JPS63108104A - Liquid fuel atomizer - Google Patents

Abstract

PURPOSE:To control the flow rate of fuel stably and inject fine spray efficiently through nozzles, by a method wherein the sectional area of a flow passageway in a primary mixing section, in which the fuel is mixed with atomizing medium primarily, is made larger than the total area of the sectional areas of the fuel and the atomizing medium. CONSTITUTION:Fuel 4 is supplied through the central path of an inner tube 2 while atomizing medium 3 is supplied through an annular path between an outer tube 1 and the inner tube 2. The inlet port of a primary mixing section 7a is tapered, therefore, the fuel flows in the form of a thin film and the atomizing medium 3 hits the fuel 4 orthogonally whereby collision energy of the atomizing medium 3 may be used effectively for atomizing the fuel 4. At the same time, the relation between the areas of respective fuel flow paths and medium flow paths is such that A1+A2<A3, therefore, respective flow speeds of the atomizing medium 3 and the fuel 4 will never be affected by either one of the atomizing medium 3 and the fuel 4 during mixing both of them. Further, the atomizing medium 3 is supplied to the primary mixing section 7a from a disc-type medium path 6a, therefore, the atomizing medium 3 collides against the fuel uniformly and the fuel 4 may be atomized uniformly and efficiently.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is applied to an atomizer that sprays a liquid fuel, for example, a mixed system of a liquid fuel such as oil, a solid such as coal, and a liquid. In particular, the present invention relates to a liquid fuel spray atomizer suitable for improving atomization performance when a coal-water slurry is spray-combusted using a spray medium such as high-pressure air or steam.

[Conventional technology]

One of the coal fluidization technologies is coal-water slurry. This is a new form of coal usage that replaces pulverized coal, and its use in power and industrial boilers is progressing. Coal-
Water slurry allows coal to be supplied to the burner using a pump in the same way as conventional petroleum-based fuels, so compared to pneumatic transportation of pulverized coal, water slurry has easier flow control and transportation advantages such as a smaller fuel supply pipe diameter. There are advantages. In addition, when considering coal-water slurry as a fuel for boilers, it is necessary to increase the calorific value of the fuel, so the concentration of coal contained in the coal-water slurry is increased from 62 to 60%.
Highly concentrated coal-water slurries, up to 70% by weight, are used as fuel for boilers.

Now, when burning a coal-water slurry that can be handled as a fluid, an atomizer is required to reduce the liquid coal-water slurry to minute atomized particles.6 The coal-water slurry reduces coal particles. Because the fluid contains coal and water and has a high viscosity, two-fluid atomizers are mainly used, which use air or steam as the atomizing medium and use the kinetic energy of the gas to atomize the coal-water slurry into minute particles. . Various structures have been proposed for two-fluid atomizers.

In the two-fluid atomizer, the coal-
An intermediate mixing method (generally referred to as the Y-jet method) in which the water slurry and spray medium are mixed; and an internal mixing method in which the two fluids enter a mixing chamber after colliding, and then the mixed fluid is ejected into the furnace. is generally well known. FIG. 4 is a cross-sectional view of a conventional internal mixing type atomizer (Japanese Patent Application Laid-Open No. 60-19692).
-36811), FIG. 4, the spray medium 3 passes through an annular passage formed between the outer cylinder 41 and the inner cylinder 42,
The fuel 4 passes through the cylindrical passage formed inside the inner cylinder 42, and then the fuel 4 passes through the central passage 43a of the intermediate mixing plate 43.
On the other hand, the spray medium 3 passes from the medium passage 45 to the central passage 43a of the intermediate mixing plate 43 through the radial passage 46 provided in the radial direction 41: to the central passage (-human mixing section).
It merges with fuel 4 at 43a. Further mixed fuel 4
and the spray medium 3 enter a mixing chamber 48 formed by an intermediate mixing plate 43 and a sprayer plate 47, and are injected into the furnace from an injection hole 49 provided in the sprayer plate 47.

