JPH06193831A - Atomizing burner - Google Patents

Abstract

PURPOSE:To provide an atomizing burner having a sufficiently large combustion allowance width even in a small area of fuel flow rate by suppressing generation of soot existing in burnt gas. CONSTITUTION:An atomizing burner comprises a flame stabilizer 22 having a swirl blade 22b and mounted at a base end side of a burning cylinder 7, atomizes fuel from a fuel injection valve 11 together with primary air for burning via a through hole 22a of the stabilizer 22 into the cylinder 7, and supplies secondary air for burning into the cylinder 7 via the stabilizer to burn in the cylinder 7. The stabilizer 22 has a tapered enlarged cylinder 22h enlarged forward and interposed on an outer periphery of the hole 22a, the blade 22b disposed on the outer periphery of the cylinder 22h, and a plurality of air pores 22i provided at the cylinder 22h to diffuse the air obliquely from the periphery toward a central axis of the burning cylinder.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a spray combustor for injecting fuel from a fuel injection valve into a combustion cylinder for combustion.

[0002]

2. Description of the Related Art As a spray proportional control combustor, Japanese Patent Application No. 2-31
In the 9239 application, the applicant provided the spray combustor shown in FIGS. FIG. 8 is a vertical sectional view of the spray combustor, and FIG. 9 is a front view of the flame stabilizer. This combustor has a central hole in the flame stabilizer.
The air sent through 22a and the air sent through the swirl vane portion 22b, which is the main body of the flame stabilizer, are completely separated and independently supplied by the primary air cylinder 2, whereby the swirl vane portion 22b is supplied. Increase the amount of air sent through the
The fuel injected into the combustion chamber N in the combustion cylinder 7 is supplied to the combustion chamber N as another air from another hole in the inner peripheral surface of the combustion cylinder 7, and the fuel injected from the fuel injection valve 11 is The air is supplied to the combustion chamber N together with air through the central hole 22a of the flame stabilizer. Further, in the application for Japanese Patent Application No. 4-193294, the applicant of the present invention has made further improvements as shown in FIGS.
The spray combustor shown in FIG. Figure 10 is a front view of the flame stabilizer,
FIG. 11 is a sectional view of the flame stabilizer. In this combustor, a flat plate region 22s reaching the central hole 22a is continuously provided on the inner peripheral side of the swirl vane portion 22b formed by cutting and raising the blades, and the flat plate region 22s is formed.
22s is provided with a plurality of air holes 22t smaller than the central hole 22a.

[0003]

However, as shown in FIG.
In the spray combustor having the configuration shown in FIG. 9, when the fuel flow rate is increased, the swirl of the air flow introduced from the swirl vane portion 22b also becomes stronger, so that the fuel spray spreads greatly from the vicinity of the outlet of the center hole 22a, Depending on the conditions, swirl vane 22
There was a drawback that the blade of b was wet and the tendency of soot to adhere to the blade increased. On the other hand, when the fuel flow rate is reduced, the contribution of the swirling air becomes small and soot is generated more frequently. On the other hand, in the spray combustor having the configuration shown in FIGS. 10 and 11, since the plurality of air holes 22t are provided in the flat plate region 22s immediately around the center hole 22a, the fuel spray flowing from the center hole 22a is The soot is prevented from adhering to the central hole 22a and the swirl vane portion 22b due to being disturbed by swirling air immediately after the inflow, because the soot is protected by the horizontal airflow from the air hole 22t for a while. However, in this configuration, when the fuel flow rate is reduced, the mixing of the atomized fuel and the air supplied from the surroundings tends to be poor, so that the generation of soot existing in the burned gas should be suppressed. However, in the region where the fuel flow rate is small, there is a drawback that the margin width of the ratio of fuel and air for proper combustion, that is, the combustion margin width cannot be sufficiently increased.

