WO2021152798A1 - Thermoacoustic device - Google Patents

Abstract

This thermoacoustic device comprises a loop-shaped waveguide and a heat exchanger. The loop-shaped waveguide is filled with a medium. The heat exchanger is provided in the waveguide and includes a low-temperature part, a high-temperature part, and a temperature gradient maintenance part that is provided between the low-temperature part and the high-temperature part and that maintains the temperature gradient generated between the low-temperature part and the high-temperature part. The temperature gradient maintenance part includes a plurality of linear thermal conductors.

Description

Thermoacoustic device

The disclosed embodiment relates to a thermoacoustic device.

Conventionally, there is known a thermoacoustic device that converts thermal energy into acoustic energy by the thermoacoustic effect, which is an interaction between heat and sound waves, and converts acoustic energy into other energy such as electric energy.

For example, a heat storage section that is sandwiched between a heat dissipation section and a heating section to generate a temperature gradient is arranged in a loop tube filled with gas, and the temperature gradient generated in the heat storage section excites the vibration of the gas, which is generated by the pressure vibration. A thermoacoustic generator is disclosed in which a generator that generates heat in response to a traveling wave and a thermoacoustic generator that takes out cold heat by reversing a heat radiating unit and a heating unit are provided in a loop tube (see, for example, Patent Document 1). ).

Japanese Unexamined Patent Publication No. 2003-324932

However, in the conventional technology, the efficiency of converting thermal energy into acoustic energy may be low. For example, in the conventional technique, when sound waves are generated in a gas by a temperature gradient between a heat source temperature of 100 ° C. or lower and room temperature, the efficiency of converting thermal energy into sound energy is low, and the sound waves are self-excited. It becomes difficult for vibration to be established.

One aspect of the embodiment is to provide a thermoacoustic device that improves the efficiency of converting thermal energy into acoustic energy.

The thermoacoustic device according to one aspect of the embodiment includes a loop-shaped waveguide and a heat exchanger. The loop-shaped waveguide is filled with a medium. The heat exchanger is provided in the waveguide and is provided in the low temperature part, the high temperature part, and between the low temperature part and the high temperature part, and holds the temperature gradient generated between the low temperature part and the high temperature part. Including part. The temperature gradient holder includes a plurality of linear thermal conductors.

According to one aspect of the embodiment, the efficiency of converting thermal energy into sound energy can be improved.

FIG. 1 is a diagram showing an example of a thermoacoustic device according to an embodiment. FIG. 2 is a diagram showing an example of a heat exchanger included in a thermoacoustic device. FIG. 3 is a diagram showing an example of a temperature gradient holding portion included in the heat exchanger. FIG. 4 is a diagram showing an example of a temperature gradient holding portion included in the heat exchanger. FIG. 5 is a diagram showing an example of each of a plurality of linear heat conductors included in the temperature gradient holding portion. FIG. 6 is a diagram showing an example of a first high temperature portion included in the high temperature portion included in the heat exchanger. FIG. 7A is a diagram showing an example of a first high temperature portion included in the high temperature portion included in the heat exchanger. FIG. 7B is a diagram showing an example of joining a first high temperature portion included in the high temperature portion included in the heat exchanger and a plurality of linear heat conductors included in the temperature gradient holding portion. FIG. 8 is a diagram showing an example of a second high temperature portion included in the high temperature portion included in the heat exchanger. FIG. 9 is a diagram showing an example of a second high temperature portion included in the high temperature portion included in the heat exchanger. FIG. 10 is a diagram showing an example of a third high temperature portion included in the high temperature portion included in the heat exchanger. FIG. 11 is a diagram showing an example of a third high temperature portion included in the high temperature portion included in the heat exchanger. FIG. 12 shows an example of joining the temperature gradient holding portion included in the heat exchanger and the first high temperature portion, the second high temperature portion, and the third high temperature portion included in the high temperature portion included in the heat exchanger. It is a figure.

Hereinafter, embodiments of the thermoacoustic apparatus disclosed in the present application will be described in detail with reference to the attached drawings. The present invention is not limited to the embodiments shown below.

FIG. 1 is a diagram showing an example of a thermoacoustic device 1 according to an embodiment. In a plurality of drawings including FIG. 1, the front side is the positive direction in the Z-axis direction in the direction orthogonal to the paper surface, and the longitudinal direction and the lateral direction of the thermoacoustic device 1 are the X-axis direction and the Y-axis direction, respectively. Shows a three-dimensional Cartesian coordinate system.

The thermoacoustic device 1 converts thermal energy into acoustic energy of sound waves by thermoacoustic effect, converts acoustic energy of sound waves into other energy such as electric energy, or cools heat from acoustic energy of generated sound waves. It is a device to take out. Here, the thermoacoustic effect is the interaction between heat and sound waves. As shown in FIG. 1, the thermoacoustic device 1 includes a waveguide 2, a heat exchanger 3, an exciter 7, and a converter 8.

The waveguide 2 is filled with gas G. The gas G is, for example, air, nitrogen (N ₂ ), helium (He), argon (Ar), hydrogen (H ₂ ), carbon dioxide (CO ₂ ), or the like. The waveguide 2 is configured to seal the gas G inside.

The pressure of the gas G filled in the waveguide 2 is, for example, 1 atm (1013.25 hPa) or more and less than 100 atm (101325 hPa). By increasing the pressure of the gas G filled in the waveguide 2, the sound energy of the converted sound wave can be increased. On the other hand, when the pressure of the gas G filled in the waveguide 2 is 1 atm, it is not necessary to improve the airtightness of the waveguide 2.

The waveguide 2 is a loop-shaped waveguide without a reflective wall. The waveguide 2 has, for example, the shape of a single loop as shown in FIG. The waveguide 2 can change the resonance frequency of the sound wave generated in the gas G by changing its length. In the thermoacoustic device 1, the phase of the temperature change of the gas G caused by the heat conduction between the heat exchanger 3 and the gas G is set with respect to the phase of the movement (transfer) of the gas G by the sound wave generated in the gas G. It is delayed by the amount corresponding to the rate of temperature rise or fall of the medium. Accordingly, the phase of the pressure change of the sound wave of the gas G is delayed by 0 ° to 90 ° from the phase of the pressure change of the gas G when there is no temperature change.

Therefore, for example, when the waveguide 2 has a reflective wall, the resonance of the sound wave having the phase delay of the pressure is hindered by interposing the temperature change generated in the gas G, and the amplitude of the sound wave generated in the gas G. Will be reduced. In the thermoacoustic device 1, the waveguide 2 has the shape of a loop without a reflection wall, so that the resonance of the sound wave generated in the gas G can be stabilized. Accordingly, the thermoacoustic device 1 can improve the output of the acoustic energy of the sound wave.

The length of the waveguide 2 is an integral multiple of the resonance wavelength of the sound wave generated in the gas G. The length of the waveguide 2 is set so that, for example, in the case of a small system, the resonance wavelength of the sound wave generated in the gas G is 1 m or less. The waveguide 2 is, for example, a hollow waveguide having a circular or square cross section. By increasing the diameter of the cross section of the waveguide 2, the output of sound wave acoustic energy can be increased.

The waveguide 2 is formed of, for example, a metal such as stainless steel (SUS) or a plastic such as vinyl chloride. When the waveguide 2 is made of plastic, the loop-shaped waveguide 2 can be easily manufactured, so that the cost of the waveguide 2 can be reduced.

The heat exchanger 3 transfers heat to the gas G filled in the waveguide 2. The heat exchanger 3 heats / cools the gas G according to the phase of advection of sound waves. The length of the heat exchanger 3 in the direction in which the waveguide 2 extends (X-axis direction) is preferably, for example, greater than or equal to the amplitude of the sound wave generated in the gas G and not more than 1/20 of the wavelength of the sound wave, for example, 1 to 5 cm. The heat exchanger 3 is provided in the waveguide 2. The heat exchanger 3 includes a low temperature section 4, a high temperature section 5, and a temperature gradient holding section 6.

