RU2359763C1 - Hydraulic cavitating device - Google Patents

Abstract

FIELD: machine building.

SUBSTANCE: invention relates to devices for creating a stream of hydrodynamic cavitation in a flowing liquid medium. The device can be used for making emulsions, suspensions, dispersing of different materials, disinfection of liquids and liquid foods. Hydraulic cavitating device includes a case which has the following things placed sequentially: input element, resonating cavity, intermediate branch pipe, divergent Borda mouthpiece. The input element is made in the form of a round cylindrical Venturi tube, a round resonating cavity with a diametre and length 3 times the diametre of the input element, intermediate branch pipe, which is analogous to the input element, a second resonating chamber on the device, analogous to the first, and a suddenly expanding branch pipe with a diametre 3 times the diametre of the input element and a length 5 times the diametre of the input element.

EFFECT: increase in the density of cavitation in a continuous flow of liquid or suspension, extension of the process of "collapse" of cavitation bubbles in the work material, simplicity of the device and repair of the flow tube.

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Description

The invention relates to devices for creating flow hydrodynamic cavitation in a flowing liquid medium, mixing in liquid-liquid, liquid-solid systems and can be used in the chemical, oil, pharmaceutical, engineering, mining industries, as well as for cooking organic fertilizers and liquid feed in agriculture. In the power system of the claimed device can be used for the preparation of high-quality water-coal suspensions, as well as various compositions of water-coal-peat, water-coal-fuel oil, water-oil spills-coal, etc.

Known rotary dispersing apparatus (options), Russian patent 2208472, consisting of a rotor mounted on a rotating shaft, having blades inside and a rim with slots made at an angle to the diameter and directed against the rotation of the rotor, and also mounted on the housing between the rotor blades and the rotor the shell is coaxial to the rotor of the stator, having a diametrical section of a trapezoidal shape, with slots made at an angle to the diameter and directed along the rotation of the rotor.

The disadvantages of the known device are:

- placement in the Central part of the rotor only blades that discard the processed suspension in the stator channel;

- the shape of the stator holes does not contribute to the formation of intense hydrodynamic cavitation;

- the shape of the holes of the outer shell of the rotor-slot also does not contribute to the formation of intensive hydrodynamic cavitation, such as, for example, circular cylindrical nozzles Borda or Venturi.

Known rotary-pulsation apparatus for obtaining predominant liquid-liquid systems, Russian patent No. 2299091, comprising a working chamber with a device for inputting the contacting phases and an outlet pipe for emulsion concentrically mounted in it with a rotor and a stator with radial channels.

The disadvantages of the known device are:

- intermittent movement of the emulsion along the rotor-stator channels (coincidence of the channels and their overlap), which cause pulsation oscillations, and not stable hydrodynamic cavitation in the liquid;

- the shape of the holes does not contribute to the formation of zones with reduced pressure, in which cavitation bubbles arise.

A device is known, cavitation thermogenerator, Russian patent No. 2305819, containing a cyclone with inlet and outlet openings, a glass-like body, an outlet nozzle, each of which is rigidly and hermetically connected with its open cavity to one of the opposite sides of the cyclone coaxially to each other, a brake element, a tank with the liquid medium into which the thermogenerator is immersed, the outlet of the cyclone in a direction tangential to the housing chamber.

The disadvantages of the known device are:

- the use of vortex cavitation, which occurs in a swirling fluid flow in the center of rotation. But there is no zone with increased pressure in which cavitation bubbles could intensively “collapse”, disappear;

- the main producer of thermal energy is the internal friction of the liquid and the friction of the swirling flow on the peripheral zone of the device.

A device is known, a hydrodynamic dispersant-emitter, Russian patent No. 2306971, comprising a housing with an internal cavity, with lateral inlet pipelines and a liquid discharge pipe, an axially movable adjusting needle mounted in a housing with a variable cross-sectional length, and a sensitive element of the movement control mechanism a needle mounted in a hole made in the housing in the region of the tapering part of the inner cavity.

