JPH08312920A - Structure of nozzle spray type burner - Google Patents

Abstract

PURPOSE: To propose the structure of nozzle spray type burner, which is capable of shortening flame and straining noise by supplying combustion air in the condition of whirling stream. CONSTITUTION: A nozzle spray type burner 6, incorporated into a warm-air generator, is provided with a diffuser 13, supplying combustion air, introduced from outer peripheral side, in the shape of whirling stream into a nozzle 14, and a stabilizer 18, positioned before the nozzle 14 and provided with penetrating holes (18c, 18d) formed in a condition that the opening rate of the holes is reduced from the center toward the outside in radial direction. High-speed whirling stream of flow of gas is formed at the central side and low-speed whirling stream of the flow of gas is formed at the outside in the radial direction relatively through the penetrating holes of the stabilizer 18. As a result, the flow of gas is in the condition of high-speed whirling stream at the central side thereof or the main stream of combustion whereby formed flame becomes short. Further, violent combustion zone due to the high-speed whirling stream at the central side is covered by mild combustion zone due to the low-speed whirling stream at the outer peripheral side and the mild combustion zone functions as a buffer zone whereby noise, accompanied by combustion, can be restrained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a nozzle spray type burner used for a hot air generator generally called a liquid fuel combustion type hot air generator used for heating or drying in a factory or the like. It is about.

[0002]

2. Description of the Related Art Generally, a hot-air generator includes a fuel tank, a nozzle spray type burner for burning a liquid fuel supplied from the fuel tank, and a combustion chamber formed on the flame blowing side of the burner. And a combustion fan for supplying combustion air, and an outside air introduction fan for mixing the outside air with the combustion gas ejected from the combustion chamber to form warm air. In operation, the fuel sprayed from the burner is ignited by the ignition rod and burns while being mixed with the combustion air. The combustion gas generated in the combustion chamber is blown out from the combustion chamber, mixed with the outside air supplied from the blower fan to become warm air, and is blown out from the warm air blowing port of the warm air generator.

In this warm air generator, attempts have been made to shorten the axial length of the combustion chamber by shortening the flame from the burner in order to make it compact, especially to reduce the axial length. For example, in Japanese Unexamined Patent Publication No. 63-46311 and Japanese Utility Model Publication No. 5-18569, a disc-shaped flame stabilizer having a configuration in which blades are radially cut and raised is arranged on the outer peripheral side of a central hole. A configuration is adopted in which combustion air is supplied from a direction orthogonal to the. With this flame stabilizer, the combustion air supplied from the combustion fan is
It is supplied to the nozzle located on the center side as a swirling flow through the blades on the outer peripheral side of the flame stabilizer. Therefore, the swirling flow promotes the mixing of air and fuel, and the flame can be shortened. Therefore, the axial length of the combustion chamber can be shortened, and the warm air generator can be made compact.

[0004]

However, when the combustion air is made into a swirling flow, another problem occurs that the noise becomes large if the swirling speed is high. In particular, in the method disclosed in the above publication,
The swirling flow formed by the flame stabilizer has a high-speed swirling flow formed on the outer peripheral side thereof, and the axial flow becomes the main flow toward the center side, so that the generation of noise accompanying the swirling flow formation is large. . If the flow velocity of the swirling flow is reduced by focusing only on the noise, the mixing of the combustion air and the atomized fuel will not be promoted, and the flame formed will become longer in the axial direction, resulting in a compact combustion chamber. Cannot be realized.

In view of this point, an object of the present invention is to propose a structure of a nozzle spray type burner capable of making combustion air into a swirling flow to shorten a flame and suppressing noise. .

[0006]

In order to solve the above-mentioned problems, a nozzle atomizing burner according to the present invention is a fuel atomizing nozzle in which combustion air introduced from the outer peripheral side is centrally located in the form of a swirling flow. And a stabilizer having a through hole formed at a position on the downstream side in the fuel spray direction of the nozzle toward the outer side in the radial direction from the center, in which a through hole is formed in a state where the aperture ratio decreases. Through the through hole of the stabilizer, a mixed gas flow of mist fuel and combustion air, which has a high-speed swirl flow on the center side and a low-speed swirl flow on the outer side in the radial direction, is formed.

Here, the stabilizer may be a plate-shaped one having a central hole and a group of slits radially formed from the outer peripheral side of the central hole and having the same width.

