Thermal sound device

Abstract

To enhance design flexibility of a thermoacoustic device.SOLUTION: A thermoacoustic device includes: piping that is configured to form an annular shape and can be filled with work gas; a prime mover; and a cooler. The piping includes: a first accommodation part that accommodates the prime mover; a second accommodation part that accommodates the cooler; and a waveguide part that connects the first accommodation part and the second accommodation part. The waveguide part includes: a main pipe part; and two enlargement parts having a larger inner diameter than that of the main pipe part. An inner diameter of each of the first accommodation part and the second accommodation part is larger than that of the main pipe part. A volume of each of the two enlargement parts is 30% or more of that of the first accommodation part. The volumes of the two enlargement parts are equal to each other.SELECTED DRAWING: Figure 6

Description

Technical Field

[0001] The technology disclosed in this specification relates to a thermoacoustic device.

Background Art

[0002] In a thermoacoustic engine (thermoacoustic device) including a loop tube filled with a working gas that propagates sound waves, and a prime mover and a passive machine (energy converter) incorporated in the loop tube, it is known to provide a sound field adjustment mechanism in the middle of the loop tube. The sound field adjustment mechanism is, for example, an expansion tube having a larger flow path cross-sectional area than other parts of the loop tube. A technique has been proposed to improve the energy conversion efficiency by arranging the prime mover and the passive machine at symmetric positions in the loop tube and arranging the sound field adjustment mechanism in a predetermined section of the loop tube (see Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the above thermoacoustic device, the section where the sound field adjustment mechanism can be arranged is extremely limited, for example, at a position of 5 to 10% of the total length of the loop tube from the prime mover, and there is a problem that the design freedom is low.

[0005] Note that such a problem is the same when the energy converter is used for applications other than the above thermoacoustic device (for example, a heat pump that performs heat transfer by inputting acoustic energy to a heat storage device).

[0006] This specification discloses a technology capable of solving the above-described problems.

Means for Solving the Problems

[0007] The technology disclosed herein can be realized, for example, in the following forms: (1) The thermoacoustic apparatus disclosed herein comprises two energy converters, each comprising: a piping configured in an annular shape and capable of containing a working gas; a heat accumulator having one face and the other face, and having a plurality of through passages penetrating from the one face to the other face; a first heat exchanger positioned opposite the one face of the heat accumulator and having a first flow path through which a first fluid can flow; and a second heat exchanger positioned opposite the other face of the heat accumulator and having a second flow path through which a second fluid can flow, wherein one of the two energy converters is a prime mover that converts thermal energy into acoustic energy, and the other is the The cooling device generates a temperature gradient by inputting acoustic energy amplified by a prime mover, and the piping includes a first housing for housing the prime mover, a second housing for housing the cooling device, and a waveguide connecting the first housing and the second housing, wherein the waveguide includes a main pipe and two enlarged sections having an inner diameter larger than the inner diameter of the main pipe, the first housing and the second housing both have an inner diameter larger than the inner diameter of the main pipe, the volume of each of the enlarged sections is 30% or more of the volume of the first housing, and the two enlarged sections have equal volumes to each other.

[0008] With the above configuration, the thermoacoustic device can operate even if there are relatively large changes in the positional relationship between the two housing sections, or between the housing section and the expansion section. This increases the design flexibility of the thermoacoustic device.

[0009] (2) In the thermoacoustic device described in (1) above, at least one of the enlarged portions is provided between the first heat exchanger provided in the prime mover and the cooler, and the central portion between the ends of at least one of the enlarged portions is provided between a position at a distance D1 calculated by the following formula (1) and a position at a distance D2 calculated by the following formula (2) from the first housing portion. D1 = La × 0.2 ·····(1) D2 = La × 0.3 ·····(2) (In the formula, La represents the total length of the pipe.)

[0010] As long as the positional relationship of at least one enlargement with respect to the first housing remains within the above range, the thermoacoustic device can operate even if there are relatively large variations in the arrangement of the second housing and the enlargement. This increases the design flexibility of the thermoacoustic device.

[0011] (3) Other thermoacoustic devices disclosed herein include two energy converters comprising: a piping configured in an annular shape and capable of containing a working gas; a heat accumulator having one face and the other face, and having a plurality of through passages penetrating from the one face to the other face; a first heat exchanger positioned opposite the one face of the heat accumulator and having a first flow path through which a first fluid can flow; and a second heat exchanger positioned opposite the other face of the heat accumulator and having a second flow path through which a second fluid can flow, wherein one of the two energy converters is a prime mover that converts thermal energy into acoustic energy, and the other is a cooler that generates a temperature gradient when acoustic energy amplified by the prime mover is input, and the piping The device includes a first housing for housing the prime mover, a second housing for housing the cooler, and a waveguide connecting the first housing and the second housing, wherein the waveguide includes a main pipe and two enlarged sections having an inner diameter larger than the inner diameter of the main pipe, the first housing and the second housing both have an inner diameter larger than the inner diameter of the main pipe, the two enlarged sections have equal volumes, the enlarged sections are not located between the second heat exchanger provided in the prime mover and the cooler, and the central part between the ends of the second housing may be located between a position a distance D3 calculated by the following formula (3) and a position a distance D4 calculated by the following formula (4) from the first housing. D3 = La × 0.2 ·····(3) D4 = La × 0.3 ·····(4) (In the formula, La represents the total length of the pipe.)

