USA As Represented by Secretary of the Navy

The Penn State Research Foundation

Other

U.S. Department of Energy

Steven L Garrett

Thomas J Hofler

Ray Scott Wakeland

Robert W M Smith

Michael R Brininstool

Jeffrey T Newmaster

Matthew E Poese

David A Brown

Dale Kent Kotter

James Arthur Smith

Robert M Keolian

Robert W Smith

Donald A Danielson

David L Gardner

Matthew L Poese

Charles B Cameron

A nuclear thermoacoustic device includes a housing defining an interior chamber and a portion of nuclear fuel disposed in the interior chamber. A stack is disposed in the interior chamber and has a hot end and a cold end. The stack is spaced from the portion of nuclear fuel with the hot end directed toward the portion of nuclear fuel. The stack and portion of nuclear fuel are positioned such that an acoustic standing wave is produced in the interior chamber. A frequency of the acoustic standing wave depends on a temperature in the interior chamber.

Thermoacoustic enhancements for nuclear fuel rods

Thermoacoustic enhancements for nuclear fuel rods and other high temperature applications

A thermocoustic device includes a housing with a thermal core supported in the housing and having a first and a second surface. The thermal core includes a first heat exchanger defining the first surface of the thermal core and a second heat exchanger defining the second surface of the thermal core. A main chamber is in fluid communication with the first surface of the thermal core and a secondary multiplier chamber is in fluid communication with the second surface of the thermal core. A working volume of a gaseous working fluid fills the main chamber, the multiplier chamber, and the thermal core at a pressure. An equilibrium pressure is defined as the pressure of the working volume of gaseous working fluids with the thermoacoustic device is in a non-operating mode. The main chamber includes a first oscillating member that is operable when the thermoacoustic device is in an operating mode to oscillate such that the pressure in both the main chamber and in the multiplier chamber is oscillated between a peak pressure greater than the equilibrium pressure and a minimum pressure less than the equilibrium pressure. A main pressure amplitude is defined as one-half of the difference between the peak pressure and the minimum pressure in the main chamber. The secondary multiplier chamber includes a second oscillating member that is operable when the thermoacoustic device is in the operating mode to oscillate such that the pressure in the multiplier chamber is oscillated between a peak pressure greater than the equilibrium pressure and a minimum pressure less than the equilibrium pressure. A multiplier pressure amplitude is defined as one-half of the difference between the peak pressure and the minimum pressure in the multiplier chamber. The first and second oscillating members oscillate at substantially the same frequency and such that the pressure oscillations in the main chamber and the multiplier chamber are substantially in phase with each other. The multiplier pressure amplitude is greater than the main pressure amplitude.

Thermoacoustic device

According to one embodiment of the present invention, a thermoacoustic device has a complaint enclosure which includes a rigid portion and a compliant portion. The compliant portion includes an oscillating member and a flexure seal with a pair of ends and a flexure body extending between the ends. One of the ends is sealed to the rigid portion and the other end is sealed to the oscillating member. The flexure seal has an average cross-sectional area and an end-to-end equilibrium length. A flexure volume is defined as the product of the average cross-sectional area and the end-to-end equilibrium length. A thermal core is disposed in the complaint enclosure and includes at least a first and a second heat exchanger. A working volume of gaseous working fluid fills the complaint enclosure. The working volume of gaseous working fluid has an equilibrium pressure. A motor is operable to oscillate the oscillating member such that the end-to-end length of the flexure seal is increased and decreased with respect to the equilibrium length. Therefore, the pressure of the working volume of gaseous working fluid is oscillated between a peak pressure greater than the equilibrium pressure and a minimum pressure less than the equilibrium pressure. In some embodiments, the working volume is less than or equal to four times the flexure volume, while in other embodiments, the working volume is less than or equal to two times or one times the flexure volume.

Compliant enclosure for thermoacoustic device

One embodiment of a spring with an integral dynamic gas seal according to the present invention includes a spring with a pair of spaced-apart ends and a spring body extending therebetween. The spring body includes a perimeter wall formed of a first material and extending in a longitudinal direction. The wall has a plurality of openings defined therein. The openings are provided in a plurality of transverse tiers. Each tier includes a plurality of separate openings each extending along a portion of the perimeter. The openings in each tier are spaced apart so as to define a post between each adjacent opening such that each tier includes a plurality of posts. The openings in each tier are staggered with respect to the openings in adjacent tiers such that each of the openings in each tier overlie one of the posts in an adjacent tier. A closure member closes each of the openings such that the spring body is sealed. The closure member is formed of a second material having a different degree of flexibility than the first material.

