RU2351406C1 - Siren-dispersant - Google Patents

Abstract

FIELD: machine building.

SUBSTANCE: present invention pertains to devices for obtaining high quality dispersion systems and can be used in engine-building for preparing fuel-air mixtures in automobile, ship, aircraft and stationary internal combustion engines, as well as in medical, chemical, pharmaceutical, energy, metallurgical and other industries. The siren-dispersant has coaxially fitted cylindrical stator in form of a circular acoustic resonator and a rotor with propellers rotating inside it, in adjoining surfaces of which there are through-windows, equispaced on a circle: n - on the stator and n+1 or n-1 - on the rotor. The siren-dispersant also has an actuator for the rotor, an inlet manifold for the pumped dispersion medium, outlets for the dispersion system and atomisers for the dispersed phase. Used here is resonant processing of the dispersion system of the rotating acoustic wave with centrifugal and spray transmission of the dispersion medium and dispersed phase, respectively. The frequency of rotation of the resonant wave exceeds the frequency of rotation of the rotor by n+1 or n-1 times, and its direction of rotation is the same or opposite the direction of rotation of the rotor.

EFFECT: widening of functionality, simplification and reliability of the device.

16 dwg

Description

The invention relates to acoustics, and in particular to devices for creating powerful resonant acoustic vibrations in a flowing medium, and can be used in the engine industry for the preparation of a fuel-air mixture (FA) in automotive, marine, aircraft and stationary internal combustion engines (ICE), and also in the medical, chemical, pharmaceutical, perfumery, cosmetic, food, energy, metallurgical and other industries for the production of all kinds of high-quality dispersed systems.

Sirens are practically the only powerful sources of acoustic vibrations containing a hollow stator and rotor with a series of equally spaced identical holes on adjacent surfaces / Bergman L. Ultrasound and its use in science and technology. M .: Publishing house of foreign countries. l-ry, 1957, 726 pp. /.

The idea of combining a siren as the most powerful source of acoustic vibrations and the phenomenon of resonance as a method of accumulating vibrational energy is implemented in a dispersant, a device for the production of high-quality dispersed systems, on rotating resonant acoustic waves / Sviyazheninov E.D. Hydroacoustic siren. Patent for invention No. 2284229. Priority 04/28/04 /.

In this device, adopted as a prototype, to coordinate the perturbation frequencies and the natural frequencies of the oscillations of the resonator, a rotating wave is excited rather than a standing wave, but running in the circumferential direction, which is achieved by modifying the perforation of the siren rotor. The frequency of rotation of the wave is many times higher than the frequency of rotation of the rotor, and the direction of its rotation can be chosen both coinciding and opposite to the direction of rotation of the rotor. The resonant mode of operation provides optimal conditions for pumping mechanical energy into the oscillatory system to perform work on the preparation of high-quality dispersed systems. This is most relevant for liquid and gaseous media that are not “afraid” of increased vibrations, pressures and fatigue damage. A rotating resonant wave fits perfectly into the technical purpose of the device, as stagnant areas inherent to standing waves are eliminated, and the product flows through the flow. The prototype introduced a siren with a new type of perforation, which allows you to create a rotating acoustic wave both coinciding and opposite to the direction of rotation of the rotor, the rotational speed of which is many times higher than the rotor speed. Such a siren is surrounded by a ring resonator tuned to the frequency of rotation of the generated acoustic oscillation wave, in which the formation of a dispersed system occurs.

The application of acoustic vibration to the dispersion process significantly improves its quality. So, fuel assemblies for ICE, prepared by vibration, are saturated with oxygen at the molecular level.

The prototype defines an effective resonant mechanism for the preparation of a dispersed system, but does not include mechanisms for separate supply of a dispersed medium and a dispersed phase.

The objective of the present invention is to provide a mechanism for the separate supply of a dispersed medium and a dispersed phase while maintaining high functionality, simplicity and reliability of the device.

The problem is achieved in that the principles of centrifugal and injection feeding, respectively, of the dispersed medium and the dispersed phase are inscribed in the resonant prototype. It is carried out as follows.