[0012] If the positional relationship of the second accommodating portion with respect to the first accommodating portion is within the above range, the thermoacoustic device can be operated even if there are relatively large variations in the volume and arrangement of the enlarged portion. As a result, the degree of freedom in the design of the thermoacoustic device is increased.

[0013] Note that the technology disclosed in this specification can be realized in various forms, for example, in the form of a thermoacoustic device and its manufacturing method.

Brief Description of the Drawings

[0014] [Figure 1] Perspective view showing a partially cut-away thermoacoustic device of an embodiment [Figure 2] Cross-sectional view taken along line II-II of FIG. 1 [Figure 3] Perspective view of a regenerator of an embodiment [Figure 4] Diagram schematically showing the shape of a first heat transfer tube provided in a first heat exchanger in an embodiment [Figure 5] Diagram schematically showing the shape of a second heat transfer tube provided in a second heat exchanger in an embodiment [Figure 6] Diagram schematically showing the configuration of a thermoacoustic device of an embodiment [Figure 7] Diagram schematically showing the positional relationship between a first accommodating portion and a first enlarged portion, and the positional relationship between the first accommodating portion and a second accommodating portion in a thermoacoustic device of an embodiment [Figure 8] Diagram schematically showing the configuration of a thermoacoustic device used in Calculation Example 4 [Figure 9] For Calculation Example 1-1, with the length L1 of the first main pipe section as the first axis (X-axis), the length L3 of the third main pipe section as the second axis (Y-axis), and the length L4 of the fourth main pipe section as the third axis (Z-axis), a three-dimensional graph plotting the minimum value of the high-temperature surface temperature Thot [Figure 10] For Calculation Example 1-1, with the length L1 of the first main pipe section as the first axis (X-axis) and the length L3 of the third main pipe section as the second axis (Y-axis), a two-dimensional graph plotting the minimum value of the high-temperature surface temperature Thot [Figure 11]For Calculation Example 1-1, taking the length L1 of the first main pipe section as the first axis (X-axis) and the length L4 of the fourth main pipe section as the second axis (Y-axis), a two-dimensional graph plotting the minimum value of the high-temperature surface temperature Thot [Figure 12] For Calculation Example 1-1, taking the length L3 of the third main pipe section as the first axis (X-axis) and the length L4 of the fourth main pipe section as the second axis (Y-axis), a two-dimensional graph plotting the minimum value of the high-temperature surface temperature Thot [Figure 13] For Calculation Example 1-2, taking the length L1 of the first main pipe section as the first axis (X-axis), the length L3 of the third main pipe section as the second axis (Y-axis), and the length L4 of the fourth main pipe section as the third axis (Z-axis), a three-dimensional graph plotting the minimum value of the high-temperature surface temperature Thot [Figure 14] For Calculation Example 1-2, taking the length L1 of the first main pipe section as the first axis (X-axis) and the length L3 of the third main pipe section as the second axis (Y-axis), a two-dimensional graph plotting the minimum value of the high-temperature surface temperature Thot [Figure 15] For Calculation Example 1-2, taking the length L1 of the first main pipe section as the first axis (X-axis) and the length L4 of the fourth main pipe section as the second axis (Y-axis), a two-dimensional graph plotting the minimum value of the high-temperature surface temperature Thot [Figure 16] For Calculation Example 1-2, taking the length L3 of the third main pipe section as the first axis (X-axis) and the length L4 of the fourth main pipe section as the second axis (Y-axis), a two-dimensional graph plotting the minimum value of the high-temperature surface temperature Thot [Figure 17] For Calculation Example 1-3, taking the length L1 of the first main pipe section as the first axis (X-axis), the length L3 of the third main pipe section as the second axis (Y-axis), and the length L4 of the fourth main pipe section as the third axis (Z-axis), a three-dimensional graph plotting the minimum value of the high-temperature surface temperature Thot [Figure 18] For Calculation Example 1-3, taking the length L1 of the first main pipe section as the first axis (X-axis) and the length L3 of the third main pipe section as the second axis (Y-axis), a two-dimensional graph plotting the minimum value of the high-temperature surface temperature Thot [Figure 19] For Calculation Example 1-3, taking the length L1 of the first main pipe section as the first axis (X-axis) and the length L4 of the fourth main pipe section as the second axis (Y-axis), a two-dimensional graph plotting the minimum value of the high-temperature surface temperature Thot [Figure 20]For calculation example 1-3, the length L3 of the third main pipe section is taken as the first axis (X axis), and the length L4 of the fourth main pipe section is taken as the second axis (Y axis), and the minimum value of the high-temperature surface temperature Thot is plotted in a 2D graph. [Figure 21] For calculation example 1-4, the length L1 of the first main pipe section is taken as the first axis (X-axis), the length L3 of the third main pipe section as the second axis (Y-axis), and the length L4 of the fourth main pipe section as the third axis (Z-axis), and the minimum value of the high-temperature surface temperature Thot is plotted in a 3D graph. [Figure 22] For calculation example 1-4, the length L1 of the first main pipe section is taken as the first axis (X axis), and the length L3 of the third main pipe section is taken as the second axis (Y axis), and the minimum value of the high-temperature surface temperature Thot is plotted in a 2D graph. [Figure 23] For calculation example 1-4, the length L1 of the first main pipe section is taken as the first axis (X-axis), and the length L4 of the fourth main pipe section is taken as the second axis (Y-axis), and the minimum value of the high-temperature surface temperature Thot is plotted in a 2D graph. [Figure 24] For calculation example 1-4, the length L3 of the third main pipe section is taken as the first axis (X axis), and the length L4 of the fourth main pipe section is taken as the second axis (Y axis), and the minimum value of the high-temperature surface temperature Thot is plotted in a 2D graph. [Figure 25] For calculation example 2-1, the length L1 of the first main pipe section is taken as the first axis (X axis), the length L2 of the second main pipe section as the second axis (Y axis), and the length L3 of the third main pipe section as the third axis (Z axis), and the minimum value of the high-temperature surface temperature Thot is plotted in a 3D graph. [Figure 26] For calculation example 2-1, the length L1 of the first main pipe section is taken as the first axis (X axis), and the length L2 of the second main pipe section is taken as the second axis (Y axis), and the minimum value of the high-temperature surface temperature Thot is plotted in a 2D graph. [Figure 27] For calculation example 2-1, the length L1 of the first main pipe section is taken as the first axis (X axis), and the length L3 of the third main pipe section is taken as the second axis (Y axis), and the minimum value of the high-temperature surface temperature Thot is plotted in a 2D graph. [Figure 28] For calculation example 2-1, the length L2 of the second main pipe section is taken as the first axis (X axis), and the length L3 of the third main pipe section is taken as the second axis (Y axis), and the minimum value of the high-temperature surface temperature TThot is plotted in a 2D graph. [Figure 29]For calculation example 2-2, the length L1 of the first main pipe section is taken as the first axis (X axis), the length L2 of the second main pipe section as the second axis (Y axis), and the length L3 of the third main pipe section as the third axis (Z axis), and the minimum value of the high-temperature surface temperature Thot is plotted in a 3D graph. [Figure 30] For calculation example 2-2, the length L1 of the first main pipe section is taken as the first axis (X axis), and the length L2 of the second main pipe section is taken as the second axis (Y axis), and the minimum value of the high-temperature surface temperature Thot is plotted in a 2D graph. [Figure 31] For calculation example 2-2, the length L1 of the first main pipe section is taken as the first axis (X axis), and the length L3 of the third main pipe section is taken as the second axis (Y axis), and the minimum value of the high-temperature surface temperature Thot is plotted in a 2D graph. [Figure 32] For calculation example 2-2, the length L2 of the second main pipe section is taken as the first axis (X axis), and the length L3 of the third main pipe section is taken as the second axis (Y axis), and the minimum value of the high-temperature surface temperature Thot is plotted in a 2D graph. [Figure 33] A schematic diagram showing the configuration of a modified thermoacoustic device. [Modes for carrying out the invention]

