Geometric optimization of a thermoacoustic regenerator

Zink, Florian; Waterer, Hamish; Archer, Rosalind; Schaefer, Laura

doi:10.1016/j.ijthermalsci.2009.05.007

Cited by 35 publications

(16 citation statements)

References 15 publications

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“…A finite element numerical method was used by Zink et al [11] in finding an optimal geometric design of a simple thermoacoustic stack with regard to the thermal losses. Their model considered four weighted objectives which are power output, heat input, viscous losses in the individual channel, and heat loss through the device boundaries and cooling medium.…”

Section: Introductionmentioning

confidence: 99%

“…By using MOGA, the appropriate position of the stack between the pressure and velocity node to get the highest performance of the stack isDownloaded by [University of Lethbridge] at 22:37 25 June 2016obtained to produce the highest COP, but at the same provide the optimum cooling load. The Pareto front built by the normalized cooling power, Q cn , as f 1 in Eq (11). and the normalized acoustic work, W n , as f 2 in Eq (12).…”

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confidence: 99%

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Optimization of the Stack Unit in a Thermoacoustic Refrigerator

Zolpakar

Mohd‐Ghazali

Ahmad

2016

Heat Transfer Engineering

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A thermoacoustic refrigerator is a device which uses acoustic power to pump heat in the absence of harmful refrigerants with no or few moving parts. However, the performance of the thermoacoustic refrigerator, particularly the standing wave types, is currently not competitive compared to its counterpart conventional vapor-compression refrigerator. Presently, thermoacoustic refrigeration prototypes only achieved 0.1-0.2 relative coefficient of performance compared with that of 0.33-0.5 for the conventional vapor-compression refrigerators. Past optimization efforts had been completed based on parametric studies where individual parameters are discretely varied and the final optimized outcome was based on the Downloaded by [University of Lethbridge] at 22:37 25 June 2016 ACCEPTED MANUSCRIPT 2 limited series of numerical/experimental tests. This paper discussed the initial investigation of the optimization of the thermoacoustic refrigerator stack parameters using multi-objective genetic algorithm. The desired output, the maximization of the cooling load and the minimization of the acoustic power at the stack, are obtained with the parameters to be optimized set within some range of values. The stack length and centre position are then optimized simultaneously. The optimized results showed that, the coefficient of performance of the thermoacoustic refrigerator improves from the published value of 1.3 to 1.37.

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Section: Introductionmentioning

confidence: 99%

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confidence: 99%

Optimization of the Stack Unit in a Thermoacoustic Refrigerator

Zolpakar

Mohd‐Ghazali

Ahmad

2016

Heat Transfer Engineering

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“…Finally, we note that although this paper is primarily concerned with Stirling engine regenerators, much of our model reduction work is likely applicable to the regenerators (stacks) of thermoacoustic engines and heat pumps [33][34][35][36]. The underlying physical mechanisms are quite similar, though the operating regimes in parameter space might be different.…”

Section: Discussionmentioning

confidence: 99%

Control-Oriented Modeling of the Dynamics of Stirling Engine Regenerators

Craun

Bamieh

2017

Journal of Dynamic Systems, Measurement, and Control

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We develop a first-principles model of the regenerator component of a generic Stirling engine. The model is based on the Euler equations of one-dimensional gas dynamics coupled with its convective/conductive heat transfer with the embedded mesh material. We investigate various methods for deriving simpler and low-order control-oriented models from this first principles model, the basic criterion being high fidelity representation of the dynamics of the regenerator when coupled to other dynamic components of the engine. We identify several nondimensional parameters that potentially categorize different modes of operation, and investigate the corresponding time-scale separation. A hierarchy of singularly perturbed models is derived in which acoustic dynamics are eliminated, periodic mesh dynamics are averaged, and the shape of the distributed regenerator gas state is approximated. In addition, since the reduced model is to be operated cyclically when connected to other parts of the engine, we develop such a feedback-aware model reduction algorithm based on a proper orthogonal decomposition (POD) with a chirped signal input (chirp-POD). This algorithm yields reduced models that are accurate over a range of engine operating frequencies.

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“…To such a situation, suppressing mean-flow buckling but keeping thermoacoustic instability is a remedy. The control of mean-flow buckling was usually through passive approaches, such as re-shaping the chambers [11][12][13][14], changing the working gas [15], re-designing the heat regeneration [16][17][18][19][20][21][22], etc., based on the analysis of computation fluid dynamics as in [11,23,24] for example. As indicated in the literature of combustion instabilities [25][26][27][28], suppression of mean-flow buckling is usually accompanied by reduction of acoustic motions.…”

Section: Open Accessmentioning

confidence: 99%

System Identification and Resonant Control of Thermoacoustic Engines for Robust Solar Power

Hong

Lin

2015

Energies

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It was found that thermoacoustic solar-power generators with resonant control are more powerful than passive ones. To continue the work, this paper focuses on the synthesis of robustly resonant controllers that guarantee single-mode resonance not only in steady states, but also in transient states when modelling uncertainties happen and working temperature temporally varies. Here the control synthesis is based on the loop shifting and the frequency-domain identification in advance thereof. Frequency-domain identification is performed to modify the mathematical modelling and to identify the most powerful mode, so that the DSP-based feedback controller can online pitch the engine to the most powerful resonant-frequency robustly and accurately. Moreover, this paper develops two control tools, the higher-order van-der-Pol oscillator and the principle of Dynamical Equilibrium, to assist in system identification and feedback synthesis, respectively.

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Geometric optimization of a thermoacoustic regenerator

Cited by 35 publications

References 15 publications

Optimization of the Stack Unit in a Thermoacoustic Refrigerator

Optimization of the Stack Unit in a Thermoacoustic Refrigerator

Control-Oriented Modeling of the Dynamics of Stirling Engine Regenerators

System Identification and Resonant Control of Thermoacoustic Engines for Robust Solar Power

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