Thermoacoustic device

Abstract

To provide a thermoacoustic device with improved efficiency.SOLUTION: The thermoacoustic device 1a includes a fluid pipe 2 filled with a working fluid and including a pipe body part 21 and a pipe large diameter part 22 having an inside diameter larger than that of the pipe body part 21, a thermoacoustic converting part 3 disposed inside the pipe large diameter part 22, and an orifice part 4 disposed inside the fluid pipe 2. In the thermoacoustic device 4a, the orifice part 4 includes a through-hole 4a through which the working fluid flows, and a small orifice diameter part 4b in which an inside diametrical size of the through-hole 4b is smaller than other parts, and the small orifice diameter part 1a is arranged in a boundary part 23 between the pipe body part 21 and the large pipe diameter part 22.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to thermoacoustic devices. [Background technology]

[0002] A conventional thermoacoustic device is described in Patent Document 1. This thermoacoustic device includes an air column, a heat accumulator, and a jet pump unit. A working fluid is sealed in the air column. The heat accumulator is disposed inside the air column. The thermoacoustic device generates thermoacoustic self-excited oscillations of the working fluid by forming a thermal gradient between both ends of the heat accumulator using a high-temperature side heat exchanger and a low-temperature side heat exchanger disposed inside the air column.

[0003] The jet pump unit is configured to provide a difference between the resistance of the working fluid flowing from the high-temperature side to the low-temperature side of the heat accumulator and the resistance of the working fluid flowing from the low-temperature side to the high-temperature side of the heat accumulator. This makes it possible to suppress the movement of the working fluid in the heat accumulator, thereby suppressing the transfer of thermal energy associated with the movement of the working fluid. As a result, it is possible to suppress a decrease in the efficiency of the thermoacoustic device caused by heat loss from the high-temperature side heat exchanger or heating of the low-temperature side heat exchanger associated with the movement of the working fluid. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2005-345023 Summary of the Invention [Problem to be solved by the invention]

[0005] However, in the prior art, sufficient consideration was not given to energy loss caused by the jet pump unit or energy loss caused by other components such as the air column, heat accumulator, high-temperature side heat exchanger, and low-temperature side heat exchanger, making it difficult to sufficiently improve the efficiency of the thermoacoustic device.

[0006] The present invention has been made in view of the above problems, and aims to provide a thermoacoustic device with improved efficiency. [Means for solving the problem]

[0007] One aspect of the present invention is A thermoacoustic device (1a) that converts between heat and sound waves using a thermoacoustic phenomenon, a fluid pipe (2) filled with a working fluid and including a pipe main body (21) and a large-diameter pipe section (22) having an inner diameter dimension larger than that of the pipe main body; a thermoacoustic converter (3) disposed inside the large diameter pipe section; an orifice portion (4) disposed inside the fluid piping; The orifice portion is a through hole (4a) through which the working fluid flows; a small orifice diameter portion (4b) in which the inner diameter dimension of the through hole is smaller than that of other portions, The small diameter orifice portion is located in the thermoacoustic device at a boundary portion (23) between the main pipe body and the large diameter pipe portion. [Effects of the Invention]

[0008] In the portion of the fluid pipe where the inner diameter dimension expands or contracts, energy loss occurs in the working fluid flowing through the fluid pipe. Examples of energy loss include acoustic energy loss due to turbulence. Such loss occurs at the boundary between the main pipe section and the large diameter section of the fluid pipe, as well as in the small diameter orifice section of the orifice section disposed in the main pipe section. In this embodiment, the small diameter orifice section is disposed at the boundary between the main pipe section and the large diameter section of the fluid pipe. This allows the location where energy loss occurs to be concentrated at the boundary between the main pipe section and the large diameter section. As a result, energy loss can be reduced compared to when multiple locations where energy loss occurs are dispersed. This improves the efficiency of the thermoacoustic device.

[0009] As described above, according to the above aspect, it is possible to provide a thermoacoustic device with improved efficiency.

[0010] In addition, the symbols in parentheses in the claims and the means for solving the problems indicate the correspondence with the specific means described in the embodiments described below, and do not limit the technical scope of the present invention. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a schematic cross-sectional view showing a thermoacoustic device according to a first embodiment. [Figure 2] 3 is a partially enlarged cross-sectional view showing a fluid pipe, an orifice portion, and a thermoacoustic converting portion in the first embodiment. FIG. [Figure 3] 10 is a graph showing the relationship between normalized acoustic energy loss and "Vo / Vc" in Experimental Example 1-1. [Figure 4] 10 is a partially enlarged cross-sectional view showing a fluid pipe, an orifice portion, and a thermoacoustic converting portion in a second embodiment. FIG. [Figure 5] FIG. 10 is a partially enlarged cross-sectional view showing a fluid pipe, an orifice portion, and a thermoacoustic converting portion in a third embodiment. [Figure 6] FIG. 10 is a partially enlarged cross-sectional view showing a fluid pipe, an orifice portion, and a thermoacoustic converting portion in a fourth embodiment. [Figure 7] FIG. 10 is a partially enlarged cross-sectional view showing a fluid pipe, an orifice portion, and a thermoacoustic converting portion in a fifth embodiment. [Figure 8] FIG. 13 is a partially enlarged cross-sectional view showing a fluid pipe, an orifice portion, and a thermoacoustic converting portion in a sixth embodiment. [Figure 9] 10 is a graph showing the relationship between normalized acoustic energy loss and the Couligan-Carpenter number in Experimental Example 6-1. [Figure 10] FIG. 13 is a partially enlarged cross-sectional view showing a fluid pipe, an orifice portion, and a thermoacoustic converting portion in a seventh embodiment. [Figure 11] FIG. 13 is a partially enlarged cross-sectional view showing a fluid pipe, an orifice portion, and a thermoacoustic converting portion in an eighth embodiment. [Figure 12] FIG. 13 is a partially enlarged cross-sectional view showing a fluid pipe, an orifice portion, and a thermoacoustic converting portion in a ninth embodiment. [Figure 13] 10 is a graph showing normalized acoustic energy loss of Example 9-1 and Example 9-2 in Experimental Example 9-1. [Figure 14] 10 is a graph showing the relationship between the pressure loss in the orifice portion and "8Rc / Ds2π" in Example 9-2. [Figure 15] 10 is a graph showing normalized acoustic energy loss of Examples 9-3 and 9-4 in Experimental Example 9-3. [Figure 16] FIG. 10 is a schematic cross-sectional view for explaining a thermoacoustic device that is an experimental model in Experimental Example 9-3. [Figure 17] 10 is a graph showing the particle velocity of the working fluid in the fluid pipe in Experimental Example 9-3. [Figure 18] FIG. 20 is a schematic cross-sectional view showing a thermoacoustic device according to a tenth embodiment. [Figure 19] FIG. 6 is a partially enlarged cross-sectional view showing the fluid piping, the orifice portion, and the thermoacoustic converting portion of Comparative Example 6-1 in Experimental Example 6-1. DETAILED DESCRIPTION OF THE INVENTION

[0012] (Embodiment 1) 1.1 Configuration of the thermoacoustic device 1a An embodiment of a thermoacoustic device 1a will be described with reference to FIGS. The thermoacoustic device 1a of this embodiment converts heat and sound waves using the thermoacoustic phenomenon. As shown in Fig. 1, the thermoacoustic device 1a includes a fluid pipe 2, a thermoacoustic converting unit 3, and an orifice unit 4. The fluid pipe 2 is filled with a working fluid and includes a pipe main body 21 and a large-diameter pipe section 22 having an inner diameter larger than that of the pipe main body 21. The thermoacoustic converting unit 3 is disposed inside the large-diameter pipe section 22. The orifice unit 4 is disposed inside the fluid pipe 2.

