JPH0611114A - Spray burner - Google Patents

Abstract

PURPOSE:To prevent adhesion and accumulation of soot and to reduce the length of a flame by a method wherein mixture of fuel and air in a primary combustion region (a flame stabilizing region) is promoted and temperature is increased in the region. CONSTITUTION:In a spray burner, a flame stabilizer 22 is attached on the base end side of a combustion cylinder 7, fuel from a fuel injection valve 11 is sprayed in the combustion cylinder through a central hole 22a of the flame stabilizer togetherwith primary air A1 for combustion to effect combustion. The flame stabilizer is provided around a central hole at least with a revolving blade part 22d, a swirler cone part 22f continuously formed therearound and expanded frontward, and a short cylinder part 22g formed in succession to the tip part of the swirler cone part. The short cylinder part is provided with a plurality of a centripetal air holes 22h opened to the center in a radiation direction of the combustion 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 Generally, in a conventional spray proportional control combustor, when the fuel flow rate is further increased in order to increase the maximum load, the vaporization of the spray in the primary combustion region (flame holding region) and the mixing with the primary air are performed. Is gradually worsened, and soot is attached and accumulated near the flame stabilizer and the air holes in the combustion cylinder.
In addition, the prolongation of flame is promoted, and the deterioration of combustibility is observed. To overcome these drawbacks, the Applicant provided the spray combustor shown in FIG. 3 on the same date as the present application.
This combustor will be briefly described with reference to FIG. Flame stabilizers (7a, 7b, 7c, 7d, 7e, 7f) are formed on the base end side of the combustion cylinder 7,
The fuel injection valve 11 faces the center hole 7d of the flame stabilizer. The flame stabilizer includes a swirler cone portion 7a which is an air flow guide, a swirl vane portion 7b formed by a cut and raised region, and the swirl vane portion 7b.
A swirl vane outer peripheral wall 7e as an airflow blocking portion formed on the entire outer circumference of the swirl vane, a flat plate region 7c reaching the central hole 7d on the inner circumferential side of the swirl vane part 7b, and a plurality of air holes 7f arranged in the region 7c. Consists of. The primary air A1 is ejected from the inside of the primary air cylinder 2 through the center hole 7d into the combustion cylinder 7 together with the fuel spray, and the secondary air A2 is discharged from the inside of the secondary air cylinder 3 into the swirl vanes 7b of the flame stabilizer and the air holes. It is introduced into the combustion cylinder 7 through 7f.

[0003]

In the spray combustor shown in FIG. 3 described above, it is possible to reduce the adhesion and accumulation of soot around the flame holder and improve the flame holding property and combustibility, but It was just a step away from the combustion load. It was also a step forward in terms of flame lengthening and flammability.

Therefore, the present invention eliminates the above-mentioned drawbacks of the conventional spray combustor, promotes the mixing of fuel and air in the primary combustion region (flame holding region), raises the temperature in this region, and soot An object of the present invention is to provide a spray combustor capable of avoiding adhesion / accumulation and shortening a flame.

[0005]

In order to achieve the above object, in the spray combustor of the present invention, a flame stabilizer is attached to the base end side of a combustion cylinder, and fuel from a fuel injection valve is attached to the center of the flame stabilizer. A spray combustor for spraying into a combustion cylinder together with primary air for combustion through a hole to perform combustion, wherein the flame stabilizer is formed around at least the swirl vane portion around the central hole and continuously around the swirl vane portion. Has a swirler cone portion that expands forward and a short tube portion that is continuously formed at the tip end of the swirler cone portion, and a plurality of openings are formed in the short tube portion toward the radial center of the combustion tube. The first feature is to have a centripetal air hole.
In addition to the first feature, the spray combustor of the present invention has
The second feature is that the inner diameter of the short cylinder portion of the flame stabilizer is smaller than the inner diameter of the combustion cylinder. In addition to the first or second feature, the spray combustor of the present invention has a supply path of air ejected together with fuel from the central hole and an air ejected through the flame stabilizer around the air supply passage. The third feature is that the supply path and the supply path are cut off from each other. The spray combustor of the present invention has, in addition to any one of the first to third characteristics, a flat plate region extending continuously to a central hole on the inner peripheral side of the swirl vane portion, and the flat plate region is provided with the central portion. The fourth feature is that a plurality of air holes smaller than the hole diameter are provided.

