JP2000167439A - Cavitation nozzle and cavitation generation system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To deaerate from a liquid and to decompose a material by cavitation. SOLUTION: The cavitation is generated around the jet stream nucleus by generating jet stream in a jetting vessel 1. Further, the generating quantity of the cavitation is increased by forming the cavitation flow into vortex flow. The liquid is stirred by the vortex flow to efficiently perform the deaeration of the gas in the liquid and the decomposition of the material. The cavitation is effectively generated by a cavitation generating condition of 8<=D/D0<=10 and L/D0<=8 when the effective diameter of a cavitation nozzle in a pressurized liquid supply passage is expressed by D0 and the effective diameter of a jetting hole is expressed by D.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cavitation nozzle and a cavitation generation system capable of degassing various gases in a liquid and reforming the liquid. More specifically, the present invention relates to a cavitation nozzle capable of degassing a gas dissolved in water and modifying a liquid in water such as a ikesu, a fish farm, and food processing, and a cavitation generation system incorporating the nozzle.

[0002]

2. Description of the Related Art Seawater or water from ikes, fish farming equipment and the like contains gases mainly composed of various components in the air. It contains various components in air that is a gas at normal temperature, such as oxygen, nitrogen, and carbon dioxide. Furthermore, it is known that harmful ammonia emitted by fish becomes a component such as nitrite (HNO ₂ ), nitrite, nitrate, etc., which is changed by the action of microorganisms and the like. Deep seawater is rich in mineral nutrients, phosphates and silicates necessary for plant growth. In the case of fresh water such as tap water, it contains chlorine and the like for disinfection.

Since these substances are generally harmful to organisms in water except for air components, it is desirable to remove them as much as possible or to convert them into stable salts which do not affect organisms. However, it is practically impossible to stabilize or selectively adsorb these harmful substances with chemicals by neutralization or the like with a fish culture apparatus having a limited capacity.

[0004] That is, if a small amount of a chemical for removal remains, it is concentrated in living organisms, leaving an adverse effect. Due to these problems, onshore aquaculture equipment is disposed of in a short time without pumping and recycling a large amount of seawater. For this reason, it consumes energy and causes polluting seawater in the near sea.

The present applicants have proposed a liquid quality reforming foam box in which cavitation accompanied by air bubbles is generated from a nozzle attached to a rectangular tank having a fixed ratio (Japanese Patent Application No. 10-10).
No. 1410). The proposed nozzle proposed a liquid quality reforming foam box having a function of disinfecting the water-blooming water in lakes and marshes, a Legionella bacterium in a natural or artificial environment, and degassing dissolved gases in a solution.

As a result of repeated experiments, it has been found that the proposed foam box for liquid quality modification has excellent degassing performance but cannot degas more than a certain amount. The presumed reason is presumed to be that the gas once degassed from the separated liquid is dissolved again in the liquid due to the substantially closed space of the liquid quality reforming foam box. Similarly, it is also presumed that the above-mentioned harmful components and nutrients for living organisms are once decomposed and then chemically recombined again.

On the other hand, a nozzle shape for efficiently generating cavitation in a liquid has also been proposed (Japanese Patent Publication No. 4-4).
3712). The proposed submerged jet nozzle has an orifice whose diameter gradually increases at an angle of 20 to 60 degrees. Above this angle, energy is lost due to entrainment of the surrounding liquid, and too small an energy loss is large. However, as far as the present inventor has conducted experiments, it has been found that cavitation can be effectively generated even in a range outside this range.

The cavitation generating nozzles proposed so far have functions of deaeration, elimination of harmful components, and decomposition of nutrients, but they are not very effective simply by spraying them directly into a liquid. It turned out that there was not.

[0009]

SUMMARY OF THE INVENTION The present invention has been made under the above-mentioned technical background, and achieves the following objects.

