JP6830650B2 - Thermoacoustic engine - Google Patents

Description

The present invention relates to a thermoacoustic engine.

In recent years, global warming and energy problems have become more serious. If it is possible to recover the enormous amount of waste heat generated in factories and vehicles and solar energy with high efficiency, it will be a trump card for solving global warming and energy problems. Therefore, in order to recover and motorize these energies, studies on thermoacoustic heat engines are being actively conducted (see, for example, Patent Document 1 and Non-Patent Documents 1 and 2).

Patent Document 1 discloses a thermoacoustic engine in which four thermoacoustic engines are arranged in a loop pipe, a branch pipe is provided in the loop pipe, and a refrigerator or a linear generator is arranged in the branch pipe. Non-Patent Document 1 discloses a thermoacoustic engine in which a branch pipe is provided in a loop pipe in which a thermoacoustic engine is arranged and acoustic energy is input from the branch pipe. Non-Patent Document 2 discloses a thermoacoustic engine in which a branch pipe is provided in a loop pipe in which three thermoacoustic engines are arranged and a loop pipe in which one refrigerator is arranged is connected to the branch pipe.

International Publication No. 2013/08843

T.Biwa, D.Hasegawa, T.Yazaki, “Low temperature differential thermoacoustic Stirlng engine”, APPLIED PHYSICS LETTERS 97, 2010 S.Hasegawa, T.Yamaguchi, Y.Oshinoya, “A thermoacoustic differential driven by a low temperature-differential, high-frequency-differential, multi-stage thermoacoustic engine”, Applied Thermal Engineering, vol.58, 2013, p.394 -399

However, the above-mentioned conventional technique has a problem that the sound power is lost in the branch pipe and the distance between the thermoacoustic engine and the refrigerator is not taken into consideration, so that the efficiency of the thermoacoustic engine is lowered.

Therefore, an object of the present invention is to provide a highly efficient thermoacoustic engine.

In view of the above problems, the thermoacoustic engine according to the present invention includes a heat storage device that heats and cools the working gas, and a heater that is adjacent to one end side of the heat storage device and heats one end portion of the heat storage device. A prime mover including a cooler adjacent to the other end side of the regenerator and releasing heat from the other end of the regenerator to the outside, and the acoustic power of the working gas amplified by the prime mover to other energy. A thermoacoustic engine including a thermoacoustic load to be converted, connecting the prime movers to each other or the prime movers and the acoustic load, and being filled with the working gas, the two or more said prime movers and one. The acoustic load and the resonance tube are arranged in a loop, and the difference between the length of the resonance tube and the preset reference length is within 20%, and the resonance tube connected to the heater of the prime mover. The cross-sectional area is a value obtained by multiplying the cross-sectional area of the resonance tube connected to the cooler of the prime mover by 0.8 to 1.0 by the absolute temperature ratio obtained by dividing the temperature of the heater by the temperature of the cooler. The cross-sectional area of all the prime movers was the same.

According to such a configuration, since the thermoacoustic engine arranges the prime mover, the acoustic load, and the resonance tube in a loop and does not have a branch tube, the loss of acoustic power can be suppressed.
Furthermore, the thermoacoustic engine made the length of the resonance tube substantially equal and expanded or contracted the cross-sectional area of the resonance tube, so that the volumetric flow velocity of the working gas in the resonance tube was made substantially uniform, and at the loop junction in the resonance tube. The pressure and flow velocity of the working gas can be substantially matched. As a result, in the thermoacoustic engine, sound waves become traveling waves in the entire resonance tube, and the loss of acoustic power in the resonance tube can be suppressed.
In addition, the arrangement in a loop means that the prime mover, the acoustic load, and the resonance tube are arranged so that the start point and the end point of the resonance tube do not branch and the resonance tube does not branch.

According to the present invention, it is possible to suppress the loss of acoustic power and provide a highly efficient thermoacoustic engine.

It is a schematic diagram which shows the structure of the thermoacoustic engine which concerns on 1st Embodiment of this invention. It is a schematic diagram which shows the structure of the thermoacoustic engine which concerns on 2nd Embodiment of this invention. It is an enlarged view of the linear generator of FIG. It is a schematic diagram which shows the structure of the thermoacoustic engine which concerns on 3rd Embodiment of this invention. It is an enlarged view of the bidirectional turbine of FIG. It is a schematic diagram which shows the structure of the thermoacoustic engine which concerns on 4th Embodiment of this invention. It is a schematic diagram which shows the structure of the thermoacoustic engine which concerns on 5th Embodiment of this invention. It is explanatory drawing explaining the continuous arrangement of a prime mover in the modification of this invention. It is a graph which shows the absolute value distribution of a pressure amplitude in Example 1 of this invention. It is a graph which shows the absolute value distribution of the flow velocity amplitude in Example 1 of this invention. It is a graph which shows the phase difference distribution between pressure flow velocities in Example 1 of this invention. In Example 1 of the present invention, the standardized acoustic impedance distribution is represented, (a) is the entire graph, and (b) is a partially enlarged graph. It is a graph which shows the standardized sound power distribution in Example 1 of this invention. It is a graph which shows the volumetric flow velocity distribution in Example 1 of this invention. It is a graph which shows the absolute value distribution of a pressure amplitude in Examples 2 and 3 and a reference example of this invention. It is a graph which shows the absolute value distribution of the flow velocity amplitude in Examples 2 and 3 and Reference Example of this invention. It is a graph which shows the volumetric flow velocity distribution in Examples 2 and 3 and Reference Example of this invention. It is a graph which shows the phase difference distribution between pressure flow velocities in Examples 2 and 3 and Reference Example of this invention. In Examples 2 and 3 and Reference Examples of the present invention, the standardized acoustic impedance distribution is represented, (a) is the entire graph, and (b) is a partially enlarged graph. It is a graph which shows the standardized sound power distribution in Examples 2 and 3 and Reference Example of this invention.

Hereinafter, each embodiment of the present invention will be described in detail with reference to the drawings as appropriate. In each embodiment, the same members are designated by the same reference numerals, and the description thereof will be omitted.