Cylindrical spring with integral dynamic gas seal

A thermoacoustic driver incorporates a linear electrodynamic motor having electrical terminals and a moving part, a driver suspension housing, a piston, and a stiffness-enhancing device for raising the mechanical resonance frequency of the electrodynamic motor without reducing the piston stroke. The stiffness enhancement is accomplished by the use of specially optimized suspension spring structures and/or by attaching one or more electrical inductors to the electrical terminals of the driver. The stiffness enhancement using mechanical springs incorporates one or more starfish structures extending between the driver suspension housing and the piston and rigidly clamped to both. The starfish structures comprise radially extending legs, which are leaf springs or beams of varying width. The shape of the beams and the shape of the overall spring structure are optimized to enhance flexural or torsional stiffness and relieve arc tension within the constraints of cost-effectiveness. In one version, two modified triangular (trapezoidal) cantilever beams are connected through a straight middle section and form a bow-tie shaped beam.

High-efficiency moving-magnet loudspeaker

This invention for the production of high amplitude acoustic standing wav which can be used for thermoacoustic heat transport purposes, describes the use of a rigid barrier in place of a piston, thereby allowing the suspension of the resonator to be external to the pressurized resonator and allowing an independent choice of motor mechanism, including the use of rotary motors instead of linear motors, while incidently providing a mechanism for circulating external heat transport fluids without requiring additional pumps or heat pipes.

Torsionally resonant toroidal thermoacoustic refrigerator

The resonance frequency of a gas-filled acoustic resonator (12) is stabilized against changes in frequency due to changes in the temperature of the gas and resonator (12) by placing a gas mixture and an adsorbent (16) within the resonator (12). If the temperature dependence of the adsorbency is different for the different species comprising the gas mixture, then it is shown that the proper amount of adsorbent (16) can maintain the acoustic resonant frequency of the gas mixture within resonator (12) very nearly equal to a constant frequency.

Passive frequency stabilization in an acoustic resonator

A high-power thermoacoustic refrigerator including a half-wave length resonator, first and second drivers located in housings at first and second ends of said resonator, two pusher cones, a plurality of heat exchangers, a first and second stack, utilizing a compressible gas mixture capable of being tuned to the driver resonance frequency, a half-wave length tube, fluids disposed within said heat exchangers for transferring heat, and voice coils wired 180 degrees out of phase for compressing said compressible fluid into a standing wave oscillating within said resonator.

High-power thermoacoustic refrigerator

An accelerometer or seismometer has an elastic disk bearing a mass distributed peripherally around the disk. The disk is supported for flexure and for isolation from mounting strain by a stob centrally through the disk. The accelerometer or seismometer has a pair of flat spirals of optical fiber, each spiral being fixedly attached to a corresponding disk side so that disk flexure lengthens a spiral on one disk side and shortens a spiral on an oppositely facing disk side and so that temperature differences between the spirals are minimized. The pair of spirals are connected as legs of a fiber optic interferometer so that the interferometer provides an output corresponding to the flexure. Several of the disks and asociated pairs of spirals may be coaxially mounted to provide increased sensitivity.

Fiber optic accelerometer with centrally supported flexural disk

An accelerometer or seismometer has a pair of flat spirals of optical fiber and has one or more elastic disks bearing a mass and supported for flexure. Each spiral is fixedly attached to a corresponding disk side so that disk flexure lengthens a spiral on one disk side and shortens a spiral on an oppositely facing disk side, the spirals being connected as legs of a fiber optic interferometer so that the interferometer provides an output corresponding to the flexure. A pair of the disks may be mounted oppositely of a sealed body with a pair of the spirals arranged to minimize the effect of pressure changes on the sensor, and a pair of the spirals may be mounted oppositely of a thermally conducting disk to minimize temperature differences between the spirals. The mass may be centrally mounted on a disk with the disk peripherally supported, or the mass may be distributed around the disk periphery with the disk centrally supported for isolation from mounting strain. Several of the disks may be coaxially mounted to provide increased sensitivity.

Fiber optic flexural disk accelerometer

A highly sensitive optical fiber interferometer sensor comprising a laser light source, a [2.times.2] optical fiber coupler to split the beam in two, a differential transducer which converts a signal of interest into optical phase shift in the laser light transmitted through the two optical fibers in the interferometer and a [3.times.3] optical fiber complex which recombines the two beams, producing interference which can be electronically detected. The use of the [3.times.3] coupler permits Passive Homodyne demodulation of the phase-modulated signals provided by the interferometer without feedback control or modulation of the laser itself and without requiring the use of electronics within the interferometer.

Demodulators for optical fiber interferometers with [3.times.3] outputs

A sensor for remotely detecting an angular position of a shaft rotatable within a frame includes: first means for generating collimated first, second, third, and polarized optical beams; second means positioned proximate to the first means for receiving and combining the first, second, third, and polarized optical beams into a composite optical beam having an intensity; and a code wheel fixedly mounted to the shaft and interposed between the first and second means. The code wheel includes first, second, and third channel mask patterns and a first polarizing filter positioned to transect the first, second, third, and polarized optical beams, respectively. Interaction between the code wheel and the light beams results in the composite light beam being encoded such that the angular position of the wheel is functionally related to the intensity of the composite opitical beam. The sensor further includes third means operably coupled to receive the composite optical beam for providing an output corresponding to the angular position of the code wheel.

Growing community of inventors

State College, PA, United States of America

Steven L Garrett