JP2017180920A - Thermoacoustic engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To preferably suppress a decline in temperature difference between a heater and a cooler by an engine, amplify an acoustic wave appropriately by an engine, and to be preferably capable of generating electrical power by a power generator using the amplified acoustic wave.SOLUTION: A power generator 20 includes a flux damping mechanism for damping a flux of a working medium inside an acoustic cylinder C. An engine 10 includes the power generator 20 in the vicinity of a side of a heater 11 in a direction of a cylinder axis of the acoustic cylinder C.SELECTED DRAWING: Figure 1

Description

  The present invention provides an acoustic cylinder in which a working medium is filled and a sound wave is propagated between a heater for heating the working medium from the outside, a cooler for cooling the working medium from the outside, the heater, and the cooler. The present invention relates to a thermoacoustic engine provided with at least one prime mover composed of a regenerator for amplifying sound waves and having at least one thermoacoustic part provided with a power generator for generating electric power from vibration of sound waves.

Conventionally, as a technique for converting thermal energy into vibration energy of sound waves by generating a temperature gradient between one end side and the other end side of the regenerator with media having different temperatures in the axial direction of the acoustic cylinder, An acoustic engine is known (see Patent Document 1).
In the thermoacoustic engine disclosed in Patent Document 1, for example, a heater that heats the working medium from the outside and a cooler that cools the working medium from the outside are provided in an acoustic cylinder that is filled with a working medium such as helium and propagates sound waves. A prime mover including a regenerator that amplifies vibration energy of sound waves between a heater and a cooler, and a power generator that generates electric power from vibrations of sound waves are provided.

JP 2013-096387 A

  In the thermoacoustic engine shown in Patent Document 1, the working medium flows from the relatively cooler side toward the relatively hot heater side inside the acoustic cylinder and flows. When the working medium comes into contact with the heater and removes the heat from the heater, the temperature difference between the cooler and the heater in the prime mover becomes small, and the sound wave cannot be sufficiently amplified in the prime mover. there were.

  The present invention has been made in view of the above-described problems, and its purpose is to appropriately suppress the reduction of the temperature difference between the heater and the cooler by the prime mover and to appropriately generate the sound wave by the prime mover. Another object of the present invention is to provide a thermoacoustic engine that can amplify and further generate electric power with an electric power generator by the amplified sound wave.

In order to achieve the above object, a thermoacoustic engine includes a heater that heats the working medium from the outside, a cooler that cools the working medium from the outside, and the heater in an acoustic cylinder that is filled with the working medium and propagates sound waves. And at least one prime mover comprising a regenerator for amplifying sound waves between the cooler and the cooler, and a thermoacoustic engine provided with at least one thermoacoustic section for providing a power generator for generating electric power from vibration of sound waves And the characteristic composition is
The power generator includes a flow damping mechanism that attenuates the flow of the working medium in the acoustic cylinder,
The power generator is provided near the heater side of the prime mover in the axial direction of the acoustic cylinder.

According to the above characteristic configuration, since the electric power generator is provided in the vicinity of the heater side of the prime mover in the axial direction of the acoustic cylinder, the flow of the working medium flowing from the low temperature side to the high temperature side is It is possible to prevent the temperature of the heater from falling due to contact with the heater due to the low-temperature working medium. Thereby, the temperature gradient between the heater and the cooler can be kept large in the prime mover, and the sound wave can be appropriately amplified in the prime mover.
Incidentally, in the present specification, in the direction of the cylinder axis of the acoustic cylinder, the vicinity of the heater side of the prime mover means a region where the distance from the heater of the prime mover is shorter than the distance from the cooler of the prime mover. And The definition is the same when a plurality of prime movers are provided.
From the above, the prime mover satisfactorily suppresses the reduction of the temperature difference between the heater and the cooler, appropriately amplifies the sound wave with the prime mover, and further, the amplified sound wave is good for the power generator A thermoacoustic engine that can generate electric power can be realized.