The disadvantages of the known device are:

- air bubbles introduced into the nozzle of the device will not “slam”, but will pulsate in areas of high pressure and leave the liquid after passing the outlet;

- the mechanism for controlling the amount of flow (MP) is located in the zone of intensive disappearance of cavitation bubbles, in the zone of high pressure formed by the collision of the jets of nozzles, which will entail its intensive destruction.

A device, a hydrodynamic cavitation reactor, Russian patent No. 2305589, including a confuser, a flow chamber containing a section made in the form of a diffuser, with axial and wall cavitators installed in it, is known.

The disadvantages of the known device are:

- insufficiently clear explanation of the operation of cavitators 3, 4, 5; indeed, between the wall of the body and cavitators 3, 4, cavitation does not occur due to compression of the fluid flow, but it occurs in the whirlpool zones behind the cavitators;

- large internal holes in the cavitators 4, 5, allow a large amount of liquid or suspension to pass without cavitation effects on its flow.

Known dispersant, patent of Russia No. 2293599, containing a housing with a channel for moving the liquid food mixture, devices that cause cavitation when they flow around the liquid food mixture, at least one partition is located in the channel for moving the liquid food mixture to separate the flow of the liquid food mixture and the surface of the septum in contact with the flow of the liquid food mixture, there are transverse corrugations or alternating protrusions and recesses.

A disadvantage of the known device is that the channel profiles formed by the partitions do not intensively contribute to the formation of cavitation bubbles.

A device, nozzle, patent of Russia No. 2190483 is known, comprising a housing with a diffuser outlet nozzle, an insert with a central confuser channel mounted in the inlet portion of the housing with the possibility of axial movement and with it the formation of an annular resonant cavity covering the outlet portion of the housing with an annular gap, box equipped with a supply pipe with a regulator of its flow area and V-shaped nozzle nozzles, wound one shelf in the holes made in the housing in the area of its diffuse nozzle and installed detecting adjacently to another shelf inner surface diffusion nozzle.

Positive in the known device is the presence of an adjustable annular resonant cavity.

The disadvantages of the known device are the use of a confuser channel and a diffuser nozzle, which do not contribute to the formation of hydraulic cavitation in the device.

The known method of hydraulic sound generation, Russian patent No. 2183511, including increasing the speed of the jet to critical and its braking with the formation of a closed cavitation area.

The disadvantages of this method are:

- the use of a confuser junction in the nozzle that impedes the operation of the cylindrical part as a round-cylindrical nozzle Borda or Venturi;

- insufficient deepening of the hole in the reflector reduces the pressure in the reflector, and therefore reduces the energy of the "collapse" of cavitation bubbles.

A device (prototype), hydrocavitation device, patent of Russia No. 2236915, comprising a housing and an input element made in the housing, designed to connect a high pressure liquid source to the source, an input cylindrical channel, at least two chambers made with an inner cylindrical surface, and a diffuser are known which are arranged coaxially and sequentially along the fluid are interconnected, at least one intermediate cylindrical channel located between the chambers is introduced, length k thinner than the length of the input cylindrical channel, the first chamber and the chamber following it are communicated with an intermediate cylindrical channel with a diameter dpr and a length lpr of which are satisfied satisfying the relations

1.0 <(d / do) <2 and 0.7 <(lpr / do) <2, for the first camera,

where do is the diameter of the input cylindrical channel;

d is the diameter of the chamber (first, second or third);

l is the length of the chamber (first, second or third).

The diameter and length of each subsequent chamber are made satisfying ratios

1.6 <(d / dpr) <2 and 0.6 <(l / dpr) <0.8,

where dpr - the diameter of the intermediate cylindrical channel in front of the desired camera;

l is the length of the chamber.

The disadvantages of the known device is:

- confuser entrance to the first cylindrical channel, preventing the compression of the jet and the formation of an annular whirlpool zone, as, for example, in the circular cylinder nozzle Venturi (RR Chugaev. Hydraulics. "Energy", Leningrad branch, 1971, p. 307);

- insufficient length of the chamber, which should work like a suddenly expanding nozzle (Bord's formula, ibid., p. 136);

- insufficient length of the intermediate cylindrical channel;

- diffuser completion of the device, which at an opening angle of 30 ° does not contribute to the formation of zones that generate navigation bubbles (ibid., p. 139, Fig. - 4-30b).

