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A seminar on

Thermo Acoustic Engine

Guided by : Submitted by: Mrs. Namita Soni (Lecturer) Karan Sirwani 12ESKME049

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ContentsWhat do you mean by Thermoacoustic??History of ThermoacousticThermoacoustic EngineThermodynamic cycleTypes of TAEComponents of TAEPerformance of TAEAdvantages and limitationsConclusion

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What do you mean by Thermoacoustic??

The word “thermoacoustic” is a combination of two words thermo (heat) and acoustic (sound).

Thermoacoustic is the interaction between temperature, density and pressure variations of acoustic waves.

The interaction of these effects in gas close to a solid surface generates thermoacoustic oscillations

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History of Thermoacoustic Discovered by Byron Higgins [1777] - demonstrated a

spontaneous generation of sound waves in a pipe.

Lord Rayleigh gave a qualitative explanation of the Sondhauss thermoacoustic oscillations phenomena.

In the 1970s’ David Ceperley postulated an acoustic wave travelling in a resonator could cause the gas to undergo a thermodynamic cycle similar to that in a Stirling engine

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Thermoacoustic Engine

Thermoacoustic engines (sometimes called "TA engines") are thermoacoustic devices which use high-amplitude sound waves to pump heat from one place to another, or conversely use a heat difference to induce high-amplitude sound waves.

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Thermodynamic cycle

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Types of TAE

Standing wave systems: A standing-wave thermoacoustic engine typically has a thermoacoustic element called the "stack“

Travelling wave systems: A standing-wave thermoacoustic engine typically has a thermoacoustic element called the “regenerator”.

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Fig a: Standing wave thermoacoustic engine

Fig b:

Travelling wave thermoacoustic engine

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Components of TAE

Heat exchanger

Resonator

Stack (on standing wave devices)

Regenerator (on travelling wave devices)

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Thermoacoustic engine

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Performance of TAE Performance of thermoacoustic engines usually is

characterized through several indicators:

Onset temperature difference

Frequency of the resultant pressure wave

Degree of harmonic distortion

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AdvantagesNo moving parts for the thermodynamic cycle, so

very reliable and a long life span.

Use of simple materials with no special requirements, which are commercially available in large quantities and therefore relatively cheap.

Environmentally friendly.

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Limitations The device usually has low power to volume ratio.

Very high densities of operating fluids are required to obtain high power densities.

The commercially-available linear alternators used to convert acoustic energy into electricity currently have low efficiencies compared to rotary electric generators.

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Conclusion Simplicity, lack of lubrication and sliding seals, and

their use of environmentally harmless working fluids were adequate compensation for their lower efficiencies.

In future might soon take over other costly, less durable and polluting engines and pumps.

The latest achievements of the former are certainly encouraging, but there are still much left to be done

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References Ceperley P.H. Gain and efficiency of a short traveling

wave heat engine. J. Acoust. Soc. Am.,1985,77:1239—1244.

Emmanuel C. Nsofor,Azrai Ali, “Experimental study on the performance of the thermoacoustic system.” Applied Thermal Engineering 29, 2009, 2672-2679.

https://en.wikipedia.org/wiki/Thermoacoustic_heat_engine

http://www.sciencedirect.com/science/article/pii/S0026269203002908

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