(First Embodiment)
<Structure of thermoacoustic engine>
The configuration of the thermoacoustic engine 1 according to the first embodiment of the present invention will be described with reference to FIG.
As shown in FIG. 1, the thermoacoustic engine 1 cools with the acoustic power amplified by the prime mover 10, and includes a prime mover 10, a refrigerator (acoustic load) 20, and a resonance tube 30. In this embodiment, the thermoacoustic engine 1 is provided with three motor ₁₀ 1 to 10 _3, and one of the refrigerator 20, the four and the resonance tube ₃₀ 1 to 30 ₄ are arranged in a loop. In other words, thermoacoustic engine 1, motor ₁₀ 1, 10 ₂ are connected via a resonance tube 30 _2, the prime mover ₁₀ 2, 10 ₃ via a resonance tube 30 ₃ are connected. Furthermore, thermoacoustic engine 1 includes a prime mover 10 ₃ via a resonance tube 30 ₄ and the refrigerator 20 is connected, and the refrigerator 20 and the motor 10 ₁ is connected via a resonance tube 30 _1. As described above, the thermoacoustic engine 1 is not provided with a branch pipe, and constitutes a loop pipe as a whole.

Further, in the present embodiment, in the thermoacoustic engine 1, all the resonance tubes 30 have the same length, the cross-sectional area (diameter) of the resonance tubes 30 is expanded before and after the prime mover 10, and before and after the refrigerator 20. The cross-sectional area of the resonance tube 30 is reduced. The length and cross-sectional area of the resonance tube 30 will be described in detail later.

[Motor]
The prime mover 10 forms a temperature gradient between both ends of the heat storage device 11 to amplify the acoustic power of the working gas, and includes the heat storage device 11, the heater 12, and the cooler 13. That is, the prime mover 10 treats the heat storage device 11, the heater 12, and the cooler 13 as one unit. Here, in the prime mover 10, the heater 12 is arranged on one end side of the heat storage device 11 so as to sandwich both ends of the heat storage device 11, and the cooler 13 is arranged on the opposite side, that is, on the other end side of the heat storage device 11. ing.

[Heat storage]
The heat storage device 11 is provided in the pipeline of the resonance tube 30 to heat and cool the working gas. That is, the heat storage device 11 forms a temperature gradient between both ends of the heat storage device 11 by the heater 12 and the cooler 13, and amplifies the acoustic power of the working gas. The heat storage device 11 is mainly a working gas by maintaining a temperature difference generated between one end portion (hereinafter, appropriately referred to as a high temperature portion 11b) and the other end portion (hereinafter, appropriately referred to as a normal temperature portion 11a). It has a function to amplify the acoustic power of. The heat storage device 11 includes, for example, a honeycomb structure made of ceramics having a large number of parallel passages in the extending direction (pipeline direction) of the resonance tube 30, and a structure in which a large number of stainless steel mesh thin plates are laminated at a fine pitch. can do. Alternatively, as the heat storage device 11, it is also possible to use a non-woven fabric or the like made of metal fibers.

[Heater]
The heater 12 is provided in the pipeline of the resonance tube 30 adjacent to one end side of the heat storage device 11 and heats one end portion (high temperature portion 11b) of the heat storage device 11. That is, the heater 12 functions as a heat input unit that heats one end of the heat storage device 11 by using external heat. The heater 12 is composed of, for example, a heat exchanger for heating. Specifically, the heater 12 is made by laminating a large number of metal plates such as mesh plates at a fine pitch. A heating device (not shown) is connected to the heater 12, and the heating treatment is performed via an annular member 12a provided on the outer periphery thereof. In the drawing, for convenience, the left wall of the annular member 12a is shown between the heat storage device 11 and the heater 12, but the heater 12 is adjacent to, that is, in close contact with one end side of the heat storage device 11 through the left wall. ing.

[Cooler]
The cooler 13 is provided in the pipeline of the resonance tube 30 adjacent to the other end side of the heat storage device 11, and releases the heat of the other end portion (normal temperature portion 11a) of the heat storage device 11 to the outside. That is, the cooler 13 has a function of releasing the heat of the other end of the heat storage device 11 to the outside to cool it by using cooling water, air, or the like. The cooler 13 is composed of, for example, a heat exchanger for cooling. The cooler 13 has basically the same configuration as the heater 12, and for example, a large number of metal plates such as mesh plates are laminated at a fine pitch. The cooler 13 has a cooling bracket 13a arranged around the cooler 13. A cooling water channel (not shown) is connected to the cooling bracket 13a, and the cooler 13 maintains a constant cooling temperature via the cooling bracket 13a by the cooling water flowing through the cooling water channel. In the drawing, for convenience, the right wall of the cooling bracket 13a is shown between the heat storage device 11 and the cooler 13, but the cooler 13 is adjacent to, that is, in close contact with the other end side of the heat storage device 11 through the right wall. doing.

[refrigerator]
The refrigerator 20 is an acoustic load that cools by consuming the acoustic power amplified by the prime mover 10 and converting it into a calorific value (heat energy). The refrigerator 20 is a reversible mechanism of the prime mover 10, and includes a heat storage device 21 for freezing, a cooler 22 for freezing, and a cold air discharger 23. That is, the refrigerator 20 handles the heat storage device 21 for freezing, the cooler 22 for freezing, and the cold air discharger 23 as one unit. Here, in the refrigerator 20, the freezing cooler 22 is arranged on one end side of the freezing heat storage device 21 so as to sandwich both ends of the freezing heat storage device 21, and the cold air discharger 23 is on the opposite side, that is, for freezing. It is arranged on the other end side of the heat storage device 21.

[Regenerator for freezing]
The freezing heat storage device 21 is provided in the conduit of the resonance tube 30 and cools the working gas. In other words, refrigerating heat accumulator 21, the motor 10 _3, one end portion of the refrigeration for the heat accumulator 21 through the resonance tube 30 (hereinafter, appropriately referred to as normal temperature portion 21a) of the acoustic power transmitted to, freezing heat accumulator 21 It has a function of converting into a temperature difference between one end portion (normal temperature portion 21a) and the other end portion (hereinafter, appropriately referred to as a low temperature portion 21b) of the freezing heat storage device 21. Since the normal temperature part 21a of the freezing heat storage device 21 is cooled by the freezing cooler 22, the low temperature part 21b of the freezing heat storage device 21 is cooled to a temperature lower than that of the normal temperature part 21a by the transmitted acoustic power. Cold air is generated. This cold air is taken out by the cold air discharger 23. The freezing heat storage device 21 is made of a cold storage material having a large heat capacity. As the cold storage material, for example, stainless steel, copper, lead or the like can be used, and various shapes can be applied to the shape of the freezing heat storage device 21.

