Fluid dynamics of oscillatory flow across parallel-plates in standing-wave thermoacoustic system with two different operation frequencies

Allafi, Waleed Almukhtar; Saat, Fatimah Al Zahrah Mohd; Mao, Xiaoan

doi:10.1016/j.jestch.2020.12.008

Cited by 9 publications

(4 citation statements)

References 23 publications

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“…So, the transient numerical iteration for each timestep of these CFD models will be iterated until the RMS residual reached these values. Similar range of convergence was also reported especially when the model is transient in nature [17,19]. In this study, the average velocity of the solution was also monitored in addition to the monitoring practice of the residual convergence.…”

Section: Methodssupporting

confidence: 71%

“…Silva et al, [15] and Kolekar et al, [16] used Shear Stress Transport (SST) k- turbulence model. The SST k- model was reported to be performing well in many flow conditions that involved both the viscid and inviscid flow regions [17][18][19][20]. The theories or formulas for SST k- turbulence model is standard and can be referred to the published documentation [16,19,20].…”

Section: Methodsmentioning

confidence: 99%

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Computational Fluid Dynamics Study of Wake Recovery for Flow Across Hydrokinetic Turbine at Different Depth of Water

Ren

Saat

Anuar

et al. 2021

CFDL

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Depletion of fossil fuel caused mankind to look for sustainable and green energy resources. The characteristic of hydrokinetic turbine with ability to operate at low head stream and at low cost made it a good choice for use to harness hydro source of energy. As hydrokinetic turbine gain attention from the industry player, many experimental and Computational Fluid Dynamics (CFD) studies related to hydrokinetic turbine have been carried out. Yet the relationship of flow depth variation and wake recovery behind the turbine is still not fully understood. There is limited study about the effects of flow depth variations on the wake recovery behind the turbine. In this paper, a CFD model investigation was done based on published experimental work. A hydrokinetic water turbine was drawn using the MHKF1-180 and NACA4418 foils dimensions. The transient CFD study was conducted using SST k-w turbulence model and dynamic mesh method. The results showed that in near wake region, the wake at deeper depth will recover faster seemingly due to pressure change at that depth and the faster rate of momentum transfer of the fluid. It can be concluded that the deeper the placement of the turbine inside the water channel, the faster the wake recovers. The wake recovery results as presented in this paper should be considered when placing set of turbines especially in array arrangement to obtain a more efficient energy conversion.

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Section: Methodssupporting

confidence: 71%

Section: Methodsmentioning

confidence: 99%

Computational Fluid Dynamics Study of Wake Recovery for Flow Across Hydrokinetic Turbine at Different Depth of Water

Ren

Saat

Anuar

et al. 2021

CFDL

Self Cite

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“…During the second half of the cycle, the air is moving in negative direction [32]. The cycle repeats many times, and the repetition of cycle depends on the frequency of the flow [33]. The stator must be designed with ability to provide continuous flow of air when the oscillatory flow of thermoacoustic is flowing from upstream and downstream locations to rotate the rotor.…”

Section: The 3d Printed Bi-directional Turbinementioning

confidence: 99%

A 3D Printed bi-directional Turbine for Thermoacoustic Standing Wave Environment at an Atmospheric Pressure

Fatimah Al Zahrah Mohd Saat

2024

AREFMHT

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This paper reports a study on the use of an in-house 3D printed bi-directional turbine for energy conversion in a standing wave thermoacoustic environment that is operated at an atmospheric pressure. The 3D printed turbine was placed at two locations along the resonator and the data were recorded for several range of flow frequency and flow amplitude. It is found that maximum output is achieved when flow is not at resonance. Resonance of the standing wave inside the rig was found at 106 Hz but the bi-directional turbine performs better at a lower frequency of 85 Hz.

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“…Understanding the fluid dynamics of flow in these systems is difficult because it has a significant impact on the overall efficacy of the system. This is primarily due to the complex nature of acoustic waves and the unique characteristics of passage through objects or structures [10].…”

Section: Introductionmentioning

confidence: 99%

Vibration-Induced Flow and Streaming in Oscillatory Flow of Thermoacoustics

Azman Hafiidz Aji,

Fatimah Al Zahrah Mohd Saat,

Fadhilah Shikh Anuar

et al. 2024

ARFMTS

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Induced acoustic streaming flow in thermoacoustic systems occurs due to acoustic vibrations, causing changes to the mean flow in the systems. This phenomenon creates a tendency to generate net fluid flow that can cause energy change within certain areas inside the system. However, the effects of the entire system’s vibrations on the flow streaming are not yet fully understood, yet it is important for a more effective operation. This study experimentally investigated the flow streaming resulting from vibration in a standing-wave thermoacoustic test rig with a flow frequency of 23.6 Hz. The existence of flow streaming due to vibration which was not counted in the theoretical formula is shown and indicated by experimental values. The result shows that there is a correlation between the amplitude of the drive ratio (DR) and the velocity of the oscillation of the flow. Upon examining both the theoretical and the practical evidence, it becomes clear that there exists a marginal flow velocity in directions other than the main flow due to the vibration of resonator’s wall as measured at the intake and outflow areas of the stack. This marginal flow velocity amplifies as the drive ratio of flow increases and it may potentially explain the observed difference between measured flow amplitude and the theoretical value.

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Fluid dynamics of oscillatory flow across parallel-plates in standing-wave thermoacoustic system with two different operation frequencies

Cited by 9 publications

References 23 publications

Computational Fluid Dynamics Study of Wake Recovery for Flow Across Hydrokinetic Turbine at Different Depth of Water

Computational Fluid Dynamics Study of Wake Recovery for Flow Across Hydrokinetic Turbine at Different Depth of Water

A 3D Printed bi-directional Turbine for Thermoacoustic Standing Wave Environment at an Atmospheric Pressure

Vibration-Induced Flow and Streaming in Oscillatory Flow of Thermoacoustics

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