The low temperature section 4 is a member contained in the heat exchanger 3 that maintains a relatively low temperature. The high temperature section 5 is a member included in the heat exchanger 3 that maintains a relatively high temperature. Here, the relatively low temperature and the relatively high temperature are based on the contrast between the temperature of the low temperature portion 4 and the temperature of the high temperature portion 5. That is, the temperature of the high temperature portion 5 is higher than the temperature of the low temperature portion 4. In the heat exchanger 3, a temperature gradient is generated between the low temperature portion 4 and the high temperature portion 5. The acoustic energy of sound waves converted from thermal energy by increasing the difference between the temperature of the low temperature section 4 and the temperature of the high temperature section 5, that is, by increasing the temperature gradient between the low temperature section 4 and the high temperature section 5. Can be increased.

The low temperature section 4 and the high temperature section 5 are connected to a heat source having a relatively low temperature and a heat source having a relatively high temperature, respectively. The heat source at a relatively low temperature may be, for example, a refrigerant such as water supplied to the pipe. The heat source at a relatively high temperature may be a heating medium such as hot water supplied to the pipe. One of the relatively low temperature heat source and the relatively high temperature heat source may be, for example, air at room temperature.

The temperature gradient holding portion 6 is a member that holds the temperature gradient generated between the low temperature portion 4 and the high temperature portion 5. The temperature gradient holding portion 6 is provided between the low temperature portion 4 and the high temperature portion 5. The temperature gradient holding unit 6 generates and amplifies sound waves in the gas G by the temperature gradient generated between the low temperature unit 4 and the high temperature unit 5.

The exciter 7 generates a sound wave in the gas G at a predetermined frequency. The exciter 7 is provided in the waveguide 2 so as to seal the gas G. When the exciter 7 is provided in a place where the pressure amplitude of the resonant sound wave is large, the pressure of the gas G is caused by the reciprocating motion of the piston inserted in the cylinder provided so as not to change the acoustic impedance of the waveguide 2. Is configured to vibrate.

The converter 8 converts the acoustic energy of the sound wave generated in the gas G into a predetermined energy and extracts the predetermined energy. The converter 8 may be, for example, a generator that generates electricity by converting the acoustic energy of sound waves generated in the gas G into electrical energy. In this case, the thermoacoustic device 1 can generate electricity by using, for example, the heat supplied from the heat source to the heat exchanger 3.

Alternatively, the converter 8 is, for example, a cooler (heat exchanger for cooling) that lowers the temperature of the medium in contact with the converter 8 by converting the acoustic energy of the sound wave generated in the gas G into the heat energy of cooling. There may be. In this case, the thermoacoustic device 1 can cool the medium by using, for example, the heat supplied from the heat source to the heat exchanger 3.

In the thermoacoustic device 1, for example, the gas G filled in the waveguide 2 is vibrated at a predetermined resonance frequency by the exciter 7. For example, the vibrating gas G moves from the low temperature side to the high temperature side of the temperature gradient holding portion 6 in the heat exchanger 3. Here, the gas G is heated and expanded by the temperature gradient held by the temperature gradient holding unit 6.

Next, the vibrating gas G moves from the high temperature side to the low temperature side of the temperature gradient holding unit 6 in the heat exchanger 3. Here, the gas G is cooled and contracted by the temperature gradient held by the temperature gradient holding unit 6. In this way, the sound wave of the gas G filled in the waveguide 2 is amplified by the repeated expansion and contraction of the gas G in the heat exchanger 3, and the heat energy is converted into the sound energy of the sound wave of the gas G.

Here, for example, the sound wave generated in the gas G filled in the waveguide 2 by the exciter 7 can be excited at a predetermined resonance frequency. The sound wave generated in the gas G is amplified and resonates in the waveguide 2 by the heat exchanger 3. When the sound wave generated in the gas G reaches the converter 8, the converter 8 converts the acoustic energy of the sound wave generated in the gas G into a predetermined energy and extracts the predetermined energy.

FIG. 2 is a diagram showing an example of a heat exchanger 3 included in the thermoacoustic device 1. As shown in FIG. 2, the heat exchanger 3 includes, for example, a low temperature portion 4, a high temperature portion 5, a temperature gradient holding portion 6, a first heat conductive member 11, and a second heat conductive member 12. include. The low temperature section 4 includes, for example, a first low temperature section 4a, a second low temperature section 4b, and a third low temperature section 4c. The high temperature section 5 includes, for example, a first high temperature section 5a, a second high temperature section 5b, and a third high temperature section 5c. The configuration of the temperature gradient holding unit 6 will be described later.

As shown in FIG. 2, a third low temperature section 4c, a second low temperature section 4b, a first low temperature section 4a, a temperature gradient holding section 6, a first high temperature section 5a, a second high temperature section 5b, and a third The high temperature part 5c of the above is joined. The first heat conductive member 11 is joined to the third low temperature portion 4c. The second heat conductive member 12 is joined to the third high temperature portion 5c.

The low temperature part 4 has the same or similar structure as the high temperature part 5. Specifically, the structure of the first low temperature portion 4a has the same or similar structure as the structure of the first high temperature portion 5a. The structure of the second low temperature portion 4b has the same or similar structure as the structure of the second high temperature portion 5b. The structure of the third low temperature portion 4c has the same or similar structure as the structure of the third high temperature portion 5c. The configuration of the first high temperature portion 5a, the configuration of the second high temperature portion 5b, and the configuration of the third high temperature portion 5c will be described later.

Each of the first heat conductive members 11 is connected to a heat source having a relatively low temperature as described above. The first heat conductive member 11 is joined to a portion including the central portion of the third low temperature portion 4c to change the temperature of the third low temperature portion 4c. Correspondingly, the first heat conductive member 11 sets the temperature of the third low temperature portion 4c, the second low temperature portion 4b, and the first low temperature portion 4a, that is, the temperature of the low temperature portion 4 relatively low. Keep in.

The second heat conductive member 12 is connected to a heat source having a relatively high temperature as described above. The second heat conductive member 12 is joined to a portion including the central portion of the third high temperature portion 5c to change the temperature of the third high temperature portion 5c. Correspondingly, the second heat conductive member 12 raises the temperature of the third high temperature portion 5c, the second high temperature portion 5b, and the first high temperature portion 5a, that is, the temperature of the high temperature portion 5 to a relatively high temperature. Maintain to.

The first heat conductive member 11 is made of metal, for example. In this case, the thermal conductivity of the first heat conductive member 11 can be improved. The metal forming the first heat conductive member 11 is, for example, copper. In this case, the cost of the first heat conductive member 11 can be reduced, and the amount of heat conduction can be increased. The second heat conductive member 12 has the same or similar structure as the structure of the first heat conductive member 11. When each of the first heat conductive member 11 and the second heat conductive member 12 is made of metal, the joining of the first heat conductive member 11 to the third low temperature portion 4c and the third high temperature portion A solder or a laser may be used to join the second heat conductive member 12 to 5c.

In the conventional technique, the temperature gradient holding portion of the heat exchanger usually has a honeycomb shape having a plurality of pores or a lattice shape having a plurality of pores. Each of the low temperature part and the high temperature part of the heat exchanger has a honeycomb shape having a plurality of pores or a lattice shape having a plurality of pores, which is equivalent to the honeycomb shape or the lattice shape of the temperature gradient holding part. .. In the temperature gradient holding part, the low temperature part, and the high temperature part of the heat exchanger, the honeycomb-shaped or lattice-shaped pores of the temperature gradient holding part and the honeycomb-shaped or lattice-shaped pores of the low-temperature part and the high-temperature part overlap each other. Is placed in.

In the conventional technique, when the gas passes through the low temperature part, the temperature gradient holding part, and the high temperature part of the heat exchanger, the gas is formed in the pores of the low temperature part, the pores of the temperature gradient holding part, and the high temperature part. It will pass through the pores. As a result, the dynamic viscous resistance of the gas increases.