[0013] The orifice portion 4 includes a through hole 4a through which the working fluid flows and a small orifice diameter portion 4b in which the inner diameter of the through hole 4a is smaller than that of other portions. The small orifice diameter portion 4b is located at a boundary portion 23 between the piping main body portion 21 and the piping large diameter portion 22.

[0014] The thermoacoustic device 1a of this embodiment can be used as a power generation means that utilizes, as a heat source, exhaust gas discharged from an industrial furnace (not shown), etc. Industrial furnaces include heating furnaces, baking furnaces, drying furnaces, exhaust gas treatment furnaces, etc. that heat an object to be heated or atmospheric gas by burning fuel.

[0015] The fluid pipe 2 of the thermoacoustic device 1a of this embodiment is of a loop type formed in a ring shape, as shown in FIG. 1 . The fluid pipe 2 according to this embodiment is formed in a substantially rectangular shape with rounded corners as a whole. The fluid pipe 2 according to this embodiment includes a substantially rectangular shaped pipe main body 21 and large diameter pipe sections 22 formed on each side of the pipe main body 21 and having an inner diameter dimension larger than the inner diameter dimension of the pipe main body 21. The large diameter pipe sections 22 are arranged on each side of the substantially rectangular shaped pipe main body 21. As a result, the fluid pipe 2 according to this embodiment includes four large diameter pipe sections 22. However, the number of large diameter pipe sections 22 is not particularly limited, and the fluid pipe 2 may be configured to include one to three, or five or more large diameter pipe sections 22.

[0016] 2, the large diameter pipe section 22 includes a storage section 22a and a connecting section 22b. The storage section 22a stores the thermoacoustic converting section 3. The storage section 22a is formed in a substantially cylindrical shape. The connecting section 22b connects the storage section 22a to the pipe main body 21. The connecting section 22b according to this embodiment is formed in a tapered shape that continuously connects the pipe main body 21 and the storage section 22a.

[0017] 2, the thermoacoustic converter 3 includes a heat accumulator 31, a low-temperature side heat exchanger 32, and a high-temperature side heat exchanger 33. The heat accumulator 31 is sandwiched between the low-temperature side heat exchanger 32 and the high-temperature side heat exchanger 33 in the arrangement direction Z of the low-temperature side heat exchanger 32, the heat accumulator 31, and the high-temperature side heat exchanger 33. In the following description, in the arrangement direction Z, the side on which the low-temperature side heat exchanger 32 is arranged relative to the heat accumulator 31 is referred to as the front side Z1, and the side on which the high-temperature side heat exchanger 33 is arranged relative to the heat accumulator 31 is referred to as the rear side Z2. It should be noted that, as shown in FIG. 1, the direction of the arrangement direction Z changes at each side of the fluid pipe 2 formed in a substantially rectangular shape.

[0018] The heat accumulator 31, the low-temperature side heat exchanger 32, and the high-temperature side heat exchanger 33 are formed in a substantially cylindrical shape. The low-temperature side heat exchanger 32 comes into contact with the end face of the front side Z1 of the heat accumulator 31, and cools the end face of the front side Z1 of the heat accumulator 31. The high-temperature side heat exchanger 33 comes into contact with the end face of the rear side Z2 of the heat accumulator 31, and heats the end face of the rear side Z2 of the heat accumulator 31.

[0019] The thermoacoustic converter 3 may be configured to convert heat into sound waves by, for example, creating a temperature gradient in the heat accumulator 31 using a low-temperature heat exchanger 32 and a high-temperature heat exchanger 33. Alternatively, the thermoacoustic converter 3 may be configured to convert sound waves output by a sound wave generator (not shown) provided in the fluid piping 2 into cold heat. In this embodiment, the thermoacoustic converter 3 is used to amplify sound waves circulating in the fluid piping 2 filled with a working fluid. Specifically, the thermoacoustic converter 3 uses the temperature difference between both ends of the heat accumulator 31 (see FIG. 2) to vibrate the working fluid, thereby generating and amplifying sound waves. A portion of the sound waves generated and amplified by the thermoacoustic converter 3 circulates in the annular piping. The working fluid of the thermoacoustic device 1a may be, for example, air, helium, argon, or the like. In this embodiment, the working fluid is compressed helium gas.

[0020] The heat accumulator 31 has a plurality of pores (not shown) penetrating the heat accumulator 31. The walls forming the pores can be formed in a lattice shape, a honeycomb shape, a cylindrical shape, or the like. Sound waves propagate through the pores separated by the walls. The heat accumulator 31 can amplify sound waves by vibrating the working fluid in the pores using the temperature difference between one end face heated by the high-temperature side heat exchanger 33 and the other end face cooled by the low-temperature side heat exchanger 32. The heat accumulator 31 can be made of, for example, a metal material such as stainless steel or ceramic. In this embodiment, the heat accumulator 31 is made of ceramic such as alumina.

[0021] The low-temperature side heat exchanger 32 may be made of a metal such as stainless steel. The low-temperature side heat medium introduced into the low-temperature side heat exchanger 32 is used to cool the regenerator 31 and the working fluid through the low-temperature side heat exchanger 32. The low-temperature side heat medium may be various fluids having a lower temperature than the exhaust gas and the high-temperature side heat medium described below. In this embodiment, the low-temperature side heat medium is circulating water used in the factory.

[0022] The high-temperature side heat exchanger 33 may be made of a metal such as stainless steel. The high-temperature side heat exchanger 33 circulates between an exhaust gas heat exchanger (not shown) that exchanges heat with exhaust gas discharged from an industrial furnace or the like and the high-temperature side heat exchanger 33. The high-temperature side heat exchanger transfers the heat of the exhaust gas recovered by the exhaust gas heat exchanger to the heat accumulator 31 and the working fluid via the high-temperature side heat exchanger 33, thereby heating the heat accumulator 31 and the working fluid. The temperature of the high-temperature side heat exchanger sent from the exhaust gas heat exchanger to the high-temperature side heat exchanger 33 may be, for example, about 300°C. Various heat transfer oils may be used as the high-temperature side heat transfer oil. Examples of heat transfer oils that may be used include synthetic heat transfer oils, paraffinic polymer oils, diphenyl heat transfer oils, and synthetic heat transfer oils.