Disclosure of invention

The technical problem to which the invention is directed is to create a device in which a liquid or suspension, passing through the device, is subsequently exposed to vortex zones in circular cylindrical openings, like Venturi or Bord nozzles, in annular resonant cavities and at the exit of the device - suddenly expanding nozzles, and thereby intensely saturated with cavitation bubbles.

The technical result that can be obtained by carrying out the invention:

- a sharp increase in the density of cavitation in a continuous flow, an increase in the formation of cavitation bubbles and the provision of conditions for their "collapse" to complete the complete thermodynamic life cycle of cavitation bubbles. Simplicity of the device and repair of worn working bodies.

This solves two important tasks, namely:

- using the device, the liquid, emulsion, suspension, etc., passing sequentially through the venturi round cylindrical nozzles (1, 3, 5) and ring resonant cavities (2, 4), as well as the suddenly expanding zone 7, are intensively saturated with cavitation bubbles ;

- due to the fact that in the inventive device there are no zones with high pressure, it means that all collapses accompanying the “collapse” of cavitation bubbles will occur behind the zone of sudden expansion and thereby protect it from cavitation destruction. To slow down abrasive wear, the flow part of the device is made by a team of rings of different sizes made of high-strength cast irons (ICH-28N, ICH-30, etc.), which simplifies the repair of the device.

To solve the problem with achieving a technical result in the inventive hydraulic device containing the housing and placed in it: an input element made in the form of a round-cylinder Venturi nozzle, followed by an annular resonating cavity (or several annular resonant cavities) made with an inner cylindrical surface and located coaxially to the input element, sequentially along the liquid, an intermediate cylindrical pipe is located behind the resonating cavity in in the form of a round-cylinder Venturi nozzle (or several nozzles) and the device ends with a suddenly expanding nozzle of Borda.

The choice of design solutions for all elements of a hydraulic cavitation device is not accidental:

- a liquid stream, heading into the hole of the input element and bypassing the edge, is compressed to a certain circular cross section in the center of the nozzle due to the inertia forces of the liquid particles entering the nozzle. Then, as you move along the nozzle, the jet expands and fills the entire nozzle.

At the same time, an annular whirlpool zone is formed between the compressed section of the transit liquid jet and the surface of the nozzle. Such a whirlpool fluid motion in these zones is pronounced unsteady.

The section surface is not clearly expressed; it is unsteady and unstable; periodically, this surface receives local curvatures that progress and turn into separate whirlpools; these whirlpools fall into the transit stream and are carried away by it; the interface is restored again so that in subsequent moments it again disintegrates and curls into new whirlpools, etc. The constant appearance in the region of the interface of new whirlpools falling into the transit stream contributes to an increase in the pulsation of velocities and pressures in it.

The whirlpool zone itself, as well as the transit stream, within this region, is characterized by the presence of vacuum. The maximum vacuum is obtained in the section where the jet has the greatest compression and where the velocities in the transit stream are greatest. This area of the nozzle is the first zone of formation of cavitation bubbles.

Passing from the input element to the annular resonating cavity, the liquid is subjected to an even more powerful vacuum-pulsation-vibrational effect.

The impact power is due to the fact that due to the sharp expansion between the transit jet and the inner cylindrical surface of the resonating cavity, a more voluminous annular whirlpool zone is formed. More powerful whirlpools, constantly separating from the annular zone, pass into a transit stream and destroy the interface.

The ring resonating cavity is the second, more powerful source of accumulation of cavitation bubbles in the transit stream.

Passing sequentially through circular cylindrical nozzles and ring resonant cavities, the liquid reaches the last element of the hydraulic cavitation device - the suddenly expanding Bord nozzle, in which a whirlpool zone is also formed, which contributes to the formation of cavitation bubbles and their saturation with the transit liquid stream.

With the passage of the side-flow transition fluid — the suddenly expanding Bord nozzle — the first stage in the life of cavitation bubbles, their formation and accumulation in the fluid, is completed.

In order to force cavitation bubbles to “slam” and take advantage of this, it is necessary to place a sufficiently large area from the liquid or suspension being treated under increased pressure on the transit jet path.