Therefore, the present invention solves the above-mentioned drawbacks of the conventional spray combustor, suppresses the generation of soot existing in the burned gas, and has a sufficiently large combustion margin even in a region where the fuel flow rate is small. For the purpose of providing.

[0005]

In order to achieve the above object, in the spray combustor of the present invention, a flame stabilizer having a swirl vane portion is attached to the base end side of the combustion cylinder, and the fuel from the fuel injection valve is set to the above-mentioned. It is a spray combustor that burns in the combustion cylinder by spraying it into the combustion cylinder together with the primary air for combustion through the center hole of the flame stabilizer and supplying secondary air for combustion to the combustion cylinder through the flame stabilizer. Then, the flame stabilizer interposes a tapered expansion cylinder portion that expands forward toward the outer periphery of the center hole, and arranges the swirl vane portion on the outer periphery of the expansion cylinder portion, and The first feature is that a plurality of small air holes that blow out air obliquely from the periphery toward the center axis of the combustion cylinder are provided in the enlarged tapered cylinder portion. Further, in addition to the first feature, the spray combustor of the present invention has a supply path of the primary air for combustion that is ejected together with the fuel from the central hole, and a secondary air for combustion that is ejected through a flame stabilizer around the path. The second feature is that it is configured such that the supply path and the supply path are cut off from each other.

[0006]

According to the first feature, the fuel and the primary air for combustion are jetted into the combustion cylinder through the central hole of the flame stabilizer, and the combustion secondary air is passed through the swirl vane portion of the flame stabilizer. Secondary air is introduced into the combustion cylinder to form a swirling flow. Then, the secondary air for combustion is further blown into the combustion cylinder through the plurality of small air holes of the tapered enlarged cylinder portion between the swirl vane portion and the center hole. The air flow from the small air holes serves to prevent the fuel spray ejected from the central hole from being immediately disturbed by the swirling flow from the swirl vane portion. Therefore, the fuel spray is affected by the swirling flow some distance from the center hole. Therefore, the flame is also formed at a distance from the center hole, and soot is prevented from adhering to the center hole and the swirl vane. In addition, the air flow blown out from the small air holes of the tapered expansion cylinder is blown obliquely from the surroundings toward the center axis of the combustion cylinder, so it collides with the fuel spray blown out from the center hole. Since the angle is relatively large and the mixing is actively performed, the generation of soot existing in the burnt gas is suppressed, and as a result, a sufficiently large combustion margin width can be obtained even in a region where the fuel flow rate is small.

Further, according to the second feature, in addition to the action of the first feature, the primary air for combustion which is ejected together with the fuel from the central hole is ejected through the supply passage and the flame stabilizer around the passage. Since the combustion secondary air supply path is cut off from each other, each air flow is completely independent, and even if the fuel flow rate is changed significantly, the amount of auxiliary air is affected. It can be adjusted independently without. Further, in particular, the secondary air side is adjusted without separating the supply paths of the air passing through the swirl vane portion and the air passing through the air small holes of the tapered enlarged cylinder portion, so that the swirl vane portion is adjusted. The ratio of the amount of air passing through to the amount of air passing through the small air holes of the tapered expansion cylinder is almost uniquely determined by the opening area ratio, and depending on the change in fuel flow rate,
Even when the air amount is changed, the flame holding property, the combustibility, and the action of avoiding soot adhesion to the flame holder etc. do not suddenly deteriorate.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings. FIG. 1 is a vertical sectional view showing an embodiment of a spray combustor of the present invention, FIG. 2 is a detailed view of a main portion thereof, (A) is a front view, (B) is a vertical sectional view, and FIG. 3 is a main portion. 2 is an enlarged vertical cross-sectional view, FIG. 4 is a cross-sectional view taken along the line AA of FIG. 2, FIG. 5 is a cross-sectional view taken along the line BB of FIG. 2, and FIG. is there. On one surface of the nozzle mounting flange 1, a primary air cylinder 2 having a substantially cylindrical shape, a secondary air cylinder 3 having a substantially circular tube shape which is fitted on the primary air cylinder 2 with a predetermined interval, and a secondary air cylinder 3 are provided. An outer cylinder 4 having a substantially tubular shape that is fitted at a predetermined interval is attached, and on the other surface of the nozzle attachment flange 1,
A substantially cylindrical air inlet tube 5 is attached.