[0010] An object of the present invention is to modify components that are harmful to living organisms and nutrients necessary for the growth of living organisms, so as to detoxify the liquid and make it easier to absorb the living organisms. It is an object to provide a cavitation nozzle and a cavitation generation system.

Another object of the present invention is to provide a cavitation nozzle and a cavitation generation system capable of degassing a liquid for degassing a gas in the liquid.

[0012] Still other objects of the present invention will be more specifically described below through embodiments.

[0013]

The cavitation nozzle according to the present invention and the cavitation generating system provided with the cavitation nozzle employ the following means to solve the above-mentioned problems. The cavitation nozzle according to the present invention is a cavitation nozzle for jetting a jet into a liquid to generate cavitation, wherein the pressurized liquid supply path through which a liquid supplied from a high-pressure liquid supply source passes is provided. The pressurized liquid supply path includes a jet hole which is in rapid communication with the pressure liquid supply path and has a step.

When the effective diameter of the pressurized liquid supply passage is represented by D0, the effective diameter of the injection hole is represented by D, and the effective length of the injection hole is represented by L, the cavitation generation condition is 2 ≦ D / When D0 ≦ 12 and L / D0 ≧ 4, it is possible to effectively degas gases such as oxygen, chlorine, ammonia, and carbon dioxide in the liquid and decompose various salts.

In the cavitation nozzle, preferably, when the effective diameter of the pressurized liquid supply path is represented by D0 and the effective diameter of the injection hole is represented by D, the cavitation generation condition is 8 ≦ D / D0 ≦ 10; In addition, when L / D0 ≧ 8, cavitation occurs more effectively.

A cavitation generating system according to the present invention comprises a cavitation nozzle for injecting a pressurized liquid to generate cavitation, a container for storing the liquid, and an outlet provided in the container for discharging the liquid. And the liquid ejected from the cavitation nozzle and introduced into the container and discharged from the outlet is formed as a jet stream that generates an irregular vortex in the container.

Preferably, the vortex causes irregular movement which is virtually unpredictable like the course of a typhoon. As the cavitation nozzle used in the cavitation generation system, the above-described cavitation nozzle of the present invention is optimal, but other known cavitation nozzles (such as Japanese Patent Publication No. 4-43712) can be used as long as they can generate cavitation. It may be.

When the container is a cylindrical body and the diameter of the cylindrical body is represented by D2, when D2 / D0 ≧ 12, gas in the liquid can be effectively degassed and dissolved substances in the liquid can be decomposed.

In the cavitation generating system, if the internal pressure of the container is represented by P1 and the injection pressure from the pressurized liquid supply path is represented by P0, the liquid in the liquid is more effectively set to P1 = P0 / 30 or less. It can degas gas and decompose dissolved substances in liquid.

Further, the cavitation generation system can further effectively reduce the liquid pressure by setting P1 = P0 / 100 or less if the internal pressure of the container is represented by P1 and the injection pressure from the pressurized liquid supply path is represented by P0. It can degas the gas inside and decompose dissolved substances in the liquid. That is, even if the upper part of the container is opened (under the atmospheric pressure), cavitation occurs and the container can be used sufficiently.
However, if the container is closed except for the outlet and the pressure of the container is gradually increased, the cavitation breaking force increases, and maximum cavitation occurs at 1/100 of the injection pressure. When the pressure is increased to 1/30 or more, cavitation does not occur. It is desirable to use an open type for degassing gas components in water and to reduce the pressure in the tank to 1/100 or less when destructive power such as sterilization is required.

The motion of the vortex flow center of the cavitation nozzle or the cavitation bubble generated by the cavitation generation system is described by a complicated equation of motion with the inner surface of the box as a boundary condition. It forms a complex system that cannot do it. The countless minute cavitation bubbles have a very large pressure / stress gradient near the boundary surface of the cavitation bubbles, for example, near a spherical surface, and change rapidly with time. Substances in the liquid that come into contact with the liquid having a pressure-stress gradient showing such a temporal change are immediately decomposed. The pressure gradient also promotes the vaporization of the gas in the liquid while generating seeds for the generation of new cavitation bubbles, thereby promoting gas-liquid separation.