Further features of the thermoacoustic engine
The power generator is located near the heater side of the prime mover in the axial direction of the acoustic cylinder and at a distance of an integral multiple of a quarter wavelength and a half wavelength of the sound wave from the heater. It is in the point provided for.
Note that the 1/4 wavelength of the sound wave and a distance that is an integral multiple of the half wavelength are distances represented by (1 + 2n) × λ / 4 (n = 0, 1, 2,...), Where λ is the wavelength. is there.

As shown in FIGS. 2 and 3, the inventors have a case where the acoustic cylinder C is composed of a loop pipe and a straight pipe connected to the loop pipe, and the two prime movers 10 are provided in the loop pipe. Inside the loop tube of the acoustic cylinder C, the pressure amplitude of the generated sound wave and the velocity of the molecule as the working medium were obtained by simulation at each position in the tube axis direction of the loop tube.
Here, the prime mover 10 is arranged at a position where the molecular velocity of the working medium is small and the pressure amplitude is large (hereinafter, sometimes referred to as a position where the acoustic impedance is high), so that heat energy is converted into acoustic energy. Conversion efficiency is increased. On the other hand, the power generator has a large power output at a position where the molecular velocity of the working medium is high.
As shown in the simulation shown in FIG. 3, when the prime mover 10 is arranged at a position where the acoustic impedance is high, the position where the molecular velocity is the largest is a distance that is an integral multiple of a quarter wavelength and a half wavelength of the sound wave from the prime mover 10. Occurs at a distant location.
According to the above characteristic configuration, the power generator is separated from the heater 11 on the heater 11 side of the prime mover 10 by a distance of an integral multiple of a quarter wavelength and a half wavelength of the sound wave in the axial direction of the acoustic cylinder. By providing at the position, the acoustic energy can be efficiently converted into electric power at the antinode of the molecular velocity at which the molecular velocity is greatest.

Further features of the thermoacoustic engine
The power generator is provided near the heater side of the prime mover in the direction of the axis of the acoustic cylinder, and at a position away from the heater by a distance of a quarter wavelength of the sound wave. It is in.

Inside the acoustic cylinder, the working medium flows from the low temperature side to the high temperature side. Therefore, there is a possibility that the working medium flows from the acoustic cylinder located on the heater side of the prime mover to the heater side from any position.
According to the above characteristic configuration, first, the power generator is provided on the heater side of the prime mover in the direction of the axial axis of the acoustic cylinder, and at a position away from the heater by a quarter wavelength of the sound wave. Therefore, the acoustic energy can be efficiently converted into electric power at the antinode of the molecular velocity at which the molecular velocity is greatest.
In addition, the power generator is the most heater in the axial direction of the acoustic cylinder on the heater side of the prime mover and at a distance from the heater that is an integer multiple of a quarter wavelength and a half wavelength of the sound wave. Because it is provided at a position that is close to the distance of 1/4 wavelength of the sound wave from the heater, the operation to the heater side at least from a position that is more than a distance of 1/4 wavelength of the sound wave from the heater. The flow of the medium can be reduced satisfactorily.

Further features of the thermoacoustic engine
The flow damping mechanism of the power generator is composed of one rotary blade provided inside the acoustic cylinder and a pair of fixed blades provided with the rotary blade interposed therebetween. .

For example, when the acoustic cylinder is provided with a film body that prevents the working medium from flowing in the axial direction of the cylinder of the acoustic cylinder, and the flow of the working medium is inhibited, the temperature difference between the heater and the cooler of the prime mover is When it is increased, there is a problem that the load on the film body is increased, the film body is damaged, and the flow of the working medium cannot be appropriately suppressed.
According to the above characteristic configuration, even when the temperature difference between the heater and the cooler of the prime mover increases, the kinetic energy associated with the flow of the working medium generated inside the acoustic cylinder is reduced. It can be satisfactorily suppressed in the form of conversion into rotational energy.

