Multiple resonance tube thermo-acoustic engine
Technical field
The present invention relates to motor, relate in particular to a kind of multiple resonance tube thermo-acoustic engine.
Background technique
Modern industry production, space technology and military engineering etc. have all proposed more and more higher requirement to the reliability and the life-span of Cryo Refrigerator.The separately placed type sterlin refrigerator of extensive use and G-M refrigerator can not satisfy these requirements fully, its key reason is to exist at least in these mechanical refrigerators two moving elements: compressor and discharger, they become influences the major obstacle that refrigerator turns round reliably and with long-term.The vascular refrigerator that the 60 to 70's of 20th century occurs, owing to do not have the mechanical moving element of low-temperature end, thus improved reliability and life-span.Through theory and the experimental research of nearest more than ten years, vascular refrigerator has progressed into the practicability stage at present.
Yet vascular refrigerator has only been eliminated the moving element of low-temperature end, and it still needs mechanical compressor to drive at indoor temperature end.How thoroughly to eliminate mechanical moving element on the driving source aspect, and then construct the cryogenic refrigerating system that does not have mechanical moving element fully, be the key point that thoroughly solves the Cryo Refrigerator integrity problem.The appearance of thermoacoustic engine provides a kind of very effectively solution route.Certainly, thermoacoustic engine is as a kind of hot machine of exporting mechanical work, and it is used not just as the driving source of vascular refrigerator, can also be applied in other power system, for example, can directly connect acoustic-electrical transducer or other multiple acoustics load.
According to the sound field characteristic difference, thermoacoustic engine mainly is divided into stationary mode, two kinds of patterns of travelling-wave type.Row wave sound field medium velocity ripple is identical with the pressure surge phase place, and the two differs 90 ° in standing-wave sound field.Standing-wave sound field medium velocity ripple and pressure wave differ 90 °, in theory can not generation sound merit, and it is that cost produces merit to reduce thermodynamic efficiency; The folded spacing of stationary mode engine plate generally should be greater than the heat penetration of gas, to realize having only portion gas and the limited thermo-contact of the folded generation of plate.The regenerator of traveling wave thermoacoustic engine is made of the enough little filler of size, its gap size is much smaller than the gas heat penetration, basically the filler temperature with this place is identical with the gas temperature in any part of assurance filler, realizes the desirable thermo-contact between solid and gas.
Because the operation of stationary mode thermoacoustic engine is based on inner irreversible [thermodynamic, the entropy that irreversible heat exchange between its gas and plate are folded causes increases the efficient that has limited the stationary mode thermoacoustic engine, its thermodynamic efficiency often can not be very high, generally all below 15%.And traveling wave thermoacoustic engine is similar and the Stirling [thermodynamic, and its process itself is reversible, so the efficient of traveling wave thermoacoustic engine is higher than the irreversible stationary mode thermoacoustic engine of its process in theory.Just because of this, utilize the heat sound machinery of row wave sound field more and more to be subjected to people's attention.
Pressure ratio is one of important parameter of estimating thermoacoustic engine, and it is defined as the ratio of maximum value with the minimum value of surge pressure, and it has determined the grade of thermoacoustic engine output sound merit.Theoretical and experiment all shows, the thermoacoustic engine pressure ratio is big more then to help driving vascular refrigerator or other hot sound refrigerating machine obtains lower cryogenic temperature and bigger refrigerating capacity more.Usually high-frequency vascular refrigerator is in order to obtain the pressure ratio of low temperature needs more than 1.20 below the 70K.At present, in the world in the pressure ratio of grinding traveling wave thermoacoustic engine about 1.2, the maximal pressure ratio can reach 1.31.The unreasonable of resonatron structure is the factor of restriction thermoacoustic engine pressure ratio.The effect of resonatron is that resonance takes place therein in the self-excited vibration that will produce in the regenerator (or heat sound plate is folded) on the one hand, so that vibration is strengthened; Be to form HR high resistance on the other hand, to reduce the loss at regenerator place at regenerator or the folded place of plate; In addition, resonatron is the main body of sound field in the thermoacoustic engine, and the size of frequency of okperation is played decisive action.Though the resonatron in the thermoacoustic engine is the simple pipeline of a root architecture,, along with sound pressure improves, its sonic transmissions mechanism is very complicated, is a nonlinear propagation process that is accompanied by sticking heat dissipation.Current research shows that the physical dimension of resonatron has determined its quality factor, and affects the power of nonlinear effect in the motor, if can be optimized the resonatron structure, makes its quality factor reach maximum, then can realize the highest engine performance.