[0023] The thermoacoustic device 1a further includes a sound wave utilization device 5. In this embodiment, the sound wave utilization device 5 is a generator 5a. The generator 5a is provided near each large diameter pipe section 22 in the pipe main body 21. The generator 5a is configured as a linear generator that converts vibrations caused by sound waves into electricity using electromagnetic induction. The sound waves amplified by the thermoacoustic conversion section 3 are then used by the generator 5a to be converted into electricity. The sound wave utilization device 5 may be various other devices besides the generator 5a, such as a heating or cooling device.

[0024] In this embodiment, sound waves amplified in one thermoacoustic converter 3 propagate to a generator 5a provided near that thermoacoustic converter 3 to generate electricity, and the sound waves that pass through that generator 5a propagate to another thermoacoustic converter 3. Then, after being amplified again by this other thermoacoustic converter 3, the sound waves propagate to a generator 5a provided near this other thermoacoustic converter 3 and are used to generate electricity. The above operation is repeated for the multiple thermoacoustic converters 3 and generators 5a provided in the piping main body 21.

[0025] 2, the orifice portion 4 includes a through hole 4a through which the working fluid flows and a small orifice diameter portion 4b in which the inner diameter of the through hole 4a is smaller than that of other portions. The orifice portion 4 according to this embodiment is disposed inside the pipe main body 21 located on the front side Z1 in the arrangement direction Z of the large diameter pipe portion 22. The orifice portion 4 is fixed to the pipe main body 21 by a known method such as welding, brazing, adhesive bonding, screwing, or riveting.

[0026] In this embodiment, the through-hole 4a of the orifice portion 4 is disposed in a penetrating direction along the arrangement direction Z. Therefore, the penetrating direction of the orifice portion 4 will be described using the arrangement direction Z, with the direction corresponding to the front side Z1 of the arrangement direction being described as the front side Z1 of the penetrating direction, and the direction corresponding to the rear side Z2 of the arrangement direction Z being described as the rear side Z2 of the penetrating direction.

[0027] There are no particular limitations on the material that constitutes the orifice portion 4, and any material can be appropriately selected, such as metal, resin, ceramic, etc. However, the orifice portion 4 may be configured to be formed integrally with the fluid pipe 2.

[0028] The small orifice diameter portion 4b according to this embodiment is formed at the end portion on the rear side Z2 in the penetration direction of the through hole 4a of the orifice portion 4. That is, the orifice portion 4 according to this embodiment is formed so that the inner diameter dimension at the end portion on the rear side Z2 in the penetration direction of the through hole 4a is smaller than the inner diameter dimension at the end portion on the front side Z1 in the penetration direction of the through hole 4a.

[0029] The inner diameter of the through hole 4a of the orifice portion 4 is formed to continuously decrease from the front side Z1 to the rear side Z2 in the penetration direction. In other words, the inner surface of the through hole 4a of the orifice portion 4 is formed in a tapered shape that decreases in diameter from the front side Z1 to the rear side Z2 in the penetration direction.

[0030] The small orifice diameter section 4b of the orifice section 4 is substantially located at the boundary 23 between the piping main body 21 and the large diameter section 22. "Substantially located" includes cases where the small orifice diameter section 4b of the orifice section 4 is located at the boundary 23 between the piping main body 21 and the large diameter section 22, and also includes cases where the small orifice diameter section 4b of the orifice section 4 is not located at the boundary 23 between the piping main body 21 and the large diameter section 22 but can be recognized as being substantially located.

[0031] The small orifice diameter section 4b according to this embodiment is disposed in the boundary section 23 between the piping main body 21 and the large diameter piping section 22, on the side where the low-temperature side heat exchanger 32 is disposed within the large diameter piping section 22. In other words, the orifice section 4 according to this embodiment is disposed in the piping main body 21 located on the front side Z1 in the arrangement direction Z of the large diameter piping section 22.

[0032] The fluid piping 2 of the thermoacoustic device 1a creates an acoustic field specific to thermoacoustics. By arranging the small orifice 4b in a location where the particle velocity in the acoustic field is relatively slow, it is possible to reduce energy loss caused by the small orifice 4b causing a sudden contraction or expansion of the working fluid. In this embodiment, the small orifice 4b is arranged near the low-temperature side heat exchanger 32, where the particle velocity in the acoustic field created in the fluid piping 2 is slow. This reduces energy loss generated in the thermoacoustic device 1a, improving the efficiency of the thermoacoustic device 1a.

[0033] Of the orifice portion 4, a portion disposed inside the pipe main body 21 is defined as the pipe main body side region 4d. In this embodiment, the entire orifice portion 4 is disposed inside the pipe main body 21, and therefore the entire orifice portion 4 is defined as the pipe main body side region 4d.

[0034] In this embodiment, if the volume of the space within the through hole 4a in the pipe main body side region 4d is Vo, and the volume of the space surrounded by the boundary surface S1 between the pipe main body 21 and the large diameter pipe section 22, the surface S2 of the orifice section 4 exposed to the large diameter pipe section 22, the inner surface S3 of the large diameter pipe section 22, and the surface S4 of the thermal sound conversion section 3 facing the orifice section 4 is Vc, Vo and Vc satisfy the following formula (3).

[0035]

number

[0036] As shown in FIG. 2, a space is formed between the small orifice diameter section 4b of the orifice section 4 and the low-temperature side heat exchanger 32 of the thermoacoustic conversion section 3. The space is surrounded by the boundary surface S1 between the piping main body 21 and the large diameter piping section 22, the surface S2 of the orifice section 4 exposed to the large diameter piping section 22, the inner surface S3 of the large diameter piping section 22, and the surface S4 of the thermoacoustic conversion section 3 facing the orifice section 4. This space reduces the particle velocity of the working fluid passing through the through-hole 4a of the orifice section 4. This prevents energy loss due to interference between the working fluid and the thermoacoustic conversion section 3, even if the particle velocity increases as the working fluid passes through the small orifice diameter section 4b. Note that particle velocity refers to the velocity of the working fluid when it vibrates. A particle refers to the volume of the working fluid, which is the unit of measurement for the vibration of the working fluid.

[0037] 1.2 Effects of this form Next, the effects of this embodiment will be described. In the thermoacoustic device 1a according to this embodiment, when the front side Z1 in the penetration direction Z of the heat accumulator 31 is cooled by the low-temperature side heat exchanger 32 and the rear side Z2 in the penetration direction of the heat accumulator 31 is heated by the high-temperature side heat exchanger 33, a temperature gradient is generated in the heat accumulator 31 from the front side Z1 to the rear side Z2. This temperature gradient causes a thermoacoustic phenomenon, i.e., self-excited pressure oscillations of the working fluid in the heat accumulator 31. This pressure oscillation of the working fluid promotes the circulation of sound waves in the direction indicated by the arrow A in FIG. 1 (clockwise direction). This sound wave is used by the generator 5a and converted into electricity.