[0008]

In the nozzle spray type burner of the present invention, the combustion air is introduced from the outer peripheral side of the diffuser and becomes a swirling flow, so that the swirling speed increases due to the inertial force toward the center side. Therefore, the mixing with the spray fuel from the nozzle located at the center is efficiently performed. next,
The gas formed by mixing is blown out through the stabilizer. Here, since the passage resistance of the mixed gas is small on the central side where the opening ratio is large, the mixed gas is blown out through the stabilizer as a high-speed swirl flow, but the passage resistance is large on the outer peripheral side where the opening ratio is small. It is swirled and blown out. In addition, the flow rate on the central side is higher,
It decreases toward the outer circumference.

As a result, a vigorous combustion state is formed in the central portion and a gentle combustion state is formed on the outer peripheral side.
Further, since the high-speed swirling flow is present on the center side of the main flow of combustion, the flame formed is short. Furthermore, the vigorous combustion region due to the high-speed swirling flow on the center side is covered by the gentle combustion flow region due to the swirling flow with a slow velocity on the outer periphery, so the gentle combustion region on the outer peripheral side functions as a buffer region. Noise associated with combustion is also suppressed.

[0010]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows the construction of a liquid fuel combustion type hot air generator incorporating a nozzle spray type burner according to the present invention. The hot air generator 1 of the present example is composed of a horizontally-oriented flat rectangular parallelepiped fuel tank 2 and a cylindrical hot air generator body 3 mounted on the upper surface thereof. The warm air generator main body 3 is provided with a cylindrical main body housing 4, and a warm air blowing port 4a is opened at the tip of this housing. Inside the housing 4, a combustion chamber outer cylinder 5 which is slightly smaller than this is arranged coaxially, and a combustion chamber 5a is partitioned and formed therein. A nozzle spray type burner 6 is coaxially attached to the rear end of the combustion chamber outer cylinder 5. Further, on the rear side of the burner 6, a blower fan 7 for introducing outside air is arranged coaxially, and the outside air introduction surface faces the rear end opening 4b of the main body housing 4.

The overall operation of the warm air generator 1 of this example is similar to that of the conventional one, and the fuel supplied from the fuel tank 2 to the burner 6 via the fuel supply passage (not shown) is Are mixed with air and ignited, and burned in the combustion chamber 5a to form high-temperature combustion gas. The combustion gas is ejected from the ejection port 5b at the front end of the combustion chamber. Further, the outside air introduced from the blower fan 7 is mixed with the combustion gas ejected from the ejection port 5b through the annular passage 8 between the main body housing 4 and the combustion chamber outer cylinder 5, and then becomes hot air. And is blown out from the outlet 4a.

Next, the structure of the nozzle spray type burner 6 of this embodiment will be described with reference to FIGS. Burner 6
Includes a cylindrical case 11 and a large-diameter cylindrical turbo case 12 attached to the rear end of the combustion chamber. An annular front wall 11a of the case 11 is formed on the rear annular end wall 5b of the combustion chamber outer cylinder 5. On the other hand, it is fixed coaxially.

Inside the cylindrical case 11, a cup-shaped diffuser 13 is coaxially arranged with its opening side facing forward, and an annular flange 13a formed at the end on the opening side. It is fixed to the annular front wall 11a of the case 11. At the center of the bottom wall 13b of the cup-shaped diffuser 13, a fuel spray nozzle 14 is arranged so as to penetrate therethrough in the front-rear direction. Bottom wall 1
The tip of the ignition rod 15 is located in front of the nozzle tip side portion protruding forward from 3b, and the ignition rod 15 is connected to the igniter 16. The rear end side of the nozzle 14 is supported by a nozzle adapter 17, and the nozzle adapter 17 is connected to the fuel tank 2 via a fuel supply path (not shown).

A shallow cup-shaped stabilizer 18 is coaxially arranged between the nozzle 14 and the annular front wall 11a of the case 11 with its opening side facing forward, and is formed at the opening end. Annular flange 18a
Is fixed to the annular front wall 11a of the case 11. A frame cone 19 that spreads forward is connected to the open end side of the stabilizer 18, and the frame cone 19 extends into the combustion chamber 5a.

On the other hand, a combustion fan 21 is built in the turbo case 12 attached to the rear side of the case 11. A turbo blower, a propeller fan, or the like can be used as the combustion fan 21. Combustion fan 21
The shaft of the impeller passes through the rear end wall 12a of the turbo case 12 and is connected to the output shaft 22a of the motor 22 coaxially attached to the rear surface of the end wall 12a.