[Problem that the invention seeks to solve]

In the above-mentioned internal mixing type atomizer, the spray medium 3 and the fuel 4 join together in the human mixing part 43a, and the total flow rate of the fluid passes therethrough, so that the flow rate increases rapidly. The spray medium 3 flowing into the single-person mixing section 43a at the same time is -
Because it expands near the outlet of the medium passage (radial passage) 46 of the human mixing part 43a, a part of the spray medium 3 flows back toward the fuel passage 50 side formed by the inner cylinder 42, and the fuel passage 50
wear on the upstream side of the fuel 4 and adverse pressure on the fuel 4 side are likely to be applied. Therefore, pressure fluctuations in the spray medium 3 also cause fluctuations in the fuel 4 side, which tends to cause a problem in which the fuel flowmeter becomes unstable.

Next, in the mixing chamber 4, the mixed fluid of the fuel 4 and the spray medium 3 is injected from the ejection holes 49 while forming a circulating flow as shown by the arrows in the figure. The fuel 4 in the mixing chamber 48 is mixed with the atomizing medium 3 and is in a homogeneous state.
It is desirable that it be injected from However, the fuel 4 that collided with the inner wall of the sprayer plate 47 is
and flows along the inner wall surface of the spray plate 47 in the form of a liquid film. When this liquid film exits into the furnace from the jetting hole 49, it does not become sufficiently atomized, but becomes coarse particles and is jetted into the furnace. Especially from the one-person mixing section 43a to the mixing room 4.
The fuel 4 that has entered the sprayer plate 47 collides with the inner wall surface of the sprayer plate 47, becomes a radial liquid film along the inner wall surface, and circulates within the mixing chamber 48, and the injection hole 49 is located therein. Therefore, this liquid film exits into the furnace from the jet hole 49 and generates a coarse spray. Also, the intermediate plate 4 in the mixing chamber 48
At the corner part on the third side, a small spiral stagnation part of the fuel circulation flow is formed, so the liquid 11 of the fuel 4 stagnates in this vicinity and tends to grow.

As described above, since the fuel 4 is affected by pressure (back pressure) due to the spray medium 3 such as steam in the human-mixing section 43a, there is a problem in that the flow rate of the fuel fluctuates. In addition, a liquid film is formed in the mixing chamber 48 on the inner wall surface and corners of the mixing chamber 4,
There is a problem in that when this liquid film is discharged from the jet hole 49, a coarse spray is generated.

The purpose of the present invention is to solve the problems of the prior art described above,
An object of the present invention is to provide a liquid atomizer that can stably control the flow rate of fuel and efficiently spray fine particles from a nozzle.

[Means for solving problems]

The above object is such that a fuel passage communicating with a primary mixing part that primarily mixes liquid fuel and a spray medium constitutes an annular passage, and a spray medium passage communicating with the primary mixing part constitutes an annular passage. It is composed of a disk-shaped passage extending in a direction substantially perpendicular to the outer peripheral side of the fuel passage, and includes a mixed fluid forming part of fuel and atomizing medium in the primary mixing part and a mixed fluid i1 on the downstream side thereof.
1. The excess cross-sectional area is made larger than the total area of the fluid passing cross-sectional area of the disk-shaped spray medium passage and the fluid passing cross-sectional area of the annular fuel passage, and the mixed fluid from the primary mixing part is introduced. A corner of the mixing chamber located on the primary mixing part side is formed in a planar shape corresponding to the flow of the circulation flow in the mixing chamber, and a wall surface of the mixing chamber adjacent to the jet hole is at least closer to the burner shaft than the jet hole. This is achieved by providing a protrusion formed in the.