[Freezing cooler]
The freezing cooler 22 is provided in the pipeline of the resonance tube 30 adjacent to one end side of the freezing heat storage device 21 and releases the heat of one end portion (normal temperature part 21a) of the freezing heat storage device 21 to the outside. Is. That is, the refrigerating cooler 22 has a function of releasing the heat of one end of the freezing heat storage device 21 to the outside and cooling it by using cooling water, air, or the like. The freezing cooler 22 is composed of, for example, a heat exchanger for cooling. Specifically, the refrigerating cooler 22 has a large number of metal plates such as mesh plates laminated at a fine pitch. The refrigerating cooler 22 has a cooling bracket 22a arranged around it. A cooling water channel (not shown) is connected to the cooling bracket 22a, and the cooling water flowing through the cooling water channel maintains a constant cooling temperature of the refrigerating cooler 22 via the cooling bracket 22a. In the drawing, for convenience, the upper wall of the cooling bracket 22a is shown between the freezing heat storage device 21 and the freezing cooler 22, but the freezing cooler 22 passes through the upper wall of the freezing heat storage device 21. Adjacent to one end side, that is, in close contact.

[Cold air discharger]
The cold air discharger 23 is provided in the pipeline of the resonance tube 30 adjacent to the other end side of the freezing heat storage device 21, and allows the cold air generated at the other end (low temperature portion 21b) of the freezing heat storage device 21 to the outside. It is something to release. That is, the cold air discharger 23 functions as a cold air output unit that takes out the cold air generated at the other end of the freezing heat storage device 21 to the outside. The cold air discharger 23 is composed of, for example, a heat exchanger for freezing. The cold air discharger 23 has basically the same configuration as the freezing cooler 22, and for example, a large number of metal plates such as mesh plates are laminated at a fine pitch. An annular member 23a made of a high thermal conductivity material (for example, copper) for extracting cold air (cold heat) is arranged at the outer peripheral position of the cold air discharger 23. In the drawing, for convenience, the lower wall of the annular member 23a is shown between the freezing heat storage device 21 and the cold air discharger 23, but the cold air discharger 23 passes through the lower wall to the other end of the freezing heat storage device 21. Adjacent to the side, that is, in close contact.

[Resonance tube]
The resonance tube 30 is a cylindrical tube filled with a working gas, and has a predetermined resonance tube length Lx1 to Lx4 and a predetermined cross-sectional area. As the working gas, nitrogen, helium, argon, a mixture of helium and argon, air, or the like is often used. Further, the resonance tube 30 is bent at an intermediate position thereof.

In this embodiment, resonance tube 30 ₁ has one end connected to the cold emitter 23 and the other end connected to the cooler 13 of the engine 10 _1. Moreover, resonance tube 30 ₂ has one end connected to the heater 12 of the motor 10 _1, the other end is connected to the cooler 13 of the prime mover 10 _2. Moreover, resonance tube 30 ₃ has one end connected to the heater 12 of the prime mover 10 ₂ and the other end connected to the cooler 13 of the engine 10 _3. Moreover, resonance tube 30 ₄ has one end connected to the heater 12 of the prime mover 10 ₃ and the other end connected to a refrigeration cooler 22.

[Cross-sectional area of resonance tube, resonance tube length]
As shown in FIG. 1, the thermoacoustic engine 1, the resonance tube ₃₀ 1 to 30 equal _fourth resonance tube length Lx1～Lx4, the cross-sectional area is enlarged in the order of the resonance tube ₃₀ 2-30 _4, the resonance tube 30 ₄ , the cross-sectional area is reduced by 30 _1. Hereinafter, the reason why the cross-sectional area of the resonance tube 30 is enlarged or reduced to make the resonance tube lengths Lx1 to Lx4 equal will be described.

The prime mover 10 also amplifies the sound power by amplifying the flow velocity amplitude. At this time, the specific acoustic impedance decreases after the output from the prime mover 10 due to the increase in the flow velocity amplitude. Here, since we want to make the specific acoustic impedance uniform before and after the prime mover 10, from the continuity of the volumetric flow velocity, the cross-sectional area of the resonance tube 30 on the downstream side of the prime mover 10 is cut off from the resonance tube 30 on the upstream side of the prime mover 10. The area may be expanded based on the acoustic power amplification factor of the prime mover 10.
The resonance tube 30 that outputs sound waves from the prime mover 10 is the resonance tube 30 on the downstream side, and the resonance tube 30 that inputs sound waves to the prime mover 10 is the resonance tube 30 on the upstream side.

In the present embodiment, the cross-sectional area of the resonance tube 30 ₂ connected to the heater 12 of the motor 10 _1, with respect to the cross-sectional area of the resonance tube 30 ₁ connected to the cooler 13 of the engine 10 _1, the prime mover 10 _first acoustic Expand based on power amplification factor. Further, the cross-sectional area of the resonance tube 30 ₃ connected to the heater 12 of the prime mover 10 _2, relative to the cross-sectional area of the resonance tube 30 ₂ connected to the cooler 13 of the prime mover 10 _2, acoustic power amplification factor of the prime mover 10 ₂ Expand based on. Furthermore, the cross-sectional area of the resonance tube 30 ₄ connected to the heater 12 of the prime mover 10 _3, relative to the cross-sectional area of the resonance tube 30 ₃ connected to the cooler 13 of the engine 10 _3, acoustic power amplification factor of the prime mover 10 ₃ Expand based on.

Here, the sound power amplification factor G of the motor 10 is determined by the ratio _W out _{/ W IN} the acoustic power _{W IN} input to sound power _{W out} and the prime mover 10 to be output from the motor 10. Sound power gain G, the temperature T _C of the temperature T _{H /} cooler 13 of the heater 12 _(absolute temperature ratio) Although it is ideal, regenerator 11 and the working gas in the resonance tube 30, such as viscous dissipation Since it is affected, it is not always according to the absolute temperature ratio, and it may be expanded by a value multiplied by a value smaller than this absolute temperature ratio (for example, 0.8 to 1.0).

Since sound power is consumed in the refrigerator 20, the cross-sectional area of the resonance tube 30 on the downstream side where the refrigerator 20 outputs sound waves is the cross-sectional area of the resonance tube 30 on the upstream side where sound waves are input to the refrigerator 20. On the other hand, it is reduced based on the sound power consumption rate of the refrigerator 20. In the present embodiment, the cross-sectional area of the resonance tube 30 ₁ connected to the cold emitter 23, with respect to the cross-sectional area of the resonance tube 30 ₄ connected to a refrigeration cooler 22, based on sound power consumption of the refrigerator 20 To shrink.

Here, the sound power consumption of the refrigerator 20 is determined by the absolute temperature ratio _T Ref / _{T A} between the temperature _{T Ref} of the cool air discharge unit 23 and the temperature _{T A} of the refrigeration cooler 22, freezing heat accumulator Since it is affected by the viscous dissipation of the working gas in 21 and the resonance tube 30, it is not always in line with the absolute temperature ratio, and is multiplied by a value smaller than this absolute temperature ratio (for example, 0.8 to 1.0). It may be reduced.