[0022]

The cavitation nozzle of the present invention and the cavitation generation system incorporating the same can effectively decompose and reform substances dissolved in liquid, and degas gases dissolved in liquid.

[0023]

[Embodiment 1] Next, Embodiment 1 of the present invention will be described. FIG. 1 is a diagram showing the principle of a cavitation nozzle and a cavitation generation system according to the present invention. The injection container 1 is cylindrical with a diameter D2. The injection container 1 may be closed, but is preferably open at the top. What is released is gas,
When harmful components and the like are vaporized, the removal efficiency is improved.

A cavitation nozzle 3 is fixed to a side wall 2 of the injection container 1. The ejection direction of the cavitation nozzle 3 is directed toward the center of the ejection container 1. The pressurized liquid is supplied from the pump 5 to the cavitation nozzle 3 via a supply pipe 4 communicating with the pump 5. Cavitation occurs when the pressure of the pump 5 is at least 3 kg / cm ² or more.

A drain pipe 6 is provided on the upper side wall 2 of the injection container 1.
Is connected. A flow control valve 7 is connected to the drain pipe 6. Therefore, when the flow control valve 7 is opened, the liquid ejected from the cavitation nozzle 3 rises to this level and is discharged from the drain pipe 6, and the liquid is always maintained at this level.

The cavitation nozzle 3 has a pressurized liquid supply hole 10 having a fixed diameter and a fixed length for supplying liquid, having a diameter D0, and an injection hole communicating with the pressurized liquid supply hole 10. 11 is the diameter D1. The angle θ between the center line of the pressurized liquid supply hole 10 and the bottom surface of the injection hole 11 is 90 degrees. That is, the pressurized liquid supply hole 10 and the injection hole 11 are continuous holes connected by steps. Cavitation generation conditions are generally L / D0, especially when the liquid is water.
≧ 4.

L is the axial length of the injection hole 11. This relationship is less affected by the viscous drag of the liquid. Such a relationship is derived from a relationship (reverse relationship) that has been conventionally studied to suppress the occurrence of cavitation. In order to actively generate cavitation,
Preferably, L / D0 ≧ 8.

Further, the cavitation occurrence condition is 2 ≦
The condition of D / D0 ≧ 12 must be satisfied. This relationship is the inverse of the relationship that has been studied for suppressing cavitation. In order to positively generate cavitation, preferably, 8 ≧
D / D0 ≧ 10. Speaking qualitatively, the conditions for the occurrence of cavitation are that a high-speed high-pressure liquid rapidly flows from a narrow place to a wide place. Cavitation does not occur wherever Bernoulli's theorem holds.

[0029] Cavitation flow also occurs over a wide area when the liquid is swirled, such as in a typhoon. The countless bubbles (cavitation) created near the jet nucleus at the exit will eventually disappear. If a vortex is generated, the bubbling continues. Due to the shear force of the vortex, the bubbles become seeds for producing other bubbles. That is, the bubbles generated from the nozzles become seeds and reproduce the bubbles in the vortex.

However, in the present invention, as described above, when a periodic vortex is generated, there is a limit to degassing of a certain amount or more of gas in the liquid or decomposition of components in the liquid. Therefore,
A container with a large internal space that does not generate eddy currents,
Although the shape is desirable, it is inevitable that a constant vortex is generated due to the injection energy for jetting the jet stream from the cavitation nozzle 3.