According to Rayleigh (L. Bergman, “Ultrasound and its Application in Science and Technology” - 1957, p. 505), at a distance r = 1,587R from the center of the bubble in the liquid at P0 = 1 atm, a pressure P = 1260 atm occurs, and at the same pressure with a ratio of Ro / R = 20, we obtain P = 10300 atm,

where R is the radius of the cavitation bubble;

Ro is the initial radius of the cavitation bubble

Therefore, all hydraulic shock waves and temperature spikes resulting from the disappearance, “collapse” of cavitation bubbles should not occur on the surfaces of the apparatuses, but in the layer of the processed liquid or suspension.

Conditions under which a cylindrical pipe (short) pipe works as a venturi

Not every nozzle attached to the hole works like Venturi nozzles. In order for the transit jet to expand and touch the inner walls of the nozzle with the formation of a stable whirlpool zone, the length of the nozzle should be in the range (3.5-4.0) do≤ln≤ (6-7) do, where d is the nozzle diameter , l - l nozzle length (R.R. Chugaev “Hydraulics”, 1971, p. 310).

This condition applies to the inlet and intermediate cylindrical nozzles.

The conditions under which ring resonant cavities operate.

dk = 3d,

lk = 3d,

where dк is the diameter of the resonating chamber;

lк1,2 is the length of the resonating chamber;

do - diameter of the pipe of the input or intermediate elements.

Flash Expansion Chamber Length

l.v. = 5do.

Practical experiments showed that a hydraulic cavitation device manufactured taking into account hydraulic laws, as well as the selection of the lengths of the resonating chambers and the camera of sudden expansion, made it possible to solve the technical problem with the achievement of the specified technical result.

Figure 1 shows a longitudinal section of the claimed device, including:

- 1 - input element (round-cylinder venturi nozzles);

- 3, 5 - intermediate cylindrical nozzles;

- 2, 4 - ring resonant cavity;

- 6 - suddenly expanding nozzles of the Board;

- 7 - housing hydraulic cavitation device;

- a - edge of the input element;

- A, B, D - annular whirlpool zones arising in the round-cylinder nozzles of Venturi;

- B, D - annular whirlpool zones arising in the resonant ring cavities;

- E - annular whirlpool zones arising in the suddenly expanding round-cylindrical nozzle of the Board;

Figure 2 shows the same as figure 1, with only one resonant cavity.

Works hydraulic cavitation device (1, 2) as follows:

- a liquid or suspension under pressure is fed into the opening of the inlet element 1, made of durable steel or cast iron in the form of a round-cylinder Venturi nozzle. Due to the inertia forces of the particles of the liquid or suspension entering the nozzles, the liquid or suspension is compressed to a certain circular cross section in the center of the nozzle, and then gradually expands and fills the nozzles. In this case, an annular whirlpool zone A is formed between the compressed section of the transit jet and the inner surface of the nozzle A. The whirlpool zone itself, just like the transit jet, is characterized by the presence of vacuum within this region. This zone of the nozzle is the first zone of formation of cavitation bubbles.

Moving from the input element to the annular resonant cavity 2, the liquid or suspension is subjected to an even more powerful vacuum-pulsating oscillatory action due to the formation of a more voluminous annular whirlpool zone B.

After the first annular resonant cavity, the liquid or suspension passes through an intermediate pipe 3 with a whirlpool zone B, a second resonant cavity 4 with a whirlpool zone G.

Then the liquid or suspension again passes through the intermediate pipe 5 with a whirlpool zone D, and then falls into a suddenly expanding nozzle Borda 6 with an annular whirlpool zone E.

After passing through all the parts and zones of the hydraulic cavitation device, the transit stream of liquid or suspension is saturated sequentially in 6 zones with cavitation bubbles, leaves the device, heading into the thickness of the treated liquid or suspension under overpressure, to complete the second phase of the life of cavitation bubbles - their intense “collapse” ".

Example No. 1

Specular material, particle size - 5 ÷ 10 mm.

The purpose of the tests is grinding, determination of the granulometric composition of specularite after cavitation dispersion, determination of the possibility of using the ground mass as a filler of weather-resistant paint.