Further, the thermoacoustic engine 1 has a resonance tube length Lx1 to Lx4 as a reference length (for example, 1 [m]) so that all the prime movers 10 and the refrigerator 20 are evenly spaced. As a result, the thermoacoustic engine 1 can make the volumetric flow velocity in the resonance tube 30 substantially uniform, and substantially match the pressure and flow velocity of the working gas at the loop junction a of the resonance tube 30.

The loop junction a represents the start point and the end point of the resonance tube 30 connected in a loop shape. This loop junction a can be set at an arbitrary position of the resonance tube 30, and in the present embodiment, it is set at an intermediate position where the resonance tube 30 ₁ is bent. The structure and appearance of the loop junction a are not different from those of other portions in the resonance tube 30.

[Action / Effect]
As described above, since the thermoacoustic engine 1 has the prime mover 10, the refrigerator 20, and the resonance tube 30 arranged in a loop and does not have a branch tube, the loss of acoustic power can be suppressed. Further, the thermoacoustic engine 1 equalizes the resonance tube lengths Lx1 to Lx4 and enlarges or reduces the cross-sectional area of the resonance tube 30. Therefore, the volumetric flow velocity of the working gas in the resonance tube 30 is made substantially uniform, and the loop junction is formed. At a, the pressure and the flow velocity of the working gas can be substantially matched. As a result, in the thermoacoustic engine 1, sound waves become traveling waves in the entire section of the resonance tube 30, and the loss of acoustic power in the resonance tube 30 can be suppressed and the efficiency can be improved.

(Second Embodiment)
<Structure of thermoacoustic engine>
With reference to FIGS. 2 and 3, the configuration of the thermoacoustic engine 1B according to the second embodiment of the present invention will be described as being different from the first embodiment.
As shown in FIG. 2, the thermoacoustic engine 1B is different from the first embodiment in that it includes a linear generator 40 instead of the refrigerator 20 (FIG. 1).

The thermoacoustic engine 1B generates electricity with the acoustic power amplified by the prime mover 10, and includes the prime mover 10, a resonance tube 30, and a linear generator 40. In this embodiment, the thermoacoustic engine. 1B, the three motor ₁₀ 1 to 10 _3, and one linear generator 40, four and resonance tube ₃₀ 1 to 30 ₄ are arranged in a loop ..

[Linear generator]
The linear generator 40 is an acoustic load that generates electric power by using the acoustic power amplified by the prime mover 10 as vibration and converting the acoustic power into electric power (electrical energy). As shown in FIG. 3, the linear generator 40 is inside the support 41, and is located between the outer yoke (cylinder) 42, the coil 43 housed in each of the outer yokes 42, and the outer yoke 42. A yoke (cylinder) 44 and a permanent magnet 45 provided between each of the outer yokes 42 and the inner yoke 44 are provided. The permanent magnet 45 is composed of S-pole and N-pole magnets, respectively , and is provided on the inner yoke 44.

Further, the movable element 46 is attached to the inner yoke 44, to one end of the movable element 46 has a piston shape with the cylinder inner wall of the resonance tube 30 ₄ (not shown). Also the other end of the movable element 46 has a piston shape with the cylinder inner wall of the resonance tube 30 ₁ (not shown). As a result, acoustic waves from the resonance tube 30 ₄ the mover 46, i.e. moved to the right and left inner yoke 44 in the drawing. The armature 46 is in the resonance tube 30 _1, transmits the acoustic waves in the structure of the piston shape.

Such a structure in the linear generator 40 employs a power generation method based on the principle that a current is generated by a time change of the magnetic flux density orbiting the coil 43. That is, when the permanent magnet 45 provided on the inner yoke 44 and the inner yoke 44 strokes based on the sound power, the magnetic flux density orbiting the coil 43 changes significantly, and power generation is performed. Further, by attaching the protrusion 44a to the inner yoke 44, it is possible to suppress a decrease in the magnetic flux density due to the passage of the magnetic flux through the air gap.

(Third Embodiment)
<Structure of thermoacoustic engine>
With reference to FIGS. 4 and 5, the configuration of the thermoacoustic engine 1C according to the third embodiment of the present invention will be described as being different from the first embodiment.
As shown in FIG. 4, the thermoacoustic engine 1C is different from the first embodiment in that it includes a bidirectional turbine (hereinafter referred to as a turbine) 50 instead of the refrigerator 20 (FIG. 1).

The thermoacoustic engine 1C generates electricity with the acoustic power amplified by the prime mover 10, and includes the prime mover 10, a resonance tube 30, and a turbine 50. In this embodiment, the thermoacoustic engine. 1C, the three motor ₁₀ 1 to 10 _3, and one turbine 50, four and resonance tube ₃₀ 1 to 30 ₄ are arranged in a loop.

The turbine 50 is an acoustic load that generates electric power by using the acoustic power amplified by the prime mover 10 as a rotational force and converting the acoustic power into electric power (electrical energy). As shown in FIG. 5, the turbine 50 includes a guide cone 52, a guide 53, and a rotary blade 54 inside the housing 51. The guide cone 52 is a member on a semi-elliptical sphere arranged near the center of the housing 51. The guide 53 has a plurality of guide members 53a arranged therein. The guide member 53a is inclined at a predetermined angle with respect to the central axis of the resonance tube 30 so that the working gas hits the rotary blade 54 from an oblique direction. The rotary blade 54 has a plurality of rotary blade members 54a arranged therein, and rotates in the direction of reference numeral α. Then, in the turbine 50, the rotary blade 54 rotates when the working gas hits each rotary blade member 54a to generate electricity.

(Fourth Embodiment)
<Structure of thermoacoustic engine>
With reference to FIG. 6, the configuration of the thermoacoustic engine 1D according to the fourth embodiment of the present invention will be described as being different from the first embodiment.
As shown in FIG. 6, the thermoacoustic engine 1D is different from the first embodiment in that the thermoacoustic engine 1D includes a temperature riser 60 instead of the refrigerator 20 (FIG. 1).

The thermoacoustic engine 1D raises the temperature with the acoustic power amplified by the prime mover 10, and includes the prime mover 10, a resonance tube 30, and a raiser 60. In this embodiment, the thermoacoustic engine. 1D, the three motor ₁₀ 1 to 10 _3, and one heating device 60, the four and the resonance tube ₃₀ 1 to 30 ₄ are arranged in a loop ..

