JP5892582B2 - Thermoacoustic engine - Google Patents

Description

  The present invention relates to a thermoacoustic engine that generates self-excited vibration of a working gas.

  In recent years, global warming and energy problems have become serious. If huge waste heat generated in factories and vehicles and solar energy can be recovered with high efficiency, it will be a trump card for solving global warming and energy problems. Therefore, research on thermoacoustic engines has been actively conducted in order to recover these energies and drive them.

  The thermoacoustic engine utilizes self-excited vibration generated in the tube. That is, when a bundle of narrow flow paths (hereinafter referred to as a heat accumulator) is installed in the pipe and the temperature ratio at both ends of the heat accumulator is set to a certain critical value or more, the fluid in the pipe causes self-excited vibration. This action can be seen thermodynamically as a prime mover having no moving parts, and a thermoacoustic engine using this action (see, for example, Patent Documents 1 and 2). Since the thermoacoustic engine is an external combustion engine driven by a Stirling cycle, there is a possibility that work can be extracted with high efficiency from any heat source such as sunlight and industrial waste heat. In addition, since it has a simple configuration in which heat is exchanged using sound waves, unlike a normal Stirling engine, it does not require any moving parts such as a piston and a turbine, and has the advantages of low cost, long life, and maintenance-free.

  Here, FIG. 10 shows a configuration of a typical thermoacoustic engine (for example, see Non-Patent Document 1) that has been studied for practical use in recent years. A thermoacoustic generator 500 shown in FIG. 10A includes a loop tube 100 and a resonance tube 111. The loop tube 100 includes a heat accumulator 210, a heater 220, and a cooler 230 that constitute the prime mover 200, and a generator (linear generator) 300 is provided at the tip of the resonance tube 111. In the thermoacoustic generator 500, when a temperature gradient is given to the regenerator 210, self-excited vibration (that is, thermoacoustic self-excited vibration) that is a sound wave is excited, and vibration energy (that is, acoustic energy) E of this sound is linearly generated. Machine 300 converts it into electric power. The thermoacoustic generator 500 is assumed to be used as a high-efficiency solar power generator that exceeds waste heat generators and solar panels.

  On the other hand, researches on a thermoacoustic refrigerator 600 (see, for example, Non-Patent Document 2) shown in FIG. The thermoacoustic refrigerator 600 includes two loop tubes 100 and 120 and a resonance tube 111. The loop pipe 100 includes a heat accumulator 210, a heater 220, and a cooler 230 that constitute the prime mover 200. The loop pipe 120 includes a refrigerating heat accumulator 410 that constitutes the refrigerator 400, and cool air discharge. 420 and a refrigeration cooler 430 are provided. In the thermoacoustic refrigerator 600, when a temperature gradient is applied to the regenerator 210 installed in one loop tube 100, self-excited vibration is excited. The acoustic energy E due to this self-excited vibration flows into the other loop tube 120 through the resonance tube 111, and the refrigerating regenerator 410 is refrigerated by executing a reverse Stirling cycle. The thermoacoustic refrigerator 600 that performs low-temperature generation using self-excited vibration that is such an in-tube acoustic wave has a potential that exceeds that of a pulse tube refrigerator.

  The thermoacoustic engines represented above are currently being studied by many companies from the viewpoint of heat recovery and next-generation energy utilization. However, since this is a new field where full-fledged research has begun in the 21st century, there is a situation where basic technology has not yet been established.

  In order to realize a high-efficiency thermoacoustic engine, it is necessary to install a heat accumulator at a traveling wave generation location and perform reversible energy conversion. However, thermoacoustic engines do not have a mechanism for adjusting the appropriate sound field distribution, so irreversible energy conversion using standing waves is often performed, and efficiency is often reduced. Absent.

  Furthermore, another problem for the practical application of thermoacoustic engines is the problem of oscillation temperature. Most of the factory waste heat is about 100 to 300 ° C., but the oscillation temperature (drive temperature) suitable for the thermoacoustic engine is generally as high as about 400 to 600 ° C. (see, for example, Non-Patent Document 3).

  In order to solve the problem of oscillation temperature, a multistage thermoacoustic engine that can significantly reduce the oscillation temperature by connecting a plurality of heat accumulators in series has been proposed (for example, see Non-Patent Document 4). However, in the multi-stage type, naturally, the regenerators are distributed with respect to the sound field, so that it is difficult to install all the regenerators at the traveling wave positions, resulting in a problem that the efficiency is reduced. It was. To solve this problem, as shown in FIG. 11, a traveling wave is generated using an acoustic driver 450, and a sound field in the tube 402 is actively adjusted by using a branch tube 401. By making it a traveling wave, it has succeeded in improving the efficiency of the multistage thermoacoustic engine 700 provided with a plurality of prime movers 403 composed of a heater, a heat accumulator, and a cooler (for example, Patent Document 3, Non-Patent Document 3) (See Patent Document 5).

JP 2006-118728 A JP 2009-74734 A JP 2011-99606 A

S. Backhaus, E. Tward and M. Petach, Appl. Phys. Lett., Vol. 85, pp. 1085-1087 (2004), FIG. M. Miwa, T. Sumi, T. Biwa, Y. Ueda and T. Yazaki, Ultrasonics, 44, e1527-e1529 (2006), Fig. 5 S. Backhaus and G. W. Swift, Nature 399 (1998), 335-338 D.L.Gardner and G.W.Swift, J.Acoust. Soc. Am.114 (2003), 1905-1919 Tetsuji Tsuji, Kei Takao, “Multistage Thermoacoustic Stirling Engine Generator”, Proceedings of the 16th Japan Society of Mechanical Engineers Power and Energy Technology Symposium, (2011), pp.261-264

As described above, in a thermoacoustic engine in which a conventional mechanism for appropriately adjusting the sound field distribution does not exist, there is a problem that the efficiency of energy conversion is often lowered.
In thermoacoustic engines using acoustic drivers, the acoustic wave is used to generate traveling waves that are input to the first heat accumulator, reducing the superiority of thermoacoustic engines that have no moving parts. doing. Therefore, if a pure traveling wave can be excited over a wide area without using an acoustic driver, it will be possible to install multiple heat accumulators at the traveling wave generation position without using moving parts. It will be a big progress toward the practical application.

By the way, since the standing wave is a superposition of waves accompanied by reflection, attenuation due to energy propagation is large. Therefore, there is a problem that sonic energy cannot be transported over a long distance. On the other hand, since the traveling wave is a work flow traveling in one direction, there is little attenuation due to energy propagation. Therefore, sonic energy can be transported over a long distance.
In view of the above, development of a thermoacoustic engine capable of generating a traveling wave in a wide area of the resonance tube without providing a movable part is required.

  The present invention has been made based on such a background, and an object thereof is to provide a thermoacoustic engine capable of generating a traveling wave in a wide area of a resonance tube without providing a movable part.