The dispersed medium is supplied by introducing an impeller with an impeller, the blades of which are located between the windows, as a rotor. Now the rotor is not only the causative agent of the resonant wave, but also a means of pumping the dispersion medium, which makes up the bulk of the produced dispersed system. The dispersed phase is injected through the nozzles into the ring resonator at the points of high flow rates of the processed product.

The essence of the above is illustrated by drawings, where Figs. 1, 2 show a diagram of a resonant siren-dispersant, Fig. 3 show the natural forms of excited resonant oscillations, Fig. 4 show the corresponding natural frequencies, Figs. 5, 6 show amplitude-frequency and phase-frequency characteristics of forced oscillations, Fig. 7 is a diagram of the resonator excitation, Fig. 8 is a diagram of the effect of gas flows flowing from the rotor windows on the stator windows, and Fig. 9 are exact solutions of the frequency equation of the ring resonator as a function of relations of the internal radius to nar Figures 10-14 show diagrams of physical quantities of acoustic oscillations and gas flow processes occurring in a ring resonator, respectively; Figures 16 and 16 show nomograms of structural parameters of a siren: resonant frequencies of oscillations of a disperse system being processed, rotor speeds, external and internal the stator radii and the number of stator holes.

The proposed siren dispersant on rotating waves (1, 2) contains a coaxially mounted hollow cylindrical stator 1 in the form of an annular acoustic resonator and a rotor 2 with an impeller rotating inside it. In adjacent surfaces of the stator and rotor, through holes are evenly spaced around the circumference: n - on the stator and n + 1 or n-1 - on the rotor. The number n is included in the multiplicity of the increase in the frequency of rotation of the acoustic wave relative to the frequency of rotation of the rotor, therefore, it must be large to achieve high-frequency vibrations. The signs + and - control the direction of rotation of the vibrational wave relative to the direction of rotation of the rotor: associated or counter, respectively. The rotor rotates evenly by the drive 3, which can be selected as the most common low-speed electric motor. When the rotor rotates, the dispersed medium is pumped through the input manifold 4. After resonant processing, the dispersed system is removed through the output nozzles 5 located tangentially on the outer radius of the stator and oriented in the direction of the traveling wave, along or against the rotation of the rotor. In the practical application of the dispersant for the preparation of fuel assemblies in the internal combustion engine, the number of nozzles can be arbitrary and large enough to provide distributed injection of the dispersed system into the cylinders. The dispersed phase is injected into the ring resonator 1 through nozzles 6. Under the influence of high-frequency vibration, the dispersed medium is mixed with the dispersed phase. At the same time, flowing motion of the forming disperse system is carried out.

The main meaning of the invention is to combine a radial siren as the most powerful source of acoustic vibrations and the phenomenon of resonance as a method of accumulating vibrational energy. It is compositionally rational to surround the siren with a circular cylindrical resonator. However, the traditional siren generates waves standing in the circumferential direction — axisymmetric and multinodular vibrations, and the thickness of the resonator having the corresponding natural frequency is unrealistically large. To match the frequency of the siren perturbation and the natural frequencies of the oscillations of the resonator, it is necessary to excite not a standing, but a traveling two-node wave in the circumferential direction. This is most functional for mixing and grinding particles of media to obtain the desired disperse system, because stagnant treatment zones inherent to standing waves are eliminated, and flowing movement of the product is carried out. To excite a traveling rotating wave, a special type of rotor perforation is proposed. As a result, a two-node asymmetric eigenoscillation wave with the lowest eigenfrequencies is easily excited in the resonator in the circumferential direction. This wave is traveling, in contrast to the standing wave generated by the traditional siren. The speed of its rotation is many times higher than the speed of rotation of the rotor. Moreover, by choosing the perforation of the rotor, the direction of rotation of the wave can easily be reversed with the same rotating rotor.

The three main results obtained from this approach are as follows.

1. The proposed siren, even without a resonator, in itself, gives a multiple increase in the frequency of rotation of the acoustic wave relative to the frequency of rotation of the rotor.

