Study of a small-scale standing-wave thermoacoustic engine

2009 ◽  
Vol 224 (1) ◽  
pp. 133-141 ◽  
Author(s):  
S Jung ◽  
K I Matveev
Keyword(s):  
Standing Wave ◽  
Acoustic Pressure ◽  
Acoustic Power ◽  
Vitreous Carbon ◽  
Working Fluid ◽  
Small Scale ◽  
Balance Theory ◽  
Reticulated Vitreous Carbon ◽  
Thermoacoustic Engine ◽  
Atmospheric Air

This article reports experimental and modelling results obtained with a small-scale standing-wave thermoacoustic engine. Reticulated vitreous carbon is used as the stack material and atmospheric air as the working fluid. The engine is tested with resonators of variable lengths in the range 57–124 mm. The engine starts generating sound at temperature differences of 200–300 °C between the hot and cold parts of the system. The acoustic pressure amplitudes up to 2 kPa are measured inside the resonator in the excited regimes. A simplified energy-balance theory adequately predicts a trend in the temperature difference for the sound onset, while underestimating actual values. Model estimations show that the stack-generated acoustic power reaches 100 mW at the stack-based efficiencies of several per cent.

Modeling of Thermoacoustic Resonators With Nonuniform Medium and Boundary Conditions

2011 ◽  
Vol 133 (3) ◽  
Author(s):  
Konstantin I. Matveev ◽  
Sungmin Jung
Keyword(s):  
Boundary Conditions ◽  
Acoustic Power ◽  
Solid Surfaces ◽  
Small Scale ◽  
Nonuniform Medium ◽  
Thermoacoustic Engine ◽  
Efficient Calculation ◽  
Thermoacoustic Engines ◽  
The Subject ◽  
Low Amplitude

The subject of this paper is modeling of low-amplitude acoustic fields in enclosures with nonuniform medium and boundary conditions. An efficient calculation method is developed for this class of problems. Boundary conditions, accounting for the boundary-layer losses and movable walls, are applied near solid surfaces. The lossless acoustic wave equation for a nonuniform medium is solved in the bulk of the resonator by a finite-difference method. One application of this model is for designing small thermoacoustic engines. Thermoacoustic processes in the regular-geometry porous medium inserted in resonators can be modeled analytically. A calculation example is presented for a small-scale thermoacoustic engine coupled with an oscillator on a flexing wall of the resonator. The oscillator can be used for extracting mechanical power from the engine. A nonuniform wall deflection may result in a complicated acoustic field in the resonator. This leads to across-the-stack variations of the generated acoustic power and local efficiency of thermoacoustic energy conversion.

scholarly journals The Influence of Stack Position and Acoustic Frequency on the Performance of Thermoacoustic Refrigerator with the Standing Wave

2017 ◽  
Vol 38 (4) ◽  
pp. 89-107 ◽  
Author(s):  
Jakub Kajurek ◽  
Artur Rusowicz ◽  
Andrzej Grzebielec
Keyword(s):  
Standing Wave ◽  
Temperature Difference ◽  
Heat Exchangers ◽  
Acoustic Power ◽  
Working Fluid ◽  
Parallel Plates ◽  
Acoustic Frequency ◽  
Plate Spacing ◽  
Resonance Frequencies ◽  
Thermoacoustic Refrigerator

Abstract Thermoacoustic refrigerator uses acoustic power to transport heat from a low-temperature source to a high-temperature source. The increasing interest in thermoacoustic technology is caused due to its simplicity, reliability as well as application of environmentally friendly working fluids. A typical thermoacoustic refrigerator consists of a resonator, a stack of parallel plates, two heat exchangers and a source of acoustic wave. The article presents the influence of the stack position in the resonance tube and the acoustic frequency on the performance of thermoacoustic refrigerator with a standing wave driven by a loudspeaker, which is measured in terms of the temperature difference between the stack edges. The results from experiments, conducted for the stack with the plate spacing 0.3 mm and the length 50 mm, acoustic frequencies varying between 100 and 400 Hz and air as a working fluid are consistent with the theory presented in this paper. The experiments confirmed that the temperature difference for the stack with determined plate spacing depends on the acoustic frequency and the stack position. The maximum values were achieved for resonance frequencies and the stack position between the pressure and velocity node.