  As means for solving the above problems, a thermoacoustic engine according to the present invention has a resonance tube filled with a working gas from one end to the other end, and is provided in a pipe line of the resonance tube. A regenerator that heats and cools, a heater that is provided in the pipe of the resonance tube adjacent to one end of the regenerator, and that is adjacent to the other end of the regenerator and that heats one end of the regenerator And a cooler that is provided in the pipe of the resonance tube and discharges heat from the other end of the heat accumulator to the outside, and forms a temperature gradient between both ends of the heat accumulator. A thermoacoustic engine for generating self-excited vibration of the working gas, wherein the resonance tube has a reference tube portion and a deformed tube portion whose inner diameter is enlarged or reduced with respect to the reference tube portion, The prime mover is provided in a pipe line of the reference pipe portion, and the deformed pipe portion has a sound obtained in advance. In the impedance distribution, the resonance tube is provided from a predetermined portion of the resonance tube where the imaginary part of the acoustic impedance becomes zero toward the other end of the resonance tube, and the inner diameter of the deformation tube portion is the density of the working gas. It is characterized in that the acoustic impedance value is set to ρc, where ρ and sound velocity are c.

  The thermoacoustic engine according to the present invention includes an annular loop tube in which a working gas is sealed, and a resonance tube connected to one end of the loop tube and connected to the loop tube. A regenerator that heats and cools the working gas, a heater that is provided adjacent to one end side of the regenerator, and that heats one end of the regenerator, and the regenerator And a cooler that is provided in a pipe line of the loop pipe adjacent to the other end side of the heater and discharges heat of the other end portion of the heat accumulator to the outside, and between both end portions of the heat accumulator A thermoacoustic engine that generates a self-excited vibration of the working gas by forming a temperature gradient in the reference tube, wherein the resonance tube includes a reference tube portion and a deformed tube having an inner diameter enlarged or reduced with respect to the reference tube portion And the deformed tube portion has a predetermined acoustic impedance distribution. It is provided from a predetermined part of the resonance tube where the imaginary part of the acoustic impedance becomes zero toward the other end of the resonance tube, and the inner diameter of the deformation tube portion is ρ for the density of the working gas and c for the speed of sound. In this case, the acoustic impedance value is set to be ρc.

  According to these configurations, one end of the regenerator is heated by the heater, and the other end of the regenerator is cooled by the cooler, so that a temperature difference, that is, a temperature gradient is generated between both ends of the regenerator. . Due to this temperature difference, a work flow is generated mainly due to self-excited vibration (pressure vibration) of the working gas. Since the deformed tube portion is provided at a predetermined position of the resonance tube, the generated work flow becomes a traveling wave in all parts of the deformed tube portion, so that a pure traveling wave is formed over a wide area in the resonance tube. be able to.

  The thermoacoustic engine according to the present invention is further provided in a pipe line of the deformable pipe part, and heat accumulator for heating and cooling the working gas, and a pipe of the deformable pipe part adjacent to one end side of the heat accumulator. A heater that heats one end of the regenerator and a pipe of the deformed tube adjacent to the other end of the regenerator, and heats the other end of the regenerator. It is characterized by comprising one or a plurality of prime movers comprising a cooler that discharges to the outside.

  According to such a configuration, it is possible to install one or a plurality of heat accumulators at traveling wave positions in the resonance tube. Thereby, highly efficient energy conversion becomes possible.

The thermoacoustic engine according to the present invention further includes a generator that is connected to the other end of the resonance tube, communicates with the deformation tube portion, and generates power in response to self-excited vibration generated in the working gas. It can be set as a thermoacoustic generator.
According to such a configuration, acoustic energy generated by the self-excited vibration generated in the working gas is converted into electric energy by the generator. And when a some heat accumulator is installed in a deformation | transformation pipe | tube part, it can drive with higher efficiency as a thermoacoustic generator.

  The thermoacoustic engine according to the present invention further includes an annular refrigeration loop pipe connected to the other end of the resonance pipe and connected to the deformed pipe portion, and a pipe line of the refrigeration loop pipe A refrigerating regenerator that cools the working gas, and a refrigerating regenerator that is provided in a pipe line of the refrigerating loop pipe adjacent to one end side through which the self-excited vibration of the refrigerating regenerator is transmitted. A refrigeration cooler that discharges heat from one end of the refrigerator to the outside, and the other end of the refrigeration regenerator that is provided in a pipe line of the refrigeration loop pipe adjacent to the other end of the refrigerating regenerator. It can be set as a thermoacoustic refrigerator by providing with the cool air discharger which discharge | releases the cool air which generate | occur | produces in a part outside.

  According to such a configuration, one end of the refrigerating regenerator is cooled by the refrigerating cooler, and acoustic energy generated by the self-excited vibration generated in the working gas is transmitted to the refrigerating regenerator. Thereby, the transmitted acoustic energy is converted into a temperature difference between one end of the refrigerating regenerator and the other end of the refrigerating regenerator. The cold air generated at the other end of the refrigerating regenerator due to the temperature difference between both ends of the refrigerating regenerator is taken out by the cold air discharger. And when a some heat accumulator is installed in a deformation | transformation pipe | tube part, it can drive with higher efficiency as a thermoacoustic refrigerator.

  According to the thermoacoustic engine of the present invention, it is possible to make all sound fields ahead of an arbitrary point in the resonance tube a traveling wave without providing a movable part such as an acoustic driver. Moreover, since energy transport using traveling waves has little energy attenuation, it is possible to transport sonic energy over a long distance. This makes it possible to realize a new energy transport network using sonic energy transport.

  Further, if a heat accumulator is installed at a position where the traveling wave is set, highly efficient energy conversion becomes possible. Furthermore, since a wide area is a traveling wave, a plurality of heat accumulators can be installed at the position where the traveling wave is set. And energy recovery using a plurality of waste heat becomes possible by installing a plurality of heat accumulators.

Furthermore, since highly efficient energy conversion is possible, the entire apparatus can be reduced in size, and the volume of the entire apparatus can be reduced.
In addition, since a plurality of regenerators can be installed at the position where the traveling wave is used, when used as a thermoacoustic generator, the amount of power generation can be improved compared to a conventional thermoacoustic engine. When used as a machine, it is possible to realize low-temperature driving as compared with a conventional thermoacoustic engine.

(A) is a schematic diagram which shows typically the structure of the straight type thermoacoustic engine which concerns on 1st Embodiment of this invention, (b) is the structure of the loop type thermoacoustic engine which concerns on 2nd Embodiment of this invention. It is a schematic diagram which shows typically. (A), (b) is a schematic diagram which shows typically the structure of the thermoacoustic engine which installed the motor | power_engine in the deformation | transformation pipe | tube part. It is a schematic diagram at the time of using the thermoacoustic engine which concerns on this invention as a thermoacoustic generator. It is a schematic diagram at the time of using the thermoacoustic engine which concerns on this invention as a thermoacoustic refrigerator. (A), (b) is a schematic diagram which shows typically the structure of the thermoacoustic engine used in the Example. It is a graph which shows impedance distribution and work flow distribution (damping distribution by energy transport) in a present Example of 1st Example, (a) is a real part of an impedance, (b) is an imaginary part of an impedance, (c) Indicates the work flow distribution. It is a graph which shows the impedance distribution and work flow distribution (damping distribution by energy transport) in the comparative example of 1st Example, (a) is a real part of an impedance, (b) is an imaginary part of an impedance, (c) is The work flow distribution is shown. It is a graph which shows impedance distribution and work flow distribution (damping distribution by energy transport) in a present Example of 2nd Example, (a) is a real part of an impedance, (b) is an imaginary part of an impedance, (c). Indicates the work flow distribution. It is a graph which shows the impedance distribution and work flow distribution (damping distribution by energy transport) in the comparative example of 2nd Example, (a) is a real part of an impedance, (b) is an imaginary part of an impedance, (c) is The work flow distribution is shown. It is the model which shows typically the structure of the conventional thermoacoustic engine, (a) is a schematic diagram at the time of using a thermoacoustic engine as a thermoacoustic generator, (b) is a thermoacoustic refrigeration. It is a schematic diagram at the time of using as a machine. It is a schematic diagram which shows typically the structure of the thermoacoustic engine using the conventional acoustic driver.

