JP2000254553A - Nozzle for ejecting jet in liquid and method for adjusting impact force thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase impact force of cavitation by actively generating cavitation bubbles generated by ejecting a jet in a liquid jet. SOLUTION: This nozzle 1 for ejecting a jet in a liquid comprises an orifice part 3 connected with a large diameter and low flow speed part 2, which is a high pressure liquid supply source and comprising a circular flow route with a prescribed cross-section area and a jetting hole part 4 coaxially extended from the outlet 3o of the orifice part 3 and having an inlet part 4i with the same diameter as that of the orifice part and is further provided with a cavitation promoting member (a cavitator) which is, for example, a rod-like member with a circular cross-section shape, penetrates the orifice part 3, and is extended in the jetting hole part 4 to actively generate cavitation bubbles in a liquid jet.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a submerged jet jet nozzle, and more particularly, to a submerged jet nozzle capable of jetting a liquid jet in a liquid to form cavitation bubbles inside and outside the liquid jet. The present invention relates to a jet injection nozzle.

[0002]

2. Description of the Related Art A high-pressure liquid is converted into a high-speed liquid jet stream by injecting a liquid pressurized at a high pressure from a small-diameter orifice into the liquid, and the collision energy of the liquid jet is subjected to various processing and processing. The so-called high-pressure liquid jet processing / processing technique used for the above is already known. Conventionally, such a high-pressure liquid jet processing / processing technique is mainly used for cleaning of a processing target / workpiece, detachment of attached matter, cutting, and the like.

[0003] Examples of conventional submerged jet jet nozzles used in the high pressure liquid jet processing / processing technology field include the following. That is, as shown in FIG.
When the liquid jet 104 is jetted in the liquid 101, cavitation bubbles 105 are actively generated around the liquid jet 104 to increase the impact force on the surface of the workpiece to be processed and to prevent nozzle clogging. It is formed in the shape of original thin and suehiro. That is, the submerged jet injection nozzle 100 extends coaxially from the outlet of the orifice portion and the orifice portion 102 having a tubular cross section having a constant cross-sectional area for increasing the flow velocity of the liquid flow and forming the liquid jet flow. , Orifice part 4-20
It has a length that is twice as long as the diameter of the orifice portion, and its diameter is 2
And a horn-shaped ejection hole 103 having a cross-sectional shape gradually expanding at an angle of 0 ° to 60 °.

[0004]

However, in the conventional submerged jet jet nozzle 100 as described above, the cavitation bubbles 105 are formed by the liquid jet 104.
Occurs in the shear layer between water and surrounding stationary water. Therefore, as shown in FIG. 4 (b), cavitation hardly occurs inside the liquid jet 104 having a large kinetic energy, but occurs due to the collapse of the cavity, which is a very unstable gas phase in the liquid phase. As shown in FIG. 4C, the impact force generated also occurs in the periphery of the liquid jet 104 corresponding to the location where the cavitation bubbles 105 are generated, and an annular shape is formed on the downstream side of the liquid jet 104. It has a peak 107. Therefore, the kinetic energy of the liquid jet 104 having a velocity distribution as shown in FIG.

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems of the conventional submerged jet jet nozzle and actively and forcibly generates cavitation bubbles generated by the submerged jet jet in the liquid jet. Submerged jet jet nozzles and their impacts to fully utilize the impact crushing effect of cavitation and effectively use the energy of the liquid jet to significantly increase the work volume of the liquid jet by the submerged jet jet compared to the past It is an object to provide a method for adjusting a force.

[0006]

According to a first aspect of the present invention, there is provided a nozzle for jetting liquid in a liquid connected to a high-pressure liquid supply source, the liquid jet from the supply source being provided as a first means. An orifice portion comprising an annular passage having a constant cross-sectional area for increasing the flow velocity of the liquid jet flow and forming a liquid jet flow;
An orifice portion extending coaxially from an outlet of the orifice portion and having an inlet portion having the same diameter as the orifice portion. A submerged jet injecting nozzle to be actively generated extends from the slit to the ejection hole at a position of a central axis of the submerged jet injecting nozzle, and cavitation bubbles are positively generated in the liquid jet. A cavitation accelerating member (hereinafter, referred to as a cavitator) to be generated is provided and configured.

