A Harmonic Balance Technique for Multistage Turbomachinery Applications

Frey, Christian; Ashcroft, Graham; Kersken, Hans-Peter; Voigt, Christian

doi:10.1115/gt2014-25230

Cited by 51 publications

(59 citation statements)

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“…Alternatively, the coupling terms can be modelled implicitly either in the time-domain or in a combined time-frequency domain implementation, as proposed by Hall et al [17] and McMullen et al [18]. The technique developed for TRACE is similar to the latter, as explained by Frey et al [19].…”

Section: Methodsmentioning

confidence: 99%

CFD-Based Investigation of Turbine Tonal Noise Induced by Steady Hot Streaks †

Holewa

Lesnik

Ashcroft

et al. 2017

IJTPP

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Abstract:The interaction of steady hot streaks from an annular ring of combustion chambers with turbine rotating blades can potentially generate tonal noise. The relevance of this source mechanism in aeroengine noise is controversially discussed in the literature. In the present paper, the streak-turbine interaction is investigated using the computational fluid dynamics (CFD) method called harmonic balance (HB)-a truncated non-linear frequency domain approach with a high potential of reducing the computational effort. The investigated high-pressure turbine is composed of a single stator-rotor stage. The first part of the present paper compares the results obtained with the HB method to those obtained with the more established time-accurate unsteady Reynolds-averaged Navier-Stokes (URANS) approach and investigates their sensitivity with respect to the computational mesh density. Thereby, no streaks are simulated, and only the turbine alone tones are considered. Convincing results are obtained on aerodynamics and acoustics. The second part of the paper deals with a parametric study on the acoustical impact of steady hot streaks. The streaks are prescribed at the inlet of the stage using a boundary condition as an attempt to simulate a ring of combustor nozzles. No vorticity is coupled into the computational domain, as the objective is to measure the effect of temperature inhomogeneity only. Overall, the turbine appears to be slightly quieter with hot streaks. The streak-to-stator-vane ratio of 1-to-2 explains the generation of new acoustic modes with distinct azimuthal orders. The acoustic power amplitude of those additional modes scales roughly with the square of the temperature difference, the fourth-power of the diameter, and the square of the entropy difference. This last result agrees well with the 1D theory of Marble and Candel. The acoustic contribution of the unsteady force on the rotor blades due to the overspeed measured in the wakes of the streaks-resulting from the flow acceleration through the stator-remains an open question.

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Section: Methodsmentioning

confidence: 99%

CFD-Based Investigation of Turbine Tonal Noise Induced by Steady Hot Streaks †

Holewa

Lesnik

Ashcroft

et al. 2017

IJTPP

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“…For completeness we will summarize the HB algorithm as it is implemented in TRACE. For a detailed description see [10]. Time-periodic solutions of Eqn.…”

Section: Harmonic Balance Methodsmentioning

confidence: 99%

A Hybrid Mesh Harmonic Balance Solver for the Aeroelastic Analysis of Turbomachinery

Kersken¹,

Ashcroft²,

Frey³

2016

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

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Abstract. An implementation of a Harmonic Balance method to simulate time-periodic, nonlinear flows in turbomachinery on hybrid grids comprising both structured and unstructured blocks is described. It has been developed with the aim to apply it to aeroelastic analysis problems which require support for deforming meshes. The necessary modifications of an existing implementation of a Harmonic Balance method on structured grids are presented. Especially block boundaries require a separate treatment. For the same spatial discretization order the solver for unstructured grids requires a moderate overhead in computational resources in terms of computation time compared to the structured solver when applied on grids with similar spatial resolution. The extended HB solver is applied to a standard turbomachinery aeroelastic test case for inviscid flows including both subsonic and transonic configurations. The computational results obtained are compared with results from a Harmonic Balance solver for structured grids and references from literature.

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“…To resolve K higher harmonics, at least N = 2K +1 points are needed. But due to the nonlinearity of the residual function, the problem of aliasing can occur [17]. Therefore a higher number of sampling points should be used.…”

Section: Solution Methods and Implementationmentioning

confidence: 99%

“…The harmonic balance method as implemented in TRACE (see [17,18]) approximates the time dependent flow solution as a Fourier series with a finite number of harmonics 1…”

Section: Harmonic Balance Methodsmentioning

confidence: 99%

See 1 more Smart Citation

Sensitivity Analysis for Forced Response in Turbomachinery Using an Adjoint Harmonic Balance Method

Engels-Putzka¹,

Frey²

2016

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

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Abstract. The analysis of aeroelastic properties is an important aspect in the design of turbomachinery components. In this study we focus on vibrations caused by the interaction of adjacent blade rows (forced response). This is an inherently unsteady phenomenon. But due to its periodic nature it can be efficiently treated by numerical methods formulated in the frequency domain, e.g. the harmonic balance method.When going from the analysis of individual designs using CFD to CFD-based optimisation it is desirable to compute also sensitivities of objective functions (targets and restrictions for the optimisation) with respect to design parameters. Since in typical applications the number of design parameters is much larger than the number of objective functions, it is advantageous to use the adjoint method for the computation of these sensitivities.An adjoint solver based on the harmonic balance method has been implemented in the framework of the flow solver TRACE. This is now extended and used to compute the sensitivities of aeroelastic objective functions to the amplitudes of a harmonic perturbation at the entry or exit of the respective blade row. These sensitivities can be validated by comparing to finite differences obtained from harmonic balance computations with different perturbations. We apply the method to model problems which are representative for turbomachinery configurations.

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A Harmonic Balance Technique for Multistage Turbomachinery Applications

Cited by 51 publications

References 0 publications

CFD-Based Investigation of Turbine Tonal Noise Induced by Steady Hot Streaks †

CFD-Based Investigation of Turbine Tonal Noise Induced by Steady Hot Streaks †

A Hybrid Mesh Harmonic Balance Solver for the Aeroelastic Analysis of Turbomachinery

Sensitivity Analysis for Forced Response in Turbomachinery Using an Adjoint Harmonic Balance Method

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