Therefore, it is desirable that the internal space of the injection container 1 be as large as possible, but there is a limit in terms of engineering. It is desirable that the size is at least such that a regular vortex does not occur. According to the experiment of the present inventor, the condition under which the regular vortex does not occur is generally D2 / D0 ≧ 12. When the injection container 1 is closed except for the outlet and the pressure of the injection container 1 is gradually increased, the destructive force of cavitation increases and 1/10 of the injection pressure of the cavitation nozzle 3 increases.
Maximum cavitation occurs at 0. 1/30
When the pressure is increased above, cavitation does not occur. For degassing the gas components in the water, an open-type injection container 61 (FIG. 11) described later is used. Is desirable.

The pressure of the injection container 1 was measured by adjusting the cross-sectional area of a valve or an orifice at the outlet to adjust the amount of water flowing out of the injection container 1. As long as it satisfies the above conditions, the cross-sectional shape is not limited to a cylinder and may be any shape, for example, a box-shaped space. When cavitation occurs, the pressure gradient in the area around the cavitation bubbles becomes extremely large spatially, and if there are cells near the cavitation bubbles, cell destruction occurs. Occur.

The liquid supplied to the cavitation nozzle 3 according to the present invention is supplied under pressure by a high-pressure pump. A plunger pump is suitable as the high-pressure pump.

Next, in order to facilitate understanding of cell destruction by cavitation, a theoretical background will be described for reference. It has long been known that a jet is described by an equation of motion based on shear stress (Reynolds stress). The specific theoretical development has been carried out by the present inventors (published).

FIG. 2 is a plan sectional view for analyzing a free turbulent jet discharged from a nozzle into a vacuum. The x-axis is set to coincide with the center line of the virtual nozzle 51 (a portion near the ejection port is formed as a conical surface for virtualization). The y-axis is set in the direction in which the jet spreads, that is, in the direction orthogonal to the direction of travel of the jet center. Therefore, the coordinate system xy is a rectangular coordinate system. When the conical surfaces of the nozzle 51 are extended and the surfaces intersect, a tip of the conical jet flow core 52 is generated. The spread of the jet at a position X sufficiently distant from the jet flow core 52 is indicated by b. As an empirical formula, b = k # j · x (1) In this specification, a subscript right subscript is preceded (left side) by #. k # j is called a jet divergence coefficient and is an important basic factor of jet characteristics.

In the case of having turbulence characteristics, b = 24k · x (2) The constant k is a coefficient representing the turbulence characteristics. The shear stress τ is expressed by the following expansion formula, that is, a polynomial.

[0037]

(Equation 1) The coefficient C # n is determined from the shear stress for the boundary condition of the equation of motion. Applying Prandtl's assumption on the Reynolds stress, the velocity distribution is expressed by the following equation in the approximate expression up to the fourth order.

[0038]

(Equation 2) Equation (3-1) derived from the conditions of the shear stress can be applied to any of the two-dimensional and three-dimensional flows of the free jet and the restricted jet. The value of η at which the right side of equation (3-1) is 0 is 1
Therefore, the jet velocity becomes zero at a position away from the x-axis by a certain distance.

When the liquid is discharged from the nozzle 51 having a finite exit cross-sectional area having a diameter D into an infinite space, when there is no pressure gradient, that is, the velocity decay of the jet on the central axis is determined by the law of conservation of momentum.

(Equation 3)

Since the speed at the nozzle outlet is zero on the central axis, the speed rapidly increases after the outlet, and as shown by arrows in FIG. Velocity vectors at positions apart from each other appear symmetrically. The jet is divided into a range up to the length X # c of the jet nucleus, that is, an initial region 53 and a range downstream thereof, that is, a main region 54. Calculating for reference, the length of the jet core is

(Equation 4)

Equations (4,5) follow the experimental results of Albertson. From equation (4,5), the jet core length X #
c is obtained, and the jet spread coefficient k # j of Expression (1) is obtained from Expression (6). Therefore, the coefficient k of Expression (2) can also be obtained. Experimentally, the velocity u # m on the jet center axis
The jet core length X # c is obtained by the measurement of the jet width b,
The jet spread coefficient k # j is obtained.