In the prior art, the temperature gradient retainer is typically manufactured by extrusion so as to have a honeycomb shape with a plurality of pores or a grid shape with a plurality of pores. In some cases, a temperature gradient holding portion is formed by stacking thin metal plates punched out from honeycomb-shaped or lattice-shaped pores. When the temperature gradient holding part is formed by extrusion molding or stacking metal thin plates with punched pores, the surface forming the honeycomb-shaped pores or the lattice-shaped pores of the temperature gradient holding part is usually formed. It has a relatively large surface roughness. As a result, the dynamic viscous resistance of the gas is further increased. Further, when a metal thin plate having punched out honeycomb-shaped or lattice-shaped pores is stacked to form a temperature gradient holding portion, the thermal conductivity of the temperature gradient holding portion becomes high, and it is difficult to maintain an appropriate temperature gradient. Met.

As described above, in the conventional technique, it is preferable to arrange the heat exchanger in a place where the velocity of the gas is relatively high in the waveguide, but as described above, the dynamic viscous resistance of the gas increases, so that heat is generated. It may be difficult to move the gas efficiently in the exchanger and the energy loss due to the dynamic viscous resistance may be large. There is also a problem that the temperature gradient cannot be kept high.

Therefore, in the conventional technology, the efficiency of converting thermal energy into acoustic energy of sound waves may be low. For example, when heat energy is converted into sound sound energy by a temperature gradient between a heat source temperature of 100 ° C. or lower and room temperature, the loss due to viscous resistance becomes relatively large, and the temperature gradient becomes low and the efficiency is low. May become.

In order for the sound wave of the gas G filled in the waveguide 2 to be amplified by repeated expansion and contraction of the gas G in the heat exchanger 3 and the heat energy to be efficiently converted into the acoustic energy of the sound of the gas G. , The phase velocity ω of the sound wave, the thermal diffusion coefficient α of the gas G, and the distance d between the plurality of heat conductors that transfer heat to the gas G of the temperature gradient holding portion.
2α / {ω × (d / 2) ² } = δ ・ ・ ・ ・ ・ (1)
It is desirable that the relationship of Here, δ is approximately 1, and the optimum value of δ changes depending on the shape and arrangement of the heat conductor. It is about 0.32 when the heat conductor forms honeycomb-shaped pores or lattice-shaped pores, and about 0.79 when the heat conductor is formed of parallel flat plate fins. The thermal diffusivity α can be written as follows using the density ρ of the gas G, the constant pressure specific heat C, and the thermal conductivity κ.
α = κ / (ρ × C) ・ ・ ・ ・ ・ (2)

On the other hand, the index relating to the dynamic viscous resistance of the gas G is ^{ω × (d / 2) 2} / 2ν, which kinematic viscosity resistance decreases when more than about several tens of large, the amplitude of vibration of the gas G is The reduction is suppressed. This index can be calculated using equation (1).
^{ω × (d / 2) 2} / 2ν = (1 / δ) × α / ν = 1 / (δ × σ) ····· (3)
Can be written. ν is the kinematic viscosity coefficient of the gas G, and is defined by the ratio of the viscosity coefficient μ of the gas G to the density ρ, μ / ρ. The ratio of the kinematic viscosity coefficient ν to the thermal diffusivity α, σ (= ν / α = C × μ / κ), is the Prandtl number, which is a physical constant that depends slightly on the temperature. The Prandtl number is about 0.6 to 0.7 regardless of the type of gas G, and is 0.67 in the case of air. Therefore, when the heat conductor forms honeycomb-shaped pores or lattice-shaped pores, the index related to the dynamic viscous resistance is about 5 from the equation (3), and δ is kept at the optimum value. It can be seen that a large dynamic viscous resistance is generated in the state of being.

On the other hand, the index of equation (3) is derived from the theoretical equation of the fluid in which the gas G has a velocity of 0 on the wall of the heat conductor. Since the surface forming the honeycomb-shaped pores or the lattice-shaped pores of the conventional temperature gradient holding portion has a relatively large surface roughness, it is close to the situation considered by the theoretical formula, but this roughness is reduced. If the gas G can be made to slide on the surface of the pores by taking measures such as the above and the viscosity coefficient μ of the gas G can be effectively reduced, the index related to the dynamic viscous resistance can be increased.

Further, when the heat conductor forms honeycomb-shaped pores or lattice-shaped pores, the temperature gradient is maintained even if the index related to the dynamic viscous resistance represented by the formula (3) is about 5. The effective dynamic viscous resistance changes depending on the pores such as the honeycomb shape and the parallel flat plate fins constituting the portion, and the amplitude of the vibration of the gas G differs. According to the result derived from the theoretical formula of the fluid, when this index is about 1, the relative amplitude of the sound wave is 0.2 in the case of pores such as honeycomb shape, but the viscous resistance is relatively low. In the case of parallel flat plate fins, which is considered to be, it increases to about 0.5. As a result of investigating the dependence of the sound wave on the amplitude by the index of the formula (3), the influence coefficient on the index in which the structure was changed from the pores to the parallel flat plate fin was about 3 times. The effective index that puts the structural influence of Eq. (3) with the influence coefficient of this structure as k is k / (δ × σ) = k / (δ × μ) × (κ / C) ・ ・ ・ ・ ・ (4) )
Can be written. Therefore, by changing the structure of the heat conductor such as the honeycomb shape of the temperature gradient holding portion and the parallel flat plate fins to a structure having a low viscous resistance, k is increased and an effective index of the dynamic viscous resistance of the equation (4). Can be further increased, and the dynamic viscous resistance can be lowered while maintaining the optimum δ.

On the other hand, when the heat conductor of the temperature gradient holding portion is formed by the honeycomb-shaped pores or the lattice-shaped pores, the optimum δ is about 0.32, and the heat conductor is composed of parallel flat plate fins. If it is, it is about 0.79. That is, when k in the case of pores is 1, and the Prandtl number of air is 0.67, the effective index related to the dynamic viscous resistance of the pores in the case of air is given by the equation (4). ) To 4.7. In the case of parallel flat plate fins, k is set to 3 and the effective index related to the dynamic viscous resistance of air is calculated to be about 5.7. Therefore, in the case of the temperature gradient holding portion of the pores and the parallel plate fins, these values are substantially the same, and in order to raise the index related to the dynamic viscous resistance, the gas should slide on the surface of the parallel plate fins or the like. Therefore, it can be expected that only lowering the effective viscosity coefficient μ is effective.

By simply performing a geometrical evaluation in a cross section perpendicular to the direction in which the waveguide 2 of the temperature gradient holding portion extends (X-axis direction), the heat conductor of the temperature gradient holding portion has honeycomb-shaped pores. Alternatively, as a result of comparison between the case of forming lattice-shaped pores, the case of being composed of parallel flat plate fins, and the case of being composed of fine wires, in the above k, the temperature gradient holding portion composed of thin wires. In the case of, it was confirmed that the temperature gradient holding portion composed of parallel flat plate fins could be about 8 to 10 times larger. On the other hand, δ when the temperature gradient holding portion is composed of thin lines is 0.32 or more, which is the value of δ when the temperature gradient holding portion is composed of pores, and the temperature gradient is maintained by the parallel flat plate fins. It was also confirmed that the value of δ when the part was composed was 0.79 or less. From these, it was confirmed that when the temperature gradient holding portion is composed of a thin wire thermal conductor, the index related to the effective dynamic viscous resistance of the equation (4) is about several tens, and the equation (4). It was shown that the dynamic viscous resistance can be further reduced by the k / δ portion of.

From the above, in the thermoacoustic device 1 according to the present embodiment, it is assumed that the temperature gradient holding portion 6 included in the heat exchanger 3 is composed of a linear heat conductor, and k is increased, and the linear heat is increased. By smoothing the surface of the conductor, the effective viscous resistance μ is lowered, and by using the optimum δ suitable for the structure of the temperature gradient holding portion 6, the phase velocity ω of the sound wave and the temperature rise / fall rate of the gas are used. Is made to correspond based on the equation (1), thereby effectively lowering the dynamic viscous resistance and increasing the efficiency of converting heat energy into sound energy.