[0015] A. Embodiments: A-1. Configuration of Thermoacoustic Device 100A The embodiments will be described with reference to Figures 1 to 7. The thermoacoustic device 100A of this embodiment is a cooling device that uses acoustic energy to maintain the temperature of an object at a temperature lower than room temperature.

[0016] (Overall configuration of thermoacoustic device 100A) As shown in Figure 1, the thermoacoustic device 100A comprises a piping 200 and a prime mover 400 and a cooler 500 arranged inside the piping 200.

[0017] The piping 200 is made of metal, for example, and as shown in Figure 1, comprises a number of main pipes 210, 220, 230, and 240, two expansion pipes 250 and 260, a prime mover piping 270, and a cooler piping 280. The prime mover 400 is housed inside the prime mover piping 270, and the cooler 500 is housed inside the cooler piping 280.

[0018] A loop-shaped conduit 290 is formed by main pipes 210, 220, 230, and 240, expansion pipes 250 and 260, prime mover piping 270, and cooler piping 280. The conduit 290 is capable of containing a working gas. The working gas is not particularly limited as long as it is a gas that can transmit sound waves, and an inert gas consisting of helium, argon, or a mixture of helium and argon, or air is preferably used.

[0019] Each of the multiple main pipes 210, 220, 230, and 240 has a constant inner diameter along its entire length. The multiple main pipes 210, 220, 230, and 240 are all pipes of the same diameter. Main pipe 210 is the pipe that connects the prime mover piping 270 to the first expansion pipe 250. Main pipe 220 is the pipe that connects the two expansion pipes 250 and 260. Main pipe 230 is the pipe that connects the second expansion pipe 260 to the cooling machine piping 280. Main pipe 240 is the pipe that connects the cooling machine piping 280 to the prime mover piping 270.

