Thermoacoustic device
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Solution Overview
Problem
Existing thermoacoustic devices face challenges in achieving high power density and efficiency while maintaining compact size and minimizing gas volume and convective heat losses, often requiring complex components like jet pumps or membranes.
Innovation Solution
Incorporating a spring-type partitioning element in the acoustic circuit near the thermoacoustic core to enforce larger volume flows through the regenerator without adding gas volume, improving phasing between pressure and velocity, and suppressing DC flow, thereby enhancing efficiency and power density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the compliance of the gas volume is increased to achieve higher volume velocities through the regenerator unit, then power density is improved, but acoustic losses increase proportionally to the square of the velocity
Solution Approach 1:
The patent introduces a movable partition element that can dynamically adjust its position within the acoustic circuit, allowing the system to optimize volume velocities and power density while controlling acoustic losses through active or passive mechanical adjustment rather than fixed compliance volumes
Solution Approach 2:
The partition element changes the effective compliance parameter of the system by its position, enabling dynamic optimization of the balance between power density (requiring high volume velocities) and acoustic losses (increasing with velocity squared)
2Power
If a large gas volume is used to achieve high volume velocities through the regenerator unit, then power density is improved, but device size and cost increase prohibitively
Solution Approach 1:
The movable partition enables dynamic control of the gas volume distribution in the acoustic circuit, allowing high volume velocities to be achieved in a compact configuration by adjusting the partition position rather than requiring a permanently large gas volume
Solution Approach 2:
The partition element introduces a new spatial dimension for control within the acoustic circuit, allowing volume velocity optimization without proportionally increasing the overall device volume through strategic placement and movement of the partition
3Loss of energy
If jet pumps or membranes are used to control gas flow and achieve desired performance, then efficiency is improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The movable partition element utilizes the acoustic pressure waves themselves to drive its movement and control gas flow, eliminating the need for external jet pumps or membranes. The system self-regulates flow based on acoustic pressure differentials, maintaining efficiency while reducing mechanical complexity
Solution Approach 2:
The patent replaces complex mechanical flow control systems (jet pumps, membranes) with a simpler movable partition that responds to acoustic pressures, substituting active mechanical control with a passive or lightly-actuated mechanical element
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The spring-type partitioning element increases power density and efficiency while reducing convective heat losses, allowing for a more compact and cost-effective thermoacoustic device design.
Implementation Method 1
a spring-type partitioning element within the loop; the spring-type partitioning element being configured to close off the cross-section of the tube and to be impermeable for the working fluid while allowing transmission of pressure waves in the working fluid through the spring-type partitioning element
Implementation Method 2
Within the thermoacoustic device a conversion process between acoustic power and thermal power, and vice versa, takes place in the regenerator
Data Source
AI summary
A thermoacoustic device includes a process volume which is filled with a working fluid through which the acoustic wave propagates. The thermoacoustic device further includes an acoustic network comprising a tubular loop configured with a passage providing an opening in the loop and configured as acoustic circuit provided with a compliance volume, a thermo-acoustic core and an inertance volume. Within the loop, the thermoacoustic core is at a first side thereof adjacent to the passage at a first path length through the loop, and at its second side, opposite to the first side, the thermoacoustic core is at a second path length from the passage.The thermoacoustic device includes within the loop a spring-type partitioning element that is configured to close off the cross-section of the tube and to be impermeable for the working fluid while allowing transmission of pressure waves in the working fluid through the spring-type partitioning element.