3 and 4 are diagrams showing an example of the temperature gradient holding unit 6 included in the heat exchanger 3. FIG. 4 shows a cross section of the temperature gradient holding portion 6 along the line AA in FIG. As shown in FIGS. 3 and 4, the temperature gradient holding portion 6 has a substantially cylindrical shape, for example, when the cross section of the waveguide 2 is circular. For example, the temperature gradient holding portion 6 includes a frame body 65 having a substantially cylindrical shape.

As shown in FIGS. 3 and 4, the temperature gradient holding portion 6 includes a plurality of linear heat conductors 60. The plurality of linear thermal conductors 60 are, for example, between both ends of the temperature gradient holding portion 6 so as to be parallel to each other in a direction parallel to the direction of the central axis (X-axis direction) of the temperature gradient holding portion 6. It is stretched. Each of the plurality of linear thermal conductors 60 has a surface orthogonal to the direction of the central axis (X-axis direction) of the temperature gradient holding portion 6, and is in contact with the gas G on this surface.

In the thermoacoustic device 1 according to the embodiment, since the temperature gradient holding portion 6 includes the plurality of linear thermal conductors 60, when the gas G passes through the temperature gradient holding portion 6, the gas G is a plurality of. It passes through the gap between the linear thermal conductors 60. As a result, the dynamic viscous resistance of the gas G in the temperature gradient holding portion 6 is controlled by the conventional honeycomb-shaped or lattice-shaped temperature gradient holding portion having a plurality of pores, or the temperature gradient composed of a plurality of parallel flat plate fins. It can be reduced as compared with the holding portion. As a result, it is possible to reduce a decrease in the speed of the gas G passing through the temperature gradient holding unit 6.

Therefore, the thermoacoustic device 1 can efficiently move the gas G in the temperature gradient holding unit 6. Accordingly, the thermoacoustic device 1 can improve the efficiency of converting thermal energy into acoustic energy of sound waves.

For example, in the thermoacoustic device 1, even when a heat source at room temperature and a heat source having a temperature of 100 ° C. or lower are connected to the low temperature section 4 and the high temperature section 5, respectively, the temperature provided between the low temperature section 4 and the high temperature section 5 is provided. The dynamic viscous resistance of the gas G in the gradient holding portion 6 can be reduced. Therefore, the thermoacoustic device 1 can efficiently utilize heat from a heat source having a temperature of 100 ° C. or lower, for example, waste heat, for example, for power generation or cooling.

The distance d (60) between the plurality of linear heat conductors 60 as shown in FIG. 3 is 1.0 mm or less in order to improve the heat conduction from the plurality of linear heat conductors 60 to the gas G. be. The distance d (60) between the plurality of linear thermal conductors 60 is preferably 0.2 mm or more and 0.4 mm or less, for example, about 0.3 mm. The diameter r (60) of each of the plurality of linear thermal conductors 60 as shown in FIG. 3 is 0.1 mm or less, for example, about 0.08 mm.

The length w (60) of each of the plurality of linear thermal conductors 60 in the direction of the central axis (X-axis direction) of the temperature gradient holding portion 6 as shown in FIG. 4 is 7 mm or more and 20 mm or less, for example, about 10 mm. Is. In this case, by obtaining the amplitude of the effective magnitude of the sound wave, it is possible to obtain the effective output of the acoustic energy of the sound wave converted from the thermal energy of the temperature gradient holding unit 6.

As shown in FIG. 4, when the temperature gradient holding portion 6 has the frame body 65, the frame body 65 is integrated with the frame body 55a of the first high temperature portion 5a described later. The length w'(60) of the portion where the linear thermal conductor 60 of the temperature gradient holding portion 6 protrudes from the frame 65 in the direction of the central axis of the temperature gradient holding portion 6 (X-axis direction) is 1.0 mm or more. It is 3.0 mm or less, for example, about 2.0 mm. A portion where the linear heat conductor 60 of the temperature gradient holding portion 6 protrudes from the frame body 65, and as will be described later, the plurality of linear heat conductors 60 are a plurality of plate-shaped fins 50a of the first high temperature portion 5a. Is joined with. Regardless of the presence or absence of the frame body 65 in the temperature gradient holding portion 6, each of the plurality of linear thermal conductors 60 is located at one end in the direction of the central axis (X-axis direction) of the temperature gradient holding portion 6. , Which will be described later, is joined to the first high temperature portion 5a, and at the other end, it is joined to the first low temperature portion 4a.

Each of the plurality of linear thermal conductors 60 is formed of, for example, a metal material having a low thermal conductivity and easy linear shape processing. The thermal conductivity of the material forming each of the plurality of linear thermal conductors 60 is, for example, 5 Wm ^-1 · K ^-1 or more and 30 Wm ^-1 · K ^-1 or less. In this case, the thermal conductivity of each of the plurality of linear thermal conductors 60 can be reduced. Therefore, it is possible to suppress the reduction of the temperature gradient in the temperature gradient holding unit 6. Accordingly, the temperature gradient holding section 6 can satisfactorily hold the temperature gradient generated between the low temperature section 4 and the high temperature section 5.

The metal forming each of the plurality of linear thermal conductors 60 is represented by, for example, a nickel-chromium alloy. In this case, for heat transfer from each of the plurality of linear heat conductors 60 to the gas G, heat conduction in the direction of the central axis (X-axis direction) in each of the plurality of linear heat conductors 60 is performed. It can be reduced satisfactorily. Therefore, the temperature gradient holding unit 6 can improve the heat transfer from the plurality of linear heat conductors 60 to the gas G. Accordingly, the temperature gradient holding section 6 can easily hold a desired temperature gradient between the low temperature section 4 and the high temperature section 5.

FIG. 5 is a diagram showing an example of each of the plurality of linear heat conductors 60 included in the temperature gradient holding unit 6.

As shown in FIG. 5, each of the plurality of linear thermal conductors 60 has a sharp end 61. For example, each of the plurality of linear thermal conductors 60 has sharp ends 61 at both ends in the direction of the central axis (X-axis direction) of the temperature gradient holding portion 6. Here, the sharp end portion 61 is an end portion having an apex in a cross section perpendicular to the surface of each of the plurality of linear thermal conductors 60 in contact with the gas G.

When each of the plurality of linear heat conductors 60 has a sharp end portion 61, when the gas G passes through the temperature gradient holding portion 6, the gas G is a plurality of linear heat conductors 60. It passes through a sharp end 61 near each end. As a result, it is possible to reduce the decrease in the velocity of the gas G in the vicinity of each end of the plurality of linear thermal conductors 60. As a result, the gas G and the linear heat conductor 60 become slippery on the surface of each of the linear heat conductors 60 in contact with the gas G, so that the dynamic viscous resistance of the gas G in the temperature gradient holding portion 6 is increased. It can be further reduced.

Therefore, the thermoacoustic device 1 can efficiently move the gas G near each end of the plurality of linear thermal conductors 60. Accordingly, the thermoacoustic device 1 can further improve the efficiency of converting thermal energy into acoustic energy of sound waves.

As shown in FIG. 5, the surface of the plurality of linear thermal conductors 60 perpendicular to the direction of the central axis (X-axis direction) has a mirror surface 62. For example, each of the plurality of linear thermal conductors 60 has a mirror surface 62 on a surface orthogonal to the direction of the central axis (X-axis direction) of the temperature gradient holding portion 6, that is, a surface in contact with the gas G. Here, the mirror surface 62 is a surface having a surface roughness (arithmetic mean roughness Sa) of, for example, 0.02 μm or less.

In the thermoacoustic device 1, when each of the plurality of linear heat conductors 60 has a mirror surface 62, when the gas G passes through the temperature gradient holding portion 6, the gas G has a plurality of linear heats. It passes between the mirror surfaces 62 included in the conductor 60. As a result, the gas G can be slid and passed near the surface of each of the plurality of linear thermal conductors 60 in contact with the gas G. As a result, the dynamic viscous resistance of the gas G in the temperature gradient holding portion 6 can be further reduced.

Therefore, the thermoacoustic device 1 can efficiently move the gas G near the surface of each of the plurality of linear thermal conductors 60 included in the temperature gradient holding unit 6. Accordingly, the thermoacoustic device 1 can further improve the efficiency of converting thermal energy into acoustic energy of sound waves.