  Next, the present invention will be described in detail with reference to the drawings. Note that the size, positional relationship, and the like of the members shown in each drawing may be exaggerated for clarity of explanation. Further, in the following description, the same name and reference sign indicate the same or the same members in principle, and the detailed description will be omitted as appropriate.

<< First Embodiment >>
The first embodiment relates to a straight type thermoacoustic engine.
<Thermoacoustic engine>
As shown to Fig.1 (a), the thermoacoustic engine 1 has the resonance tube 11 with which working gas is satisfy | filled from the one end 11a to the other end 11b. Then, a heat accumulator 21, a heater 22, and a cooler 23 are provided as a prime mover 20 in the conduit of the resonance tube 11. Further, the resonance tube 11 has a reference tube portion 14 and a deformed tube portion 15 whose inner diameter is enlarged or reduced with respect to the reference tube portion 14. Here, the case where the inner diameter of the resonance tube 11 is reduced is illustrated. However, the inner diameter of the resonance tube 11 may be enlarged. One end 11a of the resonance tube 11 is an end portion on the side where the reference tube portion 14 is formed, that is, an end portion of the reference tube portion 14, and the other end 11b is formed with a deformed tube portion 15. That is, the end of the deformed tube portion 15.
Each configuration will be described below.

[Resonance tube]
The resonance tube 11 is a straight tube filled with a working gas, and includes a reference tube portion 14 and a deformed tube portion 15 having an inner diameter reduced with respect to the reference tube portion 14.
As the working gas, nitrogen, helium, argon, a mixture of helium and argon, air, or the like is often used.
Further, here, a buffer tank 16 for enclosing a working gas is provided at one end 11 a of the resonance tube 11. When atmospheric pressure air is used as the working gas, the one end 11a may be opened without providing the buffer tank 16 (see FIG. 5A). That is, when the buffer tank 16 is provided, the working gas is filled and filled in the resonance tube 11, and when the one end 11a is opened, the working gas is filled with atmospheric pressure air.

(Reference pipe section and deformation pipe section)
The reference tube portion 14 constitutes a part of the resonance tube 11 and serves as a reference for the inner diameter of the deformable tube portion 15.
The deformation tube portion 15 constitutes a part of the resonance tube 11 and has an inner diameter larger or smaller than that of the reference tube portion 14 (here, a small inner diameter). The deformation tube portion 15 is provided from a predetermined portion of the resonance tube 11 where the imaginary part of the acoustic impedance is zero in the acoustic impedance distribution obtained in advance toward the other end 11 b of the resonance tube 11. That is, the deformable tube portion 15 is provided after a predetermined position (arbitrary point) in the pipe of the resonance tube 11 and has a predetermined inner diameter. Here, the “acoustic impedance distribution obtained in advance” is an acoustic impedance distribution obtained by numerical calculation in a resonance tube having a desired length in which the deformable tube portion 15 is not provided.
The acoustic impedance is obtained from the following equation by measuring an angular frequency ω (2πf: f is a frequency), time t, and phase difference φ using a semiconductor pressure sensor (see JP 2011-99606 A).

Acoustic impedance
The pressure amplitude of the gas is expressed as P = | P | exp (iωt)
The flow velocity amplitude of the sound wave is expressed as U = | U | exp {i (ωt + φ)}
And when
Ζ = P / U = {| P | exp (iωt)} / {| U | exp {i (ωt + φ)}}

  That is, the acoustic impedance is represented by the ratio of the pressure amplitude (P) of the gas to the flow velocity amplitude (U) of the sound wave, and is composed of a real part and an imaginary part.

  The inner diameter of the deformable tube portion 15 is set so that the acoustic impedance value is ρc, where ρ is the working gas density and c is the sound velocity. That is, the deformed tube portion 15 is a portion where the inner diameter of the resonance tube 11 is reduced so that the acoustic impedance value in the resonance tube 11 becomes ρc. In the deformed tube portion 15, the self-excited vibration of the working gas is adjusted to a traveling wave.

Here, traveling waves and standing waves will be described.
The reciprocating motion of the fluid element is classified into “traveling wave” and “standing wave”. A state where the phase difference between the pressure amplitude and the flow velocity amplitude is zero is defined as “traveling wave”, and the other is defined as “standing wave”. A normal sound field spatially includes both standing waves and traveling waves. Since the phase difference between the pressure amplitude and the flow velocity amplitude is zero (the imaginary number of the acoustic impedance (pressure amplitude / flow velocity amplitude) is zero), the maximum and minimum points of the spatial pressure amplitude distribution are locally traveling waves. It is. However, this traveling wave is established only in a narrow region where the imaginary number of the acoustic impedance is zero and is a standing wave at other positions. Only when “the phase difference between the pressure amplitude and the flow velocity amplitude is zero” and “the acoustic impedance value is multiplied by the density of the fluid element and the sound velocity satisfies ρc”, the pressure amplitude distribution and the flow velocity amplitude distribution are spatially flat, and the sound The field becomes a pure traveling wave over a wide area.

  In order to achieve highly efficient energy conversion in a thermoacoustic engine, reversible energy conversion using traveling waves is essential. When attempting to install a heat accumulator for a local traveling wave, it is impossible to install all of them in the traveling wave position because the area that becomes the traveling wave is narrow. On the other hand, if it is a “wide-area traveling wave” that is a traveling wave in a wide area, it is naturally possible to install a plurality of heat accumulators because the wide area is a traveling wave. The object of the present invention is to realize a “wide traveling wave”. Further, since the traveling wave acoustic wave is a work flow that travels in one direction, there is also an advantage that attenuation due to energy propagation is small. On the other hand, since the standing wave is a superposition of waves accompanied by reflection, attenuation due to energy propagation is large. Therefore, wide-area traveling waves are significant from the viewpoint of energy transport.

  In the present invention, for a thermoacoustic engine that operates by self-excited vibration, all sound fields beyond an arbitrary point are set as traveling wave phases. In the following, a method of “all sound fields ahead of an arbitrary point are set as traveling wave phases” will be described.

  In a wide-range traveling wave acoustic wave, the acoustic impedance is spatially uniform, and is given by a “real part” ρc where ρ is the gas density and c is the sound velocity. In order to set the acoustic impedance ahead of the arbitrary point to ρc, ρc is set at a predetermined position from the predetermined portion of the resonance tube 11 toward the other end 11b of the resonance tube 11 so that the imaginary part of the acoustic impedance becomes zero. The resonance tube may be enlarged or reduced to the inner diameter to be filled.

