Analysis of the Unsteady Flow in an Aspirated Counter-Rotating Compressor Using the Nonlinear Harmonic Method

Guidotti, Emanuele; Turner, Mark G.

doi:10.1115/gt2009-60285

Cited by 6 publications

(3 citation statements)

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“…Figure 2 depicts the meridional view of the computational domain. Previous experience with simulating the CRAC geometry by Knapke et al [25] and grid dependency studies by Guidotti and Turner [26,27] and Knapke [28] have shown that the results are sensitive to the spanwise grid resolution. For this reason, a spanwise cell count of 172 was chosen.…”

Section: Numerical Approachmentioning

confidence: 99%

Detailed Unsteady Simulation of a Counterrotating Aspirated Compressor with a Focus on the Aspiration Slot and Plenum

Knapke

Turner

2013

International Journal of Rotating Machinery

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An unsteady analysis of the MIT counterrotating aspirated compressor (CRAC) has been conducted using the Numeca FINE/Turbo 3D viscous turbulent flow solver with the Nonlinear Harmonic (NLH) method. All three blade rows plus the aspiration slot and plenum were included in the computational domain. Both adiabatic and isothermal solid wall boundary conditions were applied and simulations with and without aspiration were completed. The aspirated isothermal boundary condition solutions provide the most accurate representation of the trends produced by the experiment, particularly at the endwalls. These simulations provide significant insight into the flow physics of the aspiration flow path. Time histories and spanwise distributions of flow properties in the aspiration slot and plenum present a flow field with significant temporal and spatial variations. In addition, the results provide an understanding of the aspiration flow path choking mechanism that was previously not well understood and is consistent with experimental results. The slot and plenum had been designed to aspirate 1% of the flow path mass flow, whereas the experiment and simulations show that it chokes at about 0.5% mass flow.

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Section: Numerical Approachmentioning

confidence: 99%

Detailed Unsteady Simulation of a Counterrotating Aspirated Compressor with a Focus on the Aspiration Slot and Plenum

Knapke

Turner

2013

International Journal of Rotating Machinery

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“…The nonlinear harmonic (NLH) method has been tested and validated against several turbomachinery cases, with the result that the time savings seemed to be significant over the time-domain unsteady method. 7,8 The first priority of this study is directed toward demonstrating those claims in a counterrotating research compressor (CRRC), as the NLH method is relatively new with limited validation. Apart from this, there are several issues of interest.…”

Section: Focus Of Research Effortmentioning

confidence: 99%

Unsteady simulation of a counter–rotating research compressor using the nonlinear harmonic method

Wang

Liu

Yang

et al. 2012

Proceedings of the Institution of Mechanical Engineers, Part G:

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In this article, the nonlinear harmonic method implemented in Fine/Turbo code has been evaluated for unsteady rotor–rotor interaction analysis. Strengths and weaknesses of the nonlinear harmonic method are highlighted through direct comparison with experimental data and time-domain unsteady simulation for the Northwestern Polytechnical University counter-rotating research compressor at the design and off-design conditions. The rotor–rotor interactions were studied in detail to advance the understanding of the flow physics involved. Based on the unsteady simulation, deterministic stresses were computed and compared to the nonlinear harmonic method to analyze distinct sources of unsteadiness and their effect on the time-averaged flow field. For the present case, the nonlinear harmonic method efficiently computes unsteady flows and shows major improvements regarding the computational time (to a factor up to 10).

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“…At present, however, there are few studies on unsteady flow mechanism of counter-rotating compressor. The Turner research group of University of Cincinnati 29,30 has conducted the numerical simulations of MIT counter-rotating compressor, but mainly shed light on analyzing the compressor performance. Besides, Limin et al 31 and Mao and Liu 32 of Northwestern Polytechnical University have performed unsteady numerical simulations in the subsonic counter-rotating compressor under NS conditions, respectively.…”

Section: Introductionmentioning

confidence: 99%

The effect of wake vortex on the unsteady characteristics of tip leakage flow in a high-loading counter-rotating compressor

Zhao

et al. 2023

Proceedings of the Institution of Mechanical Engineers, Part A:

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The effect of upstream wake vortex on the unsteady characteristics of downstream tip leakage flow (TLF) in a high-loading counter-rotating compressor, have been revealed. For the strength of the tip leakage vortex (TLV) is stronger than that of the upstream wake vortex and the TLF spills from the leading edge (LE) of the neighbor blade under near stall (NS) condition, the wake vortex can only transport bypass the interface, formed by the TLF and main flow, just below the tip. The TLV is separated into several parts by the wake vortex such that it weakened rapidly and the dominant frequency of the static pressure fluctuation near the trailing edge (TE) is about 1 relative blade passing frequency (RBPF) under the NS condition. When the extent of TLV breakdown is enough, the TLV is responsible for the dominant frequency near the LE. Therefore, there are two dominant frequencies (one is located near LE, the other is located near TE) in the tip region of the downstream supersonic rotor under NS condition. It’s harmful for the stable operation of compressors due to lower frequency resulting from TLV. At small tip clearance size, affected by the upstream wake vortex, when the static pressure fluctuation caused by the TLV at the LE of the downstream rotor just appeared, the momentum ratio increases. And it locates above the limit line (applied to judge the static pressure fluctuation caused by the self-excitation of the TLF), this means the wake vortex is beneficial to suppress the self-excitation of the TLF.

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Analysis of the Unsteady Flow in an Aspirated Counter-Rotating Compressor Using the Nonlinear Harmonic Method

Cited by 6 publications

References 0 publications

Detailed Unsteady Simulation of a Counterrotating Aspirated Compressor with a Focus on the Aspiration Slot and Plenum

Detailed Unsteady Simulation of a Counterrotating Aspirated Compressor with a Focus on the Aspiration Slot and Plenum

Unsteady simulation of a counter–rotating research compressor using the nonlinear harmonic method

The effect of wake vortex on the unsteady characteristics of tip leakage flow in a high-loading counter-rotating compressor

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