In this example, the output shaft 22a of the motor 22 also projects to the rear side, and the blower fan 7 is attached to this projecting portion. As described above, the combustion fan 21 and the blower fan 7 are arranged coaxially, and the common motor 22 is arranged between them to drive them, thereby adopting a structure in which the warm air generator is compact. Is configured.

Next, the structure of the diffuser 13 of this embodiment will be described with reference to FIG. As described above, the diffuser 13 has a cup shape as a whole, and the bottom wall 13b is formed with a nozzle hole 13c for arranging the nozzle 14 so as to penetrate the nozzle 14, and the opening end thereof is outwardly provided. A wide annular end wall 13a is formed and fixed to the case front wall 11a. In the cylindrical body 13d between them, rectangular combustion air introduction holes 13e are formed at eight positions at predetermined angular intervals. These introduction holes 13
Each notch piece 13f cut out to form e is
One side in the circumferential direction is still attached to the body portion 13d,
The other three sides are separated. Then, the tip ends are bent in the same direction with the same inclination angle so as to face inward, and the tips are positioned on the same circumference.

On the rear side of the diffuser 13 of this structure, air is blown from the combustion fan 21 to the front side. This airflow is introduced from the outer peripheral side of the diffuser 13 through the respective introduction holes 13e into the inside thereof. When passing through the introduction hole 13e, the air flow is introduced as a flow deflected in an oblique direction by each notch piece 13f. As a result, a swirl flow is formed in the diffuser 13 and is supplied toward the tip side of the nozzle 14 located at the center thereof.

Next, referring to FIG. 4, the diffuser 1
The structure of the stabilizer 18 arranged on the front side of 3 will be described. The stabilizer 18 also has a thin cup shape as a whole, and an annular flange 18 is provided at its opening end.
a is formed, and this portion is attached to the rear end side of the combustion chamber. On the circular bottom plate portion 18b of the stabilizer 18,
A center hole 18c is formed in the center thereof, and a large number of slits 18d are radially formed on the outer peripheral side. In this example, 12 slits 18d are formed. These slits 18d have the same rectangular shape. Therefore, the aperture ratio of the bottom plate portion gradually decreases from the center toward the outer side in the radial direction (outer side in the radial direction).

The operation of the nozzle spray type burner 6 of the present embodiment thus constructed will be described.

When the combustion fan 21 is rotated by the motor 22, combustion air is blown forward from here. Combustion air blown out is diffuser 1
An annular passage 31 between the cylindrical body portion 13d of 3 and the case 11
Enter and from here, the cylindrical body 13d of the diffuser
It is introduced into the interior through the respective introduction holes 13e formed in. That is, the diffuser 13 is introduced into the inside thereof from the outer peripheral side. Since the notch pieces 13f inclined in the same direction are arranged in the respective introduction holes 13e, these function as a deflecting plate, and the introduced air flow becomes a swirl flow, and the nozzle 14 located at the center is positioned. Will be supplied to. In this way, the combustion air is introduced from the outer peripheral side toward the center to form the swirling flow, so that the inertial force of the air increases the flow velocity of the swirling flow toward the center side.

As a result, at the position of the nozzle 14, the combustion air that has become a high-speed swirling flow is mixed with the fuel sprayed from the nozzle. Therefore, mixing of these is facilitated.
An ignition rod 15 is arranged on the tip side of the nozzle so that the fuel is ignited. The combustion gas hits the stabilizer 18 arranged on the front side thereof and is ejected into the combustion chamber 5a through the center hole 18c and the slit 18d formed therein.

As described above, the aperture ratio of the bottom plate portion 18b of the stabilizer 18 becomes smaller toward the outer peripheral side. In addition, the central hole 18c and the slit 1
8d is a mere opening formed in the flat bottom plate portion 18b. Therefore, the combustion gas in the state of the high-speed swirling flow formed in the central portion is ejected toward the combustion chamber side through the central hole 18c in the state of the high-speed swirling flow as it is.
However, since the aperture ratio decreases toward the outer peripheral side of the bottom plate portion 18b of the stabilizer, the swirling speed of the combustion gas passing through the outer peripheral slit 18d is reduced accordingly,
It is jetted to the side of the combustion chamber in the state of low speed swirling flow. In this way, the combustion gas with a large flow rate is ejected from the central portion through the stabilizer 18 in a high-speed swirling state, and the swirling speed of the combustion gas decreases and the passing flow rate also decreases as it goes toward the outer peripheral side. Eject in the state. Figure 4 (C)
3 qualitatively shows how the axial flow velocity distribution of the gas passing through the stabilizer 18 changes at the radial position.

