Thermoacoustic system and method for connecting thermoacoustic engines

Abstract

To provide, for a thermoacoustic system in which a thermoacoustic engine and another engine are connected to each other, a technique for easily and reliably matching the acoustic impedances of connecting surfaces of the two engines.SOLUTION: In a thermoacoustic system 100 in which a first engine 10 that is a thermoacoustic engine and a second engine 20 that receives supply of acoustic energy are connected: the second engine 20 includes a receiving portion 22 that receives the acoustic energy supplied from the first engine 10 by a receiving surface C3p and generates predetermined thrust Fp; the pressure amplitude P2p of a second connection surface C2p and the pressure amplitude P3p of the receiving surface C3p are the same; and at least one of the area A1 of a first connection surface C1 and the area A2p of the second connection surface C2p is determined so that the predetermined thrust Fp is generated at the receiving portion 22 and the acoustic impedance Z1 of the first connection surface C1 matches with the acoustic impedance Z2p of the second connection surface C2p.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a thermoacoustic system in which a thermoacoustic engine that supplies acoustic energy is connected to another engine that receives the supply of acoustic energy, and to a connection method for connecting the thermoacoustic engine to the other engine. [Background technology]

[0002] The phenomenon in which sound waves are generated by thermal factors is known as the thermoacoustic phenomenon. An example of the thermoacoustic phenomenon will be described with reference to FIG. 9. In the following, for the sake of convenience, a small mass of gas will be defined. This mass is larger than a gas molecule, and will be referred to as a "gas particle Q" below.

[0003] Now, suppose that a gas particle Q inside a narrow tube is displaced in the +X direction while being compressed. Since the speed of the gas particle Q during the displacement is relatively high, no heat exchange occurs between the gas particle Q and the tube wall W. Therefore, the change at this time is adiabatic, and the temperature of the gas particle Q rises.

[0004] At point A where the displacement in the +X direction is maximum, the speed of the gas particle Q is relatively slow, so heat is exchanged between the gas particle Q and the tube wall W. If the temperature of the tube wall W in the vicinity of point A is higher than the temperature of the gas particle Q, heat flows from the tube wall W into the gas particle Q. In other words, heat is given to the gas particle Q.

[0005] Next, suppose that the gas particle Q expands and displaces in the -X direction. This change is also adiabatic, and the temperature of the gas particle Q drops.

[0006] At point B where the displacement in the -X direction is maximum, heat is exchanged with the tube wall W. If the temperature of the tube wall W near point B is lower than the temperature of the gas particle Q, heat flows from the gas particle Q to the tube wall W. In other words, heat is taken away from the gas particle Q.

[0007] When the above cycle is repeated, the amplitude of the gas particles Q gradually increases and becomes unstable, generating large pressure fluctuations (sound waves). In this way, when a specific relationship is formed between the phase of the vibration and the phases of heating and cooling, sound waves are generated from thermal factors.

[0008] As one of the heat engines utilizing this thermoacoustic phenomenon, a thermoacoustic engine (also called a thermoacoustic engine) that generates acoustic energy by inputting thermal energy is known. An example of the configuration of a thermoacoustic engine will be described with reference to FIG.

[0009] The thermoacoustic engine 9 shown here has a loop tube 91 that generates sound waves, and a resonance tube 92 that propagates the sound waves generated here. A heat accumulator 93 having a structure in which countless thin tubes are bundled is provided midway through the loop tube 91. In addition, a high-temperature side heat exchanger (heater) 94 is provided on one side of the heat accumulator 93, and a low-temperature side heat exchanger (cooler) 95 is provided on the other side.

[0010] In this configuration, when a temperature gradient exceeding a predetermined threshold value is formed at both ends of the heat accumulator 93 by the heat exchangers 94, 95, self-excited vibration of the fluid (working fluid) inside the thin tube of the heat accumulator 93 occurs due to the thermoacoustic phenomenon, and sound waves are generated in the loop tube 91. That is, thermal energy is converted into acoustic energy. At this time, a mixture of standing waves and traveling waves is generated in the resonance tube 92, and acoustic energy is transported from the base end of the resonance tube 92 (the end connected to the loop tube 91) toward the tip C1 by the traveling wave component.

[0011] In order to extract the acoustic energy generated by the thermoacoustic engine 9, it is necessary to construct a thermoacoustic system by connecting another engine (hereinafter also referred to as a "load engine") 90 that receives a supply of acoustic energy to the tip C1 of the resonance tube 92. For example, a thermoacoustic system (thermoacoustic power generation system) is known in which a generator is connected to the thermoacoustic engine 9 to convert acoustic energy into electric power (see Patent Document 1).

[0012] In a thermoacoustic system in which a thermoacoustic engine 9 and a load engine 90 are connected, if the acoustic impedance of the surface (connection surface) C1 of the thermoacoustic engine 9 connected to the load engine 90 is different from the acoustic impedance of the connection surface C2 of the load engine 90 connected to the thermoacoustic engine 9, the acoustic energy generated in the thermoacoustic engine 9 cannot be extracted by the load engine 90. That is, in order to properly transmit acoustic energy from the thermoacoustic engine 9 to the load engine 90, the acoustic impedance of the connection surface C1 on the thermoacoustic engine 9 side and the acoustic impedance of the connection surface C2 on the load engine 90 side must match (match). However, in this specification, the "acoustic impedances match" of the two connection surfaces includes not only the case where the acoustic impedances of both connection surfaces are completely matched, but also the case where the difference in acoustic impedance of each connection surface is small enough that acoustic energy is sufficiently transmitted through both connection surfaces.

[0013] However, the acoustic impedance of the connection surfaces C1, C2 of the engines 9, 90 is a value determined by a complex interaction of various specifications of the engines 9, 90, and it is highly unlikely that the acoustic impedance of the connection surface C1 of the thermoacoustic engine 9 and the acoustic impedance of the connection surface C2 of the load engine 90 will match naturally (i.e., without any adjustment). Therefore, some adjustment is required to match the acoustic impedances of the connection surfaces C1, C2 of the engines 9, 90.

[0014] For example, Non-Patent Document 1 proposes a method for matching the acoustic impedance of each connection surface of a thermoacoustic engine and a linear generator connected thereto. Here, focusing on the fact that the acoustic impedance of the connection surface on the thermoacoustic engine side depends on the length L of the resonance tube and the set temperature T of the high temperature side of the heat accumulator, and the acoustic impedance of the connection surface on the linear generator side depends on the external resistance value Z, a combination (L, T, Z) that matches the acoustic impedance of both connection surfaces is specified by experiment. The acoustic impedance of both connection surfaces can be matched by changing the length L of the resonance tube and the set temperature T of the high temperature side of the heat accumulator, which are the specifications of the thermoacoustic engine side, and the external resistance value Z, which is the specification of the linear generator side, to the specified values, respectively. [Prior art documents] [Patent documents]

[0015] [Patent Document 1] Patent No. 6233835 [Non-patent literature]

[0016] [Non-Patent Document 1] "The Fundamentals of Thermoacoustic Power Generation" Shinya Hasegawa Journal of the Japan Society of Energy 92(11), 1111-1116, 2013-11-20 Summary of the Invention [Problem to be solved by the invention]

[0017] According to the technology of Non-Patent Document 1, it is possible to match the acoustic impedance of the connection surface on the thermoacoustic engine side with that on the linear generator side. However, in order to do so, it is necessary to find a combination (L, T, Z) that matches the acoustic impedance of both connection surfaces, which requires considerable experiments. This places a heavy workload on the designer. In addition, such a combination (L, T, Z) does not always exist, and even if experiments are performed, such a combination (L, T, Z) may not be found. Furthermore, the power generation efficiency of the linear generator changes when the external resistance value Z changes, and the power generation efficiency may decrease if an external resistance value Z that can match the acoustic impedance is adopted.

[0018] The present invention has been made to solve the above-mentioned problems, and aims to provide a technology that can easily and reliably match the acoustic impedance of the connection surfaces of a thermoacoustic engine and another engine in a thermoacoustic system in which the two engines are connected. [Means for solving the problem]

[0019] In order to achieve the above object, the present invention takes the following measures.

