A thermoacoustic device includes a loop tube in which a working gas is sealed; a stack in which a temperature gradient is generated in a tube axis direction of the loop tube, the stack being provided in the loop tube; and a diaphragm structure including a diaphragm provided in the loop tube and an operating unit, the diaphragm having a surface extending in a direction intersecting the tube axis direction and being configured to vibrate with a component of vibration in the tube axis direction, and the operation unit being configured to apply a physical quantity that is required, to the diaphragm to change a rigidity of the diaphragm in the tube axis direction.

An actuator, comprising an actuation member positionable into a first retracted position and a second extended position, and a retaining member structured to maintain the actuation member in the first retracted position, and to selectively release the actuation member from the first retracted position in response to an extension force.

A thermoacoustic refrigerator includes at least one pair of pulse combustion tubes (10), preferably Rijke tubes, each tube (10) having a pair of spaced-apart Stirling engines (12), coupled together but with no separating membrane therebetween.

A thermoacoustic refrigerator includes at least one pair of pulse combustion tubes (10), preferably Rijke tubes, each tube (10) having a pair of spaced-apart Stirling engines (12), coupled together but with no separating membrane therebetween.

Methods, systems, and devices are provided that may include Stirling cycle configurations and/or linear-to-rotary mechanisms in accordance with various embodiments. Some embodiments include a Stirling cycle device that may include a first hot piston contained within a first hot cylinder and a first cold piston contained within a first cold cylinder. A first single actuator may be configured to couple the first hot piston with the first cold piston such that the first hot piston and the first cold piston are on different thermodynamic circuits. The different thermodynamic circuits may include adjacent thermodynamic circuits. The Stirling cycle configuration may be configured as a single-acting alpha Stirling cycle configuration. Some embodiments include a linear-to-rotary mechanism device. The device may include multiple linkages. The device may include a cam plate coupled with the multiple linkages utilizing a cam and multiple cam followers. The linkages may include Watt linkages.

Methods, systems, and devices are provided that may include Stirling cycle configurations and/or linear-to-rotary mechanisms in accordance with various embodiments. Some embodiments include a Stirling cycle device that may include a first hot piston contained within a first hot cylinder and a first cold piston contained within a first cold cylinder. A first single actuator may be configured to couple the first hot piston with the first cold piston such that the first hot piston and the first cold piston are on different thermodynamic circuits. The different thermodynamic circuits may include adjacent thermodynamic circuits. The Stirling cycle configuration may be configured as a single-acting alpha Stirling cycle configuration. Some embodiments include a linear-to-rotary mechanism device. The device may include multiple linkages. The device may include a cam plate coupled with the multiple linkages utilizing a cam and multiple cam followers. The linkages may include Watt linkages.

Methods, systems, and devices are provided that may include Stirling cycle configurations and/or linear-to-rotary mechanisms in accordance with various embodiments. Some embodiments include a Stirling cycle device that may include a first hot piston contained within a first hot cylinder and a first cold piston contained within a first cold cylinder. A first single actuator may be configured to couple the first hot piston with the first cold piston such that the first hot piston and the first cold piston are on different thermodynamic circuits. The different thermodynamic circuits may include adjacent thermodynamic circuits. The Stirling cycle configuration may be configured as a single-acting alpha Stirling cycle configuration. Some embodiments include a linear-to-rotary mechanism device. The device may include multiple linkages. The device may include a cam plate coupled with the multiple linkages utilizing a cam and multiple cam followers. The linkages may include Watt linkages.

Methods, systems, and devices are provided that may include Stirling cycle configurations and/or linear-to-rotary mechanisms in accordance with various embodiments. Some embodiments include a Stirling cycle device that may include a first hot piston contained within a first hot cylinder and a first cold piston contained within a first cold cylinder. A first single actuator may be configured to couple the first hot piston with the first cold piston such that the first hot piston and the first cold piston are on different thermodynamic circuits. The different thermodynamic circuits may include adjacent thermodynamic circuits. The Stirling cycle configuration may be configured as a single-acting alpha Stirling cycle configuration. Some embodiments include a linear-to-rotary mechanism device. The device may include multiple linkages. The device may include a cam plate coupled with the multiple linkages utilizing a cam and multiple cam followers. The linkages may include Watt linkages.

A compound engine assembly including a compressor, an engine core including at least one rotary internal combustion engine and having an inlet in fluid communication with an outlet of the compressor, a turbine section having an inlet in fluid communication with an outlet of the engine core and configured to compound power with the engine core, and an air conduit having at least one heat exchanger extending thereacross. An outer wall of the air conduit has a plurality of openings defined therethrough downstream of the heat exchanger(s), each selectively closable by a pivotable flap movable between a retracted position where the opening is obstructed and an extended position away from the opening. Each opening defines a fluid communication between the air conduit and the ambient air when the respective flap is in the extended position. A method of directing flow through a compound engine assembly is also discussed.

Disclosed herein is an apparatus for extracting thermal energy from thermal expansion of a working medium in the apparatus. The apparatus includes a thermal expander, a compressor for compressing the working medium after the expansion, and a force modulation unit connecting the thermal expander to the compressor. The force modulation unit consists of two conversion gears that are connected by a lever system. The lever system can be dynamically controlled so that the non-constant force from thermal expansion is modulated into a substantially constant output force of the apparatus.