[0020] The first expanding tube 250, as shown in Figure 2, is a tube having openings at both ends, and comprises two small straight tube sections 252 and 256, two tapered sections 253 and 255, and a large straight tube section 254. The two small straight tube sections 252 and 256 are two short straight tube-shaped portions located at each end of the first expanding tube 250. The large straight tube section 254 is located in the center between the two small straight tube sections 252 and 256, and is a short straight tube-shaped portion having a larger inner diameter than the small straight tube sections 252 and 256. The two tapered sections 253 and 255 connect one of the small straight pipe sections 252 and 256 to the large straight pipe section 254, and the other small straight pipe section 252 and 256 to the large straight pipe section 254, respectively, and are the parts where the diameter decreases from the large straight pipe section 254 towards the two small straight pipe sections 252 and 256. The inner diameter of the small straight pipe sections 252 and 256 is equal to the inner diameter of the main pipes 210, 220, 230, and 240.

[0021] The second expansion tube 260 has the same configuration as the first expansion tube 250, so a detailed explanation is omitted. The second expansion tube 260 has the same shape and dimensions as the first expansion tube 250.

[0022] As shown in Figure 2, the prime mover piping 270 is a pipe having an opening at one end 270E1 and the other end 270E2, and comprises two small straight pipe sections 272 and 276, two tapered sections 273 and 275, and a large straight pipe section 274. The two small straight pipe sections 272 and 276 are two short straight pipe-shaped sections located at each end of the prime mover piping 270. The large straight pipe section 274 is located in the center between the two small straight pipe sections 272 and 276 and is a short straight pipe-shaped section having a larger inner diameter than the small straight pipe sections 272 and 276. The two tapered sections 273 and 275 connect one of the small straight pipe sections 272 and 276 to the large straight pipe section 274, and the other small straight pipe section 272 and 276 to the large straight pipe section 274, respectively, and are the parts where the diameter decreases from the large straight pipe section 274 towards the two small straight pipe sections 272 and 276. The inner diameter of the small straight pipe sections 272 and 276 is equal to the inner diameter of the main pipes 210, 220, 230, and 240.

[0023] The configuration of the cooling system piping 280 is the same as that of the prime mover piping 270, so a detailed explanation is omitted. The cooling system piping 280 has the same shape and dimensions as the prime mover piping 270.

[0024] (Configuration of the 400cc engine) The prime mover 400 is a device for converting thermal energy into acoustic energy (sound waves), and is located inside the large straight pipe section 274 of the prime mover piping 270. As shown in Figures 1 and 2, the prime mover 400 includes a heat accumulator 410, a first heat exchanger 420, and a second heat exchanger 430. The first heat exchanger 420, the heat accumulator 410, and the second heat exchanger 430 are arranged in this order from one end 270E1 to the other end 270E2.

[0025] (Regenerator 410) The heat storage unit 410 is a thick, disc-shaped structure with one surface 410F1 (the right-hand surface in Figure 2) and the other surface 410F2 (the left-hand surface in Figure 2). As shown in Figure 2, the heat storage unit 410 is positioned perpendicular to the axial direction of the motor piping 270, with one surface 410F1 facing one end 270E1 of the motor piping 270 and the other surface 410F2 facing the other end 270E2 of the motor piping 270.

[0026] As shown in Figure 3, the heat storage device 410 comprises a laminate 412 formed by stacking multiple circular metal meshes 411 in a compressed state, and a fixing body 413 fixed to the outer surface of the laminate 412. The metal mesh 411 is a mesh-like member in which multiple fine metal wires are woven together. The multiple metal meshes 411 have substantially the same outer shape and are stacked with their outer edges aligned. The laminate 412 is formed by the interconnected mesh (gaps between fine wires) of the multiple metal meshes 411 and has numerous fine through passages 414 that penetrate from one surface 410F1 to the other surface 410F2 of the laminate 412. The fixing body 413 is fixed to the outer surface of the laminate 412 and plays the role of holding the outer edges of the multiple metal meshes 411 so that they do not separate from each other.

[0027] (First heat exchanger 420, second heat exchanger 430) As shown in Figure 2, the first heat exchanger 420 is arranged adjacent to one side 410F1 of the heat accumulator 410. As the first heat exchanger 420, a known heat exchanger comprising a first heat transfer tube 421 (an example of a first flow path) and fins (not shown) arranged around the first heat transfer tube 421 can be used, as shown in Figure 4. A high-temperature heat transfer medium (an example of a first fluid) can flow inside the first heat transfer tube 421, and heat exchange takes place between the working gas near the first heat exchanger 420 and the heat transfer medium. As the heat transfer medium, for example, heat transfer oil heated by waste heat from a factory can be used. The temperature of the heat transfer oil is, for example, about 200-400°C.