As described above, in this embodiment, the combustion gas ejected to the side of the combustion chamber has the largest fuel concentration, swirling speed, and flow rate at the center, and becomes smaller toward the outer peripheral side. . Therefore, a violent combustion state is formed in the central portion, and a gentle combustion state is formed in the outer periphery. As a result, since the swirling speed is high in the central portion which is the main flow of combustion, the flame formed can be shortened. Further, since the high-speed swirl flow is formed in the central part and an extremely low-speed swirl flow is formed in the outermost peripheral part, the gentle combustion region in the state of this low-speed swirl flow causes the intense combustion region in the central part. It is wrapped, and the combustion region on the outer periphery functions as a buffer region, and the generation of noise is suppressed.

In this example, the stabilizer 1
In FIG. 8, a central hole and a group of rectangular slits are formed substantially radially on the outer peripheral side of the central hole to reduce the aperture ratio toward the outer peripheral side. However, it goes without saying that the opening portion to be formed may have a shape other than this example as long as the opening ratio decreases toward the outer peripheral side.

[0027]

As described above, in the structure of the nozzle spray type burner of the present invention, the diffuser forms the combustion air flow that becomes a high-speed swirl flow at the central nozzle position, and this air flow is generated from the center. A structure is adopted in which the gas is ejected toward the combustion chamber through a stabilizer having through holes formed so that the aperture ratio decreases toward the outer peripheral side. Therefore, according to the present invention, since the combustion gas in the combustion state in which the high-speed swirling flow is intense is formed in the central portion via the stabilizer, the flame formed can be shortened. Moreover, combustion gas in a gentle combustion state of low-speed swirling flow is formed on the outer peripheral side, and this portion covers a violent combustion area due to the high-speed swirling flow on the central side, so that the gentle combustion of the outer peripheral side is performed. The region functions as a buffer region to suppress noise associated with combustion and achieve quietness.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing an overall configuration of a warm air generator to which the present invention is applied.

FIG. 2 is a schematic perspective view showing a state where a nozzle spray type burner incorporated in the warm air generator of FIG. 1 is taken out and cut.

3A and 3B are diagrams showing an example of a diffuser applicable to the present invention, FIG. 3A is a sectional view thereof, and FIG. 3B is a side view showing a partially cutaway state.

4A and 4B are diagrams showing an example of a stabilizer applicable to the present invention, in which FIG. 4A is a front view thereof, FIG. 4B is a side view showing an upper half portion in a sectional state, and FIG. It is a graph which shows the tendency of the flow velocity distribution state of a gas flow.

[Explanation of symbols]

 1 Hot Air Generator 2 Fuel Tank 3 Hot Air Generator Main Body 4 Main Body Housing 5 Combustion Chamber Outer Cylinder 5a Combustion Chamber 6 Nozzle Spray Burner 7 Blower Fan 11 Case 12 Turbo Case 13 Diffuser 13c Nozzle Hole 13d Cylindrical Body 13e For Combustion Air introduction hole 13f Cutout piece 14 Nozzle 15 Ignition rod 18 Stabilizer 18b Bottom plate portion 18c Center hole 18d Slit 21 Combustion fan 22 Motor

Claims (2)

[Claims] 1. A fuel spray nozzle, an ignition rod for igniting fuel sprayed from this nozzle, and a combustion air which is arranged coaxially with the nozzle and is introduced from the outer peripheral side in the form of a swirl flow. Is disposed coaxially with the nozzle at a position downstream of the nozzle and the ignition rod in the fuel spray direction, and the aperture ratio decreases from the center toward the outer side in the radial direction. And a stabilizer having a through hole formed in a state of
A structure of a nozzle spraying burner characterized in that a gas flow that is a high-speed swirl flow on the center side and a low-speed swirl flow on the outer side in the radial direction is formed through a through hole of the stabilizer. 2. The stabilizer according to claim 1, wherein the stabilizer has a plate-like portion including, as the through hole, a central hole and a slit group radially formed from an outer peripheral side of the central hole and having the same width. The structure of the nozzle spray type burner, which is characterized by