In the present invention, as a second means, the ejection hole portion extends coaxially from an outlet of the orifice portion, and has a diameter downstream from an inlet portion having the same diameter as the orifice portion. May be formed in a horn shape having a cross-sectional shape that gradually increases along the axial direction.

Further, in the present invention, as a third means, the cavitator may be a rod-shaped member that penetrates the orifice portion and extends to the ejection hole portion.

Further, in the present invention, the fourth aspect
It is preferable that the cavitator is a rod-shaped member held by a cavitator holding member installed in the large-diameter low-velocity section upstream of the orifice section.

In the present invention, as a fifth means, a submerged jet injection nozzle employing the fourth means is provided with a large-diameter, low-velocity portion upstream of the orifice portion and an end near the orifice portion side end. The orifice portion and the ejection hole portion 4 are integrally formed with the nozzle upstream side portion incorporating the cavitator holding member, and the nozzle downstream side portion is formed into a structure that can be divided and assembled freely. Is preferred.

According to the method for adjusting the impact force by cavitation of the nozzle for jetting liquid in liquid according to the present invention employing any one of the above first to fifth means, the length of the cavitator projecting from the outlet of the orifice portion is adjusted. It is configured to be characterized in that:

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a nozzle for jetting liquid in liquid according to the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a longitudinal sectional perspective view showing the overall configuration of an embodiment of a submerged jet jet nozzle according to the present invention. FIG. 2 is a schematic configuration of the submerged jet jet nozzle according to the present invention and its operation.
It is a conceptual diagram for demonstrating an effect, (a) is explanatory drawing which shows a schematic structure and the generation | occurrence | production state of cavitation, (b)
Is a diagram showing a velocity distribution in a direction perpendicular to the axis of the nozzle,
FIG. 3C shows the distribution of the impact force due to cavitation in the direction perpendicular to the axis of the nozzle, and FIG. 3 shows the frequency distribution of the impact force between the submerged jet ejecting nozzle of the present invention and the conventional submerged jet ejecting nozzle. FIG. 4 is a diagram showing the effect of the length of protrusion of the cavitator from the orifice outlet on the impact force frequency distribution in the submerged jet injection nozzle of the present invention.

As shown in FIGS. 1 and 2, the submerged jet injection nozzle 1 employing the first to third means of the present invention is connected to a large-diameter, low-flow-rate section 2 which is a high-pressure liquid supply source. ,
Orifice part 3 consisting of an annular passage having a constant cross-sectional area
And extending coaxially from the outlet 3o of the orifice portion 3,
A horn-shaped ejection hole portion 4 having a cross-sectional shape whose diameter gradually increases along the axial direction from an inlet portion 4i having the same diameter as the orifice portion toward the downstream, and the water jet 20 is ejected in the liquid. Then, the submerged jet injection nozzle 1 for positively generating the cavitation bubbles 22 and 23 inside and outside the water jet 20 is positioned at the center axis CL of the submerged jet injection nozzle 1 at the orifice portion 3.
And a cavitator 5 formed of a rod-shaped member having a circular cross section that extends through the horn-shaped ejection hole portion 4 and positively generates the cavitation bubbles 22 in the water jet 20. Is composed.

In the present embodiment configured as described above, as shown in FIG. 2, the vortex ring 21 derived from the liquid and the viscosity on the surface of the rod-like member is periodically discharged from the trailing edge of the cavitator 5. You. Due to the rotation of the vortex ring 21, the pressure near the center of the vortex ring 21 is reduced, and cavitation bubbles 22 are generated near the center. Accordingly, in this case, since the cavitation bubbles 22 are generated in the water jet 20 having a large kinetic energy as shown in FIG. 2B, a peak is formed on the center axis of the water jet as shown in FIG. 2C. It is possible to expect generation of a higher impact force, and it is possible to perform processing and processing operations on the material to be processed and processed in a wider range including the water jet 20.
Further, in the present embodiment, the ejection hole portion 4 is formed in a horn shape having a sectional shape whose diameter gradually increases along the axial direction from the inlet portion 4i having the same diameter as the orifice portion toward the downstream side. As a result, the cavitation bubbles 23 are efficiently formed around the water jet 20 discharged from the outlet of the orifice portion, and the cavitation bubbles 23 are not diffused so much from around the water jet 20 and the material to be processed / processed together with the water jet 20. To efficiently generate an impact force. Therefore, a large impact energy can be expected due to a synergistic effect with the impact force due to the cavitation bubbles generated in the water jet 20 by the cavitator 5.