Coupling is very important concerning thermoacoustic engine drives the vascular refrigerator even load.This is because the greatest differences of thermoacoustic engine and vascular refrigerator frequency of okperation causes.The common frequency of okperation of vascular refrigerator is relatively low, and the thermal acoustic oscillation frequency is higher relatively, is generally tens to hundreds of hertz scope.When both are linked up, just must consider the matching problem between them like this.Based on both frequency characteristics, the target of coupling should be to make their frequency optimum traffic approaching relatively as far as possible.For thermo acoustic engine, its frequency of okperation will reduce as far as possible, so as with the work of vascular refrigerator coupling.And the conventional means of at present the thermoacoustic engine frequency of okperation being regulated is to change working medium type, change resonatron length and diameter etc., but these means are subjected to restriction in various degree in practice.In addition, there are some researches show,, then can cause the saltus step of engine operation frequency, make its frequency become higher and unstable if reduce the motor frequency by the mode that prolongs resonatron simply.
In sum, resonatron plays crucial effects in thermoacoustic engine, but the optimal design of resonatron is subjected to the restriction of all many-sides again.At first, only have the resonatron physical dimension an of the best under a certain operating mode, when the working state of motor changed, resonatron just can not be brought into play due effect; Secondly, the mechanism size of thermoacoustic engine is bigger at present, seriously restricted its practicalization, and the main body of thermoacoustic engine is exactly a resonatron; Once more, to the understanding of sound transmission characteristics, linear heat sound theory is unique effective design tool based at present, and Nonlinear thermal sound is theoretical also at the early-stage, and resonatron has stronger nonlinear effect, therefore can't be merely according to existing theoretical to resonatron realization optimized design.
Summary of the invention
The purpose of this invention is to provide a kind of multiple resonance tube thermo-acoustic engine.Sound field distributes near not only helping improving regenerator, reduces the loss of thermal acoustic regenerator viscous flow; But also can regulate the frequency of okperation of thermoacoustic engine.
Multiple resonance tube thermo-acoustic engine is at the resonatron that is provided with simultaneously on the thermoacoustic engine more than 2 or 2.
Described thermoacoustic engine is traveling wave thermoacoustic engine, standing wave thermoacoustic engine or row ripple standing wave hybrid type thermoacoustic engine.Described resonatron is equal diameter pipe, change diameter tube or the combination of the two.
The sound field that the present invention optimizes in the thermoacoustic engine distributes, and reduces the loss of thermal acoustic regenerator viscous flow, suppresses the nonlinear effect in the pipeline, improves the adaptive ability of motor, reaches the purpose that improves the hot merit conversion efficiency; In addition, the present invention is by the different resonatron structure of coupling, the frequency of okperation that can regulate thermoacoustic engine easily, the frequency match of the vascular refrigerator even load of optimization thermoacoustic engine and its driving.
Description of drawings
Fig. 1 double resonance pipe traveling wave thermoacoustic engine structural representation;
Fig. 2 double resonance pipe standing wave thermoacoustic engine structural representation;
Fig. 3 three resonatron tandem type thermoacoustic engine structural representations;
Fig. 4 double resonance pipe coaxial type thermoacoustic engine structural representation;
Fig. 5 resonatron physical dimension is to terminal pressure effect on amplitude schematic representation;
Fig. 6 resonatron physical dimension is to the schematic representation that influences of input sound merit;
Fig. 7 resonatron physical dimension is to the schematic representation that influences of inlet volume flow rate.