[Heat heater]
The temperature riser 60 is an acoustic load that raises the temperature by consuming the sound power amplified by the prime mover 10 and converting it into heat (heat energy). The heater 60 forms a temperature gradient between both ends of the heating accumulator 61 and raises the temperature with the acoustic power of the working gas. The heating accumulator 61 and the heating heater 62 and a heating cooler 63 are provided. As described above, the heating element 60 treats the heating heater 61, the heating heater 62, and the heating cooler 63 as one unit. Here, in the heating element 60, the heating heater 62 is arranged on one end side of the heating heat storage device 61 so as to sandwich both ends of the heating heat storage device 61, and the heating cooler 63 is provided. It is arranged on the opposite side, that is, on the other end side of the heating heat storage device 61. Here, when the temperature is raised, the temperature riser 62 is raised to a higher temperature by keeping the temperature riser cooler 63 at room temperature.

Since the heating heat storage device 61, the heating heater 62, and the heating cooler 63 have basically the same configuration as the heat storage device 11, the heater 12, and the cooler 13, respectively, further description thereof will be given. Is omitted.

(Fifth Embodiment)
<Structure of thermoacoustic engine>
With reference to FIG. 7, the configuration of the thermoacoustic engine 1E according to the fifth embodiment of the present invention will be described as being different from the first embodiment.
As shown in FIG. 7, the thermoacoustic engine 1E is different from the first embodiment in that it includes two refrigerators 20.

In this embodiment, the thermoacoustic engine 1E includes two motor ₁₀ 1, 10 _2, and two of the refrigerator ₂₀ 1, 20 _2, four resonance tube ₃₀ 1 to 30 ₄ and are arranged in a loop Has been done. In other words, thermoacoustic engine. 1E, a prime mover 10 ₁ through the resonance tube 30 ₂ and the refrigerator 20 ₁ is connected, and the refrigerator 20 ₁ and the prime mover 10 ₂ is connected via a resonance tube 30 _3. Furthermore, thermoacoustic engine. 1E, a prime mover 10 ₂ via a resonance tube 30 ₄ and the refrigerator 20 ₂ are connected, and the refrigerator 20 ₂ and motor 10 ₁ is connected via a resonance tube 30 _1.

Further, the thermoacoustic engine 1E, equal the length of the resonance tube ₃₀ 1 to 30 _4, the cross-sectional area is enlarged in the resonance tube ₃₀ 1, 30 _2, cross-sectional area is reduced by the resonance tube ₃₀ 2, 30 _3, resonance are enlarged cross-sectional area in the tube ₃₀ 3, 30 _4, the cross-sectional area is reduced by the resonance tube ₃₀ 4, 30 _1.

In the present embodiment, the cross-sectional area of the resonance tube 30 ₂ connected to the heater 12 of the motor 10 _1, with respect to the cross-sectional area of the resonance tube 30 ₁ connected to the cooler 13 of the engine 10 _1, the prime mover 10 _first acoustic Expand based on power amplification factor. Further, the cross-sectional area of the resonance tube 30 ₃ connected to the cold emitter 23 of the refrigerator 20 _1, with respect to the cross-sectional area of the resonance tube 30 ₂ connected to a refrigeration cooler 22 of the refrigerator 20 _1, refrigerator 20 It is reduced based on the sound power consumption rate of ₁ . Further, the cross-sectional area of the resonance tube 30 ₄ connected to the heater 12 of the prime mover 10 _2, relative to the cross-sectional area of the resonance tube 30 ₃ connected to the cooler 13 of the prime mover 10 _2, acoustic power amplification factor of the prime mover 10 ₂ Expand based on. Further, the cross-sectional area of the resonance tube 30 ₁ connected to the cold emitter 23 of the refrigerator 20 _2, relative to the cross-sectional area of the resonance tube 30 ₄ connected to a refrigeration cooler 22 of the refrigerator 20 _2, the refrigerator 20 Reduce based on the sound power consumption rate of ₂ .

Incidentally, thermoacoustic engine. 1F, the two instead of the refrigerator 20 _1, 20 _2, two linear generator may be provided with two turbines or two heating machine (not shown).

(Modification example)
Although each embodiment of the present invention has been described in detail above, the present invention is not limited to each of the above-described embodiments, and includes design changes and the like within a range not deviating from the gist of the present invention.

Although each of the above-described embodiments has been described as having a total of four prime movers and acoustic loads, the present invention is not limited thereto. That is, the thermoacoustic engine may be provided with one or more prime movers and one or more acoustic loads, and the total number of prime movers and acoustic loads may be 3 or less, or 5 or more in total.

In the first to fourth embodiments described above, the prime movers are arranged continuously, and in the fifth embodiment, the prime movers and the acoustic load are arranged alternately, but the present invention is not limited thereto. That is, the thermoacoustic engine may continuously arrange not only the prime mover but also the acoustic load.

In each of the above-described embodiments, one prime mover is treated as one unit, but the present invention is not limited thereto. As shown in FIG. 8, the thermoacoustic engine 1 may treat the two prime movers 10 as one unit. Specifically, the thermoacoustic engine 1 arranges two prime movers 10 adjacent to each other via the heat insulating member 14. In this case, the thermoacoustic engine 1 expands the cross-sectional area of the resonance tube 30 based on the product of the acoustic power amplification factors of each prime mover 10.

In each of the above-described embodiments, the intermediate position of each resonance tube is bent to form a square loop in all the resonance tubes, but the present invention is not limited thereto. For example, the thermoacoustic engine may make each resonance tube arcuate and form a circular loop tube with all the resonance tubes.

(Example 1)
[Calculation model of thermoacoustic engine]
As Example 1 of the present invention, the simulation result of the sound field by the calculation model of the thermoacoustic engine will be described.
A thermoacoustic engine simulation similar to that of the first embodiment was performed using the following calculation model. This computational model is based on the thermoacoustic differential equation derived by Rott. Rott's thermoacoustic differential equation is described in detail in, for example, the document "N. Rott, Z.Angew.Math.Phys.20, pp.230-243,1969", and the following equation (1) and equation It is represented by (2).

Here, p is the pressure amplitude, U is the cross-sectional average volume flow velocity amplitude, j is the imaginary unit, ω is the angular frequency, AC is the cross-sectional area, pm is the average pressure of the working gas, γ is the specific heat ratio, and ν is the kinematic viscosity coefficient. σ is Prandtl number, Tm is the average temperature, alpha is the thermal diffusivity, .rho.m is the average density.

Further, χ _α and χ _ν are complex functions that depend on the thermal diffusivity and the kinematic viscosity coefficient. chi _alpha, the chi _[nu, when the resonance tube has a circular cross-section, can be expressed by the following equation (3).

Here, J ₀ and J ₁ are the 0th and 1st orders of the Bessel function, r is the radius, and τ _α and τ _ν are the thermal relaxation time and the kinematic viscosity relaxation time. Further, using p (x) and U (x) at the point x and p (0) and U (0) at the point where x = 0, the solution of the equation (1) is solved by the following equation (4). ) And equation (5). Here, e is the number of Napiers.