The inner diameter of the deformed tube portion is calculated from the cross-sectional area obtained by the following formula (1).
(Π · r ² · (ρc) / Z _R ) = A ··· Formula (1)
Where r is the radius of the resonance tube (inner radius), Z _R is the real part (impedance value) at the point where the imaginary part of the acoustic impedance is zero, and A is the cross-sectional area.

In the above equation, ρc is an acoustic impedance when a pure traveling wave is satisfied. When the working gas is atmospheric air at 25 ° C., ρc = about 409 Ns / m ³ . If the “real part (impedance value) at the point where the imaginary part of the acoustic impedance is zero” is larger than ρc, the resonance tube is reduced, and if it is smaller than ρc, the resonance tube is enlarged, and the sound after the point where the imaginary part becomes zero Adjust the impedance value to be ρc.

[Motor]
The prime mover 20 functions as a self-excited vibration generating unit of the thermoacoustic engine 1 and is provided in a pipe line of the reference pipe portion 14 in the resonance pipe 11. The prime mover 20 includes a heat accumulator 21 provided in the resonance tube 11, and a heater 22 and a cooler 23 provided so as to sandwich both ends of the heat accumulator 21. The heater 22 is disposed on one end side of the regenerator 21, and the cooler 23 is disposed on the opposite side, that is, the other end side of the regenerator 21. The position of the prime mover 20 is particularly limited as long as the position of the prime mover 20 is in the pipeline of the reference pipe portion 14 and the work flow caused by self-excited vibration is transmitted to the other end of the resonance tube 11 as acoustic energy E. It is not a thing.

(Regenerator)
The heat accumulator (primary motor heat accumulator) 21 is provided in the pipe of the resonance pipe 11 and heats and cools the working gas.
The heat accumulator 21 forms a temperature gradient between both ends of the heat accumulator 21 by the heater 22 and the cooler 23 to generate self-excited vibration of the working gas. That is, the regenerator 21 has a temperature difference generated between one end thereof (hereinafter appropriately referred to as a high temperature portion 21b) and the other end portion (hereinafter appropriately referred to as a normal temperature portion (primary motor side normal temperature portion) 21a). By maintaining, it has a function of generating a work flow mainly due to self-excited vibration (pressure vibration) of the working gas. The heat accumulator 21 is, for example, a ceramic honeycomb structure having a large number of parallel passages in the extending direction (pipeline direction) of the resonance tube 11 or a structure in which a large number of stainless steel mesh thin plates are laminated at a minute pitch. be able to. Alternatively, a non-woven fabric made of metal fibers can be used.

(Heater)
The heater 22 is provided in a pipe line of the resonance tube 11 adjacent to one end side of the heat accumulator 21, and heats one end portion (high temperature portion 21b) of the heat accumulator 21. That is, the heater 22 functions as a heat input unit that heats one end of the heat accumulator 21 using an external heat source. The heater 22 is composed of, for example, a heat exchanger for heating. Specifically, for example, a large number of metal plates such as mesh plates are stacked at a fine pitch. A heating device (not shown) is connected to the heater 22 and is configured to be heated through an annular member 22a provided on the outer periphery thereof. In the drawing, for convenience, the left wall of the annular member 22a is shown between the regenerator 21 and the heater 22, but the heater 22 is adjacent to, in close contact with, one end side of the regenerator 21 through the left wall. ing.

(Cooler)
The cooler 23 is provided in a pipe line of the resonance tube 11 adjacent to the other end side of the heat accumulator 21, and discharges heat of the other end portion (normal temperature portion 21a) of the heat accumulator 21 to the outside. That is, the cooler 23 has a function of cooling by discharging the heat at the other end of the heat accumulator 21 to the outside using cooling water, air, or the like. The cooler 23 is composed of, for example, a heat exchanger for cooling. The cooler 23 basically has the same configuration as that of the heater 22, for example, a configuration in which a large number of metal plates such as mesh plates are stacked at a minute pitch. The cooler 23 is provided with a cooling bracket 23a around it. A cooling water passage (not shown) is connected to the cooling bracket 23a, and the cooler 23 is configured to be able to maintain a constant cooling temperature via the cooling bracket 23a by the cooling water flowing through the cooling water passage. In the drawing, for convenience, the right wall of the cooling bracket 23a is shown between the regenerator 21 and the cooler 23, but the cooler 23 is adjacent to the other end side of the regenerator 21 through this right wall, that is, in close contact. doing.

<< Second Embodiment >>
The second embodiment relates to a loop thermoacoustic engine.
<Thermoacoustic engine>
As shown in FIG. 1B, the thermoacoustic engine 1A includes an annular loop tube 10 in which a working gas is sealed, and a resonance tube 11 that communicates with the loop tube 10 and has one end 11a connected thereto. It is. Then, a heat accumulator 21, a heater 22, and a cooler 23 are provided as a prime mover 20 in the pipe line of the loop pipe 10. Further, the resonance tube 11 has a reference tube portion 14 and a deformed tube portion 15 whose inner diameter is enlarged or reduced with respect to the reference tube portion 14. Here, the case where the inner diameter of the resonance tube 11 is enlarged is shown. However, the inner diameter of the resonance tube 11 may be reduced.
Each configuration will be described below.

[Loop tube and resonance tube]
The loop pipe (primary motor loop pipe) 10 is an annular pipe in which working gas is enclosed, and the pipe line is formed into a rounded quadrangle, and straight pipe portions 10a to 10d that form straight portions corresponding to the four sides. Consists of. That is, it has two straight pipe parts 10a and 10b arranged substantially parallel to the vertical direction, and two straight pipe parts 10c and 10d arranged substantially parallel to the horizontal direction. And one end of the straight pipe part 10a and one end of the straight pipe part 10c, one end of the straight pipe part 10b and the other end of the straight pipe part 10c, the other end of the straight pipe part 10b and one end of the straight pipe part 10d are connected to each other. Curved at the site. In addition, the other end of the straight tube portion 10a and the other end of the straight tube portion 10d are connected, and at this portion, one end of the resonance tube 11 is connected to the loop tube 10.

The resonance tube 11 is a straight tube in which a working gas is enclosed, and one end 11a thereof communicates with the loop tube 10, that is, the working gas is connected in a state where the loop tube 10 and the resonance tube 11 are movable. Has been. Here, with reference to the broken line (reference A1) in FIG. 1B, the left tube is the loop tube 10 and the right tube is the resonance tube 11 in FIG. Here, the connection portion of the resonance tube 11 with the loop tube 10 is curved on the upper side, but may be formed at a right angle. In addition, the boundary between the resonance tube 11 and the loop tube 10 is not strictly defined, and even if the broken line indicated by the symbol A1 is located slightly on the right side of the paper (for example, the uncurved portion). Good. The resonance tube 11 includes a reference tube portion 14 and a deformed tube portion 15 in which the inner diameter of the resonance tube 11 is enlarged with respect to the reference tube portion 14.
As the working gas, nitrogen, helium, argon, a mixture of helium and argon, air, or the like is often used.