[0020] That is, the present invention provides a thermoacoustic system in which a first engine, which is a thermoacoustic engine that supplies acoustic energy, and a second engine that receives the supply of acoustic energy are connected via a first connection surface of the first engine and a second connection surface of the second engine, the second engine having a receiving portion that receives the acoustic energy supplied from the first engine at a receiving surface and generates a predetermined thrust, at least one of the area of ​​the first connection surface and the area of ​​the second connection surface is determined so that the pressure amplitude of the second connection surface and the pressure amplitude of the receiving surface are the same, the predetermined thrust is generated in the receiving portion, and the acoustic impedance of the first connection surface and the acoustic impedance of the second connection surface are the same. Basic configuration Let us assume that.

[0021] However, the "matching of acoustic impedances" of the two connecting surfaces does not only mean that the acoustic impedances of the connecting surfaces are completely the same, but also includes cases where the difference in acoustic impedance between the connecting surfaces is small enough that acoustic energy is sufficiently transmitted through both connecting surfaces. In other words, when acoustic energy is sufficiently transmitted through both connecting surfaces, the acoustic impedances of both connecting surfaces are considered to match.

[0022] In addition, the "pressure amplitude is the same" on two surfaces includes not only the case where the pressure amplitudes on the two surfaces are completely the same, but also the case where the difference in pressure amplitude between the two surfaces is sufficiently small. For example, when the distance between the two surfaces is small enough to be ignored compared to the wavelength of the sound wave, the difference in pressure amplitude between the two surfaces is sufficiently small that the pressure amplitudes can be considered to be the same.

[0023] The acoustic impedance of each connection surface between the first and second engines is a value determined by various specifications of the engines, and in the above configuration, the acoustic impedance of both connection surfaces is matched by adjusting the area of ​​at least one of the connection surfaces. Therefore, the acoustic impedance of the connection surfaces of both engines can be easily and reliably matched.

[0024] A thermoacoustic system according to a first aspect of the present invention has the above basic configuration, wherein the receiving portion includes a piston, The area of ​​the first connection surface is A 1 , the pressure amplitude of the first connecting surface is P 1 , the flow velocity at the first connection surface is V 1 , the area of ​​the second connection surface is A 2p , the flow velocity at the second connection surface is V 2p , the predetermined thrust is F p , the area of ​​the second connection surface is A 2p =(A 1 V 1 F p / P 1 V 2p ) 1 / 2 The present invention is characterized in that the above-mentioned is determined by the above-mentioned formula.

[0025] According to this configuration, a predetermined thrust can be generated stably. In addition, with this configuration, the area of ​​the second connection surface can be easily determined so that a predetermined thrust is generated in the receiving portion and the acoustic impedances of the first connection surface and the second connection surface can be matched.

[0028] A thermoacoustic system according to a second aspect of the present invention has the above basic configuration, The receiving portion includes a diaphragm, before The area of ​​the first connection surface is A 1 , the pressure amplitude of the first connecting surface is P 1 , the flow velocity at the first connection surface is V 1 , the area of ​​the second connection surface is A 2d , the flow velocity at the second connection surface is V 2d , the predetermined thrust is F d , the area of ​​the second connection surface is A 2d =[(3 / 2)(A 1 V 1 F d / P 1 V 2d )] 1 / 2 The present invention is characterized in that the above-mentioned is determined by the above-mentioned formula.

[0029] According to this configuration, a predetermined thrust can be generated stably. In addition, with this configuration, the area of ​​the second connection surface can be easily determined so that a predetermined thrust is generated in the receiving portion and the acoustic impedances of the first connection surface and the second connection surface can be matched.

[0032] Also, another Method for connecting thermoacoustic engines according to the invention is a connection method for connecting a first engine, which is a thermoacoustic engine that supplies acoustic energy, and a second engine having a receiving portion that receives the acoustic energy at a receiving surface and generates a predetermined thrust, via a first connection surface of the first engine and a second connection surface of the second engine, the method comprising the steps of: defining the second connection surface and the receiving surface such that a pressure amplitude of the second connection surface is the same as a pressure amplitude of the receiving surface; determining at least one of an area of ​​the first connection surface and an area of ​​the second connection surface such that the predetermined thrust is generated at the receiving portion and an acoustic impedance of the first connection surface is the same as an acoustic impedance of the second connection surface; and connecting the first connection surface and the second connection surface. It is something that In the case where the receiving portion includes a piston, The area of ​​the first connection surface is A 1 , the pressure amplitude of the first connecting surface is P 1 , the flow velocity at the first connection surface is V 1 , the area of ​​the second connection surface is A 2p , the flow velocity at the second connection surface is V 2p , the predetermined thrust is F p , then, The area of ​​the second connection surface is A 2p =(A 1 V 1 F p / P 1 V 2p ) 1 / 2 Determined by Characterized by

[0033] Also, Furthermore Another Method for connecting thermoacoustic engines according to the invention is a connection method for connecting a first engine, which is a thermoacoustic engine that supplies acoustic energy, and a second engine having a receiving portion that receives the acoustic energy at a receiving surface and generates a predetermined thrust, via a first connection surface of the first engine and a second connection surface of the second engine, the method comprising the steps of: defining the second connection surface and the receiving surface such that a pressure amplitude of the second connection surface is the same as a pressure amplitude of the receiving surface; determining at least one of an area of ​​the first connection surface and an area of ​​the second connection surface such that the predetermined thrust is generated at the receiving portion and an acoustic impedance of the first connection surface is the same as an acoustic impedance of the second connection surface; and connecting the first connection surface and the second connection surface. It is something that In the case where the receiving portion includes a diaphragm, The area of ​​the first connection surface is A 1 , the pressure amplitude of the first connecting surface is P 1 , the flow velocity at the first connection surface is V 1 , the area of ​​the second connection surface is A 2d , the flow velocity at the second connection surface is V 2d , the predetermined thrust is F d , then, The area of ​​the second connection surface is A 2d =[(3 / 2)(A 1 V1 F d / P 1 V 2d )] 1 / 2 Determined by It is characterized by: Effect of the Invention

[0034] According to the present invention, in a thermoacoustic system in which a thermoacoustic engine is connected to another engine, the acoustic impedances of the connection surfaces of the two engines can be easily and reliably matched. [Brief description of the drawings]

[0035] [Figure 1] FIG. 1 is a diagram illustrating a thermoacoustic system according to an embodiment. [Diagram 2] FIG. 2 is an enlarged view of the vicinity of the connection between the first engine and the second engine. [Diagram 3] FIG. 4 is a diagram showing a process flow relating to a connection method for connecting a first institution and a second institution. [Figure 4] FIG. 13 is a diagram illustrating a thermoacoustic system according to a second modified example. [Diagram 5] FIG. 2 is an enlarged view of the vicinity of the connection between the first engine and the second engine. [Figure 6] 5A and 5B are diagrams for explaining the difference between when the receiving portion is configured by a piston and when the receiving portion is configured by a diaphragm. [Figure 7] FIG. 13 is a diagram showing a connection portion according to another modified example. [Figure 8] FIG. 13 is a diagram showing a connection portion according to another modified example. [Figure 9] FIG. 1 is a diagram for explaining a thermoacoustic phenomenon. [Figure 10] FIG. 1 is a schematic diagram showing a thermoacoustic system according to a conventional example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0036] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0037] <1. Thermoacoustic system configuration> The configuration of a thermoacoustic system 100 according to an embodiment will be described with reference to Fig. 1. Fig. 1 is a diagram illustrating the thermoacoustic system 100.

[0038] The thermoacoustic system 100 includes a first engine 10, which is a thermoacoustic engine that supplies acoustic energy, and a second engine 20 that receives the supply of acoustic energy, which are connected to each other.

[0039] (First Agency) The first engine 10 is a thermoacoustic engine that generates acoustic energy by inputting thermal energy, and includes a loop tube 11 that generates sound waves, a resonance tube 12 that propagates the generated sound waves, a heat accumulator 13 that amplifies the acoustic energy, and a pair of heat exchangers (a high-temperature side heat exchanger 14 and a low-temperature side heat exchanger 15) that form a temperature gradient at both ends of the heat accumulator 13.

[0040] The loop tube 11 is a cylindrical tube bent into a rectangular frame shape and closed into a loop shape. Specifically, the loop tube 11 includes four tube portions 11a, 11b, 11c, and 11d extending linearly, in which the first tube portion 11a and the second tube portion 11b are connected to each other at their ends while forming an angle of approximately 90 degrees, the second tube portion 11b and the third tube portion 11c are connected to each other at their ends while forming an angle of approximately 90 degrees, the third tube portion 11c and the fourth tube portion 11d are connected to each other at their ends while forming an angle of approximately 90 degrees, and the fourth tube portion 11d and the first tube portion 11a are connected to each other at their ends while forming an angle of approximately 90 degrees.