[0038] As shown in FIG. 1, in the thermoacoustic device 1a, not only do sound waves circulate, but the working fluid filled in the fluid pipe 2 also circulates within the fluid pipe 2 as indicated by arrow A. This occurs because a pressure gradient occurs in the working fluid as sound waves are generated, and this pressure gradient generates a mass flow of the working fluid. This mass flow has thermal energy proportional to the isobaric specific heat per unit mass of the working fluid and the temperature difference between the high-temperature side heat exchanger 33 and the low-temperature side heat exchanger 32. Therefore, this mass flow causes heat loss in the thermoacoustic device 1a by removing thermal energy that should be transferred to the regenerator 31 by the high-temperature side heat exchanger 33 and transferring thermal energy to the low-temperature side heat exchanger 32.

[0039] In this embodiment, an orifice section 4 having a small orifice diameter section 4b in which the inner diameter of the through hole 4a is smaller than that of the other sections is disposed in the fluid pipe 2. This causes a pressure loss in the working fluid that passes through the small orifice diameter section 4b, thereby suppressing the mass flow of the working fluid. This reduces the energy loss caused by the mass flow.

[0040] When the working fluid passes through the small orifice 4b, turbulence may occur downstream of the small orifice 4b. When turbulence occurs, a loss of acoustic energy occurs in the sound waves propagating through the fluid pipe 2. In addition, at the boundary 23 between the pipe main body 21, which has a small inner diameter, and the large pipe section 22, which has a large inner diameter, a loss of energy occurs due to a sudden expansion or contraction of the working fluid.

[0041] Therefore, in this embodiment, the small orifice diameter section 4b is disposed at the boundary 23 between the piping main body 21 and the large diameter piping section 22. This allows the location where energy loss occurs to be concentrated at the boundary 23 between the piping main body 21 and the large diameter piping section 22. As a result, energy loss can be reduced compared to when multiple locations where energy loss occurs are dispersed. This allows the efficiency of the thermoacoustic device 1a to be improved.

[0042] Moreover, the heat-acoustic converting unit 3 according to this embodiment includes a heat accumulator 31 into which the working fluid is introduced, a high-temperature side heat exchanger 33 arranged at one end of the heat accumulator 31, and a low-temperature side heat exchanger 32 arranged at the other end of the heat accumulator 31. The small orifice diameter section 4b is arranged in the boundary section 23 between the piping main body section 21 and the large piping diameter section 22, on the side of the boundary section 23 where the low-temperature side heat exchanger 32 is arranged within the large piping diameter section 22.

[0043] The fluid piping 2 of the thermoacoustic device 1a creates an acoustic field specific to thermoacoustics. By arranging the small orifice 4b in a location where the particle velocity in the acoustic field is relatively slow, it is possible to reduce energy loss caused by the sudden contraction or expansion of the working fluid by the small orifice 4b. In this embodiment, the small orifice 4b is arranged near the low-temperature side heat exchanger 32, where the particle velocity in the acoustic field created in the fluid piping 2 is slow. This reduces energy loss generated in the thermoacoustic device 1a, improving the efficiency of the thermoacoustic device 1a.

[0044] Further, the orifice portion 4 according to the present embodiment includes at least a pipe body portion side region 4d disposed inside the pipe body portion 21. When the volume of the space inside the through-hole 4a in the pipe body portion side region 4d is Vo, and the volume of the space surrounded by the boundary surface S1 between the pipe body portion 21 and the large-diameter pipe portion 22, the surface S2 of the orifice portion 4 exposed to the large-diameter pipe portion 22, the inner surface S3 of the large-diameter pipe portion 22, and the surface S4 of the thermoacoustic conversion portion 3 facing the orifice portion 4 is Vc, the following formula (3) is satisfied.

[0045] [Number]

[0046] The inside of the fluid pipe 2 of the thermoacoustic device 1a becomes a vibration flow field peculiar to thermoacoustics. The central position of the vibration in the vibration flow field is the small orifice diameter portion 4b of the orifice portion 4. In the vicinity of this small orifice diameter portion 4b, when Vc is sufficiently larger than Vo, the particle velocity of the particles passing through the small orifice diameter portion 4b of the orifice portion 4 and traveling to the thermoacoustic conversion portion 3 is such that, inside the large-diameter pipe portion 22, the boundary surface S1 between the pipe body portion 21 and the large-diameter pipe portion 22, the surface S2 of the orifice portion 4 exposed to the large-diameter pipe portion 22, the inner surface S3 of the large-diameter pipe portion 22, and the surface S4 of the thermoacoustic conversion portion 3 facing the orifice portion 4. It can be reduced by the surrounded space. Thereby, it is possible to reduce the energy loss caused by the interference between the particles with increased particle velocity and the thermoacoustic conversion portion 3. As a result, the efficiency of the thermoacoustic device 1a can be improved. Therefore, regarding Vo / Vc, which is the value of the ratio of Vo to Vc, 0 < Vo / Vc < 1.5 is preferable, and 0 < Vo / Vc < 1 is more preferable.

[0047] 1.3 Experimental Example 1-1 In this experimental example, in the thermoacoustic device 1a having the same basic structure as that of Embodiment 1, the volume of the space in the through-hole 4a in the pipe main body portion side region 4d is defined as Vo, and the volume of the space surrounded by the boundary surface S1 between the pipe main body portion 21 and the large pipe diameter portion 22, the surface S2 of the orifice portion 4 that is exposed to the large pipe diameter portion 22, the inner surface S3 of the large pipe diameter portion 22, and the surface S4 of the thermoacoustic conversion portion 3 that faces the orifice portion 4 is defined as Vc. The acoustic energy loss was obtained by thermal fluid analysis. The acoustic energy loss was normalized based on the largest value of the results of the thermal fluid analysis. The analysis results are shown in Fig. 3.

[0048] As shown in Fig. 3, as the value of Vo / Vc increased, the acoustic energy loss monotonically decreased. The reduction amount of the acoustic energy loss in the region of 0 < Vo / Vc < 1.5 was larger than the reduction amount of the acoustic energy loss in the region of 1.5 ≤ Vo / Vc.

[0049] Also, Vo / Vc = 1.0 is the inflection point, and at the point of Vo / Vc = 1.0, the reduction amount of the normalized acoustic energy changes rapidly. Also, at Vo / Vc = 4, the acoustic energy loss is almost 0.