(Reference pipe section and deformation pipe section)
The reference tube portion 14 constitutes a part of the resonance tube 11 and serves as a reference for the inner diameter of the deformable tube portion 15.
The deformation tube portion 15 constitutes a part of the resonance tube 11 and has an inner diameter larger or smaller than that of the reference tube portion 14 (here, a large inner diameter). The deformation tube portion 15 is provided from a predetermined portion of the resonance tube 11 where the imaginary part of the acoustic impedance is zero in the acoustic impedance distribution obtained in advance toward the other end 11 b of the resonance tube 11. That is, the deformable tube portion 15 is provided after a predetermined position (arbitrary point) in the pipe of the resonance tube 11 and has a predetermined inner diameter.
Since the resonance tube 11 is the same as the straight thermoacoustic engine of the first embodiment except that the inner diameter of the resonance tube 11 is enlarged, the description thereof is omitted here.

[Motor]
The prime mover 20 functions as self-excited vibration generating means of the thermoacoustic engine 1A. The prime mover 20 includes a heat accumulator 21 provided in the loop tube 10, and a heater 22 and a cooler 23 provided so as to sandwich both ends of the heat accumulator 21. More specifically, in the present embodiment, the prime mover 20 is provided on the side of the loop pipe 10 to which the resonance pipe 11 is connected, that is, on the pipe line of the straight pipe portion 10 a of the loop pipe 10. And the heater 22 is arrange | positioned at the straight pipe part 10d side of the heat accumulator 21, and the cooler 23 is arrange | positioned at the other side, ie, the straight pipe part 10c side of the heat accumulator 21. The position of the prime mover 20 is not particularly limited as long as the position is within the loop tube 10 and the work flow due to self-excited vibration is transmitted to the other end 11b of the resonance tube 11 as acoustic energy E. Absent.

  The heat accumulator 21, the heater 22, and the cooler 23 constituting the prime mover 20 are the same as those of the straight thermoacoustic engine of the first embodiment except that they are provided in the pipe line of the loop pipe 10. The description is omitted here.

  The thermoacoustic engine 1, 1 </ b> A can further include one or more prime movers in the deformable tube portion 15. As shown in FIGS. 2A and 2B, the thermoacoustic engines 1 </ b> B and 1 </ b> C are provided with two prime movers 20 (deformation tube portion prime movers 20 a) in the deformation tube portion 15.

  The deforming tube portion prime mover 20a functions as a self-excited vibration generating means of the thermoacoustic engines 1B and 1C, similarly to the prime mover 20 described above. The deformable tube portion prime mover 20 a is provided in the conduit of the deformable tube portion 15 in the resonance tube 11, and a deformable tube portion adjacent to one end side of the heat accumulator 21 and a heat accumulator 21 that heats and cools the working gas. A heater 22 for heating one end of the heat accumulator 21 and an other end of the heat accumulator 21 adjacent to the other end of the heat accumulator 21. And a cooler 23 for releasing the heat of the part to the outside. Since these are the same as the prime mover 20 in the first embodiment except that they are provided in the pipe line of the deformable pipe portion 15, the description thereof is omitted here.

  By providing the deformable tube portion prime mover 20a in the deformable tube portion 15, it is possible to install one or a plurality of heat accumulators 21 at the traveling wave generation position, and highly efficient energy conversion can be performed. In addition, the installation position of the deformation | transformation pipe | tube motor | generator 20a is not specifically limited, What is necessary is just to adjust suitably. Further, when a plurality of the deformable tube prime movers 20a are provided, the interval between them is not particularly limited and may be adjusted as appropriate.

The thermoacoustic engine of the present invention is mainly used as a thermoacoustic generator or a thermoacoustic refrigerator.
Next, a thermoacoustic generator and a thermoacoustic refrigerator when the thermoacoustic engine 1C is used will be described as an example of a thermoacoustic engine using a thermoacoustic engine with reference to the drawings. In addition, although what is provided with the deformation | transformation pipe part prime mover 20a is demonstrated here, you may not be provided with the deformation | transformation pipe part prime mover 20a. In addition, here, a case where a loop type thermoacoustic engine is used will be described. However, a straight type thermoacoustic engine is the same except that a loop tube is not provided.

<Thermoacoustic generator>
As shown in FIG. 3, the thermoacoustic generator 50 is connected to the other end 11 b of the resonance tube 11 in addition to the above-described thermoacoustic engine 1 </ b> C, communicates with the deformation tube portion 15, and is generated in the working gas. A generator (linear generator) 30 that generates power in response to self-excited vibration is provided. Since it is as having demonstrated the said thermoacoustic engine 1C except having provided the generator 30, the generator 30 is demonstrated here.

[Generator]
The generator 30 is connected to the other end 11b of the resonance tube 11, communicates with the deformation tube portion 15, and further communicates with a part of the loop tube 10, and self-excited vibration generated in the working gas. It functions as a linear generator that generates power in response to. That is, the inner yoke 33 is reciprocated based on the self-excited vibration that is the acoustic energy E, and the acoustic energy E is converted into electric energy. Thereby, the so-called thermoacoustic generator 50 that converts the acoustic energy E transmitted through the resonance tube 11 into electrical energy through the reciprocating motion of the inner yoke 33 can be formed.

  The generator 30 includes a pressure vessel 39 connected to the other end 11 b of the resonance tube 11, that is, the deformation tube portion 15, and receiving an internal pressure variation corresponding to the pressure variation generated inside the loop tube 10 and the resonance tube 11. . Inside the pressure vessel 39, outer yokes (cylinders) 31, 31, coils 32 and 32 accommodated in the outer yokes 31 and 31, and an inner yoke (cylinder) 33 positioned between the outer yokes 31 and 31, respectively. Permanent magnets 34, 34 provided between the outer yokes 31, 31 and the inner yoke 33, respectively. The permanent magnets 34 and 34 are composed of S-pole and N-pole magnets, respectively.

  Such a structure in the generator 30 employs a power generation method based on the principle that a current is generated by a change in magnetic flux density that circulates around the coils 32 and 32 with time. That is, when the inner yoke 33 strokes based on the self-excited vibration that is the acoustic energy E, the density of the magnetic flux that circulates around the coils 32 and 32 greatly changes, and power generation is performed. Further, by attaching the projection 33a to the inner yoke 33, it is possible to suppress a decrease in magnetic flux density due to the magnetic flux passing through the air gap.

  The linear power generation system that converts such linear motion directly into electric power has the advantage that there is no fundamental conversion loss or friction loss due to the conversion mechanism, and the entire generator is expected to be smaller and more efficient. can do. Also, if you use a free piston type Stirling engine that generates reciprocating stroke fluctuations, or if you use tidal energy, vibration energy, etc. for power generation, it is difficult to convert vibration to rotation. There is a growing need for efficient linear generators.

<Thermoacoustic refrigerator>
As shown in FIG. 4, the thermoacoustic refrigerator 60 is connected to the other end 11 b of the resonance tube 11 in addition to the above-described thermoacoustic engine 1 </ b> C, and is connected to the deformed tube portion 15 so as to communicate therewith. A loop tube 12 is provided. The refrigerating loop pipe 12 includes a refrigerating regenerator 41, a refrigerating cooler 43, and a cold air discharger 42 as the refrigerating machine 40. Except for the provision of the refrigerating machine 40, since it is as described in the thermoacoustic engine 1C, the refrigerating machine 40 and the refrigerating loop pipe 12 equipped with the refrigerating machine 40 in the pipeline will be described here.