Sample Number one 2 Dispersion time, min 10 twenty

Sample Number 1 (10 min.) 2 (20 min.) Fraction <5 μm,% 35.7 44.0 Fraction <10 μm,% 40.6 47.0 Fraction <20 μm,% 63,4 78.7 Fraction <30 μm,% 85.5 91.8 Fraction <40 μm,% one hundred one hundred The average particle size, microns 14.1 10.9

The test results show that with an increase in the time of cavitation dispersion from 10 to 20 min, partial grinding of particles (≈7%) occurs mainly with a decrease in the thickness of the flakes, which confirms a change in the medial particle size from 14 to 11 μm.

The shape of the flakes is round, flaky, practically does not change when dispersed.

Suitable for use as a filler in weatherproof dyes.

Example No. 2

Material - coal - 60%, water - 40%, particle size of coal - (0 ÷ 10 mm).

The purpose of the tests is to prepare a water-coal suspension. Processing time - 8 minutes.

Coal particle size:

<73 μm - 84.4%,

<100 μm - 92.0%,

<150 μm - 98.7%,

<200 μm - 100.0%.

The resulting water-coal suspension is stable, does not exfoliate for more than 2 years.

Example No. 3

Material - wheat grain - 50%, water - 50%.

The purpose of the tests is the implementation of "wet grinding" of grain with the preparation of liquid, disinfected feed for pigs.

Processing time - 12 minutes.

A homogeneous light brown suspension with a pleasant bread smell was obtained, which gelled during cooling, did not sour for 3 days in a pig farm.

The most successfully claimed hydraulic cavitation device can be used for disinfection of liquids and liquid food products, preparation of liquid disinfected feed mixtures, grinding of rocks, preparation of coal-water fuel, etc.

The device is easy to manufacture and can be implemented by any engineering company. The manufacture of parts with the same size will make it easy to replace parts that have undergone abrasion during operation.

Bibliography

1. Patent of Russia No. 2208472 7B01F 7/28.

2. Russian Patent No. 2305819 F24J 3/00.

3. Patent of Russia No. 2306971 B01F 5/00.

4. Patent of Russia No. 2305589 B01F 5/00.

5. Patent of Russia No. 2190483 B05B 7/32.

6. Patent of Russia No. 2183511 B06B 1/20.

7. Patent of Russia No. 2236915 B08B 3/02, B01F 5/00.

8. T. M. Bashta "Engineering Hydraulics", M., Engineering, 1971, pp. 44 ... 49, 118, 349, 375, 379 ... 381, 509 ... 512.

9. L.I. Bogomolov, K.A. Mikhailov “Hydraulics” M., Stroyizdat, 1972, p. 87 ... 92, 142 ... 150, 398 ... 405.

10. PP Chugaev, “Hydraulics”, M., Energy, Leningrad Branch, 1971, pp. 14 ... 17, 28 ... 33, 64 ... 74, 85 ... 88, 135 ... 140, 163 ... 167, 277 ... 286 , 307 ... 314.

11. I. Pirsol "Cavitation" per. from English Ph.D. Yu.F. Zhuravleva M., Mir, 1975, pp. 9 ... 20, 22 ... 25, 36 ... 50, 69 ... 89.

12. M.A. Lavrentiev, B.V. Shabat “Problems of hydrodynamics and their mathematical models” M. Nauka, 1973, pp. 350, 352 ... 357.

13. V.V. Mayer, “Cumulative effect in simple experiments,” M. 1989, pp. 44, 47, 92 ... 97, 175 ... 177.

Claims (1)

A hydraulic cavitation device comprising a housing and an input element sequentially placed in it, a resonating cavity, an intermediate pipe, a resonating cavity, an intermediate pipe, a suddenly expanding Bord nozzle, characterized in that the input element is made in the form of a circular cylindrical Venturi nozzle, an annular resonating cavity with a diameter equal to 3 diameters of the input element and a length equal to 3 diameters of the input element, intermediate pipes made similar to the input element, the second a zoning chamber, similar to the first one in the device, and suddenly expanding nozzles with a diameter equal to 3 diameters of the input element and a length equal to 5 diameters of the input element.

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