By connecting the transmission matrix B _n of each element as shown in the following equation (6), it is possible to obtain the sound field of the entire calculation model. _{Here, M all} represents a transfer matrix of the entire calculation model.

As described above, in a thermoacoustic engine, it is preferable to make the complex pressure amplitude and the complex flow velocity amplitude equal at the loop junction. Using the transfer matrix _{M all,} to determine the satisfying driving frequency and the driving temperature (drive temperature) _{T H.} Let the complex pressure amplitude and the complex volume flow velocity amplitude at the start point (x = 0) and the end point (x = L _loop ) of the _loop be p ₀ , U ₀ , p _L, and _UL , respectively. Then, using the transfer matrix _Mall , it can be expressed by the following equation (7).

At this time, the equation (7) can be rewritten into the following equation (9) by using the condition that the complex pressure amplitude and the complex flow velocity amplitude are equal at the loop junction a as in the following equation (8). it can. Note that E in equation (9) is an identity matrix.

Then, it is the following equation (11) that satisfies the condition of the following equation (10). Therefore, to calculate the drive frequency and the drive temperature _{T H} satisfying the equation (11).

The drive frequency and drive temperature (motor temperature) _TH are calculated by applying the fixed parameters shown in Table 1 below and the change parameters shown in Table 2 below to the above calculation model. Here, the reference length is set to 1 [m]. Then, the one in which the length of the total resonance tube is equal to the reference length is referred to as Example 1, and the one in which the length of the resonance tube is different is referred to as a comparative example.

The fixed parameter is a parameter common to Example 1 and Comparative Example. Further, the changed parameter is a parameter changed between the first embodiment and the comparative example. Further, the drive temperature T _H represents a temperature of the heater, T _C represents the temperature of the cooler. Further, T _Ref represents the temperature of the cool air discharge unit, T _A represents the temperature of the freezing cooler.

Here, A _C of the formula (1) is the prime mover, the cross-sectional area of the refrigerator and the resonance tube, the prime mover is determined from the diameter of the refrigerator and the resonance tube. Further, dx of dT _m / dx of the formula (1) corresponds to the axial length of the prime mover and the refrigerator. Further, r in the formula (3) corresponds to the radius of the resonance tube and the flow path diameters of the prime mover and the refrigerator. Further, the subscripts x of B _{11 to} B _{22 in} the equation (5) correspond to the length of each resonance tube.

The drive frequency and drive temperature _TH are shown in Table 3 below.
In Example 1, the drive temperature _{T H} is 95.5 [° C.], the driving frequency is 152.9 [Hz]. In contrast, in the comparative example, drive temperature _{T H} is 168.5 [° C.], the driving frequency is 153.5 [Hz].

[simulation result]
Next, the drive temperature TH and the drive frequency in Table 3 were applied to the calculation model, and the sound field was simulated. The initial point pressure of the sound field is 2% of the average pressure (30 atm). As a result of sound field simulation, the absolute value distribution of pressure amplitude (Fig. 9), the absolute value distribution of flow velocity amplitude (Fig. 10), the phase difference distribution between pressure and flow velocity (Fig. 11), and the absolute value distribution of standardized acoustic impedance distribution (Fig. 11). FIG. 12), the absolute value distribution of the standardized acoustic power distribution (FIG. 13), the volume flow velocity distribution (FIG. 14), and the thermal efficiency / refrigeration output are shown.

In FIGS. 9 to 14, the solid line represents Example 1 and the broken line represents a comparative example.
Further, in FIGS. 9 to 14, the horizontal axis x is the distance from the loop junction. That is, x = 0 and x = 5.16 are loop junctions. Therefore, the range of 0 ≦ x ≦ 5.16 is the entire section of the thermoacoustic engine. Further, the vicinity of x = 0.5, 1.9, 3.1 is the position of the prime mover, and the vicinity of x = 4.4 is the position of the refrigerator. That is, it is a section of the resonance tube except for the position of the prime mover and the prime mover.

At this time, the axial lengths of the heat storage device, the heater and the cooler are 0.03 [m]. Further, the axial lengths of the freezing heat storage device, the freezing cooler and the cold air discharger are 0.03 [m]. Further, the total length of the four resonance tubes is 4 [m]. In addition, a thermal buffer tube was provided at one end of each resonance tube in order to form a temperature gradient in the simulation calculation. Here, the thermal buffer tube was arranged between the heater of the prime mover and the resonance tube connected to the heater, and between the cold air discharger of the refrigerator and the resonance tube connected to the cold air discharger. The length of this thermal buffer tube is 0.2 [m]. In an actual thermoacoustic engine, a temperature gradient is formed in the waveguide according to the operation, so it was assumed to be 0.2 [m] in the simulation calculation.

<Absolute value distribution of pressure amplitude>
As shown in FIG. 9, in the first embodiment, the pressure amplitude falls within the range of 60 × 10 ³ to 80 × 10 ³ [Pa] over the entire section of the thermoacoustic engine. Also, at the loop junction, the pressure amplitudes are equal. On the other hand, in the comparative example, the pressure amplitude varies greatly between 20 × 10 ^{3 to} 100 × 10 ³ [Pa]. As described above, in Example 1, the change in pressure amplitude is smaller than that in Comparative Example.

<Absolute value distribution of flow velocity amplitude>
As shown in FIG. 10, in the first embodiment, the flow velocity amplitude falls within the range of 16 to 22 [m / s] in the section of the resonance tube. Also, at the loop junction, the flow velocity amplitudes are equal. On the other hand, in the comparative example, the flow velocity amplitude changes significantly between 2 and 24 [m / s] in the section of the resonance tube. As described above, it can be seen that the change in the flow velocity amplitude is small in Example 1 as compared with the Comparative Example.

<Phase difference distribution between pressure and flow velocities>
As shown in FIG. 11, in the first embodiment, the phase difference between the pressure and flow velocities becomes 0 at the positions of the prime mover and the refrigerator. From this, it can be seen that the heat storage device performs isothermal and reversible energy conversion. Further, in Example 1, since the phase difference between the pressure and flow velocities is within ± 30 [deg.] Over the entire section of the thermoacoustic engine, it is considered that a traveling wave phase is formed in all sections of the thermoacoustic engine. Be done.