[Freezing loop tube]
The refrigeration loop pipe 12 is an annular pipe in which working gas is enclosed, and the pipe path is formed into a rounded quadrangular shape and includes straight pipe portions 12a to 12d that form straight portions corresponding to the four sides. That is, it has two straight pipe parts 12a, 12b arranged substantially in parallel in the vertical direction forming a straight part corresponding to the four sides, and two straight pipe parts 12c, 12d arranged substantially in parallel in the horizontal direction. ing. Then, one end of the straight pipe part 12a and one end of the straight pipe part 12c, one end of the straight pipe part 12b and the other end of the straight pipe part 12c, the other end of the straight pipe part 12b and one end of the straight pipe part 12d are connected and curved. doing. In addition, the other end of the straight tube portion 12a and the other end of the straight tube portion 12d are connected, and the other end of the resonance tube 11 is connected to the freezing loop tube 12 at this portion. Here, on the paper surface in FIG. 4 with reference to the broken line (reference A2) in FIG. 4, the right tube portion is the freezing loop tube 12 and the left tube portion is the resonance tube 11. Here, the connection portion of the resonance tube 11 with the refrigeration loop tube 12 is curved on the upper side, but may be formed at a right angle. Further, the boundary between the resonance tube 11 and the refrigeration loop tube 12 is not strictly defined, and the broken line A2 is located slightly on the left side of the paper (for example, the uncurved portion). May be.

[refrigerator]
The refrigerator 40 functions as a heat pump unit that converts a work flow generated by the self-excited vibration of the working gas generated by the prime mover 20 and the deformation pipe portion prime mover 20a into cold air (cold heat). The refrigerator 40 includes a refrigerating regenerator 41 provided in the refrigerating loop tube 12, and a refrigerating cooler 43 and a cold air discharger 42 provided so as to sandwich both ends of the refrigerating regenerator 41. ing. More specifically, in this embodiment, the refrigerator 40 is provided on the side of the refrigeration loop pipe 12 to which the resonance pipe 11 is connected, that is, on the pipe line of the straight pipe portion 12a of the refrigeration loop pipe 12. Yes. The refrigeration cooler 43 is arranged on the straight pipe portion 12 c side of the refrigeration regenerator 41, and the cold air discharger 42 is arranged on the opposite side, that is, on the straight pipe portion 12 d side of the refrigeration regenerator 41.

(Refrigerating regenerator)
The refrigerating regenerator 41 is provided in the pipe line of the refrigerating loop pipe 12 and cools the working gas.
The refrigerating regenerator 41 is connected to one end of the refrigerating regenerator 41 (hereinafter, appropriately, through the pipes 12d, 12b, 12c, and 12a in this order from the prime mover 20 to the resonance tube 11 and the refrigerating loop tube 12). The self-excited vibration transmitted to the normal temperature part (referred to as the refrigerator normal temperature part) 41a) is converted into one end of the refrigerating regenerator 41 (normal temperature part 41a) and the other end of the refrigerating regenerator 41 (hereinafter referred to as appropriate) It has a function of converting to a temperature difference between the low-temperature portion 41b and the low-temperature portion 41b. Since the normal temperature part 41a of the refrigerating regenerator 41 is cooled by the refrigerating cooler 43, the low temperature part 41b of the refrigerating regenerator 41 is cooled to a temperature lower than the normal temperature part 41a by the transmitted self-excited vibration. Cold air is generated. This cold air is taken out by the cold air discharger 42. The refrigerating regenerator 41 is made of a cold storage material having a large heat capacity. As the regenerator material, for example, stainless steel, copper, lead or the like can be used, and various shapes can be applied.

(Refrigerator for refrigeration)
The refrigeration cooler 43 is provided in a pipe line of the refrigeration loop pipe 12 adjacent to one end side where the self-excited vibration of the refrigeration regenerator 41 is transmitted. It releases heat to the outside. In other words, the refrigeration cooler 43 has a function of cooling by releasing heat from one end of the refrigeration regenerator 41 using cooling water, air, or the like. The refrigeration cooler 43 is composed of, for example, a cooling heat exchanger. Specifically, for example, a large number of metal plates such as mesh plates are stacked at a fine pitch. The refrigeration cooler 43 is provided with a cooling bracket 43a around it. A cooling water channel (not shown) is connected to the cooling bracket 43a, and the refrigeration cooler 43 can maintain a constant cooling temperature via the cooling bracket 43a by the cooling water flowing through the cooling water channel. In the drawing, for convenience, the lower wall of the cooling bracket 43a is shown between the refrigerating regenerator 41 and the refrigerating cooler 43. However, the refrigerating cooler 43 is connected to the refrigerating regenerator 41 through the lower wall. Adjacent to one end side, that is, in close contact.

(Cold air discharger)
The cold air discharger 42 is provided adjacent to the other end of the refrigerating regenerator 41 in the pipe line of the refrigerating loop tube 12, and generates cold air generated at the other end (low temperature part 41 b) of the refrigerating regenerator 41. It will be released to the outside. That is, the cold air discharger 42 functions as a cold air output unit that extracts the cold air generated at the other end of the refrigerating regenerator 41 to the outside. The cool air discharger 42 is composed of, for example, a refrigeration heat exchanger. The cool air discharger 42 basically has the same configuration as the refrigeration cooler 43. For example, a large number of metal plates such as mesh plates are stacked at a minute pitch. An annular member 42a made of a high thermal conductivity material (for example, copper) for extracting cold air (cold heat) is disposed at the outer peripheral position of the cold air discharger 42. In the drawing, for convenience, the upper wall of the annular member 42a is shown between the refrigerating regenerator 41 and the cold air discharger 42. The cold air discharger 42 is connected to the other end of the refrigerating heat accumulator 41 through this upper wall. Adjacent to, ie in close contact with, the side.

<Operation of thermoacoustic engine>
Next, the operation of the thermoacoustic engine will be described with reference to FIGS. 3 and 4 taking the thermoacoustic generator and thermoacoustic refrigerator described above as examples. Here, the case where a loop type thermoacoustic engine is used will be described, but the operation is the same in a straight type thermoacoustic engine.

[Operation of thermoacoustic generator]
As shown in FIG. 3, first, in the prime mover 20, when the high-temperature part 21 b of the regenerator 21 is heated by the heater 22 and the normal temperature part 21 a of the regenerator 21 is cooled by the cooler 23, both ends of the regenerator 21. That is, a temperature difference is generated between the high temperature part 21b and the normal temperature part 21a. Due to this temperature difference, the prime mover 20 (specifically, the heat accumulator 21) generates a work flow mainly due to self-excited vibration of the working gas. The work flow caused by the self-excited vibration generated in the prime mover 20 is transmitted as acoustic energy E to the generator 30 through these tubes in the order of the straight tube portions 10a, 10c, 10b, and 10d of the loop tube 10 and the resonance tube 11. . Here, a work flow due to self-excited vibration is also generated in the deformable tube prime movers 20a, 20a, and is transmitted to the generator 30 as acoustic energy E. Then, by reciprocating the inner yoke 33 based on the self-excited vibration transmitted to the generator 30, the acoustic energy E is converted into electric energy to generate electric power.

