THERMOACOUSTICS

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THERMOACOUSTICS
Optimisation of the Feedback Loop of the
Thermoacoustic Travelling wave Engine
David Wee Shuon Tzern Yousif Abdalla Abakr David
Hann Paul Riley
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The Simplest form of a Travelling Wave
Thermoacoustic Engine
Regenerator
Linear Alternator
Tuning Stub
Feed Back Loop
Limiting amplitude occurs when the amplification
of the regenerator is equivalent to the power
absorbed by the system
Total Power Absorbed Power absorbed by Linear
Alternator System Losses
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SCORE -StoveTM Thermoacoustic Engine
REQUIREMENT
Efficiency
Compact
INFLUENCING PARAMETER
Elbow Bends
An understanding of the Acoustic Transmission
through bends is required in order to optimise
the system
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MICROPHONE Decomposition Method
Decomposition Transfer Function
Scattering Matrix Technique
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MICROPHONE Experimental Setup
Optimum Travelling wave Load
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MICROPHONE Experimental Setup
Investigated Bends
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Reynolds Number vs. Transmission Loss
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Dean Number vs. Transmission Power Loss
Linear Loss Region
Non-Linear Loss Region
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PIV Experimental Setup
PIVParticle Image Velocimetry
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PIV Experimental Setup
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PIV Experimental Setup
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Dean Number vs. Transmission Power Loss
Linear Loss Region
Non-Linear Loss Region
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Dean Number vs. Transmission Power Loss
Linear Loss Region
Non-Linear Loss Region
At Higher operating Amplitude such as that of the
Engine, Losses may go up to 10 or more
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CONCLUSIONS

• A monotonic relationship has been found between
  the Percentage Acoustic Transmission Loss and the
  Acoustic Dean Number. A critical Dean Number (1)
  above which the transmission losses increase
  significantly has been identified.
• Particle Image Velocimetry is being used to
  investigate the transition to nonlinearity by
  consideration of the flow field.
• Once verified this would prove an important
  breakthrough in the design of future feedback
  resonator loop for thermoacoustic systems by
  providing new information about
• the additional losses at the elbow bends.

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THANK YOU