[0041] The resonance tube 12 is a straight cylindrical tube, and one end surface of the resonance tube 12 is connected to any bent portion of the loop tube 11 (in the illustrated example, the portion where the first tube portion 11a and the fourth tube portion 11d are connected). The other end surface of the resonance tube 12 constitutes a connection surface (first connection surface) C1 that is connected to the second engine 20. That is, the first engine 10 is connected at the first connection surface C1 to a second connection surface C2 of the second engine 20, which will be described later. 2p (See Figure 2.)

[0042] The inside of the loop tube 11 and the resonance tube 12 is filled with a working fluid. Any working fluid may be used. For example, various gases such as air, nitrogen gas, helium gas, argon gas, and mixtures thereof may be used as the working fluid.

[0043] The heat accumulator 13 is a structure having a structure in which numerous thin tubes are bundled together, and is also called a stack. Specifically, the heat accumulator 13 can be made of, for example, a honeycomb structure made of ceramics, a stainless steel mesh (for example, a structure in which many stainless steel mesh thin plates are laminated at a fine pitch), a porous ceramic, a wire net, an object in which metal fibers are woven in a nonwoven fabric, or the like.

[0044] The heat accumulator 13 is provided midway through the loop pipe 11 (in the illustrated example, at the first pipe line portion 11a). However, the heat accumulator 13 is provided in such a position that the pipe line direction of the thin tube is parallel to the pipe line direction of the loop pipe 11 at the position where the heat accumulator 13 is provided (i.e., the pipe line direction of the first pipe line portion 11a).

[0045] The high-temperature side heat exchanger 14 is provided on the loop pipe 11 so as to be adjacent to one end of the heat accumulator 13. The high-temperature side heat exchanger 14 is a heat exchanger (heater) for heating, and supplies heat to one end of the heat accumulator 13 to heat the end to a predetermined set temperature (high-temperature side set temperature).

[0046] The low-temperature side heat exchanger 15 is provided on the loop pipe 11 so as to be adjacent to the other end of the heat accumulator 13. The low-temperature side heat exchanger 15 is a heat exchanger (cooler) for cooling, and releases heat from the other end of the heat accumulator 13 to cool the other end to a predetermined set temperature (low-temperature side set temperature).

[0047] In the first engine 10 having such a configuration, when a predetermined temperature gradient is formed at both ends of the heat accumulator 13 by the high-temperature side heat exchanger 14 provided at one end of the heat accumulator 13 heating the one end to a high-temperature side set temperature and the low-temperature side heat exchanger 15 provided at the other end of the heat accumulator 13 cooling the other end to a low-temperature side set temperature, a self-excited vibration of the working fluid occurs inside the thin tube of the heat accumulator 13 due to a thermoacoustic phenomenon, and a sound wave is generated in the loop tube 11. At this time, the heat accumulator 13 plays a role in promoting the destabilization of the working fluid and amplifying the acoustic energy. When a sound wave is generated in the loop tube 11, a sound wave is also generated in the resonance tube 12. At this time, a standing wave and a traveling wave are generated in the resonance tube 12, and the acoustic energy generated in the loop tube 11 is transported from one end side of the resonance tube 12 (the side connected to the loop tube 11) to the other end side (i.e., the first connection surface C1 side) by the traveling wave component.

[0048] (Second Agency) The second engine 20 is a load engine that receives the supply of acoustic energy generated by the first engine 10, which is a thermoacoustic engine. In this embodiment, the second engine 20 is a generator that converts acoustic energy into electric power. In other words, the thermoacoustic system 100 according to this embodiment is a thermoacoustic power generation system that outputs the acoustic energy generated by the first engine 10 as electric power.

[0049] The second engine 20 is a linear generator, and includes a connecting pipe 21, a receiving portion 22, a power generating portion 23, a coupling portion 24, and the like.

[0050] The connecting pipe 21 is a straight cylindrical pipe. One end surface of the connecting pipe 21 is a connecting surface (second connecting surface) C 2p That is, the second engine 20 forms a second connection surface C 2p 2, the other end surface of the connection pipe 21 is connected to one end surface of the housing section 230 that houses the power generation section 23.

[0051] The receiving portion 22 is a member that generates a predetermined thrust upon receiving acoustic energy supplied from the first engine 10, and is housed in the connecting pipe 21. In this embodiment, the receiving portion 22 is configured by a piston 221. The piston 221 is a cylindrical member, and is arranged coaxially in the connecting pipe 21. The circular end face of the piston 221 is approximately congruent with the pipe cross section of the connecting pipe 21. In other words, the circumferential surface of the piston 221 is arranged to face the inner wall of the connecting pipe 21 in sufficient proximity, and sufficient airtightness is maintained between them. On the other hand, the circumferential surface of the piston 221 receives almost no frictional resistance from the inner wall of the connecting pipe 21. Therefore, the piston 221 can smoothly advance and retreat along the pipe direction of the connecting pipe 21.

[0052] Second connection surface C of piston 221 2p The end face on the side is the second connection face C 2p Surface C receives the acoustic energy (vibration flow) propagating from the side 3p That is, the piston 221 forms a second connection surface C 2p The surface C receives the acoustic energy propagating from the 3p and vibrates (reciprocates) along the pipe direction of the connecting pipe 21 with a thrust.

[0053] The power generating unit 23 includes a mover (vibrator) 231 and a cylindrical stator 232 provided to surround the outer circumferential surface of the mover 231. A permanent magnet (not shown) is provided in the mover 231, and a coil winding (not shown) is wound around the stator 232.

[0054] The connecting portion 24 is a rod-shaped member that connects the piston 221 and the movable element 231, and has one end that is in contact with the end surface of the piston 221 (receiving surface C 3p22) and is connected at the other end to mover 231. Mover 231 is supported at a position coaxial with piston 221 by being connected to piston 221 via connecting portion 24. Therefore, when piston 221 vibrates due to receiving acoustic energy, mover 231 vibrates in synchronization therewith. That is, mover 231 vibrates relative to stator 232. This generates a magnetic flux fluctuation, and an electromotive force is generated in the winding wound around stator 232.

[0055] 2. Operation of the thermoacoustic system As described above, the thermoacoustic system 100 according to this embodiment is a thermoacoustic power generation system equipped with a generator as a load engine. The manner in which power is generated by the thermoacoustic system 100 will be described with continued reference to FIG.

[0056] When generating electricity in this thermoacoustic system 100, a high-temperature side heat exchanger 14 provided on one end of the heat storage device 13 heats the one end to a high-temperature side set temperature, and a low-temperature side heat exchanger 15 provided on the other end of the heat storage device 13 cools the other end to a low-temperature side set temperature.

[0057] As described above, when a predetermined temperature gradient is formed at both ends of the heat accumulator 13, self-excited vibration of the working fluid occurs inside the thin tubes of the heat accumulator 13 due to the thermoacoustic phenomenon, and as a result, sound waves are generated in the loop tube 11 and the resonance tube 12. At this time, a mixture of standing waves and traveling waves is generated in the resonance tube 12, and the acoustic energy generated in the loop tube 11 is transported from one end side of the resonance tube 12 to the other end side (the first connection surface C1 side) of the resonance tube 12 by the traveling wave component.

[0058] The first connection surface C1 is connected to the second connection surface C of the second engine 20. 2p As described later, in the thermoacoustic system 100, the acoustic impedance of the first connection surface C1 and the acoustic impedance of the second connection surface C 2p The second connection surface C 2p Therefore, the acoustic energy (vibration flow) propagated through the resonance tube 12 is transmitted through the first connection surface C1 and the second connection surface C2.2p 2, the piston 221 is transported into the connecting pipe 21, and the receiving surface C 3p It can be received at.

[0059] The piston 221 has a receiving surface C 3p When the piston 221 receives acoustic energy at the rotor 232, it vibrates with a predetermined thrust. The vibration of the piston 221 is transmitted to the mover 231 via the connecting portion 24, and the mover 231 vibrates relative to the stator 232. This causes a magnetic flux fluctuation, which generates an electromotive force in the winding. In other words, electricity is generated.