[0050] As described above, when Vc is sufficiently large with respect to Vo, the particle velocity of the particles that pass through the small orifice diameter portion 4b of the orifice portion 4 and proceed to the thermoacoustic conversion portion 3 can be sufficiently reduced. Thereby, the energy loss caused by the interference between the particles with increased particle velocity and the thermoacoustic conversion portion 3 can be reduced, so that the efficiency of the thermoacoustic device 1a can be improved. Therefore, for Vo / Vc, which is the value of the ratio of Vo to Vc, 0 < Vo / Vc < 1.5 is preferable, and 0 < Vo / Vc < 1.0 is more preferable.

[0051] (Embodiment 2) Next, a thermoacoustic device 1b according to a second embodiment will be described with reference to Fig. 4. The orifice portion 4 according to this embodiment is disposed inside the piping main body 21 disposed on the rear side Z2 in the arrangement direction Z of the large diameter piping portion 22. In other words, the orifice portion 4 is disposed inside the piping main body 21 on the side where the high temperature side heat exchanger 33 is disposed within the large diameter piping portion 22.

[0052] The small orifice diameter portion 4b according to this embodiment is formed at the end portion on the front side Z1 in the penetration direction of the through hole 4a of the orifice portion 4. That is, the orifice portion 4 according to this embodiment is formed so that the inner diameter dimension at the end portion on the front side Z1 in the penetration direction of the through hole 4a is smaller than the inner diameter dimension at the end portion on the rear side Z2 in the penetration direction of the through hole 4a.

[0053] The inner diameter of the through hole 4a of the orifice portion 4 is formed to continuously decrease from the rear side Z2 to the front side Z1 in the penetration direction. In other words, the inner surface of the through hole 4a of the orifice portion 4 is formed in a tapered shape that decreases in diameter from the rear side Z2 to the front side Z1 in the penetration direction.

[0054] The small orifice diameter section 4b of the orifice section 4 is substantially located at the boundary 23 between the piping main body 21 and the large diameter section 22. "Substantially located" includes cases where the small orifice diameter section 4b of the orifice section 4 is located at the boundary 23 between the piping main body 21 and the large diameter section 22, and also includes cases where the small orifice diameter section 4b of the orifice section 4 is not located at the boundary 23 between the piping main body 21 and the large diameter section 22 but can be recognized as being substantially located.

[0055] Note that, among the symbols used in the second and subsequent embodiments, the same symbols as those used in the previous embodiments represent the same components, etc. as those in the previous embodiments, unless otherwise specified.

[0056] (Embodiment 3) Next, a thermoacoustic device 1c according to a third embodiment will be described with reference to Fig. 5. In the thermoacoustic device 1c according to this embodiment, an orifice portion 4 is disposed in both the piping main body portion 21 located on the front side Z1 of the large diameter piping portion 22 and the piping main body portion 21 located on the rear side Z2 in the arrangement direction Z. The configuration of the orifice portion 4 disposed on the front side Z1 of the large diameter piping portion 22 is the same as in the first embodiment, so a duplicated description will be omitted. In addition, the configuration of the orifice portion 4 disposed on the rear side Z2 of the large diameter piping portion 22 is the same as in the second embodiment, so a duplicated description will be omitted.

[0057] According to this embodiment, the orifice portions 4 are arranged on both the front side Z1 and the rear side Z2 of the large diameter pipe portion 22, which effectively suppresses the mass flow of the working fluid flowing through the fluid pipe 2. This improves the efficiency of the thermoacoustic device 1c.

[0058] (Embodiment 4) Next, a thermoacoustic device 1d according to a fourth embodiment will be described with reference to Fig. 6. In this embodiment, the shape of the connecting portion 22b located on the front side Z1 in the arrangement direction Z of the large diameter piping portion 22 is formed into a curved shape in a cross section along the arrangement direction Z. Although not shown in detail, the shape of the connecting portion 22b located on the rear side Z2 in the arrangement direction Z of the large diameter piping portion 22 is also similar. Since the configuration other than the above is the same as that of the first embodiment, repeated explanations will be omitted.

[0059] Since the inner surface of the connecting portion 22b is formed by the smoothly curved surface 4c, the generation of turbulence in the working fluid can be suppressed at the connecting portion 22b, thereby improving the efficiency of the thermoacoustic device 1d.

[0060] (Embodiment 5) Next, a thermoacoustic device 1e according to a fifth embodiment will be described with reference to Fig. 7. In this embodiment, the end of the large diameter pipe section 22 on the front side Z1 in the arrangement direction Z and the pipe main body 21 are directly connected without the connecting portion 22b. Although not shown in detail, similarly to the above, the end of the large diameter pipe section 22 on the rear side Z2 in the arrangement direction Z and the pipe main body 21 are directly connected without the connecting portion 22b. According to this embodiment, the difference between the inner diameter dimension of the small orifice diameter section 4b and the inner diameter dimension of the large diameter pipe section 22 can be suddenly increased.

[0061] (Embodiment 6) 6.1 Configuration of the thermoacoustic device 1f according to the sixth embodiment Next, a thermoacoustic device 1f according to a sixth embodiment will be described with reference to Fig. 8. The orifice portion 4 according to this embodiment is disposed across the piping main body portion 21 and the large diameter piping portion 22. The orifice portion 4 includes a first portion 41 disposed in the piping main body portion 21 and a second portion 42 disposed in the large diameter piping portion 22. In this embodiment, the first portion 41 and the second portion 42 are formed as separate bodies.

[0062] The first portion 41 includes a first through hole 41a through which the working fluid flows, and a first small diameter portion 41b in which the inner diameter of the first through hole 41a is smaller than that of other portions. The first small diameter portion 41b is formed at an end portion of the first portion 41 on the rear side Z2 in the penetration direction of the first through hole 41a. That is, in this embodiment, the inner diameter of the first through hole 41a at the end portion on the rear side Z2 in the penetration direction is smaller than the inner diameter of the first through hole 41a at the end portion on the front side Z1 in the penetration direction.

[0063] The inner diameter of the first through hole 41a of the first portion 41 is formed to continuously decrease from the front side Z1 to the rear side Z2 in the penetration direction. In other words, the inner surface of the first through hole 41a of the first portion 41 is formed in a tapered shape that decreases in diameter from the front side Z1 to the rear side Z2 in the penetration direction.

[0064] In this embodiment, the second portion 42 is disposed inside the connecting portion 22b of the large diameter pipe portion 22. The second portion 42 is formed into a shape that increases in diameter from the front side Z1 toward the rear side Z2 of the second through hole 42a as a whole.

[0065] The second portion 42 includes a second through hole 42a through which the working fluid flows, and a second small diameter portion 42b in which the inner diameter of the second through hole 42a is smaller than that of other portions. The second small diameter portion 42b is formed at an end portion of the second portion 42 on the front side Z1 in the penetration direction of the second through hole 42a. That is, in this embodiment, the inner diameter of the second through hole 42a at the end portion on the front side Z1 in the penetration direction is smaller than the inner diameter of the second through hole 42a at the end portion on the rear side Z2 in the penetration direction.