[0028] As shown in Figure 2, the second heat exchanger 430 is arranged adjacent to the other side 410F2 of the heat accumulator 410. As the second heat exchanger 430, a known heat exchanger comprising a second heat transfer tube 431 (an example of a second flow path) and fins (not shown) arranged around the second heat transfer tube 431 can be used, as shown in Figure 5. Inside the second heat transfer tube 431, a refrigerant (an example of a second fluid) at a lower temperature than the heat transfer medium flowing inside the first heat transfer tube 421 is allowed to flow, so that the working gas near the second heat exchanger 430 is at a lower temperature than the heat transfer medium. In this embodiment, room temperature water is used as the refrigerant supplied to the second heat transfer tube 431.

[0029] (Cooler 500) The cooler 500 is a heat pump that generates a temperature gradient by receiving acoustic energy amplified by the prime mover 400, thereby maintaining the temperature of the object at a temperature lower than ambient temperature. As shown in Figure 1, it is located inside the cooler piping 280. The cooler 500 comprises a heat accumulator 510 having one side 510F1 and the other side 510F2, a first heat exchanger 520 located on one side 510F1 of the heat accumulator 510, and a second heat exchanger 530 located on the other side 510F2 of the heat accumulator 510 (see also Figure 6). The heat accumulator 510 and the heat exchangers 520 and 530 provided in the cooler 500 have the same configuration as the heat accumulator 410 and the heat exchangers 420 and 430 provided in the prime mover 400. A medium at a constant temperature (in this embodiment, water at room temperature) can circulate inside the heat transfer tubes of the first heat exchanger 520, so that the working gas near the first heat exchanger 520 reaches a temperature of approximately room temperature. The heat transfer tubes of the second heat exchanger 530 are connected to a heat exchanger in an external cooling system, and a refrigerant can circulate inside these heat transfer tubes.

[0030] A-2. Operation of the 100A thermoacoustic device: When the thermoacoustic device 100A is operated, a heat transfer medium is flowed through the first heat transfer tube 421. Then, heat exchange takes place between the working gas near one side 410F1 of the condenser 410 and the heat transfer medium. As a result, the temperature of the working gas near one side 410F1 of the condenser 410 is adjusted to approach the temperature of the heat transfer medium. In addition, room temperature water, which acts as a refrigerant, is flowed through the second heat transfer tube 431. Then, heat exchange takes place between the working gas near the other side 410F2 of the condenser 410 and the room temperature water. As a result, the temperature of the working gas near the other side 410F2 of the condenser 410 is adjusted to approach room temperature.

[0031] The action of these heat exchangers 420 and 430 creates a temperature gradient between one side 410F1 and the other side 410F2 of the heat accumulator 410. This causes the working gas inside the through-passage 414 to become unstable and begin to vibrate. This vibration amplifies acoustic energy (sound waves). The amplified acoustic energy is output from one side 410F1 of the heat accumulator 410, transmitted through the working gas sealed inside the pipe 290, and reaches the cooler 500 (see arrow in Figure 1).

[0032] Acoustic energy transmitted by the working gas is input to the heat accumulator 510 provided in the cooler 500 from one surface 510F1. This creates a temperature gradient between the surface 510F1 facing the first heat exchanger 520 and the other surface 510F2 facing the second heat exchanger 530. Since room temperature water flows through the first heat exchanger 520, which is located on the surface 510F1 into which the acoustic energy is input in the cooler 500, the temperature of the working gas near the second heat exchanger 530 in the heat accumulator 510 is adjusted to a temperature lower than room temperature by the amount of the resulting temperature gradient. Heat exchange takes place between this lower-temperature working gas and the refrigerant, and the cooled refrigerant is supplied to an external cooling system to cool the object.

[0033] A-3. Detailed configuration of piping 200: As shown in Figure 2, the main pipe 210 and the two adjacent small straight pipe sections 256 and 272 constitute a first main pipe section 292 having a constant inner diameter. Of the first expanding pipe 250, the tapered sections 253 and 255 and the large straight pipe section 254 constitute a first expanding section 296 (an example of an expanding section) having a larger inner diameter than the first main pipe section 292. Of the prime mover piping 270, the tapered sections 273 and 275 and the large straight pipe section 274 constitute a first housing section 298 having a larger inner diameter than the first main pipe section 292.

[0034] Similarly, the portion of the second expansion pipe 260 with a larger inner diameter than the main pipe sections 292, 293, 294, and 295 constitutes the second expansion section 297 (an example of an expansion section), and the portion of the cooling machine piping 280 with a larger inner diameter than the main pipe sections 292, 293, 294, and 295 constitutes the second housing section 299. The remaining portion constitutes the second main pipe section 293, the third main pipe section 294, and the fourth main pipe section 295, which have the same inner diameter as the first main pipe section 292. As shown in Figure 6, the first main pipe section 292 connects the first housing section 298 and the first expansion section 296. The second main pipe section 293 connects the first expansion section 296 and the second expansion section 297. The third main pipe section 294 connects the second expansion section 297 and the second housing section 299. The fourth main section 295 connects the second housing section 299 and the first housing section 298. The main sections 292, 293, 294, and 295, along with the extension sections 296 and 297, constitute the waveguide section 291 that connects the first housing section 298 and the second housing section 299.