Further features of the thermoacoustic engine
An output power deriving unit for deriving output power of the power generator;
A control mechanism is provided that controls the size of the power load that supplies the power generated by the power generator based on the output power derived by the output power deriving unit.

  According to the above characteristic configuration, since the size of the power load can be appropriately switched in accordance with the output power of the power generator, the power generated by the power generator is matched to the power. Proper supply to the load.

Schematic configuration diagram of a thermoacoustic engine according to the present invention Diagram showing the concept of simulation The graph which shows the pressure amplitude and the velocity of the molecule | numerator as a working medium in the cylinder axial direction of the acoustic cylinder calculated by simulation

The thermoacoustic engine 100 according to the embodiment appropriately suppresses a reduction in temperature difference between the heater and the cooler by the prime mover, appropriately amplifies the sound wave by the prime mover, and further amplifies the amplification. The present invention relates to a power generator that can generate electric power satisfactorily by sound waves.
As shown in FIG. 1, the thermoacoustic unit includes a cylindrical acoustic cylinder C formed of a loop tube that is filled with a working medium and propagates sound waves, a heater 11 that heats the working medium from the outside, and a working medium that is externally provided. And at least one prime mover 10 (one in the present embodiment) including a cooler 12 that cools from the cooler 12 and a regenerator 13 that amplifies sound waves between the cooler 12 and the heater 11. It has the electric power generator 20 which generate | occur | produces electric power from vibration of.

  Although detailed illustration is omitted, the heater 11 includes a jacket part (not shown) through which a second heat medium HW (for example, engine cooling water) guided from the outside and having heat is passed, and an acoustic wave from the jacket part. It consists of a fin (not shown) extending inside the cylinder C. The heater 11 is heated by the second heat medium HW through which the fin flows through the jacket portion, and heats the working fluid in a form that conducts heat from the fin to the working fluid inside the acoustic cylinder C.

  Similarly, the cooler 12 includes a jacket portion (not shown) that flows through a first heat medium CW (for example, LNG) having cold heat guided from the outside, and a fin that extends from the jacket portion to the inside of the acoustic cylinder C. (Not shown). The cooler 12 is cooled by the first heat medium CW in which the fins flow through the jacket portion, and the working fluid is cooled in such a manner that cold heat is conducted from the fins to the working fluid inside the acoustic cylinder C.

The regenerator 13 provided between the heater 11 and the cooler 12 is, for example, along the cylinder axis direction in a state where the plate surface is aligned in a direction orthogonal to the cylinder axis direction of the acoustic cylinder C. A plurality of thin plate members (not shown) are arranged.
For example, the thin plate member has a thickness of 50 μm or more and 100 μm or less, and is provided with about 300 to 600 sheets. The thin plate-like member is provided with a large number of through holes (not shown) penetrating in a direction along the cylinder axis direction with a diameter of about 200 μm to 300 μm.

The working fluid exists inside the acoustic cylinder C in a state in which minute fluctuations are generated in the cylinder axis direction. In other words, the working fluid fluctuates between the heater 11 and the cooler 12 in a form that forms a traveling wave from one side to the other side and a traveling wave from the other side to the one side. .
When the working fluid forms a traveling wave from the cooler 12 toward the heater 11, the working fluid passes through the plurality of through holes of the thin plate member as the regenerator 13 in the vicinity of the heater 11. While being heated in contact with the inner wall, it is expanded by being directly heated by the fins of the heater 11. On the other hand, when the working fluid forms a traveling wave from the heater 11 toward the cooler 12, the working fluid passes through the plurality of through holes of the thin plate member as the regenerator 13 in the vicinity of the cooler 12. It cools in contact with the inner wall of the through hole and contracts by being directly cooled by the fins of the cooler 12.
Thereby, the sound energy as the traveling wave causes self-excited vibration, and the thermal energy is converted into the vibration energy of the sound wave in such a form that the vibration energy is amplified.