As shown in FIG. 1, the embodiment of the submerged jet injection nozzle 1 employing the fourth means of the present invention is such that the cavitator 5 is provided with a large-diameter low-velocity section upstream of the orifice section. 2 is configured as a rod-shaped member that is press-fitted and held in the non-penetrating center hole 6ch of the cavitator holding member 6 installed in the second cavity. The cavitator holding member 6
In order not to disturb the flow of the high-pressure water, the cross-shaped thin ribs 6r, 6r, 6r, 6r and the inner surface thereof are fixed to the radially outer ends thereof, And a thin tubular member 6tp inscribed on the inner surface of the base member, and the non-penetrating center hole 6ch is drilled at the center where the center sides of the cross-shaped thin ribs 6r, 6r, 6r, 6r are gathered.

In the present embodiment configured as described above, the cavitator 5 composed of a rod-shaped member is provided on the cavitator holding member 6 installed on the downstream side of the large-diameter low-velocity section 2 upstream of the orifice section 3. And is not removed during use of the submerged jet injection nozzle 1. Further, as in the case of soldering, brazing, welding, or the like, the cavitator holding member 6 and the cavitator 5 are thermally deformed and displaced from the center axis CL, and the effect of generating the cavitation bubbles 22 is reduced, and the wake flow of the water jet 20 is reduced. There is no deviation in the impact force distribution on the side.

As shown in FIG. 1, an embodiment of a submerged jet injection nozzle 1 employing the above-described fifth means of the present invention is a large-diameter low-velocity section 2 upstream of the orifice section and its orifice section. A nozzle upstream side 7 containing the cavitator holding member 6 near the side end, and a nozzle downstream side 8 integrally formed with the orifice 3 and the ejection hole 4 can be divided into two parts and freely assembled. It is formed into a structure and basically configured.

The above embodiment further has the following specific configuration. That is, on the downstream side of the large-diameter low-velocity portion 2 provided at the center of the nozzle upstream-side portion 7, the inner diameter is larger than the inner diameter of the large-diameter low-flow portion 2 and slightly smaller than the outer diameter of the cavitator holding member 6. The large diameter portion 9 for storing the cavitator holding member is provided up to the vicinity of the downstream end 7e of the nozzle upstream side portion 7, and the cavitator holding member is provided on the upstream side of the large diameter portion 9 for storing the cavitator holding member. 6 are interpolated. And the downstream end 7 of the nozzle upstream side 7
e, the inner corners are beveled obliquely and the packing housing 10
Are formed. Further, a small-diameter portion 7sd having an outer diameter smaller than the downstream-side large-diameter portion 7bd is formed upstream of the nozzle upstream-side portion 7 at an upstream end of the cavitator holding member storing large-diameter portion 9; An external thread 7sc for connecting a high-pressure liquid supply pipe (not shown) is provided on the outer periphery of 7sd.

On the other hand, a central portion of the orifice portion 3 upstream of the nozzle downstream side portion 8 and upstream of the outlet side 3o is located downstream of the large diameter portion 9 for accommodating the cavitator holding member of the nozzle upstream side portion 7. The small-diameter portion 11 is inserted into the portion until its front end abuts on the downstream end surface of the cavitator holding member 6 and has an outer diameter slightly smaller than the inner diameter of the large-diameter portion 9 for housing the cavitator holding member. An upstream side of the entrance 3i of the orifice portion 3 at the center of the small-diameter portion 11 is a thin-walled tube portion 11tp having the same diameter as an inner diameter of the thin-walled tube portion 6p of the cavitator holding member 6, and the orifice portion is located between the thin-walled tube portion 11tp. 3 is provided with an inner diameter gradually decreasing portion 11rd connected to the entrance 3i. The downstream end of the small-diameter portion 11 of the nozzle downstream side portion 8 has the same outer diameter as the downstream end of the nozzle upstream side portion 7 and has an upstream end face that abuts on the downstream end face. A large-diameter flange-shaped portion 12 having a predetermined width is formed, and is connected to the small-diameter outer peripheral surface of the horn-shaped ejection hole portion 4 downstream from its downstream end surface with a predetermined step.