On the other hand, in Comparative Example 1, the phase difference between the pressure and flow velocities is -50 [deg.] At the position of the second prime mover, and the phase difference between the pressure and flow velocities is 30 [deg.] At the position of the refrigerator. Furthermore, in the comparative example, the phase difference between the pressure and flow velocities changes significantly to ± 60 [deg.] In the entire section of the thermoacoustic engine, so that the sound field in the thermoacoustic engine is a standing wave and the viscosity of the working gas. Dissipation increases.
From the above, it can be seen that the efficiency of the thermoacoustic engine is higher in the first embodiment because the traveling wave can be formed in the entire section of the thermoacoustic engine as compared with the comparative example.

<Standardized acoustic impedance distribution>
In FIG. 12A, the entire graph of the standardized acoustic impedance distribution is shown. In FIG. 12 (b), the normalized acoustic impedance in FIG. 12 (a) is expanded in the range of 0 to 4.

The specific acoustic impedance z is represented by the ratio of the pressure amplitude p and the flow velocity amplitude v (z = p / v). The standardized acoustic impedance is standardized by dividing the absolute value of the specific acoustic impedance z by the intrinsic acoustic impedance ρmc of the traveling wave propagating in the free space. When the value of this normalized acoustic impedance is 1, it indicates that it is equivalent to a traveling wave in free space.

As shown in FIG. 12A, in the first embodiment, the normalized acoustic impedance falls within the range of 6 to 8 at the positions of the prime mover and the refrigerator. On the other hand, in the comparative example, there are a high standardized acoustic impedance (20 to 30) and a low standardized acoustic impedance (2.5 to 4.0) at the positions of the prime mover and the refrigerator. As described above, in the first embodiment, it can be seen that the efficiency of the thermoacoustic engine is increased because there is no portion where the standardized acoustic impedance is low as in the comparative example.

Further, as shown in FIG. 12B, in the first embodiment, by expanding and contracting the cross-sectional area of the resonance tube in the section of the resonance tube, the normalized acoustic impedance (0.6 to 0.6 to near the traveling wave) is obtained. It is 1.0). As a result, in the first embodiment, the viscous dissipation of the working gas is reduced, and the efficiency of the thermoacoustic engine is increased. On the other hand, in the comparative example, since the normalized acoustic impedance fluctuates in the range of 0.3 to 3.0 in the section of the resonance tube, the viscous dissipation of the working gas becomes large and the efficiency of the thermoacoustic engine decreases. This can be seen from the fact that in the comparative example, as shown in FIG. 12B, the slope is large in the section of the resonance tube.

<Standardized sound power distribution>
As shown in FIG. 13, in the first embodiment, each prime mover amplifies the sound power at a constant amplification factor. Further, in the first embodiment, since the inclination of the resonance tube section is smaller than that of the comparative example, the loss of sound power due to the viscous dissipation of the working gas is small. On the other hand, in the comparative example, the amplification factor of the sound power of each prime mover varies. Further, in the comparative example, since the slope is large in the section of the resonance tube, the viscous dissipation of the working gas due to the deviation from the traveling wave is large, and as a result, the loss of sound power becomes large.

<Volume flow velocity distribution>
As shown in FIG. 14, in the first embodiment, the volumetric flow velocity distribution is 1.6 to 2.5 × 10 ^-3 [m ^{3] in} the entire section of the thermoacoustic engine by expanding and contracting the cross-sectional area of the resonance tube. It falls within the range of [/ s], and the volumetric flow velocity distribution becomes substantially uniform. On the other hand, in the comparative example, since the flow velocity amplitude is not adjusted by expanding or contracting the cross-sectional area of the resonance tube, the volumetric flow velocity distribution is between 0.6 and 2.4 × 10 ^-3 [m ³ / s]. It fluctuates, and the fluctuation becomes particularly large before and after the prime mover.

<Thermal efficiency / refrigeration output>
Calculate the thermal efficiency and refrigeration output under the driving conditions and sound field conditions in Table 3. The thermal efficiency η _n of each heat storage device is obtained from the sound power amplification amount ΔW _n and the heat input amount Q _n before and after each prime mover as shown in the following equation (12) (where n is the heat storage device number).

_{Let the} Carnot efficiency η _carnot, which is the upper limit of thermodynamic efficiency, be the following equation (13). Then, the ratio of the thermal efficiency η _n of each regenerator to the Carnot efficiency η _carnot is obtained as the regenerator ratio Carnot efficiency η _{2 n} as shown in the equation (14).

Next, the coefficient of performance of the refrigerator η _Ref is obtained by the refrigerating output Q _out of the refrigerator and the sound power attenuation ΔW _Ref of the refrigerator as shown in the following equation (15). Further, the efficiency η _Loop of the entire thermoacoustic engine can be obtained from the heat input Q _n and the refrigeration output Q _out of the three prime movers as shown in the following equation (16).

The Carnot efficiency η _{Ref_carnot} of the refrigerator is _calculated by the following formula (17). Then, the specific Carnot efficiency η _Loop2 of the entire thermoacoustic engine is calculated by the following equation (18).

Regenerator ratio Carnot efficiency eta _{2 n} for Example 1 and Comparative Example, the refrigerator performance coefficient eta _Ref, and the loop ratio Carnot efficiency eta _Loop2 shown in Table 4. As shown in Table 4, in the first embodiment, the Carnot efficiency η _{2 n} relative to the regenerator is within the range of about 65 to 70 [%] for each prime mover, and each prime mover has the same thermal efficiency. On the other hand, in the comparative example, since the Carnot efficiency η _{2 n} relative to the regenerator is about 39 to 92 [%] for each prime mover, the variation in the thermal efficiency of each prime mover becomes large. The coefficient of performance of the refrigerator η _Ref and the loop ratio Carnot efficiency η _Loop2 are higher in Example 1 than in Comparative Example.

As described above, in Example 1, compared with comparative example, the driving temperature T _H 70 [℃] can be reduced near (Table 3), the refrigerator performance coefficient eta _Ref, and the loop ratio Carnot efficiency eta _Loop2 becomes high. From this, it is considered that the first embodiment is effective as a thermoacoustic engine that is driven at a low temperature with high efficiency.

(Examples 2 and 3)
[When the length of the resonance tube is changed]
As Examples 2 and 3 of the present invention and Reference Examples, simulation results when the length of the resonance tube is changed will be described.
Here, as shown in Table 5, when the length of each resonance tube is ± 10% with respect to the reference length (Example 2), the length of each resonance tube is ± 20% with respect to the reference length. (Example 3), a simulation was performed when the length of each resonance tube was ± 30% of the reference length (reference example).

In Examples 2 and 3 and Reference Example, the calculation model and fixed parameters are the same as in Example 1. Then, the drive frequency and the drive temperature (motor temperature) _TH were obtained in the same manner as in the first embodiment. As shown in Table 6 below, the drive frequencies are approximately equal in all cases. Further, the drive temperature T _H is the lowest in Example 1, as the difference in the resonance tube length is increased in the order of Examples 2, 3 and Reference Examples, the drive temperature T _H is higher. In the case of the reference example, the driving temperature _TH is higher by about 80 [° C.] or more as compared with the first embodiment.