2. A new type of perforation opens up the possibility of using resonance with a siren as a pathogen.

3. The device allows one to obtain counterpropagating resonant traveling waves on one rotating shaft of the rotor, which is especially important for mixing and grinding liquid or gaseous multicomponent media.

So, the vibrations of the gaseous mixture are carried out in an annular cylindrical cavity - a stator. Axisymmetric natural vibrations of a compressible gas in an annular cavity (Fig. 3, dashed line), excited by traditional sirens with the same rotor and stator perforations, have natural frequencies that are infinitely increasing with decreasing thickness (Fig. 4, dashed line, where ρ is the internal ratio radius of the ring acoustic resonator to the outer one, 0 <ρ <1, α = α (ρ) is the root of the corresponding frequency equation), which would require an excessive increase in the rotor speed and a decrease in the perforation step (i.e., increase e the number of holes in the adjacent surfaces of the rotor and stator) to achieve the resonant frequency of the excitation and increase the thickness of the resonator to reduce the frequency of the fundamental tone of the axisymmetric oscillations. In this regard, it is advisable to create a resonant traveling two-node wave in the stator / Sviyazheninov E.D. Spectral methods for solving problems of oscillations of dissipative mechanical and electrodynamic systems with distributed parameters / dis ... doc. tech. Sciences, St. Petersburg, 1994, 432 pp. /. Two-node in the tangential direction, the natural form of oscillation in the annular cylindrical region (Fig. 3, solid line) has the lowest natural oscillation frequencies of all existing (Fig. 4, solid line), which opens the way to the use of resonance in a circular annular stator of small thickness with available low rotor speeds and not too small perforation step. When resonance is implemented, it is not necessary to pump the medium to be processed into the resonator under high pressure to create sufficient powerful excitation pulses. Even with a weak inlet pressure on the resonator, intense acoustic vibrations will occur in it due to in-phase pumping and accumulation of vibrational mechanical energy in the medium. The main (lowest) resonance of the two-node oscillation mode was selected, which has the lowest frequency and provides the greatest amplification of oscillations, which follows from the amplitude-frequency characteristic for oscillations single-period along the circumference (Fig. 6). On the phase-frequency characteristic (Fig. 7), it is seen how the phase conditions of the optimal pumping of energy into the oscillatory system are satisfied at the resonance. Resonance is first of all a phase coincidence of periodic actions on the system and its responses, which is realized when the frequencies of the driving loads coincide with the natural frequencies of vibrations.

To excite a non-axisymmetric traveling resonant wave, an unconventional siren scheme is proposed, namely, a new type of its perforation. As before, the holes on the rotor and stator are evenly distributed in the circumferential direction, but the number of rotor holes is one more (to create a direct or incident traveling wave that coincides with the direction of rotation of the rotor) or one less (to get the opposite or counter waves opposite to the direction of rotation of the rotor) than on the stator (Fig.7).

Device operation

When the rotor rotates uniformly with an angular velocity ω _p , on the surface of which there are n + 1 or n-1 radial gas flows uniformly spaced from each other, each of the n slots on the stator surface alternately experiences pressure pulsation (Fig. 7).

(при прямой волне) или на

(при обратной) толчок давления произойдет на соседнем отверстии резонатора - по ходу вращения ротора или против. При повороте ротора на угол nδ=2π/(n+1) или на nδ=2π/(n-1) импульс давления ровно один раз обежит окружность в прямом или обратном направлении. Таким образом, угловая скорость вращения импульса давления на внутреннюю поверхность резонатора составляет ω=(n+1)ω_p - в прямом и ω=(n-1)ω_p - в обратном направлении.Let at the initial moment one of the slots of the rotor and stator coincide (Fig. 8). The pressure pulse from the gas flowing out of the rotor is transmitted to the stator resonator. When the rotor rotates through an angle

(in a direct wave) or on

(at the reverse) a pressure shock will occur at the neighboring hole of the resonator - in the direction of rotation of the rotor or against. When the rotor is rotated through an angle nδ = 2π / (n + 1) or nδ = 2π / (n-1), a pressure pulse will run around the circle exactly once in the forward or reverse direction. Thus, the angular velocity of rotation of the pressure pulse on the inner surface of the resonator is ω = (n + 1) ω _p - in the forward and ω = (n-1) ω _p - in the opposite direction.

