Weakly Nonlinear Propagation in Thermoacoustic Engines: A Numerical Study of Higher Harmonics Generation up to the Appearance of Shock Waves

Olivier, Côme; Pénelet, Guillaume; Poignand, Gaëlle; Gilbert, Joël; Lotton, Pierrick

doi:10.3813/aaa.918889

Cited by 20 publications

(11 citation statements)

References 39 publications

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“…The flow verifies the compressible Navier-Stokes equations expressed in the moving frame attached to the tube, with an additional forcing source term depending on V: where p is the pressure, ρ is the density, v = u⃗ e z + v⃗ e r is the flow velocity,τ = − 2 3 µ(∇ · v)Ī + 2µD the viscous stress tensor of a Newtonian fluid,D the strain tensor, µ the dynamic viscosity which is supposed to be constant. In this formulation we have neglected the bulk viscosity since M 2 Sh 2 Re 2 ac ≪ 1 [30].…”

Section: Methodsmentioning

confidence: 99%

Inertial effects on acoustic Rayleigh streaming flow: Transient and established regimes

et al. 2017

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h i g h l i g h t s• Nonlinear inertial effects produce patterns different from DNS and experiments. • Time evolutions of streaming cells near the wall and in the core are analyzed. • The full streaming equations are solved numerically to obtain the established flow. • Nonlinear inertial effects produce patterns different from DNS and experiments. • Nonlinear inertial effects cannot explain the mutation of streaming at high levels. a b s t r a c tThe effect of inertia on Rayleigh streaming generated inside a cylindrical resonator where a mono-frequency standing wave is imposed, is investigated numerically and experimen-tally. To this effect, time evolutions of streaming cells in the near wall region and in the resonator core are analyzed. An analogy with the lid-driven cavity in a cylindrical geometry is presented in order to analyze the physical meanings of the characteristic times.Inertial effects on the established streaming flow pattern are then investigated numeri-cally using a code solving the time averaged Navier-Stokes compressible equations, where a mono-frequency acoustic flow field is used to compute the source terms.It is shown that inertia of streaming cannot be considered as the leading phenomenon to explain the mutation of streaming at high acoustic levels.

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Section: Methodsmentioning

confidence: 99%

Inertial effects on acoustic Rayleigh streaming flow: Transient and established regimes

et al. 2017

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“…118 and reproduced numerically by Olivier et al. 119 The autonomous generation of a thermoacoustic solitary wave rotating along a 20 m long closed loop, with many Helmholtz resonators connected to it, has also been recently reported by Shimizu et al. 120…”

Section: Modelling Of Thermoacoustics With Heat Additionmentioning

confidence: 72%

“…This observation motivated fundamental studies of non-linear propagation in thermoacoustic engines in the early 2000s. 116,117 More recently, the first experimental observation of thermoacoustic shock waves has been reported by Biwa et al 118 and reproduced numerically by Olivier et al 119 The autonomous generation of a thermoacoustic solitary wave rotating along a 20 m long closed loop, with many Helmholtz resonators connected to it, has also been recently reported by Shimizu et al 120…”

Section: Non-linear Observations In Flameless Thermoacoustic Devicesmentioning

confidence: 86%

Common features in the thermoacoustics of flames and engines

Lawn

Pénelet

2017

International Journal of Spray and Combustion Dynamics

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Thermoacoustic phenomena generated inadvertently during combustion, and those produced by heating and cooling material to generate a temperature gradient, have mostly been studied independently. Indeed, researchers of one phenomenon are seldom familiar with the literature on the other. This paper seeks to remedy this by reviewing the two subjects alongside one another, by comparing and contrasting them where possible. There is a brief account of the historically important papers in the development of both subjects, followed by a description of the nature of the phenomena. A selective number of papers is called upon to illustrate these principles. Techniques for handling the pure acoustics in the two subjects are addressed, before an outline is given of the modelling of the two thermoacoustic systems. Non-linear phenomena in the two systems are then explored. Finally, methods of 'control', of changing the system characteristics, are briefly discussed.

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“…Although much has been done in terms of the development of these engines and the basic understanding of their operation, efforts are still needed to promote their applications. Among the key points that still require further research are the precise characterization of sound propagation and distribution of the acoustic field by properly quantifying acoustic power distribution [ 11 ] and non-linear effects such as acoustic streaming [ 12 ] or the generation of higher harmonics [ 13 ].…”

Section: Introductionmentioning

confidence: 99%

Development and Characterization of a Low-Cost Sensors System for an Acoustic Test Bench

Moreno-Ramírez

Iniesta

González

2020

Sensors

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Existing acoustic test benches are usually costly devices based on proprietary designs, sensors, and acquisition devices. In this paper, a low-cost test bench for acoustic purposes is introduced. The design of the test bench takes into account not only the low-cost mechanical design, but also uses low-cost sensors and control boards. This test bench has been designed for a range of signals compatible with those used by thermoacoustic engines, but it can be useful for applications with similar requirements. Taking advantage of an auxiliary pressure reference, low-cost unidirectional differential pressure sensors can be used to significantly increase the accuracy of the sampling system. The acoustic and mechanical design and development are presented along with the sampling system and the sensors arrangement implemented. Both the sensor and sampling system are evaluated by comparison with a high-fidelity sound acquisition system. An unexpected effect on the time error values distribution of the low-cost acquisition system is found and described. Finally, the errors introduced by the system and the sensors in terms of time and pressure sampling are characterized. As a result, the low-cost system’s accuracy has been satisfactory assessed and validated for the conditions expected in thermoacoustic experiments in terms of frequency and dynamic pressure.

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Weakly Nonlinear Propagation in Thermoacoustic Engines: A Numerical Study of Higher Harmonics Generation up to the Appearance of Shock Waves

Cited by 20 publications

References 39 publications

Inertial effects on acoustic Rayleigh streaming flow: Transient and established regimes

Inertial effects on acoustic Rayleigh streaming flow: Transient and established regimes

Common features in the thermoacoustics of flames and engines

Development and Characterization of a Low-Cost Sensors System for an Acoustic Test Bench

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