The cavitation phenomenon in a high-speed underwater water jet can be considered based on the above analysis. Rous
The following can be estimated from the viewpoint of the turbulence characteristics of the airflow jet by e. The eddy viscosity coefficient ε of the free jet is: ε = kbu # m (7) The coefficient k relating to the turbulence characteristics is based on Prandtle's assumption.

(Equation 5)

According to equations (8, 9), b is proportional to x and u #
a three-dimensional flow in which m is inversely proportional to x (the relationship of equation (4)), and b
Is proportional to x and u # m is inversely proportional to the square root of x (relationship of equation (5)). For each jet of a two-dimensional flow, equation (3-
1) is obtained. The coefficient k can be obtained by calculation from the energy equation.

[0044]

(Equation 6) The Reynolds stress τ, which is closely related to the cavitation phenomenon, is

(Equation 7)

When the turbulent diffusion coefficient χ is large, energy diffusion that causes a cavitation effect is easily caused. As the jet spread coefficient k # j appears linearly in Equations (10, 11), it directly affects the promotion of the cavitation effect. This means that when the jet is confined due to a wall around the nozzle, the jet spread coefficient k # j changes.

As a model for causing a confined jet flow, a jet model having a horn-type side wall is known.
As shown in FIG. 3, when the jet spread coefficient k # j when the conical side wall shown by the dotted line, that is, the constraining wall 55 is provided, the three-dimensional

(Equation 8) This is the same in the two-dimensional case. The significance of equation (12) is that a relationship between the jet spread coefficient k # j and the side wall angle θ # w is obtained. For a two-dimensional flow in a flat rectangular box and a three-dimensional flow in a cylindrical box, the velocity u # m of the maximum velocity of the jet attenuates at the square root of x or in proportion to x. The present invention uses a two-dimensional flow formed in a flat box so that the attenuation is small. Moreover, the two-dimensional flow has good stability as described above.

When the cavitation initiation coefficient σ # i is represented by a graph from the equations (10) and (12), as shown in FIG. 4, the maximum value is obtained when θ # w is around 30 degrees. This graph is quoted from Numachi's experimental report (Hayaken Report, Vol. 16, 1960-1961, No. 158, No. 159). Theoretical analysis excerpted as described above in this specification (“About the basic characteristics of jets”, Jet Engineering Vol.
12, No. 2, 1995, 23-32) by Yanaida (directly below), showing good agreement between theory and experiment.

FIG. 5 shows the relationship between the ratio of D and d shown in the figure and the cavitation initiation coefficient σ # i. That is, the cavitation initiation coefficient σ # i is determined by the ratio (D / d)
(D / D0 in FIG. 1) becomes maximum around 3.
Therefore, if D is three times the unit length, L is preferably eight times the unit length.

The jet attachment distance X # R is expressed by the following equation using d in FIG. 6, the jet expansion coefficient k # j, and the side wall angle θ # w.

(Equation 9) Note that the calculation results are shown for reference.

(Equation 10)

FIGS. 6 and 7 show experimental results showing cavitation erosion ("Hydraulics of Pipelines", J.
Paul Tullis, JOHN WILEY & SONS, SONS, 1989, P170)
This is a quote from X # cp indicates the region where cavitation erosion occurs, that is, the x coordinate in the middle of the cavitation pitching zone. FIG. 7 shows the relationship between the coordinates of the ultrasonic maximum generation position and the side wall angle θ # w. The results of these two experiments prove that the existence of the specific region where cavitation erosion occurs substantially coincides with the existence of the specific region where ultrasonic waves are generated.

FIGS. 6 and 7 show the core length X obtained by the square study.
#C is also shown. As shown in FIG. 7, the maximum position of the cavitation ultrasonic wave substantially corresponds to the square core length. As shown in FIG. 6, the orifice cavitation collapse experiment corresponding to the rapid expansion is almost in agreement with the study in the square. Shear stress τ, turbulent diffusion coefficient χ
The cavitation effect, in which the nozzle and jet core lengths are closely related, is promoted by giving appropriate dimensions to the nozzle shape and box shape.