Embodiment
The resonatron of thermoacoustic engine is a straight tube with particular inside diameters normally, in order to realize 1/4 wavelength sound field condition, at the terminal standing air reservoir of putting of straight tube.Single resonance pipe traveling wave thermoacoustic engine has capable ripple loop and a resonance straight-path, and the resonatron end is provided with an air reservoir.This motor has the primary cooler, regenerator, heater, thermal buffer channel, feedback loop, acoustic capacitance, the direct current that connect successively and suppresses parts, and resonatron is drawn from threeway.Single resonance pipe standing wave thermoacoustic engine has high temperature chamber, hot end heat exchanger, folded, the cool end heat exchanger of heat sound plate that connects successively, resonatron is connected with cool end heat exchanger by the caliber transition tube, the end of resonatron also is provided with an air reservoir, resonatron partly or entirely can be conical pipe.
The present invention is directed to a kind of multi resonant vibration tube traveling wave thermoacoustic engine and provide detailed technical order and specific implementation process, describe and the multi resonant vibration tube structure on other pattern thermoacoustic engine is only provided schematic representation, their working principle is similar, repeats no more.In addition, the multi resonant vibration tube that the present invention proposes is regulated method and not only is confined to the situation that a motor is provided with two or three resonatrons simultaneously, motor can be provided with the resonatron more than three simultaneously in theory, distribute the frequency of okperation that reduces the loss of regenerator viscous flow and regulate thermoacoustic engine thereby optimize the regenerator sound field better.Only with motor two or three resonatrons being set here, is that example describes.Although on structural representation, do not mark, it is pointed out that to convenient each resonatron is regulated separately and tested, in the ingress of resonatron valve can be set.
As shown in Figure 1, the heat sound loop in the double resonance pipe traveling wave thermoacoustic engine is mainly suppressed parts 1, primary cooler 2, thermal acoustic regenerator 3, heater 4, thermal buffer channel 5, supplementary cooler and fluid director 6, feedback loop 7, acoustic capacitance 8, is linked in sequence and forms by direct current.Be provided with first resonatron 9 and second resonatron 10 simultaneously on heat sound loop, described heat sound loop is the place of hot acoustic energy conversion, and first resonatron 9 and second resonatron 10 are connected to threeway place of heat sound loop.Can change the impedance magnitude of resonatron branch road on the one hand by the volume that changes first resonatron 9 and second resonatron, 10 cavity volumes, thereby change the size and the phase place of the volume flow of the acoustic capacitance of flowing through, adjust near the pressure-volume flow phase place of regenerator and make it near traveling-wave phase, the sound field of optimizing regenerator distributes. First resonatron 9 and 10 actings in conjunction of second resonatron make to reach pressure and speed cophasing in the regenerator, realize efficient hot merit transfer process.In addition, can be simultaneously regulate the purpose that resonatron length and diameter reach the frequency of okperation of regulating thermoacoustic engine, optimize the coupling of the vascular refrigerator even load frequency of thermoacoustic engine and its driving from 10 liang of first resonatron 9 and second resonatrons.
As shown in Figure 2, mainly folded 12 by first resonatron 9, second resonatron 10, hot end heat exchanger 11, heat sound plate, the cool end heat exchanger 13 of double resonance pipe standing wave thermoacoustic engine, high temperature chamber 14 are formed.First resonatron 9 and second resonatron 10 are set on the standing wave thermoacoustic engine simultaneously, the folded sound field of living in of heat sound plate are optimized, and regulate the frequency of okperation of standing wave thermoacoustic engine.
As shown in Figure 3, three resonatron tandem type thermoacoustic engines have been realized the combination of standing wave and row wave sound field on the straight line type topological structure, and essence is row ripple standing wave hybrid type thermoacoustic engine.This tandem type thermoacoustic engine is mainly folded 12 by primary cooler 2, thermal acoustic regenerator 3, heater 4, first resonatron 9, hot end heat exchanger 11, heat sound plate, cool end heat exchanger 13, high temperature chamber 14 are formed, this pattern makes the structure of this type thermoacoustic engine obtain simplifying, and also is a kind of promising heat sound machinery.As shown in the figure, first resonatron 9, second resonatron 10 and the 3rd resonatron 15 are set simultaneously, realize sound field optimization, and regulate the frequency of okperation of tandem type thermoacoustic engine at tandem type thermoacoustic engine.