  The working medium can be composed of air composed of oxygen, nitrogen, or the like. Here, since it is desirable that heat exchange in the regenerator 13 be performed quickly, helium and hydrogen having a high thermal diffusion coefficient are desirable as the working medium. For the purpose of power generation, since a gas having a high molecular weight is desirable, a gas such as argon may be mixed. In this embodiment, helium is used as the working medium because it is thermally stable.

As described above, the vibration energy of the sound wave amplified by the prime mover 10 is converted into electric power in the acoustic cylinder C by the power generator 20 that generates electric power from the vibration of the sound wave.
As shown in FIG. 1, the electric power generator 20 includes a single rotary blade 23 and a pair of fixed blades 21 and 22 provided in a state of sandwiching the rotary blade 23 inside the acoustic cylinder C. . In this configuration, the rotary blade 23 generates a rotational force by both the sound wave swirled by the one fixed blade 21 and directed to the rotary blade 23 and the sound wave swirled by the other fixed blade 22 and directed to the rotary blade 23. The pair of fixed wings 21 and 22 are provided so that the rotational direction of the rotational force applied to the rotary wing 23 by the sound wave swirled by both is the same direction.
Further, the rotor 23 is provided with a rotor (not shown) as an induction generator, and the outer side of the acoustic cylinder C at a portion where the rotor 23 is provided in the axial direction of the cylinder of the acoustic cylinder C. A stator 24 as an induction generator is provided in the diameter portion, and an induced electromotive force E is generated by a coil as the stator 24 when the rotor rotates together with the rotary blade 23.
By adopting the configuration, the vibration energy of the sound wave generated inside the acoustic cylinder C is converted into electric energy.

Now, in the thermoacoustic engine 100 having the above-described configuration, the working medium is relatively contained inside the acoustic cylinder C (more specifically, inside the acoustic cylinder C where the regenerator 13 is not provided). It flows from the low-temperature cooler 12 side toward the relatively high-temperature heater side (from the base end side to the front end side of the arrow X in FIG. 1), and the fluidized working medium comes into contact with the heater 11 and heats it. By depriving the heat of the motor 11, the temperature difference between the heater 11 and the cooler 12 in the prime mover 10 becomes small, and there is a possibility that sound waves in the prime mover 10 cannot be sufficiently amplified.
If the explanation is added, the flow of the working medium flows not only from the cooler 12 side to the heater 11 side but also from the low temperature side to the high temperature side. It flows toward the heater 11 side from the part between the two.
Therefore, in the thermoacoustic engine 100 according to the present embodiment, the rotating blade 23 is sandwiched between the rotating blade 23 as a flow damping mechanism that attenuates the flow of the working medium inside the acoustic cylinder C. A power generator 20 having a pair of fixed blades 21 and 22 is provided in the vicinity of the heater 11 side of the prime mover 10 in the direction of the axis of the acoustic cylinder C.
Incidentally, in the present embodiment, the distance from the heater 11 of the prime mover 10 to the vicinity of the heater 11 of the prime mover 10 is greater than the distance from the cooler 12 of the prime mover 10 in the cylinder axis direction of the acoustic cylinder C. Also means a short region. This definition is the same when a plurality of prime movers 10 are provided.

  With this configuration, the flow of the working medium passing through the region not passing through the regenerator 13 inside the acoustic cylinder C is heated from the cooler 12 side to the heater 11 side, more specifically, inside the acoustic cylinder C. Since it can be attenuated in the vicinity of the heater 11, the heater 11 is prevented from coming into contact with a relatively low temperature working medium, the temperature of the heater 11 is lowered, and the prime mover 10 has the heater 11 and the cooler 12. The sound wave can be sufficiently amplified by sufficiently securing the temperature difference.