The primary air cylinder 2 has a conical cone portion 2a integrally formed at one end, and the other end is fitted to the nozzle mounting flange 1. The secondary air cylinder 3 has a circular tubular plate portion 3a integrally formed at one end, and a circular disc plate portion 3b integrally formed at the other end, and is attached to the nozzle mounting flange 1. Has been. The outer cylinder 4 is provided with a circular ring-shaped annular plate portion 4a at one end and integrally has a circular disk-shaped annular plate portion 4b at the other end, which is the secondary air cylinder 3
It abuts the nozzle mounting flange 1 via the annular plate portion 3b. A substantially cylindrical combustion cylinder 7 is fitted into one end of the outer cylinder 4 at a predetermined interval, and one end of the combustion cylinder 7 is fixed to the inner circumference of the annular plate portion 4a of the outer cylinder 4.

A flame stabilizer 22 is provided on the base end side of the combustion cylinder 7. The flame stabilizer 22 is provided between the tip of the cone portion 2a of the primary air cylinder 2 and the inner circumference of the annular plate portion 3a of the secondary air cylinder 3, and has a center hole 22a at the center and a flame stabilizer. The swirl vane portion 22b, which is the main body of the swirl blade 22, the swirl vane outer wall 22c as an air blocking wall provided on the entire outer circumference of the swirl vane portion 22b, and the swirl vane outer wall 22c, which are continuously formed from the swirl vane outer wall 22c to the front An expanding swirler cone portion 22d, a short tubular portion 22e formed continuously at the tip of the swirler cone portion 22d, and the short tubular portion 22e.
It has a plurality of swirling air holes 22f and a plurality of centripetal air holes 22g. The swirling air hole 22f is opened to have a swirling angle ω with the radial center direction so that the jetted air flow has the same swirling (rotating) direction component as the swirling component of the air flow passing through the swirl vane portion 22b. Has been done. Further, the centripetal air hole 22g is opened so that air is ejected toward the center in the radial direction. Swirl air hole 22f and centripetal air hole 22
g is smaller than the central hole 22a. Also the flame stabilizer 22
The inner diameter D1 of the short tube portion 22e is smaller than the inner diameter D2 of the combustion tube 7. The annular plate portion 3a of the secondary air cylinder 3 is also provided with an auxiliary hole 3c along the inner wall of the combustion cylinder 7 for allowing air to flow into the combustion cylinder 7.

Further, in the present invention, the flame stabilizer 22
On the inner peripheral side of the swirl vane portion 22b, a tapered enlarged cylindrical portion 22h that expands from the center hole 22a toward the inner peripheral side of the swirl vane portion 22b is provided, and the tapered enlarged cylindrical portion 22h is provided with a combustion cylinder. 7
A plurality of small air holes 22i are provided to blow air obliquely from the surroundings toward the central axis of the. This small air hole 22i is of course smaller in diameter than the central hole 22a.

A substantially cylindrical nozzle guide 25 is fitted in the cylindrical portion 1a of the nozzle mounting flange 1, and a substantially cylindrical nozzle adapter 9 is fitted in the nozzle guide 25 so as to be movable in the left-right direction in FIG. It is fitted. A fuel injection valve 11 for injecting fuel is attached to one end of the nozzle adapter 9, and a part of the fuel sprayed from the injection hole of the fuel injection valve 11 is blocked in the nozzle guide 25 by cutting off a part of the fuel. Spray cutter 26 for adjusting the spray cutter 26, the spray cutter 26 is fixed, and the spray cutter restraining plate 27 provided for capturing and collecting the fuel overflowing into the downstream of the spray cutter 26, An igniter 10 for ignition is attached. Fuel is fed under pressure from a fuel supply device (not shown) to the fuel injection valve 11 via the fuel supply pipe 20 penetrating the disk portion 5a of the air inflow cylinder 5 and the nozzle adapter 9, and the fuel cut off by the spray cutter 26 is removed. The fuel is recovered via a fuel recovery pipe 23 that penetrates the nozzle guide 25 and the air inflow cylinder 5.