[0060] <3. Configuration of connection part> As described above, in the thermoacoustic system 100, the first engine 10 and the second engine 20 are connected to each other via a first connection surface C1 of the first engine 10 and a second connection surface C2 of the second engine 20. 2p In order to transmit the acoustic energy generated in the first unit 10 to the second unit 20, the acoustic impedance of the first connection surface C1 and the acoustic impedance of the second connection surface C 2p However, as mentioned above, the acoustic impedance of each connection surface C1, C2 must match. 2p Not only when the acoustic impedance of both connection surfaces C1 and C2 is completely the same, but also when the acoustic impedance of both connection surfaces C2 and C3 is completely the same, 2p Each connecting surface C1, C2 is connected to the connecting surface C1, C3 so that acoustic energy is sufficiently transmitted through the connecting surface C1, C2. 2p This also includes cases where the difference in acoustic impedance is small.

[0061] In this thermoacoustic system 100, the second connection surface C 2p By using the area of ​​each connection surface C1, C 2p The acoustic impedance of each connection surface C1, C 2p The second connection surface C can match the acoustic impedance of 2p The manner of determining the area will be described with reference to Fig. 2. Fig. 2 is an enlarged view of the vicinity of the connection portion of both engines 10, 20, in which Fig. 2(a) shows the state before connection and Fig. 2(b) shows the state after connection.

[0062] Now, the area of ​​the first connection surface C1 is "A1", the flow velocity at the first connection surface C1 is "V1", and the pressure amplitude (sound pressure) at the first connection surface C1 is "P1". 2p The area of ​​"A 2p ", second connection surface C 2p The flow velocity at 2p ", second connection surface C 2p The pressure amplitude of "P 2p " In addition, the receiving surface C 3p The area of ​​"A 3p ", receiving surface C 3p The flow velocity at 3p ", receiving surface C 3p The pressure amplitude of "P 3p However, the "flow velocity" here refers to the velocity component of the particles (particles that make up the working fluid) along the normal direction of the target surface.

[0063] The acoustic impedance is the pressure amplitude divided by the volumetric flow rate (volume flow velocity). The volumetric flow rate of the first connection surface C1 is the area A1 multiplied by the flow velocity V1. Similarly, the volumetric flow rate of the second connection surface C1 is the area A1 multiplied by the flow velocity V1. 2p The volumetric flow rate of the area A 2p Flow velocity V 2p Therefore, the acoustic impedance Z1 of the first connecting surface C1 is given by the following (Equation 1). 2p The acoustic impedance Z 2p is given by the following (Equation 2). Z1=P1 / A1V1...(Formula 1) Z 2p =P 2p / A 2p V 2p ...(Formula 2)

[0064] On the other hand, receiving surface C 3p Pressure amplitude P 3p and the thrust force F generated at the receiving portion 22 p The following relationship (Equation 3) holds between them. P 3p =F p / A 3p ...(Formula 3) Basically, the magnitude of the electric power generated by the second engine 20 is proportional to the thrust F generated by the receiving portion 22. p In other words, when the target power to be generated by the second engine 20 is determined, the thrust F to be generated by the receiving portion 22 is determined accordingly. p is prescribed.

[0065] Here, in this thermoacoustic system 100, the second connection surface C 2p Area A 2p and receiving surface C 3p Area A 3p and are considered to be the same (A 2p =A 3p ) However, two faces C 2p ,C 3p The "area is the same" means that the two faces C 2p ,C 3p Area A 2p ,A 3p Not only when the two faces C 2p ,C 3p Area A 2p ,A 3p This also includes cases where the difference between

[0066] Furthermore, in this thermoacoustic system 100, the second connection surface C 2p Pressure amplitude P 2p and receiving surface C 3p Pressure amplitude P 3p and are considered to be the same (P 2p =P 3p ) However, two faces C 2p ,C 3p The "pressure amplitude is the same" means that the two surfaces C 2p ,C 3p Pressure amplitude P 2p ,P 3p Not only when the two faces C 2p ,C 3p Pressure amplitude P 2p ,P 3p This also includes cases where the difference between the two surfaces C is sufficiently small. 2p ,C 3p When the separation distance d between the two surfaces C is negligibly small compared to the wavelength of the sound wave,2p ,C 3p Pressure amplitude P 2p ,P 3p The difference between the pressure amplitudes P 2p ,P 3p can be considered to be the same. Therefore, here, the second connecting surface C 2p , receiving surface C 3p and a position sufficiently close to the receiving surface C 3p and a distance d between the first engine 10 and the second engine 11 is negligibly small compared to the wavelength of the sound wave propagating from the first engine 10.

[0067] Therefore, in this thermoacoustic system 100, the following (Equation 3') holds from the above (Equation 3). P 2p =F p / A 2p ...(Formula 3')

[0068] Then, the second connection surface C expressed by the above (Equation 2) 2p The acoustic impedance Z 2p is expressed as follows (Equation 2'). Z 2p =F p / A 2p 2 V 2p ...(Formula 2')

[0069] From (Equation 1) and (Equation 2'), the acoustic impedance Z1 of the first connecting surface C1 and the acoustic impedance Z2 of the second connecting surface C 2p The acoustic impedance Z 2p In order to match these, it is sufficient that the relationship in (Equation 4) below is satisfied. P1 / A1V1=F p / A 2p 2 V 2p ...(Formula 4)

[0070] The above (Equation 4) is applied to the second connecting surface C 2p Area A 2p By rearranging the above, we obtain the following (Equation 5). A 2p =(A1V1Fp / P1V 2p ) 1 / 2 ...(Formula 5)

[0071] In this thermoacoustic system 100, the second connection surface C 2p Area A 2p is determined by the above (Equation 5). As a result, the acoustic impedance Z1 of the first connecting surface C1 and the acoustic impedance Z2 of the second connecting surface C 2p The acoustic impedance Z 2p In addition, in the thermoacoustic system 100, the second connection surface C 2p Area A 2p and the pressure amplitude P 2p and receiving surface C 3p Area A 3p and the pressure amplitude P 3p Therefore, a predetermined thrust F is applied to the receiving portion 22. p While ensuring that the power generated in the second engine 20 is generated (i.e., without affecting the power generated in the second engine 20), 2p can be matched.

[0072] In general, the acoustic impedance Z1 of the first connection surface C1 of the first engine 10, which is a thermoacoustic engine, depends on the length L of the resonance tube 12. The acoustic impedance Z1 also depends on the high-temperature side set temperature T of the heat accumulator 13, and the acoustic impedance Z1 decreases as the high-temperature side set temperature T increases. Now, in a certain first engine (target first engine) 10, when the length L of the resonance tube 12 is about "3.1 (m)" and the high-temperature side set temperature T is set to about "300 (°C)", it is assumed that the acoustic impedance Z1 of the first connection surface C1 is about "600 (Ns / m)".

[0073] On the other hand, the second connection surface C of the second engine 20, which is a linear generator 2p The acoustic impedance Z 2p depends on the external resistance value Z. This external resistance value Z is also a value that determines the power generation efficiency of the linear generator. Now, in a certain second engine (target second engine) 20, when the external resistance value Z is set so that the required power generation efficiency can be obtained, the second connection surface C2p The acoustic impedance Z 2p is approximately 300 to 400 (Ns / m).

[0074] If these target engines 10 and 20 are connected as they are, each connection surface C1, C 2p The acoustic impedance Z1,Z 2p Since there is a large discrepancy between these two, the acoustic energy generated in the target first engine 10 cannot be extracted by the target second engine 20. For example, one possible solution would be to change the high temperature side set temperature T in the target first engine 10 to lower the acoustic impedance Z1 of the first connection surface C1 to approximately "300 to 400 (Ns / m)". In this case, however, it would be necessary to set the temperature at a temperature significantly higher than the initial high temperature side set temperature T, which would require a large heat exchanger or the like.

[0075] In such a case, the above-described measures (i.e., the second connection surface C 2p Area A 2p are used as adjustment parameters for each connection surface C1, C 2p The acoustic impedance Z1,Z 2p For example, in the case of the above target engines 10 and 20, the second connection surface C 2p By simply changing the diameter of the first connecting surface C1 to, for example, about 2 / 3 of the diameter of the first connecting surface C1, the acoustic impedance Z1 of the first connecting surface C1 and the acoustic impedance Z2 of the second connecting surface C1 can be reduced. 2p The acoustic impedance Z 2p In this case, since there is no need to change the high temperature set temperature T, a large heat exchanger or the like is not required. In addition, since the external resistance value Z is not changed, the power generation efficiency of the target second engine 20 is not reduced.