As shown in FIGS. 2 and 3, the inventors have a case where the acoustic cylinder C is composed of a loop pipe and a straight pipe connected to the loop pipe, and the two prime movers 10 are provided in the loop pipe. Inside the loop tube of the acoustic cylinder C, the pressure amplitude of the generated sound wave and the velocity of the molecule as the working medium were determined by simulation at each position in the tube axis direction (arrow X direction in FIG. 2) of the loop tube.
Here, the prime mover 10 is arranged at a position where the molecular velocity of the working medium is small and the pressure amplitude is large (hereinafter, sometimes referred to as a position where the acoustic impedance is high), so that heat energy is converted into acoustic energy. Conversion efficiency is increased. Therefore, the prime mover 10 is provided at a position where the molecular velocity of the working medium is small and the pressure amplitude is large, that is, a position where the acoustic impedance is high.

On the other hand, the power generator 20 has a large power output at a position where the molecular velocity of the working medium is high. As shown in the simulation shown in FIG. 3, when the prime mover 10 is arranged at a position where the acoustic impedance is high, the position where the molecular velocity becomes the largest is an integral multiple of a quarter wavelength and a half wavelength of the sound wave from the prime mover 10. Occurs at a distance of.
Therefore, in the configuration in which the acoustic cylinder C includes the power generator 20, a part of the sound wave propagating through the acoustic cylinder C is reflected by the fixed blades 21 and 22 of the power generator 20, and the standing wave Will occur. In the situation where the standing wave is generated, the power generator 20 is arranged in the direction of the cylinder axis of the acoustic cylinder C in order to provide the power generator 20 at the antinode where the molecular velocity of the standing wave is maximum. A distance in the vicinity of the heater 11 and an integral multiple of a quarter wavelength and a half wavelength of the sound wave from the heater 11 (where λ is (1 + 2n) × λ / 4 (n = 0, 1, 2,... It is preferable to be provided at a position separated by a distance represented by.

  Furthermore, from the viewpoint of more effectively reducing the flow of the relatively low temperature working medium to the heater 11, the power generator 20 is located in the vicinity of the heater 11 of the prime mover 10 in the cylinder axis direction of the acoustic cylinder C. It is preferable that the heater 11 is provided at a position separated from the heater 11 by a distance of a quarter wavelength of the sound wave (a position separated by a distance indicated by an arrow L in FIG. 1).

  According to the above configuration, for example, in the state where the attenuation of the sound wave is reduced in comparison with the case where the flow inhibiting member such as a jet pump for preventing the flow of the working medium is disposed inside the acoustic cylinder C, Can be suppressed.

In the thermoacoustic engine 100 configured as described above, it is preferable that the size of the power load can be appropriately switched according to the output power generated by the power generator 20.
Therefore, in this embodiment, a control unit S (an example of an output power deriving unit) that derives the output power of the power generator 20 is provided, and power generation is performed based on the output power derived by the control unit S. A control mechanism is provided for controlling the size of the power load that supplies the power generated by the machine 20.

The electric power generator 20 outputs electric power in a form in which a three-phase alternating current having a frequency corresponding to the number of rotations of a rotor (not shown) whose stator 24 is fixed to the rotor blades 23 is generated.
The control mechanism includes a converter S1 that converts the three-phase alternating current output from the power generator 20 into direct current, an inverter S2 that converts the direct current output from the converter S1 into a predetermined three-phase alternating current, and an output from the inverter S2. A current detecting means S3 for detecting the current value of the three-phase alternating current, a waveform shaping portion S4 for shaping the three-phase alternating current outputted from the inverter S2, and a three-phase alternating current outputted from the waveform shaping portion S4. An output terminal block S6 that outputs to S7 and a control unit S that controls the inverter S2 and the like based on the measurement result of the current detection means S3. Incidentally, a breaker S5 is provided between the waveform shaping section S4 and the output terminal block S6.

When the explanation is added, the three-phase alternating current output from the power generator 20 is rectified to direct current by switching a plurality of transistors (not shown) as the converter S1, and then smoothed by the capacitor as the converter S1. It becomes.
The direct current output from the converter S1 is converted into a three-phase alternating current by a PWM (pulse width modulation) method by switching a plurality of transistors as the inverter S2 so as to have a preset frequency and output voltage value. Is done.
The control unit S is configured to derive output power based on the current detection means S3 and a preset voltage output value, and set the power load S7 corresponding to the output power. With this configuration, it is possible to set the power load S7 corresponding to the output power from the power generator 20.