The packing housing 1 of the nozzle upstream side 7
The gasket 13 presses the space between the nozzle 0 and the corner formed by the upstream end surface of the large diameter portion 12 of the nozzle downstream side portion 8 and the outer peripheral surface of the downstream end of the small diameter portion 11. And the flange-shaped large-diameter portion 12 of the nozzle wake side portion 8.
Large diameter portion 7bd of the nozzle upstream side portion 7 from the upstream end surface of
Screws 14 are respectively screwed into a plurality of screw holes formed concentrically in the downstream half portion, and the nozzle upstream side portion 7 and the nozzle downstream side portion 8 are integrally connected to each other, thereby jetting the submerged jet. Nozzle 1 is formed.

In the present embodiment configured as described above, all of the plurality of screws 14 are removed from the screw holes, and the nozzle upstream side portion 7 and the nozzle downstream side portion 8 are separated from each other. If you pull it, you can split it into two. By forming such a structure that can be divided into two, the rod-shaped member 5 having a desired outer diameter and a desired length is press-fitted into the center hole 6ch of the cavitator holding member 6 in advance, and is held. Is inserted and arranged in the large-diameter portion 9 for housing the cavitator holding member on the upstream side of the orifice portion, and then the nozzle upstream side portion 7 and the nozzle downstream side portion 8 are integrally assembled and connected as described above. Becomes possible. As a result, the submerged jet injection nozzle 1 of the present invention
In addition to simplifying the manufacture and assembly of the cavitator, when the cavitator 5 is damaged or the shape and dimensions (outer diameter, length, shape of the downstream end, etc.) of the cavitator 5 are to be changed,
The replacement of the cavitator holding member 6 and the cavitator 5 can be easily performed.

Next, a method for adjusting the strength of the impact force due to cavitation using the submerged jet injection nozzle 1 of the present invention described in the above embodiment will be described with reference to specific experimental examples. This will be described below. As the nozzle body, the same nozzle body having the configuration described with reference to FIG. 4 which has been conventionally used was used. Cavitator 5
Has a cylindrical shape with a diameter of 0.9 mm, and is held by the cavitator holding member 6 as described in the above embodiment. The diameter of the orifice portion 3 was set to 1.75 mm in order to have the same flow area as that of the conventional submerged jet injection nozzle without the cavitator.
The downstream side of the nozzle has a horn shape, the opening angle of the horn is 60 degrees, and the length of the horn is 15 mm. The protruding length of the cavitator was the distance from the orifice outlet to the trailing edge of the cavitator, 5 mm, 12.5 mm. Three types of 20 mm were manufactured and used.

The experiment was carried out under a constant water temperature of 16.9 to 18.0 ° C., a discharge pressure p ₁ = 7.1 MPa, and a water jet ambient pressure p ₂ = 0.1 MPa. In this case, the Reynolds number Re and the cavitation coefficient σ are
Re = 1.4 × 10 ⁵ and σ = 1.4 × 10 ⁻² , respectively. Here, the Reynolds number Re and the cavitation coefficient σ are defined by the following equations 1 and 2, respectively.

[0024]

(Equation 1)

[0025]

(Equation 2)

Where, d _n : diameter of the orifice portion of the nozzle (mm) d _c : diameter of the cavitator (mm) U: flow rate at the nozzle outlet (mm / sec) ν: kinematic viscosity coefficient of water p ₁ : water jet discharge Pressure (MPa) p ₂ : Water jet ambient pressure (MPa) pν: Saturated steam pressure (MPa)

FIG. 3 shows the impact force generated in the water jet measured from the distance from the nozzle to the impact meter (hereinafter referred to as stand-off distance) and from the center of the water jet.
-It shows the frequency distribution of the impact force at the stand-off distance where the maximum impact force appeared at each cavitator length Lc (mm), measured by changing the distance in the direction orthogonal to the center axis CL of the target. From FIG. 3, it can be seen that the impact force changes depending on the presence or absence of the cavitator and the length of the cavitator, and that the impact force with the cavitator is up to three times as large as that without the cavitator. It can be seen that the frequency of the impact force is high and the frequency of the weak impact force is reduced. In other words, the generated impact force depends on the length of the cavitator. The longer the cavitator, the greater the impact force, and the larger the impact force is concentrated in the center of the water jet.