[Effect]

The passage cross-sectional area of the mixing part of fuel and spray medium in the primary mixing part and its downstream side is larger than the total passage cross-sectional area of each of the fuel and spray medium, so if the spray medium pressure is higher than the fuel pressure, Even if the fuel pressure rises, it is easier to flow to the downstream passage where the pressure can be lowered, and the upstream side of the fuel is less likely to receive back pressure, making it easier to control the fuel pressure (flow rate). In addition, since the atomizing medium passage is configured in a disk shape and is introduced from a direction perpendicular to the fuel passage in contrast to the annular fuel passage, the collision energy of the atomizing medium is transferred to the thin film-like fuel. It atomizes the fuel while penetrating the fuel.

The fuel in the mixed fluid of fuel and spray medium ejected from the primary mixing section becomes a liquid film and circulates along the inner wall surface of the mixing chamber. This liquid film is not immediately ejected into the furnace from the nozzle hole, but is circulated again to the outlet side of the primary mixing section by the protrusion close to the nozzle hole, and is atomized by the jet flow from the primary mixing section. After that, it is injected into the furnace from the nozzle. There are no corners in the mixing chamber, and each corner is formed into a surface shape that corresponds to the circulating flow in the mixing chamber, so that the circulating flow does not stagnate in the corners and circulates efficiently. After being atomized by the jet flow from the next mixing section, it is injected into the furnace from the jet hole.

[Embodiments of the invention]

FIG. 1 is a sectional view showing one embodiment of the present invention, and FIG.
FIG. 3 is a sectional view taken along line AA in the figure, and FIG. 3 is a view taken along line BB in FIG.

In FIGS. 1 to 3, a cylindrical inner tube 2 is arranged inside a cylindrical outer tube 1 concentrically with the outer tube 1. As shown in FIGS.

A flange-shaped artificial plate 1 is attached to one end of the inner cylinder 2 (on the blowhole side).
7 is formed. The annular passage formed by the inner cylinder 2 and the outer cylinder 1 constitutes a passage for the spray medium 3, and the cylindrical passage formed inside the inner cylinder 2 constitutes a passage for the fuel 4. Further, an annular passage formed between the outer peripheral surface of the brim-shaped inlet plate 17 and the circumferential surface of the outer cylinder 1 constitutes a medium passage 5a. Furthermore, an annular intermediate mixing plate 16 having a predetermined distance from the inlet plate 17 in the burner axial direction is disposed inside the outer cylinder l, and the annular passage formed by the artificial plate 17 and the intermediate mixing plate 16 is It constitutes a radial passage 6a.

Next, a shaft core 11 is arranged on the central axis of the inner cylinder 2 and the intermediate mixing plate 17. This shaft core 11 has a conical protrusion 14 formed at its end on the inner cylinder 2 side, and the other end of a cylindrical body whose one end is continuous with the conical protrusion 14 is formed into a tapered shape. The portion 11a is continuous with a cylindrical portion Ilb having a smaller diameter than the cylindrical portion. and the axis 1
The annular passage formed by the cylindrical portion 11b and the intermediate mixing plate 16 constitutes a single-person mixing section 7a.

The tapered portion 11a corresponds to the exit surface of the medium radial passage 6a.

A truncated conical sprayer plate 10 is connected to the outer cylinder 1.
As shown in FIG. 3, the sprayer plate 10 is provided with a plurality of ejection holes 9 arranged at predetermined intervals along a circle. An annular protrusion 13 is formed close to these ejection holes 9 and closer to the axis of the spray plate IO than the ejection holes 9 are. The height of the annular protrusion I3 gradually increases from the shaft side of the soubreya plate 10 toward the outside, and the soubreya plate 10
A surface perpendicular to the inner wall surface is formed.

Also, the intermediate mixing plate 16 and the sprayer plate 10
The space formed by this constitutes the mixing chamber 8, and an annular protrusion 15 is formed on the circumferential edge of the surface of the intermediate mixing plate 16 facing the mixing chamber 8. The annular protrusion 15 gradually becomes higher toward the end of the intermediate mixing plate 16 in the circumferential direction.