6 and 7A are diagrams showing an example of a first high temperature portion 5a included in the high temperature portion 5 included in the heat exchanger 3. FIG. 7A shows a cross section of the first high temperature portion 5a along the line AA in FIG. As shown in FIGS. 6 and 7A, the first high temperature portion 5a has, for example, a substantially cylindrical shape having a substantially circular cross section. For example, the first high temperature portion 5a includes a frame body 55a having a substantially cylindrical shape.

As shown in FIGS. 6 and 7A, the first high temperature portion 5a includes a plurality of plate-shaped fins 50a. As will be described later, the plurality of plate-shaped fins 50a are joined to the plurality of linear heat conductors 60 included in the temperature gradient holding portion 6.

The plurality of plate-shaped fins 50a have, for example, surfaces having normals in a direction (Y-axis direction) orthogonal to the direction of the central axis (X-axis direction) of the first high-temperature portion 5a and parallel to each other. .. Each of the plurality of plate-shaped fins 50a has a surface in contact with the gas G having a normal in a direction (Y-axis direction) orthogonal to the direction of the central axis (X-axis direction) of the first high temperature portion 5a. Have.

The distance d (50a) of the plurality of plate-shaped fins 50a as shown in FIG. 6 is larger than the distance d (60) of the plurality of linear thermal conductors 60 included in the temperature gradient holding portion 6. The distance d (50a) between the plurality of plate-shaped fins 50a is three times or more and five times or less the distance d (60) between the plurality of linear heat conductors 60, for example, about 1.6 mm.

When the distance d (50a) of the plurality of plate-shaped fins 50a is larger than the distance d (60) of the plurality of linear heat conductors 60 included in the temperature gradient holding portion 6, the gas G is the first. When passing through the high temperature portion 5a, the gas G passes through the gaps between the plurality of plate-shaped fins 50a, which are larger than the gaps between the plurality of linear heat conductors 60.

By making the distance between the plurality of plate-shaped fins 50a larger than the gap between the plurality of linear heat conductors 60 in this way, the gas G passes through the first high temperature portion 5a rather than the gas G passing through the temperature gradient holding portion 6. The decrease in the velocity of the gas G can be reduced. As a result, the dynamic viscous resistance of the gas G when the gas G passes through the first high temperature portion 5a is reduced as compared with the dynamic viscous resistance of the gas G when the gas G passes through the temperature gradient holding portion 6. Can be done. The dynamic viscous resistance of the gas G when the gas G passes through the first high temperature portion 5a is substantially inversely proportional to the square of the distance d (50a) of the plurality of plate-shaped fins 50a.

Therefore, the thermoacoustic device 1 can efficiently move the gas G in the first high temperature portion 5a. Accordingly, the thermoacoustic device 1 can further improve the efficiency of converting thermal energy into acoustic energy of sound waves.

The thickness t (50a) of each of the plurality of plate-shaped fins 50a as shown in FIG. 6 is larger than the diameter t (60) of each of the plurality of linear heat conductors 60 included in the temperature gradient holding portion 6. big. The thickness t (50a) of each of the plurality of plate-shaped fins 50a is twice or more and three times or less, for example, about 0.2 mm of the diameter t (60) of each of the plurality of linear thermal conductors 60. ..

When the thickness t (50a) of each of the plurality of plate-shaped fins 50a is larger than the diameter r (60) of each of the plurality of linear heat conductors 60 included in the temperature gradient holding portion 6, the first The thermal conductivity of the high temperature portion 5a of 1 can be improved. For example, the temperature distribution at the end of the first high temperature portion 5a on the side of the temperature gradient holding portion 6 can be made more uniform. As a result, the thermal conductivity from the first high temperature portion 5a to the temperature gradient holding portion 6 can be improved. Accordingly, the thermoacoustic device 1 can further improve the efficiency of converting thermal energy into acoustic energy of sound waves.

When the thickness t (50a) of each of the plurality of plate-shaped fins 50a is larger than the diameter t (60) of each of the plurality of linear heat conductors 60 included in the temperature gradient holding portion 6, a plurality of them. The plate-shaped fins 50a can more reliably hold the plurality of linear thermal conductors 60 joined to the plurality of plate-shaped fins 50a. As a result, the first high temperature portion 5a can more reliably hold the temperature gradient holding portion 6.

The length w (50a) of each of the plurality of plate-shaped fins 50a in the direction of the central axis (X-axis direction) of the first high temperature portion 5a as shown in FIG. 7A is 3 mm or more and 5 mm or less, for example, about 4 mm. Is. When the first high temperature portion 5a has the frame body 55a, the frame body 55a is integrated with the frame body 65 of the temperature gradient holding portion 6. As shown in FIG. 7A, each of the plurality of plate-shaped fins 50a has a convex portion protruding from the frame body 55a of the first high temperature portion 5a in the direction of the central axis (X-axis direction) of the first high temperature portion 5a. Has. The length w'(55a) of the convex portion protruding from the frame body 55a of the first high temperature portion 5a in the direction of the central axis (X-axis direction) of the first high temperature portion 5a is 2 mm or more and 4 mm or less, for example, 2 mm. Degree. The convex portion of the first high temperature portion 5a protruding from the frame body 55a is joined to the second high temperature portion 5b as described later. Regardless of the presence or absence of the frame body 55a in the first high temperature portion 5a, each of the plurality of plate-shaped fins 50a is one end portion in the direction of the central axis (X-axis direction) of the first high temperature portion 5a. In, it is joined to the second high temperature portion 5b described later, and is joined to the temperature gradient holding portion 6 at the other end portion.

As shown in FIGS. 7A and 7B, the plurality of plate-shaped fins 50a have a plurality of connecting portions 51a for joining at least a part of the plurality of linear thermal conductors 60 included in the temperature gradient holding portion 6. Each of the plurality of connecting portions 51a included in the plurality of plate-shaped fins 50a is provided so as to connect the portion of length w'(60) from the end of the temperature gradient holding portion 6 as shown in FIG. The length w (51a) of the connecting portion 51a in the direction of the central axis (X-axis direction) of the first high temperature portion 5a as shown in FIGS. 7A and 7B is the temperature gradient holding portion 6 as shown in FIG. It is substantially equal to the length w'(60) of the convex portion protruding from the frame body 65 of the temperature gradient holding portion 6 in the direction of the central axis (X-axis direction).

When the plurality of plate-shaped fins 50a have a plurality of connecting portions 51a having a length w (51a) for connecting at least a part of the plurality of linear thermal conductors 60 included in the temperature gradient holding portion 6. Can join a plurality of plate-shaped fins 50a to a plurality of linear thermal conductors 60. As a result, the thermal conductivity from the first high temperature portion 5a to the temperature gradient holding portion 6 can be improved. Accordingly, the thermoacoustic device 1 can further improve the efficiency of converting thermal energy into acoustic energy of sound waves. A solder or a laser may be used for joining the plurality of linear thermal conductors 60 and the connecting portion 51a.

Further, the plurality of plate-shaped fins 50a can more reliably hold the plurality of linear heat conductors 60 joined to the plurality of plate-shaped fins 50a. As a result, the first high temperature portion 5a can more reliably hold the temperature gradient holding portion 6.

Each of the plurality of plate-shaped fins 50a preferably has a sharp end. For example, each of the plurality of plate-shaped fins 50a has sharp ends at both ends in the direction of the central axis (X-axis direction) of the first high temperature portion 5a. Here, the sharp end is an end having an apex in a cross section perpendicular to the surface in contact with the gas G in each of the plurality of plate-shaped fins 50a.

When each of the plurality of plate-shaped fins 50a has a sharp end, when the gas G passes through the first high temperature portion 5a, the gas G is a member of each of the plurality of plate-shaped fins 50a. It passes through a sharp end near the end. As a result, it is possible to reduce a decrease in the velocity of the gas G in the vicinity of each end of the plurality of plate-shaped fins 50a included in the first high temperature portion 5a. Thereby, the dynamic viscous resistance of the gas G in the first high temperature portion 5a can be further reduced.