[0066] The inner diameter of the second through hole 42a of the second portion 42 is formed so as to continuously increase in diameter from the front side Z1 to the rear side Z2 in the penetration direction. In other words, the inner surface of the second through hole 42a of the second portion 42 is formed in a tapered shape so as to increase in diameter from the front side Z1 to the rear side Z2 in the penetration direction.

[0067] In this embodiment, the central axis C1 of the first through hole 41a and the central axis C2 of the second through hole 42a are arranged so as to substantially coincide with each other in the radial direction of the piping main body 21. However, the central axis C1 of the first through hole 41a and the central axis C2 of the second through hole 42a may be configured so as to be misaligned with each other in the radial direction of the piping main body 21.

[0068] The first small diameter portion 41b of the first portion 41 is substantially located at the boundary 23 between the piping main body 21 and the large diameter portion 22. The second small diameter portion 42b of the second portion 42 is substantially located at the boundary 23 between the piping main body 21 and the large diameter portion 22. An end face of the first portion 41 on the rear side Z2 in the penetration direction abuts against an end face of the second portion 42 on the front side Z1 in the penetration direction. As a result, the first small diameter portion 41b of the first portion 41 and the second small diameter portion 42b of the second portion 42 are located adjacent to each other in the penetration direction. The first small diameter portion 41b of the first portion 41 and the second small diameter portion 42b of the second portion 42 form the small orifice diameter portion 4b of the orifice portion 4. The first through hole 41a of the first portion 41 and the second through hole 42a of the second portion 42 are in communication with each other. The through hole 4a of the orifice portion 4 is formed by the first through hole 41a and the second through hole 42a.

[0069] The inner diameter of the first small diameter portion 41b of the first portion 41 and the inner diameter of the second small diameter portion 42b of the second portion 42 are set to be substantially the same. As a result, the inner surface of the first through hole 41a and the inner surface of the second through hole 42a are continuous without creating a step in the area where the first small diameter portion 41b and the second small diameter portion 42b are adjacent. This makes it possible to suppress the generation of turbulence in the working fluid in the area where the first portion 41 and the second portion 42 are adjacent.

[0070] 6.2 Experimental Example 6-1 (1) Example 6-1 In Example 6-1, in a thermoacoustic device 1f having the same basic structure as in the sixth embodiment, the change in acoustic energy loss due to the orifice portion 4 with respect to the Couligan-Carpenter number was measured.

[0071] In the fluid pipe 2, a plurality of pressure sensors (not shown) were arranged on the front side Z1 and the rear side Z2 of the orifice portion 4 in the arrangement direction Z, and pressure fluctuations of the working fluid were measured. From these pressure fluctuations, the sound field distribution in the fluid pipe 2 was derived using the two-sensor method (A. Fusco, W. Ward and G. Swift, J. Acoust. Soc. Am. 91, pp. 2229-2235, (1992); T. Biwa, Rev. of Sci. Inst. 78(8), pp. 086110-1-3, (2007)). From these results, the acoustic energy loss in the fluid pipe 2 was calculated. Regarding the measurement results, the acoustic energy loss was normalized using the position with the largest acoustic energy loss in Comparative Example 6-1, which will be described later, as the reference point.

[0072] The Couligan-Carpenter number represents the aspect ratio of the area that moves during one period in an oscillatory flow field. In this Example 6-1, the number was calculated with the amplitude of the sound wave as the numerator and the diameter of the small orifice diameter portion 4b of the orifice portion 4 as the denominator. The results are shown in Figure 9.

[0073] (2) Comparative Example 6-1 A thermoacoustic device 1f' according to Comparative Example 6-1 is shown in Figure 19. In Comparative Example 6-1, the small orifice diameter section 4b of the orifice section 4 is disposed on the front side Z1 in the arrangement direction Z with respect to the boundary 23 between the piping main body 21 and the large diameter piping section 22. The distance between the small orifice diameter section 4b and the boundary 23 between the piping main body 21 and the large diameter piping section 22 was 0.1 m. Except for the above, the experiment was conducted in the same manner as in Example 6-1. The results are shown in Figure 9.

[0074] As shown in Figure 9, for Example 6-1 and Comparative Example 6-1, the acoustic energy loss increased as the Cooligan-Carpenter number increased. Even when the Cooligan-Carpenter number changed, the acoustic energy loss in Example 6-1 was smaller than that in Comparative Example 6-1. This is thought to be because, in Example 6-1, the area where acoustic energy is reduced is concentrated at the boundary 23 between the pipe main body 21 and the large diameter pipe section 22, whereas in Comparative Example 6-1, the area where acoustic energy is reduced is dispersed between the small orifice diameter section 4b and the boundary 23 between the pipe main body 21 and the large diameter pipe section 22.

[0075] (Embodiment 7) Next, a thermoacoustic device 1g according to a seventh embodiment will be described with reference to Fig. 10. The orifice portion 4 according to this embodiment differs from that of the sixth embodiment in that the first portion 41 and the second portion 42 are integrally formed. Since the configuration other than the above is the same as that of the sixth embodiment, duplicated explanations will be omitted. According to this embodiment, the number of parts can be reduced, thereby reducing the manufacturing cost of the thermoacoustic device 1g.

[0076] (Embodiment 8) Next, a thermoacoustic device 1h according to an eighth embodiment will be described with reference to Fig. 11. The orifice portion 4 according to this embodiment has a curved surface 4c at the tip edge of the small orifice diameter portion 4b that protrudes radially inward of the through hole 4a. The curved surface 4c has a curved cross section along the central axis C of the through hole 4a. However, the tip edge of the small orifice diameter portion 4b of the fourth or fifth embodiment may also have the curved surface 4c. The other configurations are the same as those of the first embodiment, so repeated explanations will be omitted.

[0077] According to this embodiment, the curved surface 4c is formed on the tip edge of the small orifice portion 4b, which can suppress the generation of turbulence in the working fluid near the small orifice portion 4b. This allows a desired pressure loss to be generated in the small orifice portion 4b, thereby suppressing the mass flow of the working fluid. As a result, the efficiency of the thermoacoustic device 1h can be improved.

[0078] Furthermore, the generation of turbulence can be suppressed, which also reduces energy loss, thereby improving the efficiency of the thermoacoustic device 1h.

[0079] (Embodiment 9) 9.1 Configuration of the thermoacoustic device 1i according to the ninth embodiment Next, a thermoacoustic device 1i according to a ninth embodiment will be described with reference to Fig. 12. The orifice portion 4 according to this embodiment differs from that of the sixth embodiment in that a first curved surface 41c is formed on the leading edge of the first small diameter portion 41b of the first portion 41, and a second curved surface 42c is formed on the leading edge of the second small diameter portion 42b of the second portion 42.

[0080] In this embodiment, a first curved surface 41c is formed on a tip edge of the first small diameter portion 41b that protrudes radially inward of the first through hole 41a, and the tip edge of the second small diameter portion 42b that protrudes radially inward of the second through hole 42a is formed on a second curved surface 42c that protrudes radially inward of the second through hole 42 ....