As described above, the cavitation generation region, its degree, etc. can be analyzed globally from the equation of motion of shear stress based on the momentum distribution described on the coordinate system with the core nucleus as a unit, and the analysis is simple and simple. It was shown that there is.

Next, it is also necessary to locally consider one cavitation bubble.

There are also reports that note the relationship between the air content and the cavitation initiation coefficient. 12th International Towing
According to an experimental report released at the Tank Conference (ITTC),
This means that if the state of the cavitation nuclei contained in the experimental water is different, the state of cavitation changes significantly. Figure 8 (R.Oba et al., Cavitation-Nuclei Mea
surements by a Newly Made Coulter-Counter without
Adding Salt in Water, Rep.Inst.High Speed Mech.,
Tohoku University, Sendai, 43-340 (1981), 173)
It shows the relationship between the diameter of underwater nuclei (air nuclei, chlorine nuclei, etc.) in tap water and the number of nuclei. The distribution of the nucleus diameter and its number 24 hours after the collection has changed significantly. Thus, the presence of cavitation nuclei in tap water is not stable.

FIG. 9 (Numachi's study) shows the relationship between the number of underwater nuclei (number density distribution), the air content related to the nucleus diameter, and the initial cavitation coefficient K. Regardless of the temperature change, the air content can significantly affect the primary cavitation coefficient (the definition is described in detail in Ryoji Kobayashi: Cavitation, Waterjet, 1-2 (1984, 1-13)). It is clearly shown. The numerator of the air content α / α # s is the actual air content,
α # s indicates the saturated air content.

Although cavitation looks like a white cloud when observed with the naked eye, it can be seen from high-speed photographs and instant photographs that it is formed from moving bubbles and cavities fixed to the solid surface. Looking at the temporal fluctuation of bubbles, a bubble has a lifetime, has a growth period and a disappearance period, and may be accompanied by a rebound process after disappearance. (Rayleigh) Theory (1
According to 917), assuming that one spherical vapor bubble is in a sufficiently large still space, the bubble has an initial bubble radius R #.
The maximum value p # max of the pressure generated near the bubble when it disappears from 0 to the bubble radius R is expressed by the following equation.

[0057]

[Equation 11] p # ∞ is the pressure of the surrounding space. Assuming that the bubble radius R is 1/20 of the initial radius, the maximum pressure is 1280 times the pressure of the surrounding space. The theoretical value of the pressure distribution p (r) in the radial direction when one vapor bubble containing a small amount of gas disappears and rebounds and its time change shows a sharp pressure rise that is seen as a shock wave during the rebound period. .

This has been confirmed by schlieren photography. It has been recognized that the impact pressure generated during the bubble extinction / rebound period is an important cause of the mechanism for describing cavitation erosion. One of the causes is the microjet theory, which is based on the assumption that the microjets are formed inside the disappearing cavitation bubbles.

FIG. 10 shows a numerical simulation of the annihilation process of a spherical bubble on a solid surface, and shows how a micro jet formed in the bubble hits the solid surface. Such a phenomenon has been confirmed by experiments.

Cavitation research has hitherto been carried out from the viewpoints of material damage, cleaning of solid surfaces, and the like. However, the impact pressure fluctuation at the time of cavitation collapse is combined with the cavitation effect of the active introduction of air. It has never been done for the technical means of destructive purification and separation. The impact pressure of the cavitation bubbles uniformly dispersed and diffused can effectively destroy cells and effectively separate gas and liquid.

The jet nucleus is also generated by the rotation of the rotor.
In this case, the air can be drawn into the jet stream generated from the surface of the rotor from a hole formed in a part of the hollow rotor.

