Onset and damping characteristics of a closed two-phase thermoacoustic engine

Tan, Jingqi; Wei, Jianjian; Jin, Tao

doi:10.1016/j.applthermaleng.2019.114086

Cited by 32 publications

(8 citation statements)

References 26 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Except for the regenerator, all other components in the modified two-phase thermofluidic oscillator follow the definitions of Markides and Smith [5]. The detailed formulation of the acoustic-electric analogy elements and their impedances can be referred in the works of Markides and Smith [5] and Tan et al [9,10].…”

Section: Acoustic-electric Analogy Modelmentioning

confidence: 99%

“…Our previous work [9,10] proposed a modified twophase thermofluidic oscillator, where a screen-stacked regenerator was introduced for reducing the irreversible loss induced by heat transfer. An onset temperature difference as low as 8.2°C was obtained when adopting R134a as working fluid, showing good applicability to low-grade thermal energy.…”

Section: Introductionmentioning

confidence: 99%

“…However, R134a, as a hydrofluorocarbon refrigerant, has a high global warming potential (GWP) of 1300, and thus contributes greatly to the global warming. The United States Environmental Protection Agency (USEPA) declared that hydrofluorocarbon refrigerants such as R134a and R143a would no longer be adopted from 2024 [10]. In order to alleviate the environmental pressure, there is an urgent need to use the alternatives with zero ozone depletion potential (ODP) and low GWP as working fluids in the twophase thermofluidic oscillator.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Performance of a Modified Two-Phase Thermofluidic Oscillator With Low GWP Working Fluids for Lowgrade Waste Heat Recovery

Jingqi¹,

Tan²,

Luo³

et al. 2020

Preprint

Self Cite

View full text Add to dashboard Cite

Two-phase thermofluidic oscillator has attracted considerable attention for low-grade heat recovery, thanks to its ability to operate across a small temperature difference between heat source and sink. The performance of a modified two-phase thermofluidic oscillator with the working fluids of low global warming potential (e.g., R152a, R1234yf and R1234ze(E)) for harvesting low-grade waste heat is investigated. An acoustic-electric analogy model is proposed for predicting the onset temperature difference and oscillation frequency, which is then verified by experiments. The model can well predict the oscillation frequency, with the differences of 4.4-6.8% from experimental data. The predicted and measured onset temperature differences are also in reasonable agreement, for the model underestimates by 5.4-13.4% compared with the experimental results. The influences of the lengths and diameters of feedback connection tube and vapor connection tube on the performance are also numerically studied. A lowest onset temperature difference of 14.4℃ can be obtained with the vapor connection tube diameter of 0.015 m and the working fluid of R1234yf. In addition, a highest oscillation frequency achieved is 3.04 Hz with R152a as working fluid, when the feedback connection tube diameter is increased to 0.019 m. This work verifies the feasibility of recovering low-grade waste heat to drive a two-phase thermofluidic oscillator with the low global warming potential working fluids.

show abstract

Section: Acoustic-electric Analogy Modelmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Performance of a Modified Two-Phase Thermofluidic Oscillator With Low GWP Working Fluids for Lowgrade Waste Heat Recovery

Jingqi¹,

Tan²,

Luo³

et al. 2020

Preprint

Self Cite

View full text Add to dashboard Cite

show abstract

“…Most of those regenerator optimizations [7][8][9][10][11][12] analyzed parameters of the working field, working gas and the hydraulic radius, whereas the quantitative investigation of important pa-rameters, for example, the length of the regenerator, on the behavior of thermoacoustic devices was still lacking. In the previous design, [13][14][15][16][17][18][19][20][21][22][23][24][25] the selection of the regenerator length was dependent on the experience, which caused the design with some blindness and results without prescient considerations, as well as the limited performance rather than the optimal.…”

Section: Introductionmentioning

confidence: 99%

Synthetical optimization of the structure dimension for the thermoacoustic regenerator