[0081] In this embodiment, when the inner diameter dimension of the through hole 4a in the small orifice diameter portion 4b is Ds, the radius of curvature of the first curved surface 41c of the first small diameter portion 41b is R1, and the radius of curvature of the second curved surface 42c of the second small diameter portion 42b is R2, the conditions of the following formulas (1) and (2) are satisfied.

number

[0082]

number

[0083] Furthermore, the radius of curvature R1 of the first curved surface 41c and the radius of curvature R2 of the second curved surface 42c may be the same or different. When the radius of curvature R1 of the first curved surface 41c and the radius of curvature R2 of the second curved surface 42c are the same, the first curved surface 41c and the second curved surface 42c are configured as a single continuous curved surface 4c, which improves the manufacturing efficiency when manufacturing the orifice portion 4.

[0084] According to this embodiment, by considering the radius of curvature R1 of the first curved surface 41c of the first small diameter portion 41b and the radius of curvature R2 of the second curved surface 42c of the second small diameter portion 42b, it is possible to optimize the radius of curvature R1 of the first small diameter portion 41b and the radius of curvature R2 of the second small diameter portion 42b. This allows a desired pressure loss to be generated in the small diameter orifice portion 4b, thereby suppressing the mass flow of the working fluid and improving the efficiency of the thermoacoustic device 1i.

[0085] Furthermore, since the generation of turbulence can be suppressed, the loss of energy can also be suppressed, thereby improving the efficiency of the thermoacoustic device 1i.

[0086] 9.2 Experimental Example 9-1 (1) Example 9-1 In Example 9-1, the acoustic energy loss in the fluid pipe 2 was calculated using the two-sensor method in the thermoacoustic device 1f according to the sixth embodiment, in the same manner as in Example 1-1. The acoustic energy loss was normalized based on the acoustic energy loss in Example 9-2 (described later). The results are shown in FIG. 13.

[0087] (2) Example 9-2 In Example 9-2, the acoustic energy loss in the fluid pipe 2 was calculated using the two-sensor method in the thermoacoustic device 1i according to the 9th embodiment, in the same manner as in Example 1-1. The acoustic energy loss was normalized based on the acoustic energy loss in this Example 9-2. The results are shown in FIG. 13.

[0088] 13, Example 9-2, which includes an orifice portion 4 having a first curved surface 41c and a second curved surface 42c, exhibited less acoustic energy loss than Example 9-1, which includes an orifice portion 4 without a first curved surface 41c and a second curved surface 42c. This is thought to be because the generation of turbulence was suppressed in the small orifice diameter portion 4b, thereby reducing the acoustic energy loss.

[0089] Example 9-2 had smaller variations in normalized acoustic energy loss than Example 9-1. This is also thought to be because Example 9-2 was able to reduce acoustic energy loss by suppressing the generation of turbulence in the small orifice diameter portion 4b.

[0090] 9.3 Experimental Example 9-2 In this experimental example, as shown in FIG. 14, in a thermoacoustic device 1i having the same basic structure as that of the ninth embodiment, the pressure loss in the small orifice diameter portion 4b is calculated by (8×R1) / (Ds 2 To measure the pressure loss in the small orifice diameter portion 4b, multiple pressure sensors (not shown) were placed on the front side Z1 and rear side Z2 of the orifice portion 4 in the arrangement direction Z of the fluid piping 2, and the pressure fluctuation of the working fluid was measured.

[0091] 0.1≦(8×R1) / (Ds 2 When (8×R1) / (Ds 2 × π). This makes it possible to easily predict the pressure loss in the small orifice portion 4b. As a result, by generating a desired pressure loss in the small orifice portion 4b, the mass flow of the working fluid can be suppressed, thereby improving the efficiency of the thermoacoustic device 1i.

[0092] Furthermore, since the generation of turbulence can be suppressed, the loss of energy can also be suppressed, thereby improving the efficiency of the thermoacoustic device 1i.

[0093] (8×R1) / (Ds 2 ×π)>1.25, the working fluid flowing through the fluid pipe 2 is in a turbulent or near-turbulent state. This makes it difficult to predict the pressure loss in the small orifice diameter portion 4b, which is not preferable.

[0094] (8×R1) / (Ds 2 ×π)<0.1, the pressure loss in the small orifice diameter portion 4b becomes relatively small, which is undesirable because it reduces the effect of suppressing the mass flow of the working fluid in the fluid pipe 2.

[0095] In addition, (8×R2) / (Ds 2 ×π), the value of (8×R1) / (Ds 2 ×π), so a duplicated explanation will be omitted.

[0096] 9.4 Experimental Example 9-3 (1) Example 9-3 In Example 9-3, the acoustic energy loss in the fluid pipe 2 was calculated using the two-sensor method in the thermoacoustic device 1i according to Embodiment 9, in the same manner as in Example 1-1. In this example, the orifice section 4 was disposed in the pipe main body 21 located on the front side Z1 in the arrangement direction Z of the large diameter pipe section 22. In other words, the orifice section 4 according to this embodiment was disposed in the pipe main body 21 located on the side of the low-temperature side heat exchanger 32 disposed in the large diameter pipe section 22. The acoustic energy loss was normalized based on the acoustic energy loss in Example 9-4, which will be described later. The results are shown in FIG. 15.

[0097] (2) Example 9-4 In Example 9-4, in the thermoacoustic device 1i according to the basic structure embodiment 9, the orifice portion 4 was arranged in the piping main body 21 arranged on the rear side Z2 in the arrangement direction Z of the large diameter piping portion 22. In other words, the orifice portion 4 according to this embodiment was arranged in the piping main body 21 located on the high temperature side heat exchanger 33 side arranged in the large diameter piping portion 22. In this case, the acoustic energy loss in the fluid piping 2 was calculated using the two-sensor method in the same manner as in Example 1-1. The acoustic energy loss was normalized based on the acoustic energy loss of this Example 9-4. The results are shown in FIG. 15.

[0098] Example 9-3, in which the orifice 4 was arranged in the piping main body 21 on the low-temperature side heat exchanger 32 side, had a lower acoustic energy loss than Example 9-4, in which the orifice 4 was arranged in the piping main body 21 on the high-temperature side heat exchanger 33 side. This is thought to be because the small orifice diameter section 4b was arranged in a location where the particle velocity in the acoustic field was relatively slow. This is explained below.

[0099] The fluid piping 2 of the thermoacoustic device 1i creates an acoustic field specific to thermoacoustics. By locating the small orifice 4b in a location where the particle velocity in the acoustic field is relatively slow, it is thought that it is possible to reduce energy loss caused by the sudden contraction or expansion of the working fluid by the small orifice 4b.