Further, as in Example 1, the absolute value distribution of the pressure amplitude (FIG. 15), the absolute value distribution of the flow velocity amplitude (FIG. 16), the volumetric flow velocity distribution (FIG. 17), the phase difference distribution between the pressure and flow velocity (FIG. 18), and the standard. The chemical impedance distribution (Fig. 19) and the standardized sound power distribution (Fig. 20) were obtained.
In FIGS. 15 to 20, Example 1 is shown by a solid line, Example 2 is shown by a two-dot chain line, Example 3 is shown by a one-dot chain line, and a reference example is shown by a broken line.

<Absolute value distribution of pressure amplitude>
As shown in FIG. 15, in Example 1, the change in pressure amplitude is the smallest. Then, the change in pressure amplitude increases in the order of Examples 2 and 3 and Reference Example. That is, it can be seen that the larger the difference in resonance tube length, the larger the fluctuation of the sound field from the constant state.

<Absolute value distribution of flow velocity amplitude>
As shown in FIG. 16, in Example 1, the change in pressure amplitude is the smallest in the section of the resonance tube. Then, in the section of the resonance tube, the change in the flow velocity amplitude becomes larger in the order of Examples 2 and 3 and Reference Example.

<Volume flow velocity distribution>
As shown in FIG. 17, in the first embodiment, the volumetric flow velocity distribution becomes substantially uniform in the section of the resonance tube. Then, in the section of the resonance tube, the change in the volumetric flow velocity distribution increases in the order of Examples 2 and 3 and Reference Example.

<Phase difference distribution between pressure and flow velocities>
As shown in FIG. 18, in the first embodiment, the phase difference between the pressure and flow velocities falls within the range of ± 30 [deg.] In the entire section of the thermoacoustic engine. Further, in the order of Examples 2 and 3 and Reference Example, the fluctuation of the phase difference between the pressure and flow velocities becomes large in the entire section of the thermoacoustic engine. Further, when there is a difference in the resonance tube length as in Examples 2 and 3 and the reference example, the phase difference between the pressure and flow velocities deviates from 0 [deg.] At the positions of the prime mover and the refrigerator, and the energy conversion is isothermally reversible. It turns out that it is a sound field that performs irreversible energy conversion.

<Standardized acoustic impedance>
As shown in FIG. 19, in the first embodiment, the normalized acoustic impedance falls within the range of 6 to 8 at the positions of the prime mover and the refrigerator. Further, in Examples 2 and 3 and the reference example, there are places where the standardized acoustic impedance is high and places where the standardized acoustic impedance is low at the positions of the prime mover and the refrigerator. Then, in the order of Examples 2 and 3 and Reference Example, the difference in standardized acoustic impedance increases between the high portion and the low portion.

<Standardized sound power distribution>
As shown in FIG. 20, in the first embodiment, each prime mover amplifies the sound power to the same extent, and the slope of the dissipation of the sound power in the resonance tube becomes small. Further, in Examples 2 and 3 and the reference example, there are places where the amplification of sound power is small and places where the amplification is large. The slope of the dissipation of sound power also increases in the order of Examples 2 and 3 and Reference Example.

Summarizing the above, regarding the loss of sound power, in Example 1, a traveling wave can be realized in the entire resonance tube of the thermoacoustic engine, whereas in Examples 2 and 3 and the reference example, there is a deviation from the traveling wave. appear. From this, it is considered that Example 1 in which all the resonance tubes have the same length and Examples 2 and 3 in which the length is within ± 20% of the reference length are practical as thermoacoustic engines. ..

1,1B~1E thermoacoustic engine 10, 10 ₁ to 10 ₃ prime mover 20, 20 _1, 20 ₂ refrigerator (acoustic load)
30, 30 ₁ to 30 ₄ Resonator tube 40 Linear generator (acoustic load)
50 Bidirectional turbine (acoustic load)
60 Heater (acoustic load)

Claims (8)

A heat storage device that heats and cools the working gas, a heater that is adjacent to one end side of the heat storage device and heats one end of the heat storage device, and a heater that is adjacent to the other end side of the heat storage device and other than the heat storage device. A prime mover with a cooler that releases heat from the edges to the outside,
An acoustic load that converts the acoustic power of the working gas amplified by the prime mover into other energy,
A thermoacoustic engine including a resonance tube that connects the prime movers or the prime movers to the acoustic load and is filled with the working gas.
Two or more of the prime movers, one or more of the acoustic loads, and the resonance tube are arranged in a loop.
The difference between the length of the resonance tube and the preset reference length is within 20%.
The cross-sectional area of the resonance tube connected to the heater of the prime mover is the absolute temperature ratio obtained by dividing the temperature of the heater by the temperature of the cooler with respect to the cross-sectional area of the resonance tube connected to the cooler of the prime mover. Enlarged by multiplying by 0.8 to 1.0 ,
A thermoacoustic engine characterized in that the cross-sectional areas of all the prime movers are equal . The acoustic load is a refrigerator.
Wherein the cross-sectional area of the resonance tube connected to the cold emitter of the refrigerator, to the cross-sectional area of the resonance tube connected to a refrigeration cooler of the refrigerator, the cold air ejectors temperature cooler for the refrigeration The thermoacoustic engine according to claim 1 , wherein the thermoacoustic engine is reduced by a value multiplied by a value equal to or less than an absolute temperature ratio divided by the temperature of. The cross-sectional area of the resonance tube connected to the cold air discharger of the refrigerator is such that the temperature of the cold air discharger is the temperature of the refrigerating cooler with respect to the cross-sectional area of the resonance tube connected to the refrigerating cooler of the refrigerator. The thermoacoustic engine according to claim 2 , wherein the temperature is reduced by multiplying the absolute temperature ratio divided by the temperature by 0.8 to 1.0. The thermoacoustic engine according to claim 2 or 3, wherein the cross-sectional area of the refrigerator is equal to the cross-sectional area of the prime mover. The thermoacoustic engine according to claim 1 , wherein the acoustic load is either a linear generator or a bidirectional turbine. The thermoacoustic engine according to any one of claims 1 to 5, wherein all the resonance tubes have the same length. The thermoacoustic engine according to any one of claims 1 to 6, wherein the number of prime movers is two and the number of acoustic loads is two. The thermoacoustic engine according to any one of claims 1 to 6, wherein the number of prime movers is three and the number of acoustic loads is one.

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