[0006]

According to the first feature, the fuel and the primary air are ejected into the combustion cylinder through the central hole of the flame stabilizer, and the air is injected into the combustion cylinder through the swirl vanes of the flame stabilizer. Was introduced to
Form a swirling flow. At this time, air is also sent from the centripetal air holes of the short tube portion of the flame stabilizer toward the radial center of the combustion tube. The air flow sent from this centripetal air hole is toward the center of the primary combustion region, and is in a direction different from the flow of the primary air and the swirling flow (almost a right angle direction),
Mixing becomes relatively active even with a small amount of air. Therefore, combustion is actively performed, the temperature is increased in the primary combustion region (flame holding region), and soot generation is reduced. On the other hand, since the swirling flow is not hindered by setting the small air amount,
Does not have much effect on flame holding. Further, the air flow sent from the centripetal air holes toward the radial center of the combustion tube promotes mixing and combustion, and shortens the flame.
Further, according to the second feature, by making the inner diameter of the short cylinder portion of the flame stabilizer smaller than the inner diameter of the combustion cylinder, the air flow blown out from the centripetal air hole of the flame stabilizer short cylinder portion is generated. As a result, it reaches the center of the combustion tube more easily (the penetration distance becomes smaller), and mixing is further promoted. Therefore, the combustion is further promoted, soot generation can be prevented and the flame can be shortened. Further, according to the third feature, the supply path of the air ejected together with the fuel from the central hole and the air supply path of the air ejected through the flame stabilizer around the central hole are cut off from each other. By completely separating and separating the air passing through the center hole and the air passing through the swirl vane portion and the like around it, a stable flame can be formed even if the fuel flow rate is largely changed. Further, according to the fourth feature, the flat plate region reaching the center hole is continuously provided on the inner peripheral side of the swirl vane portion, and a plurality of air holes smaller than the center hole diameter are provided in the flat plate region. The air from the holes prevents the spray from being prematurely disturbed by the swirling flow,
Therefore, the flame is formed apart from the flame stabilizer with certainty, and soot is prevented from adhering to the center hole and the swirl vane portion.

[0007]

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, and (B) is a vertical sectional view. On one surface of the nozzle mounting flange 1, a substantially cylindrical primary air cylinder 2, a substantially cylindrical secondary air cylinder 3 which is fitted onto the primary air cylinder 2 at a predetermined interval, and a secondary air cylinder 2 are provided. A substantially cylindrical outer cylinder 4 which is fitted at a predetermined interval is attached, and a substantially cylindrical air inflow cylinder 5 is attached to the other surface of the nozzle mounting flange 1.

The primary air cylinder 2 integrally has a cone portion 2a having a tapered shape 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 tubular plate portion 3b integrally formed at the other end, and is attached to the nozzle mounting flange 1. It is installed. The outer cylinder 4 is
The circular tube plate-shaped annular plate portion 4a is provided at one end, and the circular tube plate-shaped annular plate portion 4b is integrally provided at the other end, which is through the secondary air cylinder annular plate portion 3b. It is in contact with the nozzle mounting flange 1. A combustion cylinder 7 having a substantially cylindrical shape is provided at one end of the outer cylinder 4.
Are fitted inside 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 swirl vane portion 22d which is a main body thereof, A swirl vane outer peripheral wall 22e as an air blocking wall provided on the entire outer circumference of the swirl vane 22d, a swirler cone part 22f continuously formed from the outer peripheral wall 22e and expanding forward, and the swirler cone part 22f. 22 g of short tubular part formed continuously at the tip of
A plurality of centripetal air holes 22h opened in the short cylinder portion 22g toward the radial center of the combustion cylinder 7, and a flat plate region provided on the inner peripheral side of the swirl vane portion 22d which is the blade cutting and raising region. 22b and a plurality of air holes provided in the flat plate region 22b
22c and a central hole 22a at the center. The air hole 22c and the centripetal air hole 22h are smaller than the central hole 22a. The inner diameter D1 of the short cylinder portion 22g of the flame stabilizer 22 is smaller than the inner diameter D2 of the combustion cylinder 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.