[0035] In this embodiment, the first enlarged section 296, the second enlarged section 297, the first housing section 298, and the second housing section 299 have equal volumes. Nothing is placed inside the first enlarged section 296, and the volume of the first enlarged section 296 is the sum of the capacities of the tapered sections 253 and 255 and the large straight pipe section 254. The same applies to the second enlarged section 297. The prime mover 400 is placed inside the first housing section 298, and the volume of the first housing section 298 is the sum of the capacities of the tapered sections 273 and 275 and the large straight pipe section 274, minus the volume occupied by the actual parts of the components constituting the prime mover 400, excluding the internal space of the first heat transfer tube 421 and the internal space of the through passage 414 of the heat accumulator 510. The same applies to the second housing section 299.

[0036] Two enlarged sections 296 and 297 are positioned between the first heat exchanger 420, which is provided on the prime mover 400, and the cooler 500. Furthermore, no enlarged sections are positioned between the second heat exchanger 430, which is also provided on the prime mover 400, and the cooler 500. In other words, the first housing section 298, the first enlarged section 296, the second enlarged section 297, and the second housing section 299 are arranged in this order along the direction in which the acoustic energy amplified by the prime mover 400 is transmitted (indicated by the dotted arrows in Figures 2 and 6).

[0037] As shown in Figure 7, of the two enlarged sections 296 and 297, the first enlarged section 296, which is closer to the first housing section 298 (i.e., located upstream of the flow of acoustic energy amplified by the prime mover 400), is preferably positioned between a position D1, calculated by formula (1) below, and a position D2, calculated by formula (2) below, from the boundary position BP1 between the first housing section 298 and the first main pipe section 292. More specifically, in the pipeline 290, the central part CP1 between the two ends of the first enlarged section 296 is preferably positioned between a position D1, calculated by formula (1) below, and a position D2, calculated by formula (2) below. Note that distances D1 and D2 are distances measured along the pipeline 290, starting from the boundary position BP1.

[0038] D1 = La × 0.2 ·····(1) D2 = La × 0.3 ·····(2) In the formula, La represents the total length of pipe 290.

[0039] Furthermore, as shown in Figure 7, it is preferable that the second housing section 299 is located between a position D3, calculated by formula (3) below, and a position D4, calculated by formula (4) below, from the boundary position BP2 between the first housing section 298 and the fourth main pipe section 295. More specifically, it is preferable that the central part CP2 of the second housing section 299 between its ends is located between a position D3, calculated by formula (3) below, and a position D4, calculated by formula (4) below, in the pipeline 290. Note that distances D3 and D4 are distances measured along the pipeline 290, starting from the boundary position BP2.

[0040] D3 = La × 0.2 ·····(3) D4 = La × 0.3 ·····(4) (In the formula, La represents the total length of the pipe.)

[0041] A4. Effects of this embodiment: As described above, the thermoacoustic device 100A of this embodiment comprises a piping 200 configured in an annular shape and capable of containing a working gas, a prime mover 400, and a cooler 500. The prime mover 400 comprises a heat accumulator 410 having one side 410F1 and the other side 410F2, and having a plurality of through passages 414 penetrating from the one side 410F1 to the other side 410F2, a first heat exchanger 420 positioned opposite the one side 410F1 of the heat accumulator 410 and equipped with a first heat transfer tube 421 through which a heat transfer medium can flow, and a second heat exchanger 430 positioned opposite the other side 410F2 of the heat accumulator 410 and equipped with a second heat transfer tube 431 through which water at room temperature can flow. The cooler 500 similarly comprises a heat accumulator 510, a first heat exchanger 520, and a second heat exchanger 530. The piping 200 includes a first housing section 298 and a second housing section 299, each housing a prime mover 400 and a cooler 500, respectively, and a waveguide section 291 connecting the first housing section 298 and the second housing section 299. The waveguide section 291 includes main pipe sections 292, 293, 294, and 295, and two enlarged sections 296 and 297 having larger inner diameters than the main pipe sections 292, 293, 294, and 295. The housing sections 298 and 299 have larger inner diameters than the main pipe sections 292, 293, 294, and 295, and the volume of each of the two enlarged sections 296 and 297 is 30% or more of the volume of the housing sections 298 and 299, and the two enlarged sections 296 and 297 have equal volumes.

[0042] With the above configuration, the thermoacoustic device 100A can operate even if there are relatively large changes in the positional relationship between the two housing sections 298 and 299, or between the housing sections 298 and 299 and the expansion sections 296 and 297. This increases the design flexibility of the thermoacoustic device 100A.

[0043] Furthermore, enlarged sections 296 and 297 are positioned between the first heat exchanger 420 provided in the prime mover 400 and the cooler 500, and the central section CP between the ends of the first enlarged section 296 is positioned between a position at a distance D1 calculated by the following formula (1) and a position at a distance D2 calculated by the following formula (2) from the first housing section 298 that houses the prime mover 400.

[0044] D1 = La × 0.2 ·····(1) D2 = La × 0.3 ·····(2) (In the formula, La represents the total length of the pipe.)