With the above structure, the combustion air chamber 12 surrounded by the air inflow cylinder 5 and the nozzle mounting flange 1 is formed.
A first air chamber 13 which is surrounded by the primary air cylinder 2 and the nozzle mounting flange 1 and communicates with the inside of the combustion cylinder 7 through the center hole 22a of the flame stabilizer 22, the primary air cylinder 2 and the secondary air. A second air chamber 14 formed between the cylinder 3 and a third air chamber 15 surrounded by the outer cylinder 4, the nozzle mounting flange 1, the secondary air cylinder 3 and the combustion cylinder 7 is formed. ing. The nozzle mounting flange 1 has a plurality of rectifying air holes 16 for communicating the combustion air chamber 12 and the first air chamber 13, and a plurality of rectifying air holes 16 for communicating the combustion air chamber 12 and the second air chamber 14. Air hole
17 and a plurality of rectifying air holes 18 that connect the combustion air chamber 12 and the third air chamber 15 to each other. A large number of holes 19 are partially formed in the combustion cylinder 7.

Next, the operation will be described. The fuel supplied to the fuel injection valve 11 via the fuel supply pipe 20 and the nozzle adapter 9 is injected from the injection hole of the fuel injection valve 11 and flows into the combustion cylinder 7 through the central hole 22a of the flame stabilizer. To do. At this time, if the nozzle adapter 9 is retracted to the right of the position shown in FIG. 1, a part of the fuel sprayed from the injection hole of the fuel injection valve 11 is blocked by the spray cutter 26 and the fuel recovery pipe 23 is blocked. The amount of fuel sprayed to the combustion cylinder 7 is reduced because the fuel is sprayed through the combustion cylinder 7. The amount of this reduction depends on the position of the fuel injection valve 11. On the other hand, the combustion air chamber 12 via the combustion air supply pipe 6
The combustion air that has been pressure-fed to the first air chamber 13 passes through the straightening air hole 16 of the nozzle mounting flange 1 which also serves as a straightening plate.
Is sent to the combustion cylinder 7 as primary air A1 through the center hole 22a of the flame stabilizer together with the fuel sprayed from the fuel injection valve 11. Therefore, even when the amount of fuel sprayed into the combustion cylinder 7 is small, the fuel can be sufficiently penetrated by the primary air A1.

Combustion air in the combustion air chamber 12 is supplied as secondary air to the second air chamber 14 through the rectifying air holes 17 and passes through the swirl vanes 22b of the main body of the flame stabilizer. To do. At this time, the secondary air A2 that has passed through the swirl vane portion 22b becomes a swirl flow that flows forward and in the circumferential direction, flows into the combustion cylinder 7, and swirler / cone portion 22d that is an airflow guide of the combustion cylinder 7.
By this, it becomes a smooth flow and plays a role of holding flame. In addition, the secondary air A2 is formed by the swirl vent 22f of the short tube portion 22e of the flame stabilizer 22, the centripetal air hole 22g, and the annular plate 3a of the secondary air tube 3.
The auxiliary holes 3c also flow into the combustion cylinder 7. Further, by configuring the swirl vane outer peripheral wall 22c that is the airflow blocking wall, the outflow of the airflow that tries to go out in the radial direction of the swirl vane portion 22b is prevented, and a smooth swirl flow is generated in the forward and circumferential airflows. It is formed.