A substantially cylindrical nozzle adapter 9 is provided with a fuel injection valve 11 for spraying fuel at its tip, and an igniter 10 is also 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 and the nozzle adapter 9. Reference numeral 23 is a fuel return pipe. A combustion air supply pipe 6 connected to a combustion air supply device (not shown) is connected to 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 surrounded by the primary air cylinder 2 and the nozzle mounting flange 1 and communicating 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 chamber 13. A second air chamber 14 formed between the empty 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. Has been done. 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. An air hole 17 and a plurality of rectifying air holes 18 that connect the combustion air chamber 12 and the third air chamber 15 are formed. 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 the flame stabilizer central hole.
It flows into the combustion cylinder 7 through 22a. On the other hand, the combustion air that has been pressure-fed to the combustion air chamber 12 through the combustion air supply pipe 6 is sent to the first air chamber 13 through the rectification air hole 16 of the nozzle mounting flange 1 that also functions as the rectification plate. Fuel injection valve
Along with the fuel atomized from 11, the primary air A1 flows into the combustion cylinder 7 through the central hole 22a of the flame stabilizer. 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.

Further, the combustion air in the combustion air chamber 12 is supplied as secondary air to the second air chamber 14 through the rectifying air hole 17, and the swirling blade portion 22d and the swirling blade portion 22d of the main body of the flame stabilizer are swirled. It passes through the air holes 22c in the flat plate region 22b on the inner peripheral side of the blade portion 22d. At this time, the secondary air A2 that has passed through the swirl vane portion 22d becomes a swirl flow that flows forward and in the circumferential direction and flows into the combustion cylinder 7, and the swirler cone portion 22f that is an air flow guide of the combustion cylinder 7
By this, it becomes a smooth flow and plays a role of holding flame. The secondary air A2 also flows into the combustion cylinder 7 from the centripetal air hole 22h of the short cylinder portion 22g of the flame stabilizer 22 and the auxiliary hole 3c of the annular plate 3a of the secondary air cylinder 3.

Since the outer peripheral wall 22e of the swirl vane, which is an airflow blocking wall, is formed, the outflow of the airflow that tries to go out in the radial direction of the swirl vane portion 22d is prevented, and the airflow in the forward and circumferential directions is smooth. A swirl flow is formed. Further, the secondary air A2 that has passed through the air holes 22c provided in the flat plate region 22b on the inner peripheral side of the swirl vane portion 22d flows inward from the spray boundary region. The inward airflow prevents the spray from being disturbed by the swirling flow in an early stage of spray formation, that is, immediately after entering the combustion cylinder 7. It is possible to avoid the adverse effects of, fuel wetting and soot adhesion to the swirl vane. In addition, if this air hole 22c is not present, a stagnation area is formed, which is one of the factors that cause soot adhesion, but the effect of the air hole 22c is to prevent the creation of a stagnation area and to hold flame. Both the effect of lifting from the vessel will work, and the central hole 22a
The primary combustion zone 24 will be formed at a distance from. Further, the ratio of the amount of air passing through the swirl vane portion 22d to the amount of air passing through the air hole 22c is substantially determined by the opening area ratio, so that the flow rate of the secondary air A2 changes depending on the change in the fuel flow rate. Even if it is made, the flame holding property, the flammability, and the effect of avoiding the soot adhesion to the flame holder are not significantly changed. Further, the primary air cylinder 3 blocks the supply path of the primary air A1 ejected together with the fuel from the center hole from the supply path of the secondary air A2 ejected from the side around which the swirl vanes are present. Therefore, even if the fuel flow rate is largely changed, a stable flame can be formed, and flame holding property and combustibility can be improved.