[0076] <4. Connection method> Next, a connection method for connecting the first institution 10 and the second institution 20 will be described with reference to Fig. 3 in addition to Fig. 1 and Fig. 2. Fig. 3 is a diagram showing the flow of processing related to the connection method.

[0077] (Step S1) When connecting the first engine 10 and the second engine 20, first, the second connection surface C 2p Area A 2p and receiving surface C 3p Area A 3p and are the same (A 2p =A 3p ), and the second connection surface C 2p Pressure amplitude P 2p and receiving surface C 3p Pressure amplitude P 3p (P 2p =P 3p ), second connection surface C 2p and receiving surface C 3p This section stipulates:

[0078] (Step S2) Next, a predetermined thrust F p occurs, and the acoustic impedance Z1 of the first connecting surface C1 and the acoustic impedance Z2 of the second connecting surface C 2p The acoustic impedance Z 2p The second connecting surface C is aligned so that 2p Area A 2p Specifically, first, the area A1 of the first connection surface C1, the flow velocity V1, the pressure amplitude P1, and the area of ​​the second connection surface C 2p Flow velocity V 2p is determined by measurement experiments, theoretical calculations, etc. In addition, the thrust force F to be generated at the receiving portion 22 is p are specified based on the specifications of the second engine 20. Then, the specified values ​​A1, V1, P1, and V 2p ,F p Substituting this into the above (Equation 5), the second connection surface C 2p Area A 2p Determine.

[0079] (Step S3) Next, the first connecting surface C1 and the second connecting surface C 2p The second connection surface C determined in step S2 is connected to the 2p Area A 2p does not necessarily coincide with the area A1 of the first connecting surface C1. 2p If they do not match, the areas A1,A 2pTo fill the gap, a flange part G (Fig. 2(b)) is inserted between the connecting surfaces C1 and C2. 2p In addition, the second connection surface C 2p Area A 2p is smaller than the area A1 of the first connecting surface C1. 2p Area A 2p may be larger than the area A1 of the first connecting surface C1.

[0080] Through the above steps S1 to S3, the first unit 10 and the second unit 20 are connected, and the thermoacoustic system 100 is constructed.

[0081] <5. Effects> In the above embodiment, a first engine 10, which is a thermoacoustic engine that supplies acoustic energy, and a second engine 20 that receives the supply of acoustic energy are connected to each other via a first connection surface C1 of the first engine 10 and a second connection surface C2 of the second engine 20. 2p In the thermoacoustic system 100, the second engine 20 receives the acoustic energy supplied from the first engine 10 through a surface C 3p The thrust force F is received by p and a receiving portion 22 that generates the second connection surface C 2p Pressure amplitude P 2p and receiving surface C 3p Pressure amplitude P 3p and a predetermined thrust F p occurs, and the acoustic impedance Z1 of the first connecting surface C1 and the acoustic impedance Z2 of the second connecting surface C 2p The acoustic impedance Z 2p The area A1 of the first connecting surface C1 and the area A2 of the second connecting surface C 2p Area A 2p At least one of the above has been determined.

[0082] The acoustic impedances Z1 and Z2 of the connection surfaces of the first engine 10 and the second engine 20 are 2p is a value determined from various specifications of the engine. In the above configuration, at least one of the connecting surfaces C1, C 2p Area of ​​A1,A 2pBy adjusting the two connection surfaces C1 and C 2p The acoustic impedance Z1,Z 2p Therefore, the connection surfaces C1 and C2 of the engines 10 and 20 are aligned. 2p The acoustic impedance Z1,Z 2p In the above configuration, the connection surfaces C1 and C2 can be easily and reliably aligned with each other. 2p Area of ​​A1,A 2p When using as an adjustment parameter, the second connection surface C 2p Area A 2p and the pressure amplitude P 2p and receiving surface C 3p Area A 3p and the pressure amplitude P 3p Since the thrust force F is equal to the thrust force F of the receiving portion 22, p While ensuring that acoustic impedance Z1,Z 2p can be matched.

[0083] Moreover, in the thermoacoustic system 100 according to the above embodiment, the receiving portion 22 includes the piston 221 .

[0084] According to this configuration, a predetermined thrust can be generated stably.

[0085] In addition, in the thermoacoustic system 100 according to the above embodiment, the area of ​​the first connection surface C1 is A1, the pressure amplitude of the first connection surface C1 is P1, the flow velocity at the first connection surface C1 is V1, and the flow velocity at the second connection surface C2 is V2. 2p The area of ​​A 2p , second connection surface C 2p The flow velocity at V 2p , a given thrust F p , then the second connection surface C 2p Area A 2p but, A 2p =(A1V1F p / P1V 2p ) 1 / 2 It is determined by.

[0086] According to this configuration, a predetermined thrust F is applied to the receiving portion 22. p occurs, and the first connection surface C1 and the second connection surface C 2p Acoustic impedance Z1, Z 2p The area A of the second connecting surface is such that 2p can be easily determined.

[0087] The above embodiment also includes a first engine 10 that is a thermoacoustic engine for supplying acoustic energy, and a surface C 3p The thrust force F is received by p The first engine 10 is connected to a second engine 20 having a receiving portion 22 that generates a torque of 100 rpm by a first connecting surface C1 of the first engine 10 and a second connecting surface C2 of the second engine 20. 2p A connection method in which a connection is made via a second connection surface C 2p Pressure amplitude P 2p and receiving surface C 3p Pressure amplitude P 3p The second connecting surface C is the same as 2p and receiving surface C 3p A step of determining the thrust force F at the receiving portion 22 (step S1). p occurs, and the acoustic impedance Z1 of the first connecting surface C1 and the acoustic impedance Z2 of the second connecting surface C 2p The acoustic impedance Z 2p The area A1 of the first connecting surface C1 and the area A2 of the second connecting surface C 2p Area A 2p (Step S2) determining at least one of the first connecting surface C1 and the second connecting surface C 2p and (step S3) connecting the

[0088] According to this configuration, the connection surfaces C1 and C2 of the first engine 10 and the second engine 20 2p At least one of the areas A1,A 2p By adjusting the two connection surfaces C1 and C 2p The acoustic impedance Z1,Z 2p Therefore, the connection surfaces C1 and C2 of the engines 10 and 20 are aligned. 2p The acoustic impedance Z1,Z 2pIn the above configuration, the connection surfaces C1 and C2 can be easily and reliably aligned with each other. 2p Area of ​​A1,A 2p When using as an adjustment parameter, the second connection surface C 2p Area A 2p and the pressure amplitude P 2p and receiving surface C 3p Area A 3p and the pressure amplitude P 3p Since the thrust force F is equal to the thrust force F of the receiving portion 22, p While ensuring that acoustic impedance Z1,Z 2p can be matched.

[0089] <6. Variations> <6-1. First modified example> In the above embodiment, the second connection surface C 2p Area A 2p is used as an adjustment parameter, and the area is set to a value determined by the above (Equation 5), so that the acoustic impedance Z1 of the first connecting surface C1 and the acoustic impedance Z2 of the second connecting surface C 2p The acoustic impedance Z 2p However, the area A1 of the first connecting surface C1 may be used as an adjustment parameter.

[0090] For example, when the above (Equation 4) is rearranged with respect to the area A1 of the first connecting surface C1, the following (Equation 6) is obtained. A1=A 2p 2 V 2p P1 / V1F p ...(Formula 6)

[0091] By setting the area A1 of the first connection surface C1 to a value determined by the above (Equation 6), a predetermined thrust F is applied to the receiving portion 22 in the same manner as in the above embodiment. p While ensuring that both acoustic impedances Z1 and Z 2p can be matched.

[0092] In addition, the area A1 of the first connecting surface C1 and the area A2 of the second connecting surface C 2p Area A2p Both of the areas A1 and A2 may be used as adjustment parameters. 2p should be set to a value that satisfies the above (Equation 4).

[0093] <6-2. Second modified example> In the thermoacoustic system 100 according to the above embodiment, the receiving portion 22 is configured by the piston 221, but the configuration of the receiving portion 22 is not limited to this. For example, in the thermoacoustic system 100, the receiving portion 22 may be configured by a diaphragm.