[Operation of thermoacoustic refrigerator]
As shown in FIG. 4, in the same manner as the operation of the thermoacoustic generator described above, a work flow is generated mainly by the self-excited vibration of the working gas in the prime mover 20 (specifically, the heat accumulator 21). The work flow caused by the self-excited vibration generated in the prime mover 20 is transmitted as acoustic energy E to the refrigerator 40 through the resonance tube 11. More specifically, from the high temperature part 21b of the regenerator 21, as the acoustic energy E, the straight pipe parts 10a, 10c, 10b, 10d of the loop pipe 10, the resonance pipe 11, and the straight pipe parts 12d, 12b of the freezing loop pipe 12 , 12c, 12a are transmitted to the normal temperature part 41a of the refrigerating regenerator 41. Here, in the deformable tube prime movers 20a and 20a, a work flow due to self-excited vibration is generated and transmitted to the refrigerator 40 as acoustic energy E.

  Next, the self-excited vibration transmitted to the refrigerating regenerator 41 is generated by the refrigerating regenerator 41 being cooled by releasing heat to the outside by the refrigerating cooler 43 and the refrigerating regenerator 41. It is converted into a temperature difference with the low temperature part 41b. Then, the cold air (cold heat) generated in the low temperature portion 41b of the refrigerating regenerator 41 due to the temperature difference between both ends of the refrigerating regenerator 41 is taken out by the cold air discharger 42, whereby the refrigerating capacity is obtained.

  Next, examples according to the present invention will be described. In this example, for the straight type thermoacoustic engine and the loop type thermoacoustic engine, for the one having a deformed tube portion and the one not having the conventional deformed tube portion, the traveling wave generation state, and The work flow distribution was investigated.

[First embodiment]
In the first example, a test was conducted on a straight type thermoacoustic engine having one end of the resonance tube as an open end. FIG. 5 (a) shows a straight type thermoacoustic engine as a target. In FIG. 5A, the shape of the straight type thermoacoustic engine is schematically shown for easy understanding.
As a present example, when the working gas density is ρ and the sound velocity is c, a thermoacoustic engine in which the inner diameter of the resonance tube is reduced so as to satisfy ρc at a position where the imaginary part of the acoustic impedance is zero and the sound field is adjusted. Prepared. The diameter (inner diameter) of the resonance tube was 40 mm up to the point where the imaginary part of the acoustic impedance becomes zero (this position is referred to as the zero point). On the other hand, after the zero point, the inner diameter of the resonance tube was changed to satisfy ρc.
As a comparative example, a thermoacoustic engine in which the inner diameter of the resonance tube was 40 mm and uniform and the sound field was not adjusted was prepared (not shown).

  FIG. 6 shows the impedance distribution and work flow distribution (attenuation distribution due to energy transport) at the time of sound field adjustment obtained by numerical calculation for the thermoacoustic engine of this embodiment, and the sound field unadjusted for the thermoacoustic engine of the comparative example. FIG. 7 shows the acoustic impedance distribution and work flow distribution at the time.

Here, the work flow measurement method is shown below (Tetsuji Tsuji: “Introduction to Measurement for Thermoacoustic Engineering Beginners”. Cryogenic Engineering, Vol. 43, pp.517-526 (2008)).
That is, the work flow W is related to Z _R (acoustic impedance real part) by the following equation.
W = (A / 2) (Z _R ) | U | ²
At this time, Z _{R is the} real part of the acoustic impedance, A is the cross-sectional area of the flow path in the pipe, and U is the amplitude of the flow velocity.
The sign of the work flow W given by the above equation represents the direction of the flow of acoustic power. If it is positive, it flows in the direction of the coordinate axis, and if it is negative, it indicates a flow in the opposite direction.

  6 and 7, the horizontal axis represents the distance from the zero point when the opening end is the zero point, and the vertical axis represents the impedance or work flow. 6 (a) and 7 (a) are the real part of the impedance (Real part), FIG. 6 (b) and FIG. 7 (b) are the imaginary part of the impedance (Imaginary part), FIG. 6 (c), FIG. 7C shows a work flow distribution (Work flow). In addition, the thick line (Regenerator) in a figure has shown the regenerator position, and the broken line has shown the approximate position of the scale line of a vertical axis | shaft and a horizontal axis.

FIG. 6 (a), the as shown in (b), x = when 1.12m larger than real part of the acoustic impedance 409Ns / ^{m 3,} and the imaginary part it is found that meets the 0Ns / ^{m 3.} That is, in the thermoacoustic engine shown in FIG. 5A, it is adjusted to a pure traveling wave after x = 1.12 m. In this example, since the real part at the point where the imaginary part of the acoustic impedance becomes zero is 5191 Ns / m ³ (see FIGS. 7A and 7B (corresponding to the acoustic impedance distribution obtained in advance)), In equation (1), the resonance tube cross-sectional area A is π · (40 mm / 2) ² · (409 Ns / m ³ ) / 5191 Ns / m ³ ) = 99.0 mm ² , that is, the inner diameter is 40 mm to 11. By changing to 2 mm, a pure traveling wave could be realized.

On the other hand, as shown in FIGS. 7A and 7B, the sound field of the resonance tube of the thermoacoustic engine shown in the comparative example is standing wave, and the real part of the acoustic impedance varies greatly in space. At the same time, the imaginary part is far from zero. Further, comparing the work flow distributions of FIG. 6C and FIG. 7C, it can be confirmed that the attenuation of the work flow is less when the sound field is adjusted to be a traveling wave.
From the above, it has been shown that by changing the inner diameter of the tube so as to satisfy ρc at the position where the imaginary part of the acoustic impedance is zero, the subsequent sound wave can be adjusted to the traveling wave phase. That is, it was confirmed that it is possible to make a traveling wave ahead of an arbitrary point.

[Second Embodiment]
In the second example, a test was conducted on a loop type thermoacoustic engine. The target loop type thermoacoustic engine is shown in FIG. FIG. 5B schematically illustrates the shape of the loop thermoacoustic engine for easy understanding.
In this example, when the working gas density is ρ and the sound velocity is c, the inner diameter of the resonance tube is expanded so that the acoustic impedance satisfies ρc at the position where the imaginary part of the acoustic impedance is zero, and the sound field is adjusted. A thermoacoustic engine was prepared. The diameter (inner diameter) of the resonance tube was set to 40 mm until the imaginary part of the acoustic impedance became zero. On the other hand, after the zero point, the inner diameter of the resonance tube was changed to satisfy ρc.
As a comparative example, a thermoacoustic engine in which the inner diameter of the resonance tube was 40 mm and uniform and the sound field was not adjusted was prepared (not shown).

FIG. 8 shows the impedance distribution and work flow distribution at the time of sound field adjustment obtained by numerical calculation for the thermoacoustic engine of this example, and the acoustic impedance distribution and work at the time of sound field unadjusted for the thermoacoustic engine of the comparative example are shown in FIG. The flow distribution is shown in FIG.
8 and 9, the horizontal axis represents the distance from the zero point when the center (T-shaped portion) of the joint portion of the loop tube and the resonance tube (the connecting portion of the straight tube portion 10a and the straight tube portion 10d) is the zero point. The vertical axis represents impedance or work flow. FIGS. 8A and 9A are the real part of the impedance, and FIGS. 8B and 9B are the imaginary part of the impedance, FIG. 8C, and FIG. 9 (c) is a work flow distribution (Work flow). In addition, the thick line (Regenerator) in a figure has shown the regenerator position, and the broken line has shown the approximate position of the scale line of a vertical axis | shaft and a horizontal axis.