[Another embodiment]
(1) In the said embodiment, the acoustic cylinder C was taken as the cylindrical shape which consists of a loop pipe | tube.
However, the acoustic cylinder C can adopt various shapes as long as the sound wave can propagate in a state in which the sound wave is less attenuated. For example, a pair of acoustic cylinders formed of a cylindrical loop tube is connected to a straight tube. It can be configured such that it has a shape that is connected in communication with an acoustic tube having a shape, or an acoustic tube that consists of a cylindrical loop tube and a straight tube-shaped acoustic tube that are connected in communication.

(2) In the above embodiment, the configuration example including one prime mover 10 and one power generator 20 with respect to the acoustic cylinder C has been described.
However, a configuration including two or more prime movers 10 and two or more power generators 20 may be employed. In this case, from the viewpoint of suppressing the temperature difference between the heater 11 and the cooler 12 from being reduced due to the flow of the working medium, the power generator 20 is arranged in the direction of the cylinder axis of the acoustic cylinder C. It is preferable to provide in the vicinity of the heater 11 and at a position away from the heater 11 by an integral multiple of a quarter wavelength and a half wavelength of the sound wave.
That is, from the viewpoint of appropriately suppressing the temperature difference between the heater 11 and the cooler 12 due to the flow of the working medium, one power generator 20 is provided for one prime mover 10. preferable.

  The configuration disclosed in the above embodiment (including another embodiment, the same shall apply hereinafter) can be applied in combination with the configuration disclosed in the other embodiment, as long as no contradiction occurs. The embodiment disclosed in this specification is an exemplification, and the embodiment of the present invention is not limited to this. The embodiment can be appropriately modified without departing from the object of the present invention.

  The thermoacoustic engine of the present invention suppresses the reduction of the temperature difference between the heater and the cooler satisfactorily in the prime mover, appropriately amplifies the sound wave in the prime mover, and further uses the amplified sound wave to generate power. It can be effectively used as a thermoacoustic engine that can generate electric power with a generator.

10: prime mover 11: heater 12: cooler 13: regenerator 20: power generator 21, 22: fixed blade 23: rotary blade 24: stator 100: thermoacoustic engine C: acoustic cylinder S: control unit S7: electric power load

Claims (5)

The acoustic cylinder in which the working medium is filled and the sound wave propagates is amplified between a heater for heating the working medium from the outside, a cooler for cooling the working medium from the outside, and the heater and the cooler. A thermoacoustic engine provided with at least one prime mover composed of a regenerator and provided with at least one thermoacoustic part for providing a power generator for generating electric power from vibration of sound waves,
The power generator includes a flow damping mechanism that attenuates the flow of the working medium in the acoustic cylinder,
A thermoacoustic engine including the power generator in the vicinity of the heater side of the prime mover in the direction of the axis of the acoustic cylinder.   The power generator is located near the heater side of the prime mover in the axial direction of the acoustic cylinder and at a distance of an integral multiple of a quarter wavelength and a half wavelength of the sound wave from the heater. The thermoacoustic engine of Claim 1 with which it is equipped.   The power generator is provided near the heater side of the prime mover and at a distance of a quarter wavelength of the sound wave from the heater in the axial direction of the acoustic cylinder. Item 3. The thermoacoustic engine according to item 2.   2. The flow damping mechanism of the power generator is composed of one rotary blade provided inside the acoustic cylinder and a pair of fixed blades provided with the rotary blade interposed therebetween. The thermoacoustic engine as described in any one of -3. An output power deriving unit for deriving output power of the power generator;
The control mechanism which controls the magnitude | size of the electric power load which supplies the electric power which generate | occur | produces in the said electric power generator based on the output electric power derived | led-out by the said output electric power derivation | leading-out part is provided. The thermoacoustic engine described in 1.

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