[0094] <6-2-1. Thermoacoustic system configuration> The configuration of a thermoacoustic system 100d including a receiving portion 22d formed by a diaphragm 222 will be described with reference to Figs. 4 and 5. Fig. 4 is a schematic diagram of the thermoacoustic system 100d. Fig. 5 is an enlarged view of the vicinity of the connection portion between the first unit 10 and the second unit 20d, with Fig. 5(a) showing the state before connection and Fig. 5(b) showing the state after connection. In the following, only the points that differ from the above embodiment will be described, and the points that are the same will be omitted. Also, the same elements as those in the above embodiment will be denoted by the same reference numerals.

[0095] The thermoacoustic system 100d has a configuration in which a first engine 10, which is a thermoacoustic engine, and a second engine 20d, which is a load engine, are connected, similarly to the thermoacoustic system 100 according to the above embodiment. The first engine 10 has the same configuration as the first engine 10 provided in the thermoacoustic system 100 according to the above embodiment. On the other hand, the second engine 20d has almost the same configuration as the second engine 20 provided in the thermoacoustic system 100 according to the above embodiment, but differs in that the receiving portion 22d is formed by a diaphragm 222 instead of a piston 221.

[0096] The diaphragm 222 is a thin film formed of an elastically deformable material (for example, a rubber film formed of natural rubber), and is stretched in the connecting pipe 21. That is, the diaphragm 222 has a circular shape substantially identical to the cross-section of the connecting pipe 21, and is airtightly connected to the inner wall of the connecting pipe 21 over the entire circumference thereof.

[0097] The second connection surface C on the diaphragm 222 2d The side surface constitutes 2d a receiving surface C for receiving the acoustic energy propagating from the side of the second connection surface C 3d . That is, the diaphragm 222 receives the acoustic energy propagating from the side of the second connection surface C 2d with the receiving surface C 3d and repeats periodic deformation with thrust. Specifically, the diaphragm 222 periodically deforms between a planar shape parallel to the cross-section of the connecting pipe 21 (the shape shown by the solid line in FIG. 5) and a semi-elliptical shape bulging in the pipe direction of the connecting pipe 21 (the shape shown by the two-dot chain line in FIG. 5).

[0098] The connecting portion 24d is a rod-shaped member that connects the diaphragm 222 and the mover 231. One end is connected to the central portion of the diaphragm 222, and the other end is connected to the mover 231. The mover 231 is supported at a position coaxial with the axis passing through the center of the diaphragm 222 by being connected to the diaphragm 222 via the connecting portion 24d. Therefore, when the diaphragm 222 is periodically deformed by receiving acoustic energy and its central portion vibrates in the axial direction, the mover 231 vibrates synchronously therewith. That is, the mover 231 vibrates with respect to the stator 232. Then, a magnetic flux fluctuation occurs, and an electromotive force is generated in the winding wound around the stator 232.

[0099] <6-2-2. Aspect of determining the area of the second connection surface C 2d > Also in this thermoacoustic system 100d, similar to the thermoacoustic system 100, by using the area of the second connection surface C 2d as an adjustment parameter, each connection surface C1, C 2dThe acoustic impedance of each connection surface C1, C 2d The second connection surface C can match the acoustic impedance of 2d The manner in which the area is determined will be described with continued reference to FIG.

[0100] In the following, the area, flow velocity, and pressure amplitude of the first connection surface C1 are respectively designated as "A1", "V1", and "P1" as in the above embodiment. 2d The area, flow velocity, and pressure amplitude of the 2d ", "V 2d " and "P 2d " In addition, the receiving surface C 3d The area, flow velocity, and pressure amplitude of the 3d ","V 3d " and "P 3d "

[0101] In addition, similar to the acoustic system 100 according to the above embodiment, in this thermoacoustic system 100d, the second connection surface C 2d Area A 2d and receiving surface C 3d Area A 3d and are considered to be the same (A 2d =A 3d ). Also, the second connection surface C 2d Pressure amplitude P 2d and receiving surface C 3d Pressure amplitude P 3d and are considered to be the same (P 2d =P 3d ).

[0102] As described above, the acoustic impedance is the pressure amplitude divided by the volumetric flow rate. The volumetric flow rate U1 of the first connection surface C1 is the area A1 multiplied by the flow velocity V1, and the acoustic impedance Z1 of the first connection surface C1 is given by the above (Equation 1). Z1=P1 / U1=P1 / A1V1...(Formula 1)

[0103] On the other hand, the second connection surface C 2d Volume flow rate U2d is the receiving surface C 2d Volume flow rate U 3d and the receiving surface C 2d Volume flow rate U 3d is expressed by the following (Equation 21d) using the volume formula for an ellipsoid (such as a formula using the Jacobian matrix). U 3d =(2 / 3)A 3d V 3d ...(Formula 21d)

[0104] From the above (Equation 21d), the second connection surface C 2d Volume flow rate U at 2d is expressed as follows (Equation 21d'). U 2d =(2 / 3)A 2d V 2d ...(Formula 21d')

[0105] Therefore, the second connection surface C 2d The acoustic impedance Z 2d is given by the following (Equation 2d). Z 2d =P 2d / U 2d =(3 / 2)P 2d / A 2d V 2d ...(Formula 2d)

[0106] On the other hand, like the acoustic system 100 according to the above embodiment, the receiving surface C 3d Pressure amplitude P 3d and the thrust force F generated at the receiving portion 22d. d The following relationship (Equation 3d) holds between them. Furthermore, from (Equation 3d), the following relationship (Equation 3d') holds. P 3d =F d / A 3d ...(Formula 3d) P 2d =F d / A 2d ...(Formula 3d')

[0107] Then, the second connection surface C expressed by the above (Equation 2d)2d The acoustic impedance Z 2d is expressed as follows (Equation 2d'). Z 2d =(3 / 2)F d / A 2d 2 V 2d ...(Formula 2d')

[0108] From (Equation 1) and (Equation 2d'), the acoustic impedance Z1 of the first connecting surface C1 and the acoustic impedance Z2 of the second connecting surface C 2d The acoustic impedance Z 2d In order to match these, it is sufficient that the relationship in (Equation 4d) below is satisfied. P1 / A1V1=(3 / 2)F d / A 2d 2 V 2d ...(Formula 4d)

[0109] The above (Equation 4d) is applied to the second connecting surface C 2d Area A 2d By rearranging, we obtain the following (Equation 5d). A 2d =[(3 / 2)(A1V1F d / P1V 2d )] 1 / 2 ...(Formula 5d)

[0110] In the thermoacoustic system 100d according to this modification, the second connection surface C 2d Area A 2d is determined by the above formula (5d). As a result, the acoustic impedance Z1 of the first connecting surface C1 and the acoustic impedance Z2 of the second connecting surface C 2d The acoustic impedance Z 2d In addition, in the thermoacoustic system 100d according to this modification, the second connection surface C 2d Area A 2d and the pressure amplitude P 2d and receiving surface C 3d Area A 3d and the pressure amplitude P 3d Therefore, a predetermined thrust F is applied to the receiving portion 22d.d While ensuring that acoustic impedance Z1,Z 2d can be matched.

[0111] Needless to say, the area A1 of the first connection surface C1 may be determined by rearranging the above (Equation 4d) with respect to the area A1 of the first connection surface C1. In other words, by using the area A1 of the first connection surface C1 as an adjustment parameter, the area A1 of each connection surface C1, C 2d The acoustic impedance of the first and second electrodes may be matched.

[0112] <6-3.Third modified example> The thermoacoustic system according to the third modification has the same configuration as the thermoacoustic system 100d according to the second modification (see Figs. 4 and 5). 2d By using the area of ​​each connection surface C1, C 2d The acoustic impedance of the two is matched.

[0113] As described in the above embodiment, when the receiving portion 22 is constituted by the piston 221, the appropriate second connection surface C 2p Area A 2p (That is, each connection surface C1, C 2p The second connection surface C can match the acoustic impedance of 2p Area A 2p ) can be determined from the above-mentioned (Equation 5). In this modified example, by taking into consideration the difference between when the receiving portion 22 is constituted by the piston 221 and when the receiving portion 22d is constituted by the diaphragm 222, this (Equation 5) is modified to determine an appropriate second connection surface C 2d Area A 2d An equation for determining is derived. A mode for deriving such an equation will be described below with reference to Fig. 6 in addition to Fig. 5. Fig. 6 is a diagram for explaining the difference between a case where receiving portion 22 is configured by piston 221 and a case where receiving portion 22d is configured by diaphragm 222.