[0045] Furthermore, the second housing section 299 is positioned between a position D3, calculated by formula (3) below, and a position D4, calculated by formula (4) below, from the boundary position BP2 between the first housing section 298 and the fourth main pipe section 295.

[0046] D3 = La × 0.2 ·····(3) D4 = La × 0.3 ·····(4) (In the formula, La represents the total length of the pipe.)

[0047] As long as the positional relationship of the second housing section 299 with respect to the first housing section 298 is within the above range, the thermoacoustic device 100A can operate even if there are relatively large fluctuations in the volume and arrangement of the enlarged sections 296 and 297. This increases the design flexibility of the thermoacoustic device 100A.

[0048] A-5. Performance evaluation: The relationship between the arrangement of the housing and expansion sections in a thermoacoustic device and the operability of the device was evaluated through simulation.

[0049] (Calculation example 1-1) A thermoacoustic device 100A having the same configuration as the above embodiment was set as a simulation model (see Figure 6). The specifications of the enlarged sections 296 and 297 were set as shown in Table 1, and the volume of each of the two enlarged sections was set to 100% of the volume of the first housing section.

[0050] The following calculation conditions were applied to the above simulation model. In a heat storage device installed in a prime mover, the temperature of the surface (one surface 410F1) on which the first heat exchanger is located (high temperature surface temperature T) hot ) Search range: 100-300℃ In a heat storage unit installed in a cooling machine, the temperature of the side on which the second heat exchanger is located (other side 510F2) is (low temperature side temperature T ewf Target temperature: -20℃ In a heat regenerator installed in a prime mover, the side on which the second heat exchanger is located (other side 410F2), in a heat regenerator installed in a cooler, the side on which the first heat exchanger is located (one side 510F1), and the temperature T of the working gas sealed inside the piping. amb :20℃ Type of working gas: Helium Average pressure of the working gas: 3 MPa

[0051] The sum of the lengths L1, L2, L3, and L4 of the main pipe sections 292, 293, 294, and 295 is fixed at 10m, and the lengths L1, L2, L3, and L4 of each main pipe section 292, 293, 294, and 295 are varied in 0.1m increments from 0.1m to 6m, so that vibration of the working gas occurs (i.e., the thermoacoustic device operates) at a high surface temperature T hot We explored it.

[0052] (Calculation example 1-2) The specifications of the enlarged sections were set as shown in Table 1, and the volume of each of the two enlarged sections was set to 50% of the volume of the first storage section. Other conditions were set in the same way as in Calculation Example 1-1, and the analysis was performed.

[0053] (Calculation example 1-3) The specifications of the enlarged sections were set as shown in Table 1, and the volume of each of the two enlarged sections was set to 30% of the volume of the first storage section. Other conditions were set in the same way as in Calculation Example 1-1, and the analysis was performed.

[0054] (Calculation example 1-4) The specifications of the enlarged sections were set as shown in Table 1, and the volume of each of the two enlarged sections was set to 10% of the volume of the first storage section. Other conditions were set in the same way as in Calculation Example 1-1, and the analysis was performed.

[0055] [Table 1]

[0056] (Calculation example 2-1) As a simulation model, as shown in Figure 8, a thermoacoustic device 100B was set up that has the same configuration as the thermoacoustic device 100A, except that it does not have a second enlargement section 297, the first enlargement section 296 and the second housing section 299 are connected by a second main pipe section 293B, and the first housing section 298 and the second housing section 299 are connected by a third main pipe section 294B.

[0057] The same calculation conditions as in Calculation Example 1-1 were applied to this simulation model. Furthermore, the specifications of the first expansion section 296 were set in the same way as in Calculation Example 1-1, and the volume of the first expansion section 296 was set to 100% of the volume of the first housing section 298. The sum of the lengths L1, L2, and L3 of the main pipe sections 292, 293B, and 294B was fixed at 10m, and the lengths L1, L2, and L3 of each main pipe section 292, 293B, and 294B were varied from 0.1m to 6m in 0.1m increments, and the high-temperature surface temperature T at which vibration of the working gas occurs was calculated in the same way as in Calculation Example 1-1. hot We explored it.

[0058] (Calculation example 2-2) The specifications of the first enlarged section were set in the same way as in Calculation Example 1-2, and the volume of the first enlarged section was set to 50% of the volume of the first storage section. Other conditions were set in the same way as in Calculation Example 2-1, and the analysis was performed.

[0059] (result) Comparing calculation examples 1-1, 1-2, 1-3, and 1-4, all of which have two enlarged sections, it was found that in calculation example 1-4, where the volume of the enlarged section is 10% of the volume of the housing section, the thermoacoustic device only operates within the range where the length L4 of the fourth main pipe section is approximately 2m, as shown in Figure 21-24. In other words, it was found that the distance between the first housing section 298 and the second housing section 299 is a significant constraint for the thermoacoustic device to be operational. However, if the length L4 of the fourth main pipe section is approximately 2m, the thermoacoustic device can operate even if the lengths L1 of the first main pipe section and L3 of the third main pipe section fluctuate relatively large, indicating that even with a small volume of the enlarged section, there is a high degree of design freedom for the thermoacoustic device.