In particular, according to the present invention, the secondary air A2 also flows into the combustion cylinder through the small air holes 22i formed in the side wall of the enlarged tapered cylinder portion 22h formed inside the swirl vane portion 22b. The fuel spray from the center hole 22a is swirled from the swirl vane portion 22b at an early stage due to the shielding effect by the primary air blown from the center hole 22a and especially the air blown from the air small holes 22i around it. It will not be disturbed by the flow. Therefore, the flame is
Formed a distance from the exit of the center hole 22a
And soot is prevented from adhering to the swirl vane portion 22b. Furthermore,
The air flow blown obliquely from the surroundings toward the center axis of the combustion cylinder 7 from the small air holes 22i of the tapered expansion cylinder portion 22h is large with respect to the spread angle of the fuel spray from the center hole 22a. Since the angle φ is provided (see FIG. 3), the fuel spray and the air are more actively mixed near the outlet of the central hole 22a as compared with the conventional case (FIG. 11). Therefore, the generation of soot existing in the burnt gas can be suppressed, and as a result, a large combustion margin width can be secured even in a region where the fuel flow rate is small (see FIG. 6).

Further, the center hole 22a is formed by the primary air cylinder 2.
From the supply path of the primary air A1 that is ejected together with fuel from
Since the swirl vane portion 22b around the swirl vane portion 22b and the supply path of the secondary air A2 ejected from the side are cut off from each other, a stable flame is formed even if the fuel flow rate is largely changed, and the flame holding property and Combustibility can be improved. Further, the air flow from the swirl vane portion 22b and the air flow from the air small hole 22i of the tapered enlarged cylinder portion 22h are supplied from the second air chamber 14 which is the same secondary air supply path. Since the paths are not separated, the air flow ratio of both is stable, and the performance of the flame stabilizer 22 can be stabilized at a constant level. That is, the swirling airflow by the swirling vane portion 22b serves to attract the flame upstream, while the air small hole 22i of the tapered enlarged cylindrical portion 22h is provided.
As one of the roles of the air flow from the, the role of pushing the flame downstream is fulfilled. Therefore, the ratio between the swirling air flow rate and the air flow rate from the small air hole 22i is uniquely determined by the opening area ratio, and therefore, even when the air flow rate is changed according to the change in the fuel flow rate, The flame holding property, the flammability, and the effect of avoiding the attachment of soot to the flame holder 22 and the like are not significantly changed.

Further, since the inner diameter D1 of the short cylinder portion 22e of the flame stabilizer 22 is made smaller than the inner diameter D2 of the combustion cylinder 7, the penetration distance of the air blown from the swirling air hole 22f and the centripetal air hole 22g. Becomes shorter and mixing is promoted accordingly. Further, fresh secondary air also flows in along the inner wall of the combustion cylinder 7 from the auxiliary hole 3c provided in the annular plate portion 3a of the secondary air cylinder 3, and soot is suppressed from adhering to the inner wall of the combustion cylinder 7. To be done. In addition, the combustion air in the combustion air chamber 12 is supplied to the third air chamber 15 through the rectifying air hole 18 and flows into the combustion cylinder 7 through the hole 19 as the tertiary air A3. Thus, when the fuel injected from the injection hole of the fuel injection valve 11 is ignited by the igniter 10, a stable flame is formed in the combustion cylinder 7. Incidentally, an auxiliary flame hole may be provided in the swirler cone portion 22d in combination with the installation of the side wall hole of the flame stabilizer 22.

In the second embodiment shown in FIG. 7, a tapered enlarged cylindrical portion 22h and a small air hole 22i are provided in the side wall of the swirling blade portion 22b between the central portion 22a and the swirling blade portion 22b. On the outer peripheral side of the swirl vane portion 22b, a swirler cone portion 22d extends directly to the combustion cylinder 7, but a short cylinder portion 22e is not provided. Such a configuration is also included in the scope of the present invention.