[0114] In the following, a second connection surface (hereinafter also referred to as a "piston second connection surface") C when the receiving portion 22 is constituted by the piston 221 will be referred to as a "piston second connection surface" below. 2p The area, flow velocity, and pressure amplitude of the 2p ","V 2p " and "P 2p In this case, the thrust generated at the receiving portion 22 is expressed as "F p On the other hand, when the receiving portion 22d is formed by the diaphragm 222, the second connection surface (hereinafter also referred to as the "diaphragm second connection surface") C 2d The area, flow velocity, and pressure amplitude of the 2d ","V 2d " and "P 2d In this case, the thrust generated at the receiving portion 22d is expressed as "F d "

[0115] Here, it is assumed that the first engine 10 is not changed, and the configuration of the receiving portion is changed from the piston 221 to the diaphragm 222. Therefore, the piston second connection surface C 2p Flow velocity V 2p and diaphragm second connection surface C 2d Flow velocity V 2d The condition is that the same (V 2p =V 2d ) In addition, the piston second connection surface C 2p Pressure amplitude P 2p and diaphragm second connection surface C 2d Pressure amplitude P 2d It is also a condition that 2p =P 2d ).

[0116] Also in this modified example, the second diaphragm connection surface C 2d Area A 2d and receiving surface C 3d Area A 3d and are considered to be the same (A 2d =A 3d ) Also, the second diaphragm connection surface C 2d Pressure amplitude P2d and receiving surface C 3d Pressure amplitude P 3d and are considered to be the same (P 2d =P 3d ).

[0117] First, the piston second connection surface C 2p Area A 2p and the second diaphragm connection surface C 2d Area A 2d and examine the relationship.

[0118] Piston second connection surface C 2p Volume flow rate U at 2p is the area A 2p Flow velocity V 2p and is expressed by the following (Equation 71). U 2p =A 2p V 2p ...(Formula 71)

[0119] On the other hand, the second diaphragm connection surface C 2d Volume flow rate U at 2d is expressed by the following (Equation 72) (see (Equation 21d') above). U 2d =(2 / 3)A 2d V 2d ...(Formula 72)

[0120] As mentioned above, the piston second connection surface C 2p Flow velocity V 2p and diaphragm second connection surface C 2d Flow velocity V 2d is the same (V 2p =V 2d ). Therefore, the piston second contact surface C 2p Volume flow rate U 2p and the second diaphragm connection surface C 2d Volume flow rate U 2d When the piston second connection surface C 2p Area A 2p and the second diaphragm connection surface C 2d Area A 2d The following equation (73) holds between A 2p =(2 / 3)A 2d ...(Formula 73) In other words, if this (equation 73) holds, the piston second connection surface C 2p Volume flow rate U 2p and the second diaphragm connection surface C 2d Volume flow rate U 2d can be matched with.

[0121] Next, a thrust force F generated in the receiving portion 22 formed by the piston 221 p and a thrust force F generated at the receiving portion 22d formed by the diaphragm 222. d and examine the relationship.

[0122] As described above, the thrust F generated at the receiving portion 22 p , piston second connection surface C 2p Area A 2p , and the pressure amplitude P 2p The relationship expressed by the following (Equation 81) holds between (see Equation 3' above). P 2p =F p / A 2p ...(Formula 81)

[0123] In addition, the thrust F generated at the receiving portion 22d d , diaphragm second connection surface C 2d Area A 2d , and the pressure amplitude P 2d The relationship expressed by the following (Equation 82) holds between (see Equation 3d' above). P 2d =F d / A 2d ...(Formula 82)

[0124] Here, the piston second connection surface C 2p Pressure amplitude P 2p and diaphragm second connection surface C 2d Pressure amplitude P 2d Since these are equal, the following (Equation 83) holds. F p / A 2p =F d / A 2d ...(Formula 83)

[0125] Furthermore, when the relationship of (Equation 73) above is established, (Equation 83) above can be expressed as the following (Equation 83'). F d =(3 / 2)F p ...(Formula 83')

[0126] As described above, the acoustic impedance Z1 of the first connecting surface C1 and the acoustic impedance Z2 of the piston second connecting surface C 2p The acoustic impedance Z 2p The piston second connection surface C can be matched with 2d Area A 2p is given by the following (Equation 91) (see Equation 5 above). A 2p =(A1V1F p / P1V 2p ) 1 / 2 ...(Formula 91)

[0127] Substituting the above equations (73) and (83') into this equation (91), and calculating "V 2p =V 2d " relationship, we obtain the following (Equation 92). (2 / 3)A 2d =((2 / 3)A1V1F d / P1V 2d ) 1 / 2 ...(Formula 92)

[0128] The above (Equation 92) is applied to the second diaphragm connection surface C 2d Area A 2d By rearranging, we obtain the following (Equation 93). A 2d =[(3 / 2)(A1V1F d / P1V 2d )] 1 / 2 ...(Formula 93)

[0129] In the thermoacoustic system according to this modification, the second connection surface C is arranged so that the above (Equation 93) is satisfied. 2dArea A 2d and the thrust force F generated by the receiving portion 22d. d In other words, in this modified example, the area A 2d and thrust F d By using one or both of the two parameters as adjustment parameters, the second connection surface C 2d The acoustic impedance Z 2d This adjusts the acoustic impedance Z1 of the first connecting surface C1 and the acoustic impedance Z2 of the second connecting surface C 2d The acoustic impedance Z 2d can be matched with.

[0130] Needless to say, the area A1 of the first connection surface C1 may be determined by rearranging the above (Equation 91) with respect to the area A1 of the first connection surface C1. In other words, by using the area A1 of the first connection surface C1 as an adjustment parameter, the area A1 of each connection surface C1, C 2d The acoustic impedance of the first and second electrodes may be matched.

[0131] <6-4. Other variations> In the above embodiment, the area A1 of the first connecting surface C1 and the area A2 of the second connecting surface C 2p Area A 2p If they do not match, the areas A1 and A 2p To fill the gap, a flange part G (Fig. 2(b)) is inserted between the connecting surfaces C1 and C2. 2p However, as shown in FIG. 7, for example, a tubular part Ga that expands (or contracts) from one end to the other end is connected to both connection surfaces C1 and C2. 2p Between the two connection surfaces C1 and C 2p With this configuration, it is possible to reduce the piping loss at the connection portion. However, in this case, both connection surfaces C1 and C 2p It is preferable that the length of the tubular part Ga is made sufficiently short so that the separation distance t between the tubular part Ga and the tubular part Ga is sufficiently short (i.e., so small that it can be ignored compared to the wavelength of the sound wave).

[0132] 8, the connection pipe 21 and the resonance pipe 12 are connected to each other at their connection surfaces C1 and C2. 2p Area of ​​A1,A 2p For example, inside the connecting pipe 21, the outer diameter corresponds to the area A1, and the inner diameter corresponds to the area A 2p Alternatively, the connection pipe 21 and the resonance pipe 12 may be connected after inserting a cylindrical inner tube Gb corresponding to the first connection surface C1. In this case, however, the receiving portion 22 is also disposed inside the inner tube Gb. Needless to say, the area A1 of the first connection surface C1 is larger than the area A2 of the second connection surface C2. 2p Area A 2p If the outer diameter is smaller than the area A 2p and an inner tube Gb having an inner diameter corresponding to the area A1 may be inserted into the resonance tube 12.

[0133] In the above embodiment, the second connecting surface C 2p Area A 2p Alternatively, by determining the area A1 of the first connecting surface C1, the acoustic impedance Z1 of the first connecting surface C1 and the acoustic impedance Z2 of the second connecting surface C1 can be calculated. 2p The acoustic impedance Z 2p The acoustic impedances Z1 and Z2 are set to be the same. 2p The areas A1 and A2 that match 2p The manner of determining is not limited to this, and may be determined, for example, through experiments, etc. The same applies to the second and third modified examples.