Kang¹,

Zhang²,

Shen³

et al. 2022

Chinese Phys. B

View full text Add to dashboard Cite

The quantitative investigation of parameters in the renegerator is essential for the optimization of thermoacoustic devices, while the majority of the previous research only considered parameters of the working field, working gas and the hydraulic radius. Based on the linear thermoacoustic theory, this paper extracts a normalized parameter for low-amplitude conditions, which is called the regenerator operation factor. By extracting the regenerator operation factor and relative hydraulic radius, the influence of frequency on the efficiency can be controlled and offset. It can be found that thermoacoustic devices with different frequencies can perform the same efficiency by adjusting the radius in proportion to the axial length. Finally, this paper synthetically optimizes the dimension of the thermoacoustic regenerator by taking the regenerator operation factor, relative hydraulic radius and acoustic field parameter as variables. Conclusions in this paper are of great significance for explaining the best working conditions of engines and directing the miniaturization and optimal design of thermoacoustic devices.

show abstract

“…Another group of complex behaviour is related to nonlinear dynamics. Examples of such phenomena include hysteresis [19][20][21], chaotic oscillations [22], mode transition [23], phase-locking and amplitude death (or quenching) due to synchronization [24][25][26], etc The last type of complex observations in thermoacoustic engines is called periodic switching/surging [27][28][29], a phenomenon that involves the energy transition between the heat storage in the stack/regenerator and acoustic energy of the oscillating fluid. The 'double-threshold effect [30]' and 'fishbone-like instability [31]' are also believed to share the same underlying energy conversion mechanism.…”

Section: Introductionmentioning

confidence: 99%

Underlying physics of limit-cycle, beating and quasi-periodic oscillations in thermoacoustic devices

Chen

Tang

2020

J. Phys. D: Appl. Phys.

View full text Add to dashboard Cite

Under certain circumstances, spontaneous acoustic oscillations inside thermoacoustic systems exhibit beating and quasi-periodic patterns, in contrast to constant-amplitude limit-cycle oscillations regularly studied in the literature. This paper explores the underlying mechanisms of limit cycles, beating and quasi-periodicity in thermoacoustic devices from acoustic/vibrational and thermodynamic/hydrodynamic perspectives. Firstly, the acousto-mechanical coupling between the thermoacoustic engine (TAE) and external load is investigated using a lumped element model (LEM), which is verified against a distributed parameter model (DPM). The effect of external load on the natural frequencies and mode shapes of intrinsic oscillation modes is investigated. Secondly, the thermoacoustic coupling between the temperature and acoustic fields is analysed using a reduced-order network model based on the linear thermoacoustic theory. The effect of thermoacoustic core on stability of oscillation modes is studied. Finally, the steady-state behaviour of the device is examined by considering the unsteady linear decay/growth and nonlinear saturation processes. This study demonstrates that the linear mode selection decides whether the steady state is static (quiescent) or dynamic. Apart from linear mode selection, the dynamic steady-state responses are also affected by nonlinear mode competition during the saturation process. Simultaneous excitement of oscillation modes at different external loads may lead to distinctively different steady-state waveforms including beating and quasi-periodicity. Discussions on the steady-state energy transition/conversion indicate that, to improve the performance of the thermoacoustic device, excitation of the oscillation mode whose frequency is close to that of the external load is encouraged. It is suggested that ultra-compliant transducers be employed for better acoustic power extraction.

show abstract

Onset and damping characteristics of a closed two-phase thermoacoustic engine

Cited by 32 publications

References 26 publications

Performance of a Modified Two-Phase Thermofluidic Oscillator With Low GWP Working Fluids for Lowgrade Waste Heat Recovery

Performance of a Modified Two-Phase Thermofluidic Oscillator With Low GWP Working Fluids for Lowgrade Waste Heat Recovery

Synthetical optimization of the structure dimension for the thermoacoustic regenerator

Underlying physics of limit-cycle, beating and quasi-periodic oscillations in thermoacoustic devices

Contact Info

Product

Resources

About