Here, the relationship between d and d2 shown in FIG. 1 is d, < d,
It becomes. Further, the sum of the passage cross-sectional area A of the annular passage formed between the axis 11 and the inner cylinder 2 and the passage cross-sectional area A2 of the medium passage 6a is smaller than the passage cross-sectional area A3 of the -person mixing section 7a. ing.

Next, the operation of the atomizer configured as described above will be explained.

The fuel 4 is supplied through a cylindrical central passage in the inner cylinder 2, and the atomizing medium 3 is supplied through an annular passage formed between the outer cylinder 1 and the inner cylinder 2. Next, the fuel 4 changes from a cylindrical flow to an annular flow by the conical protrusion 14 and is introduced into the annular passage, while the spray medium 3 passes from the medium passage 5a through the disc-shaped medium passage 6a. It flows into the single-person mixing section 7a from a direction perpendicular to the passage and merges with the fuel 4 (merging section 12). At this time, since the population of the negative-person mixing section 7a is tapered, it becomes a constraint for fuel No. 4,
The flow becomes '1illI*, and the spray medium 3 hits the fuel 4 in this state in a direction substantially perpendicular to it. As a result, the collision energy of the spray medium 3 is effectively used to atomize the fuel 4 while penetrating the thin film of fuel 4. At the same time, each fuel flow path and medium flow path is
Since there is a relationship of 1 + At < Al, the respective flow velocities of the spray medium 3 and the fuel 4 are not influenced by either the spray medium 3 or the fuel 4, and the two are mixed.

In addition, since the spray medium 3 is supplied to the human mixing part 7a from the disk-shaped medium passage 6a, the spray medium 3 collides uniformly with the fuel 4, so that the atomization of the fuel 4 is uniform and efficient. It is often done. In addition to the above-mentioned effects, the disk-shaped medium passage 6a also has an inlet plate 17 and an intermediate mixing plate]6.
The gap between the two parts facilitates machining.

Next, the shape of the mixing chamber 8 is formed into a trapezoidal shape so that the jet flow from the jet holes 9 provided in the sprayer plate 10 has a constant spread. A circulating flow is formed around the central axis of the mixing chamber 8, and a predetermined amount of fuel 4 and spray medium 3 are ejected from the ejection holes 9. At this time, the annular protrusion 15 maintains the circulating flow velocity without causing the circulating flow to stagnate at the corner of the mixing chamber 8.
The liquid film along the wall surface is re-atomized by colliding with the jet stream coming out as an annular flow from a. Further, the liquid film circulating along the front surface of the inner wall of the sprayer plate 10 is not immediately ejected from the ejection hole 9 by the annular protrusion 13, but is circulated to the vicinity of the ejection port of the single-person mixing section 7a as shown by the arrow in the figure. After being re-atomized by the jet flow from the -human mixing part 7a, it is jetted into the furnace from the jet hole 9.

In this way, by combining the efficient fuel atomization function in the human mixing section 7a with the selective and efficient fuel atomization function and jetting function in the mixing chamber 8, the optimal atomization of the fuel is achieved. is achieved.

In the embodiment shown in FIG. 1, the annular protrusion 15 has a triangular cross section, but in the present invention, the annular protrusion 1
Instead of 5, it is preferable that the cross-sectional shape of the surface in contact with the reflux be circular or a shape similar to a circular shape. In this case, the formation of the circulating flow in the mixing chamber 8 becomes smoother, and the jetted flow from the single-person mixing section 7a collides with the circulating liquid film in a state where the circulating flow is not disturbed and a high-speed circulating flow is achieved. Atomization of the fuel in the mixing chamber 8 is further improved.