[0134] In the above embodiment, the second connection surface C 2p , receiving surface C 3p By defining the position as close as possible to the two surfaces C 2p ,C 3p Pressure amplitude P 2p ,P 3p For example, the second connecting surface C 2p , receiving surface C 3p By defining the distance d from the surface to be an integer multiple of the wavelength, 2p ,C 3p Pressure amplitude P 2p ,P 3pIn order to extract the maximum amount of acoustic energy propagating from the first engine 10, the receiving surface C 3p and the second connection surface C 2p In either case, it is also preferable to adjust the length of the connecting pipe 21 so that the positions correspond to the antinodes of the sound waves.

[0135] In the above embodiment, the second connection surface C 2p Area A 2p and receiving surface C 3p Area A 3p These areas A 2p ,A 3p However, it is considered that the smaller the difference between the two is, the higher the accuracy of impedance matching is. 2p Area A 2p and receiving surface C 3p Area A 3p Even if the areas of the first and second modifications are different, it is preferable that the difference between them is sufficiently small. The same applies to the second and third modifications.

[0136] In the above-mentioned second modified example, the diaphragm 222 stretched inside the connecting pipe 21 has a planar shape (a planar shape parallel to the cross section of the connecting pipe 21) in a natural state where it is not subjected to acoustic energy, but the diaphragm 222 may have a cone shape that contracts in the pipe direction of the connecting pipe 21 in a natural state. However, when a diaphragm of such a shape is adopted, the diaphragm receiving surface C 3d Area A 3d Rather than using the above (Equation 5d) as is when determining (Equation 5d), it is necessary to make appropriate modifications to (Equation 5d) taking into account the deformation that occurs in the cone-shaped diaphragm when it receives acoustic energy.

[0137] The configuration of the first engine 10 is not limited to that exemplified in the above embodiment. For example, the shape of the loop pipe 11 may be straight, U-shaped, or the like. Also, for example, a plurality of heat accumulators may be provided in the middle of the resonance pipe 12, and a pair of heat exchangers (i.e., a high-temperature side heat exchanger and a low-temperature side heat exchanger) for forming a temperature gradient may be provided at both ends of each heat accumulator. With this configuration, the traveling wave propagating through the resonance pipe 12 can be amplified to increase the acoustic energy.

[0138] The configuration of the second engine 20 is not limited to that exemplified in the above embodiment. For example, the power generating unit 23 of the second engine 20 may be any type that can convert vibration energy into electrical energy. For example, in the above embodiment, the power generating unit 23 is an inner movable type in which the mover 231 is disposed inside the stator 232, but it may be an outer movable type in which the mover 231 is disposed outside the stator 232.

[0139] In the above embodiment, the second engine 20 connected to the first engine 10 is a linear generator, but various other generators may be used as the second engine. Specifically, for example, an impulse turbine or the like may be used as the second engine.

[0140] Furthermore, in the above embodiment, the second engine 20 connected to the first engine 10, which is a thermoacoustic engine, is a generator, but the second engine connected to the first engine 10 is not limited to a generator. For example, the second engine may be a piezoelectric element, a thermoacoustic heat pump, a thermoacoustic engine, or the like.

[0141] Other configurations can also be modified in various ways without departing from the spirit of the present invention. [Explanation of symbols]

[0142] 10. First Agency 11 Loop tube 12 Resonance tube 13 Heat storage 14 High temperature side heat exchanger 15 Low temperature side heat exchanger 20. Second Institution 21 Connecting pipe 22,22d Receiving part 221 Piston 222 Diaphragm 23 Power Generation Department 24,24d Connecting part C1 First Connection Surface Z1 Acoustic impedance of the first connection surface C 2p ,C 2d Second connection surface Z 2p ,Z 2d Acoustic impedance of the second connection surface C 3p ,C 3d Receiving surface 100,100d Thermoacoustic System

Claims

1. A thermoacoustic system in which a first engine, which is a thermoacoustic engine that supplies acoustic energy, and a second engine that receives the supply of the acoustic energy are connected via a first connection surface of the first engine and a second connection surface of the second engine, The second engine includes a receiving portion that receives acoustic energy supplied from the first engine at a receiving surface and generates a predetermined thrust, The pressure amplitude of the second connection surface is equal to the pressure amplitude of the receiving surface, at least one of an area of ​​the first connection surface and an area of ​​the second connection surface is determined such that the predetermined thrust is generated in the receiving portion and an acoustic impedance of the first connection surface and an acoustic impedance of the second connection surface are equal to each other; The receiving portion includes a piston, The area of ​​the first connection surface is A １ , the pressure amplitude of the first connecting surface is P １ , the flow velocity at the first connection surface is V １ , the area of ​​the second connection surface is A ２ｐ , the flow velocity at the second connection surface is V ２ｐ , the predetermined thrust is F ｐ , then, The area of ​​the second connection surface is A ２ｐ =(A １ V １ F ｐ / P １ V ２ｐ ) １／２ A thermoacoustic system, characterized in that the thermoacoustic system is determined by the formula:

2. A thermoacoustic system in which a first engine, which is a thermoacoustic engine that supplies acoustic energy, and a second engine that receives the supply of the acoustic energy are connected via a first connection surface of the first engine and a second connection surface of the second engine, The second engine includes a receiving portion that receives acoustic energy supplied from the first engine at a receiving surface and generates a predetermined thrust, The pressure amplitude of the second connection surface is equal to the pressure amplitude of the receiving surface, at least one of an area of ​​the first connection surface and an area of ​​the second connection surface is determined such that the predetermined thrust is generated in the receiving portion and an acoustic impedance of the first connection surface and an acoustic impedance of the second connection surface are equal to each other; The receiving portion includes a diaphragm, The area of ​​the first connection surface is A １ , the pressure amplitude of the first connecting surface is P １ , the flow velocity at the first connection surface is V １ , the area of ​​the second connection surface is A ２ｄ , the flow velocity at the second connection surface is V ２ｄ , the predetermined thrust is F ｄ , then, The area of ​​the second connection surface is A ２ｄ =[(3 / 2)(A １ V １ F ｄ / P １ V ２ｄ )] １／２ A thermoacoustic system, characterized in that the thermoacoustic system is determined by the formula:

3. A connection method for connecting a first engine, which is a thermoacoustic engine that supplies acoustic energy, and a second engine having a receiving part that receives the acoustic energy at a receiving surface and generates a predetermined thrust, via a first connection surface of the first engine and a second connection surface of the second engine, defining the second connecting surface and the receiving surface such that a pressure amplitude of the second connecting surface and a pressure amplitude of the receiving surface are the same; determining at least one of an area of ​​the first connection surface and an area of ​​the second connection surface such that the predetermined thrust is generated in the receiving portion and an acoustic impedance of the first connection surface and an acoustic impedance of the second connection surface are equal to each other; connecting the first connection surface and the second connection surface; The present invention provides In the case where the receiving portion includes a piston, When the area of ​​the first connection surface is A 1 , the pressure amplitude of the first connection surface is P 1 , the flow velocity at the first connection surface is V 1 , the area of ​​the second connection surface is A 2p , the flow velocity at the second connection surface is V 2p , and the predetermined thrust is F p , The area of ​​the second connection surface is A 2p = (A 1 V 1 F p / P 1 V 2p ) 1 / 2 A method for connecting a thermoacoustic engine, characterized in that the connection is determined by:

4. A connection method for connecting a first engine, which is a thermoacoustic engine that supplies acoustic energy, and a second engine having a receiving part that receives the acoustic energy at a receiving surface and generates a predetermined thrust, via a first connection surface of the first engine and a second connection surface of the second engine, defining the second connecting surface and the receiving surface such that a pressure amplitude of the second connecting surface and a pressure amplitude of the receiving surface are the same; determining at least one of an area of ​​the first connection surface and an area of ​​the second connection surface such that the predetermined thrust is generated in the receiving portion and an acoustic impedance of the first connection surface and an acoustic impedance of the second connection surface are equal to each other; connecting the first connection surface and the second connection surface; The present invention provides In the case where the receiving portion includes a diaphragm, When the area of ​​the first connection surface is A 1 , the pressure amplitude of the first connection surface is P 1 , the flow velocity at the first connection surface is V 1 , the area of ​​the second connection surface is A 2d , the flow velocity at the second connection surface is V 2d , and the predetermined thrust is F d , The area of ​​the second connection surface is A 2d = [(3 / 2) (A 1 V 1 F d / P 1 V 2d )] 1 / 2 A method for connecting a thermoacoustic engine, characterized in that the connection is determined by:

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