As shown in FIGS. 8A and 8B, after x = 2.462 (“1.217 + 1.245” in FIG. 5B) m, the real part of the acoustic impedance is 409 Ns / m ³ and the imaginary number It can be seen that the part satisfies 0 Ns / m ³ . That is, in the thermoacoustic engine of FIG. 5B, after x = 2.462 m, it is adjusted to a pure traveling wave. In this example, the real part at the point where the imaginary part of the acoustic impedance becomes zero is 8.474 Ns / m ³ (see FIGS. 9A and 9B (corresponding to the acoustic impedance distribution obtained in advance)). In the above-described formula (1), the resonance tube cross-sectional area A is π · (40 mm / 2) ² · (409 Ns / m ³ ) /8.4673 Ns / m ³ ) = 60699 mm ² , that is, the inner diameter is from 40 mm. A pure traveling wave could be realized by changing to 278 mm.

  On the other hand, as shown in FIGS. 9A and 9B, the sound field of the resonance tube of the thermoacoustic engine shown in the comparative example is standing wave, and the real part of the acoustic impedance varies greatly in space. At the same time, the imaginary part is far from zero. Further, comparing the work flow distributions of FIG. 8C and FIG. 9C, it can be confirmed that the attenuation of the work flow is less when the sound field is adjusted to the traveling wave.

  From the above, it has been shown that by changing the inner diameter of the tube so as to satisfy ρc at the position where the imaginary part of the acoustic impedance is zero, the subsequent sound wave can be adjusted to the traveling wave phase. That is, it was confirmed that it is possible to make a traveling wave ahead of an arbitrary point.

  The present invention has been described in detail with reference to the embodiments and examples. However, the gist of the present invention is not limited to the above-described contents, and the scope of right is widely interpreted based on the description of the claims. Must. Needless to say, the contents of the present invention can be widely modified and changed based on the above description.

  For example, the configurations of the thermoacoustic generator and the thermoacoustic refrigerator are not limited to those described above, but in other commonly used thermoacoustic generators and thermoacoustic refrigerators Moreover, the structure which has a deformation | transformation pipe | tube part in this invention is applicable. For example, in a thermoacoustic generator, the configuration of the generator (linear generator) is not limited to the one described above, and any configuration can be used as long as the generator is used as a thermoacoustic generator. May be. In the thermoacoustic refrigerator, the prime mover and the refrigerator may be provided in the same loop pipe, and one loop pipe may be provided.

  Further, the shape of the loop tube or the loop tube for freezing in plan view is a rounded square in the above-described embodiment, but these shapes are not limited to this, for example, a square, a circle, or an ellipse The shape may also be

1, 1A, 1B, 1C Thermoacoustic engine 10 Loop tube 11 Resonant tube 12 Refrigeration loop tube 14 Reference tube portion 15 Deformation tube portion 16 Buffer tank 20 Prime mover 20a Prime mover (deformation tube prime mover)
21 Regenerator 22 Heater 23 Cooler 30 Generator (Linear Generator)
DESCRIPTION OF SYMBOLS 40 Refrigerator 41 Refrigerating regenerator 42 Cold air discharge device 43 Refrigeration cooler 50 Thermoacoustic generator 60 Thermoacoustic refrigerator

Claims (5)

A resonance tube filled with a working gas from one end to the other, provided in a pipe line of the resonance tube, and a heat accumulator that heats and cools the working gas; and adjacent to one end of the heat accumulator A heater for heating one end of the regenerator provided in a pipe of the resonance tube, and a second end of the regenerator provided in a pipe of the resonance tube adjacent to the other end of the regenerator. A thermoacoustic engine comprising a prime mover composed of a cooler that discharges the heat of the outside and generating a self-excited vibration of the working gas by forming a temperature gradient between both ends of the heat accumulator,
The resonance tube has a reference tube portion and a deformed tube portion whose inner diameter is enlarged or reduced with respect to the reference tube portion,
The prime mover is provided in a pipe line of the reference pipe part,
The deformation tube portion is provided from a predetermined portion of the resonance tube such that an imaginary part of the acoustic impedance is zero in the acoustic impedance distribution obtained in advance, toward the other end of the resonance tube,
The thermoacoustic engine is characterized in that an inner diameter of the deformable tube portion is set so that an acoustic impedance value is ρc, where ρ is a density of the working gas and c is a sound velocity. An annular loop tube in which a working gas is sealed, and a resonance tube that communicates with the loop tube and has one end connected thereto, and is provided in a pipe line of the loop tube to heat and cool the working gas. A heat accumulator, a heater provided adjacent to one end side of the heat accumulator, and a loop for heating one end of the heat accumulator; and the loop adjacent to the other end side of the heat accumulator. A prime mover that is provided in a pipe line and discharges heat from the other end of the heat accumulator to the outside, and forms a temperature gradient between both ends of the heat accumulator to form the working gas. A thermoacoustic engine that generates self-excited vibration,
The resonance tube has a reference tube portion and a deformed tube portion whose inner diameter is enlarged or reduced with respect to the reference tube portion,
The deformation tube portion is provided from a predetermined portion of the resonance tube such that an imaginary part of the acoustic impedance is zero in the acoustic impedance distribution obtained in advance, toward the other end of the resonance tube,
The thermoacoustic engine is characterized in that an inner diameter of the deformable tube portion is set so that an acoustic impedance value is ρc, where ρ is a density of the working gas and c is a sound velocity.   Furthermore, a heat accumulator that is provided in a pipe line of the deformable pipe part, heats and cools the working gas, and is provided in a pipe line of the deformed pipe part adjacent to one end side of the heat accumulator, A heater that heats one end, and a cooler that is provided adjacent to the other end of the heat accumulator and that is provided in a pipe line of the deformed tube and discharges heat from the other end of the heat accumulator to the outside. The thermoacoustic engine according to claim 1, further comprising one or more prime movers.   2. The generator according to claim 1, further comprising a generator connected to the other end of the resonance tube, communicating with the deformable tube portion, and generating power in response to self-excited vibration generated in the working gas. The thermoacoustic engine according to claim 3.   Furthermore, it has an annular refrigeration loop pipe connected to the other end of the resonance pipe and connected to the deformation pipe section, and is provided in a pipe line of the refrigeration loop pipe to cool the working gas. A refrigerating regenerator and an end of the refrigerating regenerator adjacent to one end where the self-excited vibration is transmitted to the pipe of the refrigerating loop tube, and heat from one end of the refrigerating regenerator to the outside A refrigeration cooler to be discharged and a refrigeration loop pipe disposed adjacent to the other end of the refrigeration regenerator and discharging the cold air generated at the other end of the refrigeration regenerator to the outside The thermoacoustic engine according to any one of claims 1 to 3, further comprising a cool air discharger.

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