Development of Combustion-Driven Thermoacoustic Engine

2008 ◽  
Author(s):  
Najmeddin Shafrei Tehrany ◽  
Chien Shung Lin ◽  
Cory Bloomquist ◽  
Jeongmin Ahn ◽  
Konstantin Matveev
Keyword(s):  
Heat Transfer ◽  
Acoustic Power ◽  
High Energy ◽  
High Energy Density ◽  
Small Scale ◽  
Developmental Study ◽  
Prime Mover ◽  
Power Devices ◽  
Thermoacoustic Engine ◽  
Thermoacoustic Engines

Miniature thermoacoustic engines driven by combustion and producing electricity are promising candidates for small-scale power devices. The elemental development of the system including a small thermoacoustic engine and a Swiss roll combustor is discussed in this work. A standing-wave thermoacoustic prime mover consists of a resonator with a stack of porous material inside where a temperature gradient is maintained. This engine generates acoustic power from heat. The sound energy can be converted in electricity by an electroacoustic transformer. The Swiss roll combustor utilizes the high energy density of hydrocarbon fuels in order to provide the necessary heat transfer required to generate acoustic power from the engine. Some results of this developmental study are presented.

Design and Experimental Study of a Cascade Thermoacoustic Engine for Remote and Rural Communities

2017 ◽  
Vol 139 (3) ◽  
Author(s):  
Isares Dhuchakallaya ◽  
Patcharin Saechan
Keyword(s):  
Rural Communities ◽  
Rural Areas ◽  
Traveling Wave ◽  
Low Frequency ◽  
Acoustic Power ◽  
Point Of View ◽  
Working Fluid ◽  
Thermoacoustic Engine ◽  
The People ◽  
In Series

The design, construction, and experimental evaluation of a cascade thermoacoustic engine are presented in this paper. The system was designed and built under the constraint of an inexpensive device to meet the energy needs of the people based in remote and rural areas. From the cost and straightforward system point of view, the air at atmospheric pressure was applied as a working fluid, and the main resonator tubes were then constructed of conventional polyvinyl chloride (PVC) pipes. Such device consists of one standing-wave unit and one traveling-wave unit connected in series. This topology is preferred because the traveling-wave unit provides an efficient energy conversion, and a straight-line series configuration is easy to build and allows no Gedeon streaming. The system was designed to operate at a low frequency of about 57 Hz. The measured results were in a reasonably good agreement with the predicted results. So far, this system can deliver up to 61 W of acoustic power, which was about 17% of the Carnot efficiency. In the further step, the proposed device will be applied as the prime mover for driving the thermoacoustic refrigerator.

On the Coupling Between Standing-Wave Thermoacoustic Engine and Piezoelectric Transducer

2007 ◽  
Author(s):  
Konstantin I. Matveev ◽  
Andy Wekin ◽  
Cecilia D. Richards ◽  
Najmeddin Shafrei-Tehrany
Keyword(s):  
Mathematical Model ◽  
Energy Conversion ◽  
Standing Wave ◽  
Electric Energy ◽  
Small Scale ◽  
Thermoacoustic Engine ◽  
Power Sources ◽  
Thermoacoustic Engines ◽  
Piezoelectric Elements ◽  
Simplified Mathematical Model

Small thermoacoustic engines integrated with piezoelectric elements can be effective small-scale power sources to convert heat to electricity. A simplified mathematical model is developed to illustrate the effect of transducer parameters on the frequency and onset temperature difference in a standing-wave engine and to estimate efficiencies of energy conversion. Results of sample calculations show that efficiencies for the acoustic-electric energy conversion on the order of 10% are feasible.

Performance of Thermoacoustic-Standing Wave as a Power Generator

2013 ◽  
Vol 388 ◽  
pp. 40-46
Author(s):  
Adi Surjosatyo ◽  
Irawan Sentosa
Keyword(s):  
Standing Wave ◽  
Thermal Power ◽  
Acoustic Power ◽  
Stirling Engine ◽  
Effect Of Temperature ◽  
Thermoacoustic Engine ◽  
Optimal Position ◽  
Power Generator ◽  
Stirling Cycle ◽  
Research Show

This study is relating to analyze performance of thermoacoustic-standing wave. Stirling cycle thermoacoustic engine is developed conventional stirling engine. This system is more efficient than ordinary stirling engine because does not use a moving piston[7]. The engine uses thermal power to generate acoustic power. It consists mainly of three parts: a thermodynamic part consisting of a stack, two heat exchangers, and a thermal buffer tube; an acoustic network consisting of an acoustic compliance and an inertance; and a resonator. When thermodynamic part heated, it will generate sounds. The sounds will flow along cylinder tube. Some aspects can be analiyzed to determine performance of tharmoacoustic-standing wave. The effect of temperature difference, stack geometry, stack position determine performance of the thermoacoustic-standing wave. Some research show that acoustic power will increase with increasing of temperature at hot heat exchanger. And optimal position and geometry of stack will generated optimal acoustic power.