Therefore, the thermoacoustic device 1 can efficiently move the gas G near each end of the plurality of plate-shaped fins 50a included in the first high temperature portion 5a. Accordingly, the thermoacoustic device 1 can further improve the efficiency of converting thermal energy into acoustic energy of sound waves.

8 and 9 are diagrams showing an example of a second high temperature portion 5b included in the high temperature portion 5 included in the heat exchanger 3. FIG. 9 shows a cross section of the second high temperature portion 5b along the line AA in FIG. As shown in FIGS. 8 and 9, the second high temperature portion 5b has, for example, a substantially cylindrical shape. For example, the second high temperature portion 5b includes a frame body 55b having a substantially cylindrical shape.

As shown in FIGS. 8 and 9, the second high temperature portion 5b includes a plurality of first lattice-shaped fins 50b. The plurality of first lattice-shaped fins 50b are joined to the plurality of plate-shaped fins 50a included in the first high temperature portion 5a, as will be described later.

The plurality of first grid-like fins 50b are, for example, in a direction (approximately 45 ° with respect to the Y-axis or Z-axis) orthogonal to the direction of the central axis (X-axis direction) of the second high-temperature portion 5b. ) Has a plurality of lattices. Each of the plurality of first grid-shaped fins 50b is in a direction (approximately 45 ° with respect to the Y-axis or Z-axis) orthogonal to the direction of the central axis (X-axis direction) of the second high temperature portion 5b. ) Has a surface in contact with the gas G.

The surface of each of the plurality of first lattice-shaped fins 50b in contact with the gas G is approximately 45 ° with the surface of each of the plurality of plate-shaped fins 50a contained in the first high temperature portion 5a in contact with the gas G. Has an angle of. Since the lattices in the plurality of first lattice-shaped fins 50b are arranged in a direction of approximately 45 ° with respect to the plates in each of the plurality of plate-shaped fins 50a included in the first high temperature portion 5a, a plurality of plates are arranged. The morphology of the first lattice-shaped fins 50b and the plurality of plate-shaped fins 50a joined to the plurality of first lattice-shaped fins 50b can be more reliably held.

The distance d (50b) of the plurality of first lattice-shaped fins 50b as shown in FIG. 8 is larger than the distance d (50a) of the plurality of plate-shaped fins 50a included in the first high temperature portion 5a. The distance d (50b) between the plurality of first lattice-shaped fins 50b is, for example, twice or more and three times or less, for example, about 4.5 mm with respect to the distance d (50a) between the plurality of plate-shaped fins 50a.

When the distance d (50b) between the plurality of first lattice-shaped fins 50b is larger than the distance d (50a) between the plurality of plate-shaped fins 50a included in the first high temperature portion 5a, the gas G is produced. When passing through the second high temperature portion 5b, the gas G passes through the gaps between the plurality of first grid-like fins 50b, which are larger than the gaps between the plurality of plate-shaped fins 50a.

As a result, it is possible to reduce the decrease in the velocity of the gas G passing through the second high temperature portion 5b as compared with the gas G passing through the first high temperature portion 5a. As a result, the dynamic viscous resistance of the gas G when the gas G passes through the second high temperature portion 5b is reduced as compared with the dynamic viscous resistance of the gas G when the gas G passes through the first high temperature portion 5a. be able to. For example, the spacing d (50b) of the plurality of first lattice-shaped fins 50b may be set so that the dynamic viscous resistance of the gas G when the gas G passes through the second high temperature portion 5b can be ignored. can.

Therefore, the thermoacoustic device 1 can efficiently move the gas G in the second high temperature portion 5b. Accordingly, the thermoacoustic device 1 can further improve the efficiency of converting thermal energy into acoustic energy of sound waves.

The thickness t (50b) of each of the plurality of first lattice-shaped fins 50b as shown in FIG. 8 is the thickness t (50b) of each of the plurality of plate-shaped fins 50a included in the first high temperature portion 5a. Greater than 50a). The thickness t (50b) of each of the plurality of first lattice-shaped fins 50b is, for example, twice or more and three times or less, for example, 0, respectively, as the thickness t (50a) of each of the plurality of plate-shaped fins 50a. It is about 0.6 mm.

When the thickness t (50b) of each of the plurality of first lattice-shaped fins 50b is larger than the thickness t (50a) of each of the plurality of plate-shaped fins 50a included in the first high temperature portion 5a. In addition, the thermal conductivity of the second high temperature portion 5b can be improved even if the fin spacing of the first lattice-shaped fins 50b is increased. For example, the temperature distribution at the end of the second high temperature portion 5b on the side of the first high temperature portion 5a can be made more uniform. As a result, the thermal conductivity from the second high temperature portion 5b to the first high temperature portion 5a can be improved. Accordingly, the thermoacoustic device 1 can further improve the efficiency of converting thermal energy into acoustic energy of sound waves.

When the thickness t (50b) of each of the plurality of first lattice-shaped fins 50b is larger than the thickness t (50a) of each of the plurality of plate-shaped fins 50a included in the first high temperature portion 5a. The plurality of first grid-shaped fins 50b can more reliably hold the plurality of plate-shaped fins 50a joined to the plurality of first grid-shaped fins 50b. As a result, the second high temperature portion 5b can more reliably hold the first high temperature portion 5a.

The length w (50b) of each of the plurality of first lattice-shaped fins 50b in the direction of the central axis (X-axis direction) of the second high temperature portion 5b as shown in FIG. 9 is 4 mm or more and 6 mm or less, for example. It is about 5 mm. When the second high temperature portion 5b has the frame body 55b, as shown in FIG. 9, each of the plurality of first lattice-shaped fins 50b is in the direction of the central axis of the second high temperature portion 5b (X-axis direction). ), It has a convex portion protruding from the frame body 55b of the second high temperature portion 5b. The length w'(55b) of the convex portion protruding from the frame body 55b of the second high temperature portion 5b in the direction of the central axis of the second high temperature portion 5b (X-axis direction) is 3 mm or more and 4 mm or less, for example, 3 mm. Degree. The convex portion of the second high temperature portion 5b protruding from the frame body 55b is joined to the third high temperature portion 5c as described later. Regardless of the presence or absence of the frame body 55b in the second high temperature portion 5b, each of the plurality of first lattice-shaped fins 50b is one of the directions of the central axis (X-axis direction) of the second high temperature portion 5b. At the end of the above, it is joined to the third high temperature portion 5c described later, and at the other end, it is joined to the first high temperature portion 5a.

As shown in FIG. 9, the plurality of first lattice-shaped fins 50b have a plurality of first recesses 51b accommodating at least a part of the plurality of plate-shaped fins 50a included in the first high temperature portion 5a. Have. Each of the plurality of first recesses 51b included in the plurality of first lattice-shaped fins 50b accommodates a convex portion protruding from the frame body 55a of the first high temperature portion 5a as shown in FIG. 7A. Provided. The length w (51b) of the first recess 51b in the direction of the central axis (X-axis direction) of the second high temperature portion 5b as shown in FIG. 9 is the length w (51b) of the first high temperature portion 5a as shown in FIG. 7A. It is equal to the length w'(50a) of the convex portion protruding from the frame body 55a of the first high temperature portion 5a in the direction of the central axis (X-axis direction).

When the plurality of first lattice-shaped fins 50b have a plurality of first recesses 51b accommodating at least a part of the plurality of plate-shaped fins 50a included in the first high temperature portion 5a, the plurality of first lattice-shaped fins 50b may be present. The first lattice-shaped fins 50b can be joined to a plurality of plate-shaped fins 50a. As a result, the thermal conductivity from the second high temperature portion 5b to the first high temperature portion 5a can be improved. Accordingly, the thermoacoustic device 1 can further improve the efficiency of converting thermal energy into acoustic energy of sound waves.

Further, the plurality of first lattice-shaped fins 50b can more reliably hold the plurality of plate-shaped fins 50a joined to the plurality of first lattice-shaped fins 50b. As a result, the second high temperature portion 5b can more reliably hold the first high temperature portion 5a.