Further, the annular protrusion 13 formed near the ejection hole 9 has an annular shape with respect to the central axis of the atomizer, but may also be an annular protrusion relative to the central axis of the ejection hole 9. In this case, it is difficult for the circulating liquid film to enter the jet hole 9, which has a recess formed in the center of the protrusion.
After passing above the water and being atomized by the jet stream from the single-person mixing section 7a, it is jetted out from the jet hole 9. It is desirable that the outer circumferential surface of the protrusion has a sawtooth shape that widens toward the bottom in the height direction. However, since the high-speed VA circulation collides with the protrusion, it is recommended that the protrusion be made of ceramic (or the protrusion). If a processing method is adopted in which the parts forming the part are fitted into the ejection hole 9, the processing of the atomizer becomes simple.

〔Effect of the invention〕

As described above, according to the present invention, the cross-sectional area of the flow path in the one-person mixing section that primarily mixes the fuel and the spray medium is determined from the total area of the cross-sectional area of the fuel passage and the passage cross-sectional area of the spray medium. Since the pressure and flow rate on the fuel side are also increased due to changes in the spray medium pressure and 2a amount, the spray medium collides with the thin film of fuel in the single-person mixing section from a direction perpendicular to the fuel, which reduces the amount of fuel. Atomization is promoted, and the formation of a circulating flow of fuel in the mixing chamber is promoted, and this circulating flow is not immediately ejected into the furnace from the nozzle hole, but is re-atomized by the ejected flow from the one-person mixing section. be converted into Therefore, since the atomized fuel is reliably injected into the furnace from the injection hole, the ignitability of the fuel is improved.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a liquid fuel spray atomizer according to the present invention, FIG. 2 is a sectional view taken along line A-A in FIG. 1, FIG. 3 is a view taken along line B-B in FIG. 1, and FIG. 4 is a conventional 1 is a cross-sectional view of a liquid fuel atomizer of FIG. 1... Outer cylinder, 2... Inner cylinder, 3...
... Spray medium, 4... Fuel, 5a...
Medium passage, 6a...Radial medium passage, 7...
...-Next mixing section, 8...Mixing chamber, 9...
...Blowout hole, 10...Sprayer plate, 11
...Axis, 13.15...Annular protrusion, 14...Conical protrusion, 16...Intermediate mixing plate, 17...・Entrance plate. Agent: Patent attorney Masaru Nishimoto - Figure 1

Claims (4)

[Claims] (1) A primary mixing section that primarily mixes liquid fuel and a spray medium inside the atomizer, and a mixed flow from the primary mixing section that passes through a mixing chamber and is ejected through a plurality of ejection holes. In the liquid fuel atomizer, the fuel passage communicating with the primary mixing part constitutes an annular passage, and the atomizing medium passage communicating with the primary mixing part is substantially perpendicular to the annular fuel passage from the outer peripheral side thereof. The mixed fluid passage cross-sectional area of the mixed fluid forming part of the fuel and spray medium in the primary mixing part and the downstream side thereof is equal to the fluid passage cross-sectional area of the disc-shaped spray medium passage. A corner portion of the mixing chamber located on the primary mixing section side is formed into a planar shape that corresponds to the flow of the circulation flow within the mixing chamber, and is larger than the total area of the annular fuel passage and the fluid passage cross-sectional area thereof. A liquid fuel spray atomizer, characterized in that a protrusion is provided on an inner wall surface of the mixing chamber close to the ejection hole, the protrusion being formed at least closer to the burner shaft than the ejection hole. (2) Claim (1) characterized in that the protrusion is a protrusion that is provided in an annular shape on the circumference of the burner axis and is located closer to the burner axis than the ejection hole.
The liquid fuel atomizer described in Section 1. (3) The liquid fuel spray atomizer according to claim (1), wherein the protrusion is an annular protrusion surrounding the ejection hole. (4) The fuel passage is an annular passage formed around the axis, with an axis having a conical protrusion at its tip disposed on the central axis of the burner. A liquid fuel spray atomizer according to scope item (1).