Vortex trajectory prediction and mode analysis of compressor stall with strong non-uniformity

Fu, Li; Hu, Chenxing; Yang, Ce; Bao, Wenrui; Zhou, Mi

doi:10.1016/j.ast.2020.106031

Cited by 11 publications

(4 citation statements)

References 41 publications

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“…16 In recent years, the data of turbomachinery numerical simulation have been applied using DMD or POD method. [17][18][19] We have performed DMD with the data of numerical simulation as well, and unsteady flow structures in the tip region of axial compressor is well analyzed. 20 In this paper, the extension of DMD method in experiments allows for further identification of the characteristic correlations between the flow profile, the dominant vortex structure, and unsteady flow patterns.…”

Section: Introductionmentioning

confidence: 99%

Time-delay-locked dynamic mode decomposition for extracting flow patterns of compressor in experiment

Wang

Chen

Song

et al. 2022

Proceedings of the Institution of Mechanical Engineers, Part G:

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Dynamic mode decomposition (DMD) is widely used in extracting the main features of high-dimensional nonlinear systems in computational fluid dynamics. However, it cannot be directly applied to real compressors due to the limitations of data acquisition over the entire flow field. In order to overcome this limitation, our paper proposes a time-delay-locked DMD algorithm. It combines the idea of phase locking, Hankel time-delay method, and DMD method. Based on it, the flow patterns are successfully extracted and the unsteady flow phenomena including rotating stall and rotating instability are explained as modal waves. Multi-peak spectrum nearly 1/2 BPF observed under off-design RI conditions is explained. In addition, multi-scale of rotating stall is analyzed and shock wave is captured.

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Section: Introductionmentioning

confidence: 99%

Time-delay-locked dynamic mode decomposition for extracting flow patterns of compressor in experiment

Wang

Chen

Song

et al. 2022

Proceedings of the Institution of Mechanical Engineers, Part G:

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show abstract

“…12 Examples include but not limited to POD of compressor wake, 13 POD and DMD of compressor surge, 14 DMD of corner separation, 15 and DMD of spike-type rotating stall. 16 POD extracts coherent structures in turbulent flows by identifying the optimal set of orthogonal modes ranked by their modal energy. However, the physical meaning of each mode may be difficult to interpret, because the mode shape involves flow field information at different frequencies.…”

Section: Introductionmentioning

confidence: 99%

Spectral proper orthogonal decomposition of compressor tip leakage flow

Zhou

Rigas

et al. 2021

Physics of Fluids

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To identify the spatiotemporal coherent structure of compressor tip leakage flow, spectral proper orthogonal decomposition (SPOD) is performed on the near-tip flow field and the blade surface pressure of a low-speed compressor rotor. The data used for the SPOD analysis are obtained by delayed-detached eddy simulation, which is validated against the experimental data. The investigated rotor near-tip flow field is governed by two tip leakage vortices (TLV), and the near-tip compressor passage can be divided into four zones: the formation of main TLV (Zone I), the main TLV breakdown (Zone II), the formation of tip blockage cell (Zone III), and the formation of secondary TLV (Zone IV). Modal analysis from SPOD shows that a major part of total disturbance energy comes from the main TLV oscillating mode in Zone I and the main TLV vortex shedding mode in Zone III, both of which are low-frequency and low-rank; on the contrary, modal components in Zones II and IV are broadband and non-low-rank. Unsteady blade forces are mainly generated by the impingement of the main TLV on the blade pressure surface in Zone III, rather than the detachment of the secondary TLV from the blade suction surface in Zone IV. These identified coherent structures provide valuable knowledge for the aerodynamic/aeroelastic effects, turbulence modeling, and reduced-order modeling of compressor tip leakage flow.

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“…In recent decades, more and more investigators focus on the research of stall vortex, which is a typical phenomenon that resulted from flow separation in blade tip region link to sudden drop of flow velocity. To explore its formation mechanism, most studies pay attention to the field of compressors, axial flow pumps, and mixed flow pumps [16][17][18][19]. To better capture the vortex structure and obtain more superior flow field information, many scholars have introduced the DDES turbulence model into the numerical simulation analysis of rotating machinery, which is the relatively accurate turbulence model at present [20][21][22].…”

Section: Introductionmentioning

confidence: 99%

Analysis of Unsteady Flow Characteristics of Centrifugal Pump under Part Load Based on DDES Turbulence Model

Tang

Liu

Zhao

et al. 2021

Shock and Vibration

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To better reveal the mechanism of the rotor-stator interference between the impeller and the guide vane and the evolution process of the stall vortex under the part-load conditions, numerical simulation is carried out based on the DDES turbulence model, which can better capture vortex structure. And the pressure pulsation and the radial velocity distribution of the centrifugal pump are studied. The vortex structure and pressure fluctuation of pump internal flow field under part-load condition of Q = 0.4 Qdes are mainly analyzed. The analysis results show that the stall vortex is formed at the inlet of the impeller and evolves to the outlet of the impeller, the front cover to the rear cover according to the fluid flow direction, and then disappears. Besides, under the part-load condition, the vorticity of the impeller outlet is always obviously less than that of the impeller inlet as the flow rate increases. Due to the asymmetric action of the volute, the radial velocity distribution law of flow channel C1 is different from other flow channels at different blade heights. By analyzing the radial velocity, the phenomenon that the jet-wake flow impacts the guide vane with the rotation of the impeller is the main reason for the rotor-stator interference. And large radial velocity gradients appear at the front and rear cover plates, which will cause high energy loss and reduce pump efficiency. Besides, the conclusion can be drawn that the region with the strongest rotor-stator interference is the inlet region of the guide vane suction surface. It also occurs near the volute tongue but is lower due to the effect of the guide vane. This research may serve as a reference for the safe operation of centrifugal pumps under part-load conditions.

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Vortex trajectory prediction and mode analysis of compressor stall with strong non-uniformity

Cited by 11 publications

References 41 publications

Time-delay-locked dynamic mode decomposition for extracting flow patterns of compressor in experiment

Time-delay-locked dynamic mode decomposition for extracting flow patterns of compressor in experiment

Spectral proper orthogonal decomposition of compressor tip leakage flow

Analysis of Unsteady Flow Characteristics of Centrifugal Pump under Part Load Based on DDES Turbulence Model

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