As described above, the strength of the impact force due to the cavitation of the submerged jet jet nozzle can be freely adjusted by changing the length of the cavitator projecting from the orifice outlet. An optimal impact force according to the type of processing / processing to be performed or the processing / processing object is obtained, the efficiency is high, and unnecessary surface damage to the processing / processing object can be prevented.

Although the embodiment of the present invention has been described above, the present invention is not limited to the above-described embodiment, and includes other embodiments without departing from the gist of the configuration. For example, in the above-described embodiment, the case where water is used as the liquid has been described. However, the liquid in the present invention is not limited to this, and it is considered that cavitation bubbles are easily generated and the pressure loss of the liquid jet is taken into consideration. Liquid of appropriate viscosity to obtain a predetermined impact force efficiently and
Alternatively, a liquid such as an organic solvent having a high vapor pressure and easily generating cavitation bubbles may be used.

Further, the cross-sectional shape of the ejection hole is not limited to the horn shape as in the above embodiment, and cavitation bubbles are efficiently formed around the liquid jet discharged from the outlet of the orifice portion. Any cross-sectional shape that does not significantly diffuse from the surroundings of the liquid jet and does not hinder efficient arrival of the material to be processed and processed with the liquid jet may be used.

Furthermore, the cavitator is not formed of a circular straight rod-shaped member as in the above-described embodiment, but a small-diameter portion and a large-diameter portion are alternately arranged in the longitudinal direction so that a vortex ring is easily generated on the surface of the cavitator. It may be a rod that is provided periodically, or may be a rod that has a large diameter portion at the downstream end. Further, the cavitator is rocked or vibrated using an actuator such as a piezoelectric element or a magnetostriction blocking element,
A vortex ring may be easily generated on the surface of the cavitator.

Furthermore, from the viewpoint of ensuring the holding of the cavitator and minimizing the eccentricity of the cavitator from the axis of the submerged jet injection nozzle,
Instead of press-fitting and holding the cavitator made of a rod-shaped member into the non-penetrating center hole of the cavitator holding member as in the above-described embodiment, it is more preferable to integrally form the cavitator holding member and the cavitator by precision casting. ,

[0033]

The nozzle for jetting liquid in liquid according to the present invention comprises:
It has the following excellent effects. (1) Cavitation bubbles generated by submerged jet injection are positively and forcibly generated in the liquid jet as well, making full use of the impact crushing effect of cavitation, and making effective use of the energy of the liquid jet to produce submerged liquid. It is possible to significantly increase the work amount of the liquid jet by the jet injection as compared with the related art.

(2) If the ejection hole is formed in a horn shape having a cross-sectional shape whose diameter gradually increases along the axial direction from the inlet portion having the same diameter as the orifice portion toward the downstream side, the orifice portion can be formed. Cavitation bubbles are efficiently formed around the liquid jet discharged from the outlet of the liquid jet, and do not diffuse much from around the liquid jet. Generate. Therefore, a large impact energy can be expected due to a synergistic effect with the impact force due to the cavitation bubbles generated in the water jet by the cavitator.

(3) By forming the nozzle upstream side portion and the nozzle downstream side portion into a structure that can be divided and assembled freely, it is easy to manufacture and assemble the submerged jet jet nozzle of the present invention. In addition, when the cavitator is damaged or when it is desired to change the shape or size (outer diameter, length, shape of the downstream end, etc.) of the cavitator, the cavitator holding member and the cavitator can be easily replaced.

According to the method of adjusting the impact force of the submerged jet injection nozzle by cavitation of the present invention, the length of the cavitator projecting from the outlet of the orifice portion is changed. The strength of the impact force due to cavitation can be adjusted freely, and the optimal impact force according to the type of target processing / processing and the processing / processing object can be obtained, high efficiency and processing -Unnecessary surface damage to the workpiece can be prevented.

[Brief description of the drawings]

FIG. 1 is a vertical cross-sectional perspective view showing an overall configuration of an embodiment of a submerged jet injection nozzle of the present invention.

FIG. 2 shows the operation of the submerged jet jet nozzle of the present invention.
It is a conceptual diagram for explaining an effect.