[0100] FIG. 16 shows an experimental model of the thermoacoustic device 1a', which is the thermoacoustic device 1a of the first embodiment shown in FIG. 1 , omitting the generator 5a and the orifice 4. The remaining configuration is the same as that of the first embodiment, and therefore, redundant explanations will be omitted. FIG. 17 shows the particle velocity of the working fluid in the fluid piping 2 within the region L indicated by the dashed line for the thermoacoustic device 1a', which is the experimental model. Region L includes the large-diameter piping section 22 accommodating the thermoacoustic converter 3 and the piping main body 21. The particle velocity of the working fluid was measured by the two-sensor method using a semiconductor pressure sensor PMS-5M-5 manufactured by JTEKT Corporation. In FIG. 16, region M indicates the portion of the piping main body 21 close to the high-temperature side heat exchanger 33, and region N indicates the portion of the piping main body 21 close to the low-temperature side heat exchanger 32.

[0101] As shown in FIG. 17, in the thermoacoustic converter 3 disposed in the large diameter pipe section 22, the particle velocity of the working fluid is relatively small.

[0102] 17, the particle velocity of the working fluid in region M of the piping main body 21, which is close to the high-temperature side heat exchanger 33, is relatively high. On the other hand, the particle velocity of the working fluid in region N of the piping main body 21, which is close to the low-temperature side heat exchanger 32, is lower than the particle velocity of the working fluid in region M, which is close to the high-temperature side heat exchanger 33. In this embodiment, the small orifice diameter section 4b is disposed near the low-temperature side heat exchanger 32, where the particle velocity is slow in the acoustic field formed within the fluid piping 2. This makes it possible to suppress the loss of energy generated in the thermoacoustic device 1i and improve the efficiency of the thermoacoustic device 1i.

[0103] (Embodiment 10) Next, a thermoacoustic device 1j according to a tenth embodiment will be described with reference to Fig. 18. The fluid piping 2 of the thermoacoustic device 1j of this embodiment is of a loop type having an annular piping 24 formed in an annular shape and a branch piping 25 branching from the annular piping 24, as shown in Fig. 18.

[0104] The annular piping 24 includes a piping main body 241 and a large diameter piping section 242. For example, one or more large diameter piping sections 242 can be installed in the middle of the annular piping 24. In this embodiment, one large diameter piping section 242 is installed in the middle of the annular piping 24.

[0105] The thermoacoustic device 1j also includes a generator 5a. The generator 5a in this embodiment is provided at the end of the branch pipe 25 and is configured as a linear generator that converts vibrations caused by sound waves into electricity using electromagnetic induction. The generator 5a converts the sound waves amplified in the annular pipe 24 into electricity.

[0106] The present invention is not limited to the above-described embodiments, and can be applied to various embodiments within the scope of the present invention. [Explanation of symbols]

[0107] 1a, 1b, 1c, 1d, 1e, 1f, 1g, 1h, 1i, 1j, 1k: thermoacoustic device, 2: fluid piping, 3: thermoacoustic conversion part, 4: orifice part, 4a: through hole, 4b: small diameter orifice part, 4c: curved surface, 4d: piping main body part side region, 21, 241: piping main body part, 22, 242: large diameter piping part, 23: boundary part, 31: heat accumulator, 32: low temperature side heat exchanger, 33: high temperature side heat exchanger, 41: first part, 41a: first piping through hole, 41b: first small diameter portion, 41c: first curved surface, 42: second portion, 42a: second through hole, 42b: second small diameter portion, 42c: second curved surface, C, C1, C2: central axis, R1: radius of curvature, R2: radius of curvature, S1: boundary surface between the main pipe body and the large diameter pipe portion, S2: surface of the orifice portion exposed to the large diameter pipe portion, S3: inner surface of the large diameter pipe portion, S4: surface of the thermal sound conversion portion facing the orifice portion, Z: penetration direction,

Claims

1. A thermoacoustic device (1a) that utilizes a thermoacoustic phenomenon to convert between heat and sound waves, a fluid pipe (2) filled with a working fluid and including a pipe main body (21) and a large-diameter pipe part (22) having an inner diameter dimension larger than that of the pipe main body; A thermoacoustic converter (3) disposed inside the large diameter pipe section; an orifice portion (4) disposed inside the fluid piping; The orifice portion is a through hole (4a) through which the working fluid flows; a small orifice diameter portion (4b) in which the inner diameter dimension of the through hole is smaller than that of other portions, The small diameter orifice portion is disposed at a boundary portion (23) between the main pipe body portion and the large diameter pipe portion.

2. 2. The thermoacoustic device according to claim 1, wherein a curved surface (4c) is formed on a tip edge of the small orifice diameter portion that protrudes radially inward of the through hole, and the cross-sectional shape along the central axis (C) of the through hole is curved.

3. The orifice portion is The pipe is disposed across the pipe main body and the large diameter pipe portion, a first portion (41) disposed in the piping main body; a second portion (42) disposed in the large diameter pipe portion, The first part comprises: a first through hole (41a) through which the working fluid flows; a first small diameter portion (41b) in which the inner diameter dimension of the first through hole is smaller than that of other portions, a first curved surface (41c) having a curved cross section along a central axis (C1) of the first through hole is formed on a tip edge of the first small diameter portion that protrudes radially inward of the first through hole, The second part comprises: a second through hole (42a) through which the working fluid flows; a second small diameter portion (42b) in which the inner diameter dimension of the second through hole is smaller than that of other portions, a second curved surface (42c) having a curved cross section along a central axis (C2) of the second through hole is formed on a tip edge of the second small diameter portion that protrudes radially inward of the second through hole, an inner diameter dimension of the through hole at the small orifice diameter portion is defined as Ds; a radius of curvature of the first curved surface of the first small diameter portion is R1; When the radius of curvature of the second curved surface of the second small diameter portion is R2, The thermoacoustic device according to claim 2, which satisfies the conditions of the following formulas (1) and (2). [Equation 1] [Equation 2]

4. The thermoacoustic converter is a heat accumulator (31) into which the working fluid is introduced; a high-temperature side heat exchanger (33) disposed at one end of the heat accumulator; a low-temperature side heat exchanger (32) disposed at the other end of the heat accumulator; 2. The thermoacoustic device according to claim 1, wherein the small orifice diameter section is arranged at least at the boundary between the piping main body and the large piping diameter section, on the side of the large piping diameter section where the low-temperature side heat exchanger is arranged.

5. The orifice portion includes at least a pipe main body side region (4d) arranged inside the pipe main body, The volume of the space within the through hole in the piping main body side region is Vo, The thermoacoustic device according to any one of claims 1 to 4, wherein the volume of the space surrounded by the boundary surface (S1) between the piping main body and the large diameter piping section, the surface (S2) of the orifice section exposed to the large diameter piping section, the inner surface (S3) of the large diameter piping section, and the surface (S4) of the thermoacoustic conversion section facing the orifice section is Vc, satisfies the following formula (3). [Equation 3]

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