In particular, in the present invention, a part of the secondary air A2 is sent from the centripetal air hole 22h of the short cylinder portion 22g of the flame stabilizer 22 toward the center of the combustion cylinder 7 in the radial direction. This air flow is toward the center of the primary combustion region 24 and is different from the flow direction of the primary air (axial air) or swirling air blown out with the fuel, so even a small amount of air can be compared. Active mixing becomes active. Further, since the air flow rate is small, it does not hinder the swirling flow, and therefore does not adversely affect the flame holding.
Further, the mixing region does not need to extend for a long time and to extend downstream as compared with the case where holes are provided in the tapered portion such as the swirler cone portion 22f. Further, since the inner diameter D1 of the short cylinder portion 22g of the flame stabilizer 22 is smaller than the inner diameter D2 of the combustion cylinder 7, the penetration distance of the air blown from the centripetal air hole 22h is shortened and the mixing is promoted accordingly. Be done. 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 air hole may be provided in the swirler cone portion 22f in combination with the installation of the side wall air hole of the flame stabilizer 22. Further, although the fuel return type nozzle is adopted in this embodiment, an air injection nozzle, an ultrasonic nozzle or the like may be used. A spray cut method may be used as one of the fuel proportional control injection methods. Alternatively, a single input nozzle may be used.

[0017]

According to the present invention, which has the above-described structure,
According to the spray combustor described in (1), since the short cylinder portion of the flame stabilizer has a plurality of centripetal air holes that are opened toward the radial center of the combustion cylinder, the centric air holes form the center of the primary combustion region. The air flow sent to the part can promote the mixing and combustion of fuel and air, thus preventing the generation of soot,
In addition, it is possible to shorten the flame. According to the spray combustor described in claim 2, in addition to the effect of the configuration described in claim 1, since the inner diameter of the short cylinder portion of the flame stabilizer is smaller than the inner diameter of the combustion cylinder, The airflow blown out from the centripetal air hole of the short tube part of the vessel easily reaches the center of the combustion tube (the penetration distance becomes smaller), so combustion is further promoted, soot generation is prevented and flames are shortened. be able to. According to the spray combustor described in claim 3, in addition to the effect of the configuration described in claim 1 or 2, in addition to the effect of the air blown out from the center hole with the fuel, the flame stabilizer around the supply path. Since it is configured so as to be cut off from the supply path of the air jetted therethrough, it is possible to form a stable flame even when the fuel flow rate changes greatly, and to improve flame holding property and combustibility. According to the spray combustor described in claim 4, in addition to the effect of the configuration described in any one of claims 1 to 3, a flat plate region reaching the central hole is continuously formed on the inner peripheral side of the swirl vane portion. Since the plurality of air holes smaller than the central hole diameter are provided in the flat plate region, the air from the air holes is prevented from prematurely disturbing the spray by the swirling flow, and thus the flame is a flame stabilizer. Formed reliably away from,
It is possible to prevent soot from adhering to the flame stabilizer.

[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 a vertical sectional view showing an example of a conventional spray combustor.

[Explanation of symbols]

 7 Combustion cylinder 11 Fuel injection valve 22 Flame stabilizer 22a Center hole 22b Flat plate area 22c Air hole 22d Swirling vane part 22f Swirler cone part 22g Short cylinder part 22h Centric air hole

Claims (4)

[Claims] 1. A spray combustion in which a flame stabilizer is attached to a base end side of a combustion cylinder, and fuel from a fuel injection valve is sprayed into a combustion cylinder together with primary air for combustion through a central hole of the flame stabilizer to perform combustion. The flame stabilizer has at least a swirl vane portion around the central hole, a swirler cone portion continuously formed around the swirl vane portion and expanding forward, and continuously formed at a tip portion thereof. And a plurality of centripetal air holes opened toward the center of the combustion cylinder in the radial direction. 2. The spray combustor according to claim 1, wherein the inner diameter of the short cylinder portion of the flame stabilizer is smaller than the inner diameter of the combustion cylinder. 3. The method according to claim 1 or 2, wherein a supply path of the air ejected together with the fuel from the central hole and an air supply path of the air ejected through the flame stabilizer around the center hole are cut off from each other. The spray combustor described. 4. The flat plate region extending to the central hole is continuously provided on the inner peripheral side of the swirl vane portion, and a plurality of air holes smaller than the central hole diameter are provided in the flat plate region. The spray combustor described.