FIG. 3 is a conceptual diagram for explaining a schematic configuration of the nozzle for jetting liquid in liquid of the present invention and its operation and effect;
(A) is an explanatory diagram showing a schematic configuration and a state of occurrence of cavitation, (b) is a diagram showing a velocity distribution in a direction perpendicular to the nozzle axis, and (c) is an impact due to cavitation in a direction perpendicular to the nozzle axis. It is a figure showing distribution of force.

4A and 4B are conceptual diagrams for explaining a schematic configuration of a conventional submerged jet injection nozzle and its operation, in which FIG. 4A is an explanatory diagram showing a schematic configuration and a state of occurrence of cavitation, and FIG. FIG. 3C is a diagram illustrating a velocity distribution in a direction perpendicular to the nozzle axis, and FIG. 4C is a graph illustrating an impact force distribution due to cavitation in a direction perpendicular to the nozzle axis.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Submerged jet injection nozzle 2 Large diameter low flow velocity part 3 Orifice part 4 Horn-shaped ejection hole part 5 Cavitator (rod-like member) 6 Cavitation holding member 6ch Non-through center hole 6r Rib 6tp Thin tube part 7 Nozzle upstream side 7ld Large Diameter part 7sd Small diameter part 7e Downstream end part 7sc Male thread part 8 Nozzle downstream side part 9 Large diameter part for storing cavitator holding member 10 Packing accommodation part 11 Small diameter part 11tp Thin tube part 11rd Internal diameter gradually decreasing part 12 Large diameter part 13 Packing 14 Screw 20 Water jet 21 Vortex ring 22 Cavitation bubble 23 Cavitation bubble CL Central axis

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Takashi Usui 1679-1 Tosagi, Kosugi-cho, Imizu-gun, Toyama Prefecture 1-401 Sanra Is Taikakuyama 1-406 (72) Inventor Eiji Sengoku 1--1, Taikakuyama, Kosugi-cho, Imizu-gun, Toyama Prefecture 54 Alphaheim 201 F term (reference) 3B201 AB01 BB02 BB32 BB87 BB90 BB92 CB01 3C060 AA20 CE01 4F033 AA14 BA01 BA04 CA01 DA01 EA01 JA07 KA03 NA01

Claims (6)

[Claims] An orifice portion connected to a high-pressure liquid supply source, the orifice portion comprising a tubular passage having a constant cross-sectional area for increasing a flow rate of the liquid flow from the supply source to form a liquid jet flow; An orifice portion extending coaxially from an outlet, the orifice portion having an inlet portion having the same diameter as the orifice portion,
A nozzle for injecting a liquid jet in a liquid to actively generate cavitation bubbles inside and outside the liquid jet, the nozzle for injecting a liquid jet, wherein the slit is provided at a position of a central axis of the nozzle for injecting liquid. A cavitation facilitating member that extends from the portion to the ejection hole portion and positively generates cavitation bubbles in the liquid jet. 2. A cross section in which the ejection hole portion extends coaxially from an outlet of the orifice portion, and has a diameter gradually increasing along an axial direction from an inlet portion having the same diameter as the orifice portion toward a downstream side. The nozzle for submerged jet injection according to claim 1, wherein the nozzle is formed in a horn shape having a shape. 3. The jet for liquid jet according to claim 1, wherein the cavitation facilitating member is a rod-shaped member that penetrates the orifice portion and extends to the ejection hole portion. nozzle. 4. The cavitation facilitating member is a rod-shaped member held by a cavitation facilitating member holding member installed in a large-diameter low-velocity part upstream of the orifice part. Item 4. A submerged jet jet nozzle according to item 3. 5. The nozzle according to claim 1, wherein the submerged jet injection nozzle includes a large-diameter low-velocity portion upstream of the orifice portion and a nozzle upstream side portion having the cavitation facilitating member holding member provided near an end of the orifice portion. An orifice portion and the nozzle downstream side portion formed integrally with the ejection hole portion,
The nozzle for submerged jet injection according to claim 4, wherein the nozzle is formed in a structure that can be divided into two parts and is freely assembled. 6. A method for adjusting an impact force by cavitation of a submerged jet injection nozzle according to claim 1, wherein the cavitation facilitating member protrudes from an outlet of the orifice portion. A method for adjusting the impact force of a submerged jet injection nozzle, characterized by adjusting the length.