The effectiveness of cell destruction, decomposition of various salts, etc.
Less affected by air introduction. It largely depends on the spatial and temporal pressure gradient (dP / dx · dP / dt) in the process of cavitation generation and its disappearance. Cavitation occurs around the above-described core formed downstream from the nozzle outlet. The amount of cavitation and the shape and distribution of the core are not directly related. The amount of cavitation increases when the liquid flows at a high speed from a small-diameter port to an orifice having a diameter larger than the diameter of the port.

The cavitation nozzle 3 according to the present invention generates a large amount of cavitation when the cavitation nozzle 3 suddenly exits from the pressurized supply passage 10 to the stepped injection hole 11 having a large diameter. In the cavitation nozzle 3, it is more advantageous for the occurrence of cavitation that the above-mentioned jet nucleus (core) is not clearly present.

[Embodiment 2] FIG. 11 shows another embodiment of the injection container. The injection container 61 has a cylindrical shape with an open top. The bottom surface of the injection container 61 is supported by a support 62. A reinforcing member 63 is fixed to the upper portion of the injection container 61 so as to bridge in the diameter direction for reinforcement and to support the jet flow collision plate 65. Reinforcement 6
An upper end of the collision plate support member 65 is fixed to the lower surface of 3.

A jet flow collision plate 64 is fixed to the lower end of the collision plate support 65. Bottom plate 66 of injection container 61
Has a cavitation nozzle 67 fixed thereto.
The structure and function of the cavitation nozzle 67 are the same as those in the first embodiment, and thus description thereof is omitted. A pump 68 is connected to the cavitation nozzle 67 via a pipe, and the pressurized liquid is supplied. The liquid ejected from the cavitation nozzle 67 is applied to the jet flow impingement plate 6.
Collision 4

One end of a discharge tube 68 is connected to the bottom plate 66. The discharge port 69 of the discharge tube 68 is arranged at the upper part of the side surface of the injection container 61. Therefore, the injected liquid is discharged from the outlet after rising to the level of the outlet 69. Since the upper part of the injection container 61 is open,
From this opening, the dissolved substance in the liquid and the gas dissolved in the liquid are easily vaporized.

(Other Embodiments) The cavitation nozzle used in the cavitation generation system is as follows.
Although the above-described cavitation nozzle of the present invention is optimal, other known cavitation nozzles (Japanese Patent Publication No. 4-43712) may be used as long as they can generate cavitation.
Number etc.).

In the cavitation generating systems of the first and second embodiments described above, the cavitation nozzles 3 and 6 are arranged on the side wall 2 of the injection container 1 or on the bottom plate 66 of the injection container 61. However, a type in which the cavitation nozzles 3 and 6 are inserted into the ejection container 1 or the ejection container 61 by piping and ejected may be used.

(Experimental Example) FIG. 12 is a comparative table showing the degassing performance of oxygen in fresh water according to the present invention. It can be seen that degassing of oxygen in water is well performed. FIG. 13 is a performance test of the cavitation nozzle according to the present invention,
It is a figure which shows the time change of the deaeration performance of the dissolved oxygen in fresh water. This data shows that 10 liters of water is pumped at 30 kg
This is data when the liquid was circulated at a flow rate of 24 / liter with a liquid of / cm ² . It can be confirmed that deaeration of oxygen in the water proceeds.

[Brief description of the drawings]

FIG. 1 is a conceptual diagram of a cavitation generation system according to the present invention.

FIG. 2 is a sectional view showing a coordinate system for jet flow analysis.

FIG. 3 is a cross-sectional view showing a coordinate system for jet analysis of a restricted jet model.

FIG. 4 is a graph showing a relationship between a nozzle opening shape and a cavitation initiation coefficient.

FIG. 5 is a graph showing a relationship between a rapidly expanding nozzle and a cavitation initiation coefficient.

FIG. 6 is a graph showing the relationship between cavitation erosion and jet core length.