10 and 11 are diagrams showing an example of a third high temperature portion 5c included in the high temperature portion 5 included in the heat exchanger 3. FIG. 11 shows a cross section of the third high temperature portion 5c along the line AA in FIG. As shown in FIGS. 10 and 11, the third high temperature portion 5c has, for example, a substantially cylindrical shape. For example, the third high temperature portion 5c includes a frame body 55c having a substantially cylindrical shape.

As shown in FIGS. 10 and 11, the third high temperature portion 5c includes a plurality of second lattice-shaped fins 50c. The plurality of second grid-like fins 50c are joined to the plurality of first grid-like fins 50b included in the second high temperature portion 5b, as will be described later.

The plurality of second grid-shaped fins 50c form a plurality of grids in a direction (Y-axis direction or Z-axis direction) orthogonal to the direction of the central axis (X-axis direction) of the third high-temperature portion 5c, for example. Have. Each of the plurality of second grid-shaped fins 50c contacts the gas G in a direction (Y-axis direction or Z-axis direction) orthogonal to the direction of the central axis (X-axis direction) of the third high-temperature portion 5c. Has a surface to be.

The surface in contact with the gas G in each of the plurality of second grid-like fins 50c is substantially 45 with the surface in contact with the gas G in the plurality of first grid-like fins 50b included in the second high temperature portion 5b. Has an angle of °. Because the grids in the plurality of second grid-like fins 50c are arranged in a direction of approximately 45 ° with respect to the grids in each of the plurality of first grid-like fins 50b included in the second high temperature portion 5b. , The plurality of second grid-like fins 50c can more reliably retain the form of the plurality of first grid-like fins 50b joined to the plurality of second grid-like fins 50c.

The distance d (50c) of the plurality of second grid-like fins 50c as shown in FIG. 10 is larger than the distance d (50b) of the plurality of first grid-like fins 50b included in the second high temperature portion 5b. Is also big. The distance d (50c) between the plurality of second grid-like fins 50c is, for example, twice or more and three times or less, for example, about 12.8 mm as the distance d (50b) between the plurality of first grid-like fins 50b. Is.

When the distance d (50c) of the plurality of second grid-like fins 50c is larger than the distance d (50b) of the plurality of first grid-like fins 50b included in the second high temperature portion 5b, When the gas G passes through the third high temperature portion 5c, the gas G has a gap between the plurality of second grid-like fins 50c that is larger than the gap between the plurality of first grid-like fins 50b. Pass through.

As a result, it is possible to reduce the decrease in the velocity of the gas G passing through the third high temperature portion 5c as compared with the gas G passing through the second high temperature portion 5b. As a result, the dynamic viscous resistance of the gas G when the gas G passes through the third high temperature portion 5c is reduced as compared with the dynamic viscous resistance of the gas G when the gas G passes through the second high temperature portion 5b. be able to. For example, the interval d (50c) of the plurality of second lattice-shaped fins 50c may be set so that the dynamic viscous resistance of the gas G when the gas G passes through the third high temperature portion 5c can be ignored. can.

Therefore, the thermoacoustic device 1 can efficiently move the gas G in the third high temperature portion 5c. Accordingly, the thermoacoustic device 1 can further improve the efficiency of converting thermal energy into acoustic energy of sound waves.

The thickness t (50c) of each of the plurality of second grid-like fins 50c as shown in FIG. 10 is the thickness of each of the plurality of first grid-like fins 50b included in the second high temperature portion 5b. Is greater than t (50b). The thickness t (50c) of each of the plurality of second grid-like fins 50c is, for example, twice or more and three times or less the thickness t (50b) of each of the plurality of first grid-like fins 50b. For example, it is about 1.6 mm.

The thickness t (50c) of each of the plurality of second grid-like fins 50c is higher than the thickness t (50b) of each of the plurality of first grid-like fins 50b contained in the second high temperature portion 5b. If it is also large, the thermal conductivity of the third high temperature portion 5c can be improved even if the distance between the second lattice-shaped fins 50c is large. For example, the temperature distribution at the end of the third high temperature portion 5c on the side of the second high temperature portion 5b can be made more uniform. As a result, the thermal conductivity from the third high temperature portion 5c to the second high temperature portion 5b can be improved. Accordingly, the thermoacoustic device 1 can further improve the efficiency of converting thermal energy into acoustic energy of sound waves.

The thickness t (50c) of each of the plurality of second grid-like fins 50c is higher than the thickness t (50b) of each of the plurality of first grid-like fins 50b contained in the second high temperature portion 5b. If also large, the plurality of second grid-like fins 50c may more reliably hold the plurality of first grid-like fins 50b joined to the plurality of second grid-like fins 50c. can. As a result, the third high temperature portion 5c can more reliably hold the second high temperature portion 5b.

The length w (50c) of each of the plurality of second lattice-shaped fins 50c in the direction of the central axis (X-axis direction) of the third high temperature portion 5c as shown in FIG. 11 is 5 mm or more and 6 mm or less, for example. It is about 5 mm. When the third high temperature portion 5c has the frame body 55c, each of the plurality of second lattice-shaped fins 50c has a third in the direction of the central axis (X-axis direction) of the third high temperature portion 5c. It does not have a convex portion protruding from the frame body 55c of the high temperature portion 5c. Further, regardless of the presence or absence of the frame body 55c in the third high temperature portion 5c, each of the plurality of second lattice-shaped fins 50c is one of the directions of the central axis (X-axis direction) of the third high temperature portion 5c. At the end of the, it is joined to the second high temperature part 5b.

As shown in FIG. 11, the plurality of second grid-like fins 50c accommodates at least a part of the plurality of first grid-like fins 50b contained in the second high temperature portion 5b. It has a recess 51c. Each of the plurality of second recesses 51c included in the plurality of second lattice-shaped fins 50c accommodates a convex portion protruding from the frame body 55b of the second high temperature portion 5b as shown in FIG. Provided. The length w (51c) of the second recess 51c in the direction of the central axis (X-axis direction) of the third high temperature portion 5c as shown in FIG. 11 is the length w (51c) of the second high temperature portion 5b as shown in FIG. It is equal to the length w'(50b) of the convex portion protruding from the frame body 55b of the second high temperature portion 5b in the direction of the central axis (X-axis direction). As shown in FIG. 11, the length obtained by subtracting the length w (51c) of the second recess 51c from the length w (50c) of each of the plurality of second lattice-shaped fins 50c. Is represented by w'(50c).

When the plurality of second grid-like fins 50c have a plurality of second recesses 51c accommodating at least a part of the plurality of first grid-like fins 50b included in the second high temperature portion 5b. , A plurality of second grid-like fins 50c can be joined to a plurality of first grid-like fins 50b. As a result, the thermal conductivity from the third high temperature portion 5c to the second high temperature portion 5b can be improved. Accordingly, the thermoacoustic device 1 can further improve the efficiency of converting thermal energy into acoustic energy of sound waves.

Further, the plurality of second grid-like fins 50c can more reliably hold the plurality of first grid-like fins 50b joined to the plurality of second grid-like fins 50c. As a result, the third high temperature portion 5c can more reliably hold the second high temperature portion 5b.

Each of the plurality of plate-shaped fins 50a, the plurality of first grid-shaped fins 50b, and the plurality of second grid-shaped fins 50c is formed of, for example, metal. In this case, the thermal conductivity of each of the plurality of plate-shaped fins 50a, the plurality of first grid-shaped fins 50b, and the plurality of second grid-shaped fins 50c can be improved. The metal forming each of the plurality of plate-shaped fins 50a, the plurality of first lattice-shaped fins 50b, and the plurality of second lattice-shaped fins 50c is, for example, copper. In this case, the cost of each of the plurality of plate-shaped fins 50a, the plurality of first grid-shaped fins 50b, and the plurality of second grid-shaped fins 50c can be reduced.

FIG. 12 shows a first high temperature portion 5a, a second high temperature portion 5b, and a third high temperature portion included in the temperature gradient holding portion 6 included in the heat exchanger 3 and the high temperature portion 5 included in the heat exchanger 3. It is a figure which shows an example of the junction of 5c.

