Study of internal time-resolved flow dynamics of a subsonic fluidic oscillator using fast pressure sensitive paint

Zhou, Luanliang; Wang, Shiqi; Song, Jinsheng; Li, Ziyan; Liu, Xu; Peng, Di; Wen, Xin; Liu, Yingzheng

doi:10.1007/s00348-021-03370-w

Cited by 9 publications

(2 citation statements)

References 40 publications

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“…The rotor rotation frequency is 49 Hz since the rotating speed is 2930 rpm (the design speed). Combined with the three key parameters of TA36 described above, a low-speed and low-frequency fluidic oscillator was redesigned based on models of Wang et al [38] and Zhou et al [39,40] in order to achieve unsteady micro tip injection on TA36.…”

Section: Research Subjects and Methodologymentioning

confidence: 99%

“…Therefore, when facing severe working environments inside aeroengines, it is essential to explore the feasibility of unsteady stall margin expansion based on fluidic oscillators. Thus, a low-frequency and low-speed oscillator configuration for a low-speed compressor was redesigned based on the models of Wang et al [38] and Zhou et al [39,40]. A series of experiments were conducted to investigate the characteristics of this configuration in detail by using hot-wire anemometer and other measurement methods.…”

Section: Introductionmentioning

confidence: 99%

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Characteristics of a Fluidic Oscillator with Low Frequency and Low Speed and Its Application to Stall Margin Improvement

et al. 2022

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Active flow control methods are commonly used in expanding the operating range of compressors. Indeed, unsteady active control methods are the main focus of researchers due to their effectiveness. For constructing an unsteady active control system, reliable actuators are significant. To compare with conventional actuators such as synthetic jet actuators and rotating valves, fluidic oscillators have structurally robust characteristics and can generate self-excited and self-sustained oscillating jets, which leads to its higher applicability in compressors under severe working conditions. Thus, to explore the feasibility of unsteady active control systems by the usage of fluidic oscillators, a low-frequency and low-speed oscillator is first designed and experimentally studied for improving the stability of a low-speed axial flow compressor. During the experiments, a special casing is designed to install 15 uniformly distributed oscillators in the tip region of compressor. Based on the unsteady micro injections of the rotor tip with rotor rotation frequency, the results indicate that the frequency/period of oscillators are flexible, in which the values are decoupled with the variation of inlet pressure. When the inlet-to-outlet pressure ratio of the oscillator is in the range of 1.1~2.0, the maximum velocity ranges from 30 m/s to 80 m/s. Moreover, the mass flow rate of the single oscillator only varies from 0.017‰ to 0.059‰ from the designed compressor mass flow rate. For the improvement of the compressor stall margin, the value is 3.45% when the total mass flow of oscillators is 0.08% of the designed compressor mass flow.

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Section: Research Subjects and Methodologymentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Characteristics of a Fluidic Oscillator with Low Frequency and Low Speed and Its Application to Stall Margin Improvement

et al. 2022

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Time-series image denoising of pressure-sensitive paint data by projected multivariate singular spectrum analysis

2022

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Time-series data, such as unsteady pressure-sensitive paint (PSP) measurement data, may contain a significant amount of random noise. Thus, in this study, we investigated a noise-reduction method that combines multivariate singular spectrum analysis (MSSA) with low-dimensional data representation. MSSA is a state-space reconstruction technique that utilizes time-delay embedding, and the low-dimensional representation is achieved by projecting data onto the singular value decomposition (SVD) basis. The noise-reduction performance of the proposed method for unsteady PSP data, i.e., the projected MSSA, is compared with that of the truncated SVD method, one of the most employed noise-reduction methods. The result shows that the projected MSSA exhibits better performance in reducing random noise than the truncated SVD method. Additionally, in contrast to that of the truncated SVD method, the performance of the projected MSSA is less sensitive to the truncation rank. The projected MSSA achieves denoising effectively by extracting smooth trajectories in a state space from noisy input data. Expectedly, the projected MSSA will be effective for reducing random noise in not only PSP measurement data, but also various high-dimensional time-series data. Graphic abstract

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Flow mechanism study and geometrical parameters analysis of fluidic oscillators based on pressure-sensitive paint measurements and modal analysis

Song,

Wang,

Qiu

et al. 2024

Exp Fluids

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The present study optimized some novel uidic oscillator designs, measured their internal-external uid dynamics, and used modal analysis to reveal their underlying oscillation mechanisms. It also investigated the effects of structural parameters on their uid dynamics. The time-resolved internalexternal pressure elds of the oscillators were determined by using pressure-sensitive paint (PSP) measurement. Proper orthogonal decomposition (POD) and dynamic mode decomposition (DMD) were used for modal analysis and phase reconstruction. The time-averaged pressure-eld and phasereconstruction results reveal that recirculation bubbles inside the mixing chamber and the feedback ow have underpinned the mechanism of formation of internal and external continuous sweeping ows. The modal analysis results reveal the spatial modal structures and their time evolution, which dominated the internal-external ow pattern. The inlet-wedge width and feedback-channel inlet diameter were found to be the structural parameters affecting feedback ow and recirculation-bubble size, and thereby in uenced ow characteristics such as jet oscillation frequency and divergence angle. Different Coandă surfaces altered the recirculation bubbles and feedback ow of the mainstream, thereby in uencing the formation mechanism of the sweeping jet.

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Study of internal time-resolved flow dynamics of a subsonic fluidic oscillator using fast pressure sensitive paint

Cited by 9 publications

References 40 publications

Characteristics of a Fluidic Oscillator with Low Frequency and Low Speed and Its Application to Stall Margin Improvement

Characteristics of a Fluidic Oscillator with Low Frequency and Low Speed and Its Application to Stall Margin Improvement

Time-series image denoising of pressure-sensitive paint data by projected multivariate singular spectrum analysis

Flow mechanism study and geometrical parameters analysis of fluidic oscillators based on pressure-sensitive paint measurements and modal analysis

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