[0060] In calculation examples 1-1, 1-2, and 1-3, where the volume of the enlarged section is 100%, 50%, and 30% of the volume of the housing section, as shown in Figure 9-20, the range of the main pipe section length L1-L4 in which the thermoacoustic device can operate is wider compared to calculation example 1-4. This confirms that the larger the ratio of the volume of the enlarged section, the wider the operating range. Therefore, focusing on the relationship between the volume of the enlarged section and the degree of design freedom of the thermoacoustic device, it can be said that the degree of design freedom can be increased if the volume of the enlarged section is 30% or more of the volume of the housing section, it is preferable that it is 50% or more, and even more preferable that it is 100%.

[0061] Furthermore, comparing calculation example 1-1 with calculation example 2-1, and calculation example 1-2 with calculation example 2-2, it was confirmed that when the ratio of the volume of the expansion section to the volume of the housing section is the same, having two expansion sections provides a wider range of the main pipe length L1-L4 in which the thermoacoustic device can operate compared to having one expansion section. From this, it can be said that having two expansion sections provides greater design flexibility for the thermoacoustic device compared to having one expansion section.

[0062] Table 2 shows the high-temperature surface temperature T for calculation examples 1-1 to 1-4. hot When the value of is minimized, the lengths L1, L2, L3, L4 of the main pipe section and the high-temperature surface temperature T hot The minimum value was shown. Similarly, Table 3 shows the results for calculation examples 2-1 and 2-2.

[0063] [Table 2]

[0064] [Table 3]

[0065] B. Variations: The technologies disclosed herein are not limited to the embodiments described above and can be modified in various forms without departing from their essence, for example, the following modifications are possible. (1) In the above embodiment, the first housing section 298, the first enlarged section 296, the second enlarged section 297, and the second housing section 299 were arranged in this order. However, the order of the housing sections and enlarged sections is not limited to the above embodiment. For example, as in the thermoacoustic device 100C shown in Figure 33, the positions of the second enlarged section 297 and the second housing section 299 may be swapped. (2) In the above embodiment, one of the two enlarged portions was positioned between a position D1 and a position D2 away from the boundary position BP1. However, both of the two enlarged portions may be positioned between the position D1 and the position D2 away from the boundary position BP1, only one may be positioned there, or neither may be positioned there. [Explanation of Symbols]

[0066] 100A, 100B, 100C: Thermoacoustic device 200: Piping 210, 220, 230, 240: Main pipe 250: First expansion pipe 252, 256: Small straight pipe section 253, 255: Tapered section 274: Large straight pipe section 260: Second expansion pipe 270: Piping for prime mover 270E1: One end 270E2: Other end 272, 276: Small straight pipe section 273, 275: Tapered section 274: Large straight pipe section 280: Piping for cooler 290: Pipeline 291: Waveguide section 292: First main pipe section 293, 293B: Second main pipe section 294, 294B: Third main pipe section 295: Fourth main pipe section 296: First expansion section 297: Second enlargement section 298: First housing section 299: Second housing section 400: Prime mover (energy converter) 410: Heat accumulator 410F1: One side 410F2: Other side 411: Metal mesh 412: Laminate 413: Fixed body 414: Through passage 420: First heat exchanger 421: First heat transfer tube (first flow path), 430: Second heat exchanger 431: Second heat transfer tube (second flow path) 500: Cooler (energy converter) 510: Heat accumulator 510F1: One side 510F2: Other side 520: First heat exchanger 530: Second heat exchanger BP1, BP2: Boundary locations, CP1, CP2: Central points, D1, D2, D3, D4: Distances, La: Total length of the pipeline

Claims

[Claim 1] A pipe configured in an annular shape and capable of containing a working gas, Two energy converters comprising: a heat accumulator having one surface and another surface, and having a plurality of through passages penetrating from the one surface to the other surface; a first heat exchanger positioned opposite the one surface of the heat accumulator and having a first flow path through which a first fluid can flow; and a second heat exchanger positioned opposite the other surface of the heat accumulator and having a second flow path through which a second fluid can flow; Equipped with, One of the two energy converters is a prime mover that converts thermal energy into acoustic energy, and the other is a cooler that generates a temperature gradient when the acoustic energy amplified by the prime mover is input to it. The piping includes a first housing for housing the prime mover, a second housing for housing the cooler, and a waveguide connecting the first housing and the second housing. The waveguide section includes a main tube section and two enlarged sections having an inner diameter larger than the inner diameter of the main tube section. The first housing section and the second housing section have an inner diameter larger than the inner diameter of the main pipe section. The two enlarged portions have equal volumes to each other. The enlarged portion is not disposed between the second heat exchanger provided in the prime mover and the cooler. The central part between the two ends of the second housing is located between a position a distance D3 calculated by the following formula (3) and a position a distance D4 calculated by the following formula (4) from the first housing. Thermoacoustic device. D3=La×0.2 (3) D4=La×0.3...(4) (In the formula, La represents the total length of the pipe.)

Images