In the above embodiments, a great effect is obtained when the spray cut method is adopted, but from the viewpoint of flame holding property exerted on proportional control, a fuel return nozzle, an air injection nozzle, an ultrasonic nozzle, etc. may be used. Good. Alternatively, a single input nozzle may be used.

[0021]

According to the spray combustor according to the first aspect of the present invention, the flame stabilizer has a tapered shape that expands forward around the outer periphery of the center hole. A plurality of blown-out air blown obliquely from the periphery toward the central axis of the combustion cylinder to the tapered expansion cylinder part with the expansion cylinder part interposed, the swirl vane portion being arranged on the outer periphery of the expansion cylinder part. Since the small air holes are provided, the fuel spray ejected from the center hole into the combustion cylinder is not disturbed by the swirling air flow from the early stage, preventing soot from adhering to the center hole and the swirl vane. can do. Furthermore, since the air flow blown out from the small air holes of the tapered expansion cylinder is blown out obliquely from the periphery toward the center axis of the combustion cylinder, the collision angle with respect to the fuel spray blown out from the center hole is It is relatively large and can be actively mixed. Therefore,
Generation of soot existing in the burnt gas is suppressed, and as a result, a sufficiently large combustion margin width can be obtained even in a region where the fuel flow rate is small. According to the spray combustor described in claim 2, in addition to the effect of the configuration described in claim 1, a supply path of the primary air for combustion ejected together with the fuel from the central hole and a flame stabilizer around the supply path. Since it was configured to cut off the supply path of the secondary air that is ejected through each other, each air flow can be made completely independent, and even if the fuel flow rate is greatly changed, the amount of auxiliary air is It can be adjusted independently without being affected.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing an embodiment of a spray combustor of the present invention.

FIG. 2 is a detailed view of a main part of the spray combustor shown in FIG.

FIG. 3 is an enlarged vertical sectional view of a main part of the spray combustor shown in FIG.

4 is a cross-sectional view taken along the line AA of FIG.

5 is a sectional view taken along line BB in FIG.

FIG. 6 is a diagram showing a relationship between an appropriate combustion region, a fuel amount, and an air amount in the spray combustor of the embodiment.

FIG. 7 is a vertical cross-sectional view showing a second embodiment.

FIG. 8 is a vertical sectional view showing an example of a conventional spray combustor.

FIG. 9 is a front view of a flame stabilizer showing an example of a conventional spray combustor.

FIG. 10 is a front view of a flame stabilizer showing an example of another conventional spray combustor.

FIG. 11 is a cross-sectional view of a flame stabilizer showing an example of another conventional spray combustor.

[Explanation of symbols]

 7 Combustion cylinder 11 Fuel injection valve 22 Flame stabilizer 22a Center hole 22b Swirl vane part 22c Swirl vane outer wall 22d Swirler cone part 22e Short cylinder part 22f Swirl air hole 22g Centric air hole 22h Tapered expansion cylinder part 22i Air Small hole

Claims (2)

[Claims] 1. A flame stabilizer having swirl vanes is attached to a base end side of a combustion cylinder, and fuel from a fuel injection valve is sprayed into the combustion cylinder together with primary air for combustion through a central hole of the flame stabilizer. Further, it is a spray combustor that performs combustion in the combustion cylinder by supplying secondary air for combustion to the combustion cylinder through the flame stabilizer, and the flame stabilizer is directed forward toward the outer periphery of the center hole. The swirl vane portion is arranged around the outer periphery of the enlarged cylindrical portion with the tapered enlarged cylindrical portion interposed therebetween, and the tapered enlarged cylindrical portion is arranged from the periphery toward the central axis of the combustion cylinder. A spray combustor having a plurality of small air holes for blowing air in an oblique direction. 2. A configuration in which the supply path of the primary combustion air that is ejected from the central hole together with the fuel and the supply path of the secondary combustion air that is ejected through the flame stabilizer around the center hole are cut off from each other. 1. The spray combustor according to 1.