FIG. 7 is a graph showing a relationship between a cavitation ultrasonic maximum position and a jet core length.

FIG. 8 is a graph showing a relationship between a rapidly expanding nozzle and a cavitation initiation coefficient.

FIG. 9 is a graph showing the relationship between the diameter of a nucleus and the number thereof.

FIG. 10 is a graph showing the relationship between the air content and the initial cavitation coefficient.

FIG. 11 is a sectional view showing another embodiment of the injection container.

FIG. 12 is a comparison table showing the degassing performance of oxygen in fresh water according to the present invention.

FIG. 13 is a diagram showing a time change of the degassing performance of dissolved oxygen in fresh water according to the present invention.

[Description of Signs] 1 ... Injection container 3 ... Cavitation nozzle 5 ... Pump 6 ... Drain pipe 10 ... Pressurized liquid supply hole 11 ... Injection hole

 ────────────────────────────────────────────────── ─── Continuing from the front page (72) Inventor Teruo Masumoto 1534 Hara, Karatsu-shi, Saga Prefecture, Japan WYB-M Corporation (72) Inventor Mamoru, 1534 Hara, Karatsu-shi, Saga Prefecture F-term in WYM Corporation, Inc. 4D037 AA01 AA08 AA09 AB03 AB11 AB18 BA23 BA26 BB04 BB05 BB07 4D050 AA08 AB06 AB31 AB32 AB35 AB46 BB01 BC02 CA03 4F033 AA09 BA03 CA04 DA01 EA01 JA07 NA01

Claims (8)

[Claims] 1. A cavitation nozzle for jetting a jet into a liquid to generate cavitation, comprising: a pressurized liquid supply path through which a liquid supplied from a high-pressure liquid supply source passes; A cavitation nozzle which is in communication with the injection hole which has a step from the pressurized liquid supply path and is rapidly expanded. 2. The cavitation nozzle according to claim 1, wherein an effective diameter of the pressurized liquid supply passage is represented by D0, an effective diameter of the ejection hole is represented by D, and an effective length of the ejection hole is represented by D0. A cavitation nozzle characterized in that the cavitation occurrence condition is represented by L, 2 ≦ D / D0 ≦ 12 and L / D0 ≧ 4. 3. The cavitation nozzle according to claim 1, wherein when the effective diameter of the pressurized liquid supply path is represented by D0 and the effective diameter of the injection hole is represented by D, the cavitation generation condition is 8 ≦. A cavitation nozzle, wherein D / D0 ≦ 10 and L / D0 ≧ 8. 4. A cavitation nozzle comprising: a cavitation nozzle for injecting a pressurized liquid to generate cavitation; a container for storing the liquid; and an outlet provided in the container for discharging the liquid. The cavitation generating system is characterized in that the liquid ejected at the outlet and introduced into the container and discharged from the outlet is formed as a jet flow that generates an irregular vortex in the container. 5. The cavitation generating system according to claim 4, wherein the container is a cylindrical body, and when the diameter of the cylindrical body is represented by D2, D2 / D0 ≧ 12. Cavitation generation system equipped. 6. The cavitation generating system according to claim 4, wherein the container is a closed container except for the outlet, and the internal pressure of the container is represented by P1, and the pressurized liquid supply path is provided. A cavitation generating system characterized by the following equation: P1 = P0 / 30 or less if the injection pressure from the fuel can be represented by P0. 7. The cavitation generating system according to claim 4, wherein the internal pressure of the container is represented by P1, and the injection pressure from the pressurized liquid supply path is represented by P0. A cavitation generation system, characterized in that: 8. The cavitation generating system according to claim 4, wherein the cavitation nozzle communicates with a pressurized liquid supply path through which a liquid supplied from a high-pressure liquid supply source passes. A cavitation generating system comprising: a jetting hole which is rapidly expanded with a step from the pressurized liquid supply path.