As shown in Figure 4, double resonance pipe coaxial type thermoacoustic engine mainly is made up of primary cooler 2, thermal acoustic regenerator 3, heater 4, supplementary cooler and fluid director 6, first resonatron 9, the coaxial type thermoacoustic engine is a capable ripple standing wave hybrid type thermoacoustic engine in essence, first resonatron 9 is set simultaneously on 2 positions of coaxial type thermoacoustic engine and 10, two resonatrons of second resonatron can have different physical dimensions.
For on mechanism multiple resonance tube thermo-acoustic engine being made explanations, we are research object with the resonatron, set up mathematics physics model, by finding the solution the acoustic transmission characteristic that obtains resonatron.Be the cavity that convenience of calculation is simplified to resonatron the elongated straight tube of one equal diameter and joins with it, in fact long straight tube can be other various non-isodiametric pipelines, and as the combination of Taper Pipe, different-diameter pipeline, cavity also can be cylindrical body, spheroid etc.We call resonatron to long straight tube, and cavity is called air reservoir.Adopting high pure nitrogen in calculating is working medium, and the maintenance working pressure is 2.27MPa, frequency of okperation 25.3Hz, and setting the incoming pressure amplitude is 5.0 * 10
4Pa.The diameter of resonatron is 29mm.The volume by changing terminal air reservoir and the length of resonatron are studied the transmission characteristic of resonatron.
Fig. 5 is that the gentle storage capacity of different resonatron length is down long-pending, terminal pressure oscillation amplitude change situation.Can see that under certain operating conditions, resonatron has tangible amplification to pressure amplitude, maximum pressure amplitude reaches 5.0 * 10
5Pa, the amplitude power gain reaches 10.Under particular end air reservoir volume, the terminal pressure amplitude changes with the variation of resonatron length, and the peak value of a terminal pressure amplitude is all arranged under each air reservoir volume.
Fig. 6 is under the different resonatron physical dimensions, the situation of change of input sound merit.As seen, the sound merit transmittability of resonatron changes on a large scale with its physical dimension among the figure, and its merit transmittability can reach multikilowatt under specific air reservoir volume and resonatron length, has very strong sound merit transmittability.If increase the resonatron diameter again, transmittability also can further strengthen.The air reservoir volume is big more, and the peak value of input sound merit is also just big more.
Fig. 7 is under the different resonatron physical dimensions, the situation of change of resonatron inlet volume flow rate.As seen, can make its inlet volume flow rate reach 4.5 * 10 among the figure by the length of regulating resonatron
-2m
3More than/the s.Usually, single resonance pipe traveling wave thermoacoustic engine is when the resonatron diameter is 100mm, and the inlet volume flow rate is 1.0 * 10
-2~1.0 * 10
-1m
3Between/the s, 4.5 * 10
-2m
3/ s be one with a suitable value of single resonance pipe thermoacoustic engine resonatron inlet flow rate.By increasing the diameter and the terminal air reservoir volume of resonatron, the room for promotion of resonatron inlet volume flow rate is also very big, can surpass 1.0 * 10
-1m
3/ s.
In sum, resonatron is the acoustic element with remarkable sound transmission characteristics, under specific physical dimension, it has the bearing capacity of certain pressure amplitude amplifying power, sound merit transmittability and inlet volume flow rate, illustrates that this structure of resonatron can transmit sound wave well.The more important thing is, this structure is coupled into thermo-acoustic engine system will produces considerable influence sound field in intrasystem, can make rational sound field distribution of realization or acoustic impedance distribution in the thermoacoustic engine, this theoretical foundation of the present invention just by the physical dimension of optimizing resonatron.