ротора 2 (фиг.1, 2) связана с частотой акустических колебаний статора 1 (фиг.1, 2)

аналогичным образом:We proceed from the angular velocity of the rotor and the circular vibration frequency, respectively, to the rotation and vibration frequencies. We get that speed

rotor 2 (figure 1, 2) is associated with the frequency of acoustic vibrations of the stator 1 (figure 1, 2)

the same way:

f = ν / (n + 1) - for a siren on a direct traveling wave and

f = ν / (n-1) - for a siren on a reverse traveling wave,

where n is the number of holes of the stator 1.

For resonant excitation, the frequency ν should be close to one of the eigenfrequencies, in this case, the lowest.

From the rotor side, a rapidly rotating excess pressure pulse acts on the surface of the stator resonator. The harmonic composition of a single pulse is a series of circumferential harmonics, of which the two-node (single-period) in the tangential direction has the largest amplitude. It is this fundamental harmonic that serves to excite the resonant traveling wave of oscillations - a single-period (two-node) in the tangential direction of the sine wave. The amplitude-frequency characteristic of the two-node oscillations of a viscous heat-conducting compressible liquid medium in the resonator (Fig.6) shows that the first (main) resonance provides the greatest amplification of the oscillations. For an annular cylindrical resonator 1 (figure 1, 2) of the outer radius R with the ratio of the inner radius to the outer ρ, the frequency of the fundamental tone is equal to:

where c is the speed of sound in the fluid (gas) filling the rotor, α = α (ρ) is the first (lowest) root of the transcendental frequency equation:

where J ₁ (α), N ₁ (α) are the first-order Bessel and Neumann functions, respectively.

. Фиг.4 показывает также, что собственные частоты осесимметричных колебаний неограниченно увеличиваются с ростом ρ (штриховая линия), тогда как частоты двухузловых - монотонно убывают с ростом ρ (и асимптотически приближаясь к α=1), что и требуется для согласования сирены (возбудителя) с акустической камерой (резонатором).The function α = α (ρ) from formula (1) is represented by a graph (Fig. 4, solid line) for all real specific ratios of the inner radius of the ring resonator to the outer 0 <ρ <1. In Fig. 4, the first subscript i of the function α _ik (ρ) means that this is the ith root of equation (2) in order of increase, and the second subscript k shows the number of pairs of nodes of the excited waveform in the tangential direction. So, i = 1 corresponds to the first (lower) root of the equation, k = 1 corresponds to the two-node (with one nodal diameter) eigenoscillation implemented in the device, while k = 0 is axisymmetric, i.e. independent of the angular coordinate. Both of these forms are depicted in figure 3. Figure 4 shows that when ρ = 0 we have a particular case of a continuous resonator, which is indicated by the superscripts (c) for the corresponding values of the quantities

. Figure 4 also shows that the eigenfrequencies of axisymmetric oscillations increase unlimitedly with increasing ρ (dashed line), while the frequencies of two-node ones monotonically decrease with increasing ρ (and asymptotically approaching α = 1), which is required for matching the siren (pathogen) with an acoustic camera (resonator).

The exact solutions of the frequency equation (2) of the ring resonator α _ik (ρ) are constructed as a function of the ratio of the inner radius to the outer ρ (Fig. 9), which are necessary for determining the natural vibration frequencies.

So, providing the condition for resonance in the stator 1 (Fig. 1, 2), we obtain the simultaneous flow of two processes in it: acoustic vibrations (Fig. 10-12) and flow (Fig. 13, 14). The diagrams of vibrational pressures and accelerations are shown in Figs. 10-12, and the flow velocities are shown in Figs. 13, 14. The diagrams of the currents contain regions of increased velocities directed towards the outlet pipes. In these zones, nozzles 6 are located (FIGS. 1, 2) for injecting the dispersed phase into the ring resonator 1. The application of high-frequency vibration to the flow is the mechanism for producing a high-quality dispersed system.