As shown in FIG. 12, a plurality of plate-shaped fins 50a including a portion of the temperature gradient holding portion 6 having a length w'(60) from the end of the plurality of linear heat conductors 60 in the first high temperature portion 5a. The temperature gradient holding portion 6 is joined to the first high temperature portion 5a by joining to the plurality of connecting portions 51a included in the above. By inserting the convex portion of the first high temperature portion 5a protruding from the frame body 55a into the plurality of first concave portions 51b included in the plurality of first lattice-shaped fins 50b included in the second high temperature portion 5b. , The first high temperature portion 5a is joined to the second high temperature portion 5b. By inserting the convex portion of the second high temperature portion 5b protruding from the frame body 55b into the plurality of second concave portions 51c included in the plurality of second lattice-shaped fins 50c included in the third high temperature portion 5c. , The second high temperature portion 5b is joined to the third high temperature portion 5c.

When each of the plurality of plate-shaped fins 50a, the plurality of first grid-shaped fins 50b, and the plurality of second grid-shaped fins 50c are made of metal, the plurality of plate-shaped fins 50a , A solder or a laser may be used to join the plurality of first grid-like fins 50b and the plurality of second grid-like fins 50c. In this case, the plurality of second plate-shaped fins 50a, the plurality of first grid-shaped fins 50b, and the plurality of second grid-shaped fins 50c can be more reliably joined.

In this way, the temperature gradient holding portion 6, the first high temperature portion 5a, the second high temperature portion 5b, and the third high temperature portion 5c can be joined. The lengths of the temperature gradient holding portion 6, the first high temperature portion 5a, the second high temperature portion 5b, and the third high temperature portion 5c in the direction of the central axis (X-axis direction) of the heat exchanger 3 are w. (60) + w'(50a) + w'(50b) + w'(50c).

In the thermoacoustic device 1, the waveguide 2 is filled with the gas G, but the waveguide 2 may be filled with a medium other than the gas G. For example, the waveguide 2 may be filled with a liquid in a range in which sound waves are effectively generated and amplified.

In the thermoacoustic device 1, the waveguide 2 has the shape of a single loop, but the waveguide 2 may have the shape of a plurality of loops connected by at least one tube, for example. .. In this case, the thermoacoustic device 1 may include a plurality of heat exchangers 3 and a plurality of converters 8 in the same loop or different loops of the waveguide 2.

In the thermoacoustic device 1, the gas G filled in the waveguide 2 is vibrated or excited by the exciter 7, but the thermoacoustic device 1 may not include the exciter 7.

In this case, when a temperature gradient is generated between the low temperature portion 4 and the high temperature portion 5 of the heat exchanger 3, sound waves are generated in the gas G using the 1 / f noise existing in the waveguide 2 as a sound source. The sound wave generated in the gas G is amplified by the temperature gradient generated between the low temperature portion 4 and the high temperature portion 5, and resonates stably in the waveguide 2.

As described above, even when the thermoacoustic device 1 does not include the exciter 7, the thermoacoustic device 1 uses, for example, the thermal energy supplied to the heat exchanger 3 as the acoustic energy of the sound sound generated in the gas G. Can be converted.

In the thermoacoustic device 1, the low temperature section 4 is composed of three low temperature sections such as the first low temperature section 4a, the second low temperature section 4b, and the third low temperature section 4c, and the high temperature section 5 is the first. Although it is assumed that it is composed of three high-temperature parts such as the high-temperature part 5a, the second high-temperature part 5b, and the third high-temperature part 5c of 1, the low-temperature part 4 and the high-temperature part 5 are each one or two. , Or 4 or more low temperature parts and 1, 2, or 4 or more high temperature parts.

In the thermoacoustic device 1, the frame 65 of the temperature gradient holding portion 6, the frame 55a of the first high temperature portion 5a, the frame 55b of the second high temperature portion 5b, and the frame 55c of the third high temperature portion 5c. The configuration of the high temperature section 5 was described with reference to. Since each of the first high temperature portion 5a, the second high temperature portion 5b, and the third high temperature portion 5c in the high temperature portion 5 is securely held by the joint described above, the frame body 55a, the frame body 55b, and the frame Body 55c may be absent. In the frame body 65, the plurality of linear heat conductors 60 and the plurality of plate-shaped fins 50a are joined via a connecting portion 51a by soldering or a laser, and the rigidity of the plurality of linear heat conductors 60 is sufficient. If there is, it can be omitted.

Further effects and modifications can be easily derived by those skilled in the art. For this reason, the broader aspects of the invention are not limited to the particular details and representative embodiments expressed and described as described above. Thus, various modifications can be made without departing from the spirit or scope of the general concept of the invention as defined by the appended claims and their equivalents.

1 Thermal acoustic device 2 waveguide 3 heat exchanger 4 low temperature part 5 high temperature part 6 temperature gradient holding part 7 exciter 8 converter 11 first heat conductive member 12 second heat conductive member 50a plate-shaped fin 51a connection Part 50b First grid-like fin 51b First recess 50c Second grid-like fin 51c Second recess 55a, 55b, 55c Frame 60 Linear heat conductor 61 Sharp end 62 Mirror surface 65 Frame G gas

Claims (15)

1. A loop-shaped waveguide filled with a medium,
   A temperature gradient holding provided in the waveguide and provided between the low temperature portion, the high temperature portion, and the low temperature portion and the high temperature portion to hold the temperature gradient generated between the low temperature portion and the high temperature portion. With the heat exchanger including the part
   With
   The temperature gradient holding portion includes a plurality of linear heat conductors.
   Thermoacoustic device.
2. Each of the plurality of linear thermal conductors has a sharp end.
   The thermoacoustic device according to claim 1.
3. Each surface of the plurality of linear thermal conductors has a mirror surface.
   The thermoacoustic device according to claim 1 or 2.
4. At least one of the low temperature portion and the high temperature portion includes a plurality of plate-shaped fins bonded to the plurality of linear thermal conductors.
   The thermoacoustic device according to any one of claims 1 to 3.
5. The distance between the plurality of plate-shaped fins is larger than the distance between the plurality of linear thermal conductors.
   The thermoacoustic device according to claim 4.
6. The thickness of each of the plurality of plate-shaped fins is larger than the diameter of each of the plurality of linear heat conductors.
   The thermoacoustic device according to claim 4 or 5.
7. The plurality of plate-shaped fins have a plurality of connecting portions for joining at least a part of the plurality of linear thermal conductors.
   The thermoacoustic apparatus according to any one of claims 4 to 6.
8. At least one of the low temperature portion and the high temperature portion includes a plurality of first lattice-shaped fins joined to the plurality of plate-shaped fins.
   The thermoacoustic apparatus according to any one of claims 4 to 7.
9. The distance between the plurality of first grid-like fins is larger than the distance between the plurality of plate-like fins.
   The thermoacoustic device according to claim 8.
10. The thickness of each of the plurality of first lattice-shaped fins is larger than the thickness of each of the plurality of plate-shaped fins.
    The thermoacoustic device according to claim 8 or 9.
11. The plurality of first lattice-shaped fins have a plurality of first recesses accommodating at least a part of the plurality of plate-shaped fins.
    The thermoacoustic apparatus according to any one of claims 8 to 10.
12. At least one of the low temperature portion and the high temperature portion includes a plurality of second grid-like fins joined to the plurality of first grid-like fins.
    The thermoacoustic apparatus according to any one of claims 8 to 11.
13. The distance between the plurality of second grid-like fins is larger than the distance between the plurality of first grid-like fins.
    The thermoacoustic device according to claim 12.
14. The thickness of each of the plurality of second grid-like fins is larger than the thickness of each of the plurality of first grid-like fins.
    The thermoacoustic device according to claim 12 or 13.
15. The plurality of second grid-like fins have a plurality of second recesses accommodating at least a part of the plurality of first grid-like fins.
    The thermoacoustic apparatus according to any one of claims 12 to 14.

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