scholarly journals Recent advances on modified reticulated vitreous carbon for water and wastewater treatment – A mini-review

Chemosphere ◽  
2021 ◽  
pp. 131573
Author(s):  
Vanessa M. Vasconcelos ◽  
Géssica O.S. Santos ◽  
Katlin I.B. Eguiluz ◽  
Giancarlo R. Salazar-Banda ◽  
Iara de Fatima Gimenez
Keyword(s):  
Wastewater Treatment ◽  
Vitreous Carbon ◽  
Reticulated Vitreous Carbon ◽  
Water And Wastewater Treatment ◽  
Recent Advances ◽  
Water And Wastewater

scholarly journals Numerical Modeling and Performance Evaluation of Standing Wave Thermoacoustic Refrigerators with a Multi-Layered Stack

Energies ◽  
2020 ◽  
Vol 13 (17) ◽  
pp. 4360
Author(s):  
Umar Nawaz Bhatti ◽  
Salem Bashmal ◽  
Sikandar Khan ◽  
Rached Ben-Mansour
Keyword(s):  
Standing Wave ◽  
Numerical Study ◽  
Temperature Drop ◽  
Acoustic Power ◽  
Heat Energy ◽  
Coefficient Of Performance ◽  
Material Layer ◽  
And Performance ◽  
Stacked Material ◽  
Thermoacoustic Refrigerators

Thermoacoustic refrigerators have huge potential to replace conventional refrigeration systems as an alternative clean refrigeration technology. These devices utilize conversion of acoustic power and heat energy to generate the desired cooling. The stack plays a pivotal role in the performance of Standing Wave Thermoacoustic Refrigerators (SWTARs), as the heat transfer takes place across it. Performance of stacks can be significantly improved by making an arrangement of different materials inside the stack, resulting in anisotropic thermal properties along the length. In the present numerical study, the effect of multi-layered stack on the refrigeration performance of a SWTAR has been evaluated in terms of temperature drop across the stack, acoustic power consumed and device Coefficient of Performance (COP). Two different aspects of multi-layered stack, namely, different material combinations and different lengths of stacked layers, have been investigated. The combinations of four stack materials and length ratios have been investigated. The numerical results showed that multi-layered stacks produce lower refrigeration temperatures, consume less energy and have higher COP value than their homogeneous counterparts. Among all the material combinations of multi-layered stack investigated, stacks composed of a material layer with low thermal conductivity at the ends, i.e., RVC, produced the best performance with an increase of 26.14% in temperature drop value, reduction in the acoustic power consumption by 4.55% and COP enhancement of 5.12%. The results also showed that, for a constant overall length, an increase in length of side stacked material layer results in an increase in values of both temperature drop and COP.

Simulation of a standing-wave thermoacoustic engine using compressible SIMPLE algorithm

2010 ◽  
Author(s):  
Dongwei Zhang ◽  
Yaling He ◽  
Yong Wang ◽  
Jing Huang ◽  
Liejin Guo ◽  
...  
Keyword(s):  
Standing Wave ◽  
Simple Algorithm ◽  
Thermoacoustic Engine

scholarly journals Automated Insertion of Objects Into an Acoustic Robotic Gripper

Proceedings ◽  
2020 ◽  
Vol 64 (1) ◽  
pp. 40
Author(s):  
Marc Röthlisberger ◽  
Marcel Schuck ◽  
Laurenz Kulmer ◽  
Johann W. Kolar
Keyword(s):  
Acoustic Field ◽  
Acoustic Waves ◽  
Acoustic Pressure ◽  
Pressure Field ◽  
Acoustic Power ◽  
Industrial Applications ◽  
High Density ◽  
Analytical Models ◽  
Acoustic Levitation ◽  
Mechanical Contact

Acoustic levitation forces can be used to manipulate small objects and liquid without mechanical contact or contamination. To use acoustic levitation for contactless robotic grippers, automated insertion of objects into the acoustic pressure field is necessary. This work presents analytical models based on which concepts for the controlled insertion of objects are developed. Two prototypes of acoustic grippers are implemented and used to experimentally verify the lifting of objects into the acoustic field. Using standing acoustic waves and by dynamically adjusting the acoustic power, the lifting of high-density objects (>7 g/cm3) from acoustically transparent surfaces is demonstrated. Moreover, a combination of different acoustic traps is used to lift lower-density objects from acoustically reflective surfaces. The provided results open up new possibilities for the implementation of acoustic levitation in robotic grippers, which have the potential to be used in a variety of industrial applications.

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