To carry out design analysis and calculation of structural parameters according to the above calculation formulas, nomograms of the dispersant siren are constructed (Fig. 15, 16). It is most easy to select its main structural parameters from them: resonant frequencies of oscillations of the processed disperse system, rotor rotational frequencies, outer and inner radii of the stator - the resonant sounding chamber, and the number of stator holes. For example, we set the resonant vibrational frequency ν and the ratio of the internal and external radii of the resonator ρ. Then, from the curve ν (R), we determine the corresponding external radius R, and from the family of lines ν (f) we select a combination of perforation n and the number of rotor revolutions f. It can be seen from the nomograms that for real-life practical systems, siren parameters are easily implemented. So, as a drive, it is quite possible to use the most common low-speed asynchronous electric motors.

An example of calculating the parameters of a dispersant siren

Let the processed medium be a fuel assembly, and it is required to excite its processing frequency ν = 500 Hz in a ring resonator with a ratio of internal radius to external ρ = 0.5.

Then, along the curve ν (R) of Fig. 15, 16 we find the necessary external radius of the resonator chamber: R = 15 cm. According to the family of lines ν (f) or according to the formulas:

f = ν / (n + 1)

- for a siren on a direct rotating wave and

f = ν / (n-l)

for a siren on a reverse rotating wave, we obtain possible combinations of the number of stator holes n and the rotor speed f.

It can be seen from the presented table that for real practically important cases of a sufficiently large number of stator openings, the rotor rotation frequency, which provides resonant excitation of a rotating wave, either direct or counter, is the same.

Thus, due to an increase in the frequency of rotation of the acoustic wave ν by n ± 1 times relative to the frequency of rotation of the rotor f and the excitation of low-frequency two-node eigenmodes of oscillation of the ring resonator, resonant modes in the stator are easily achieved at the smallest frequencies of rotation of the rotor f, which gives a very simple reliable effective device for high quality dispersed systems.

References

1. Bergman L. Ultrasound and its application in science and technology. M .: Publishing house of foreign countries. L-Ry, 1957, 726 p.

2. Sviyazheninov E.D. Hydroacoustic siren. Patent for invention No. 2284229. Priority 04/28/04 (prototype).

3. Sviyazheninov E. D. Spectral methods for solving problems of oscillations of dissipative mechanical and electrodynamic systems with distributed parameters / dis ... doc. tech. Sciences, St. Petersburg, 1994, 432 p.

Claims (1)

Dispersant siren, including a coaxially mounted cylindrical stator in the form of a ring acoustic resonator and a rotor, in adjacent surfaces of which through holes are evenly spaced around the circumference - windows, the number of which on the stator n and rotor n ± 1 differs by one for the implementation of the resonance line (associated , relative to the direction of rotation of the rotor) of the rotating acoustic wave - in the case of n + 1 or reverse (oncoming) - for n-1, the drive for uniform rotation of the rotor and the tangential output nozzles n and a stator in the direction of the corresponding rotating waves to output the disperse system, characterized in that for pumping the dispersed medium the siren rotor is equipped with an impeller, the blades of which are located between the windows, so that the number of blades is equal to the number of windows, and nozzles are made for the dispersed phase injection on the end surface of the stator , while the device parameters are selected from the expressions:
f = ν / (n + 1) - for a direct wave dispersant,
f = ν / (n-1) - for a backward-wave dispersant,

,
where ν is the frequency of the generated acoustic vibrations in the resonator, which coincides with its lowest natural frequency;
f is the rotor speed;
n is the number of stator holes;
R is the outer radius of the resonator;
C is the speed of sound in a dispersed medium entering the resonator;
α = α (ρ) is the lowest root of the transcendental equation of frequencies:

,
where J ₁ , N ₁ - respectively, the Bessel and Neumann functions of the first order;
ρ is the given ratio of the inner radius of the ring resonator to the outer R.

Images