatively cheap computational power coupled to improvements in numerical methods and physical modelling in simulation codes have enabled the development of aircraft propulsion systems that are more powerful and yet more efficient than ever before. However, the design challenges are correspondingly greater, especially to reduce environmental impact. The simulation requirements to achieve a reduced environmental impact are described along with the implications of continued growth in available computational power. It is concluded that achieving the environmental goals will demand large-scale multi-disciplinary simulations requiring significantly increased computational power, to enable optimization of the airframe and propulsion system over the entire operational envelope. However even with massive parallelization, the limits imposed by communications latency will constrain the time required to achieve a solution, and therefore the position of such large-scale calculations in the industrial design process.

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An Accelerated 3D Navier-Stokes Solver for Flows in Turbomachines

Cited by 62 publications

References 14 publications

Phase-averaged flow statistics in compressors using a rotated hot-wire technique

Phase-averaged flow statistics in compressors using a rotated hot-wire technique

Pathways to Improved Aerodynamic Design

Delivering better power: the role of simulation in reducing the environmental impact of aircraft engines

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