JPS6350604B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a combustion device using a fuel spray nozzle, and particularly relates to reduction in combustion noise, short flame length, and size reduction.

Conventional Structure and Problems Conventionally, this type of combustion apparatus has a plurality of swirling air holes 3 on the outer periphery of a combustion tube 2 of the same diameter installed upright in a combustion chamber 1, as shown in FIG. In addition, an auxiliary combustion tube 6 having a recirculation port 4 and a fuel supply port 5 is provided approximately concentrically at a constant interval on the outer periphery of the combustion tube 2.
Because the main combustion flame 7 is formed on the swirling air holes 3 that are closely formed in the upper part of the combustion tube 2, the air jets interfere with each other in the upper, lower, left, and right directions, resulting in a turbulent flow. Therefore, the mixing action mainly in the three air holes is disturbed, and the flame holding state becomes unstable, leading to pulsating combustion and increasing combustion noise, especially infrasound, which is a problem. Furthermore, the main combustion flame 7 was longer than necessary, making it difficult to downsize the combustion chamber 1.

Purpose of the Invention The present invention eliminates these drawbacks of the conventional technology, and by making the main flame shape on the combustion tube into a fishtail shape, the mixing action is stabilized and promoted, stabilization of flame holding is achieved, and combustion noise is reduced. The purpose is to reduce the heat and shorten the flame.

Structure of the Invention In order to achieve this object, the present invention provides an air hole structure that serves as a combustion main flame forming section in the upper part of the combustion cylinder by protruding the upper circumferential wall surface of the combustion cylinder in a horizontal V-shape, for example. By providing a slit-shaped air hole in the part and configuring it so that the air flow injected from this air hole is radial or swirling,
The ejected air flow is fishtail-shaped, and while the upper part creates an air curtain, the lower part sucks the rich mixed gas rising from the mixing chamber into the valleys between the air holes, and the ejection speed increases at the base of the lower part of the air holes. Since the mixture is fast, it is sufficiently mixed, and after being mixed, it is rapidly decelerated and spreads out in a fishtail shape, ensuring a sufficient combustion surface.With complete combustion, flame stability is stable and combustion noise is greatly reduced. As a result, the fishtail-shaped main combustion flames overlap in a flower-like pattern, and the overall main combustion flame becomes extremely short.

DESCRIPTION OF EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. 2 and 3.

1 is the combustor body which also serves as a heat exchanger such as a water can wall. Reference numeral 2 denotes a combustion cylinder having a plurality of air holes 3, 4, and 5, which are installed approximately in the center of the combustor body 1, and are arranged densely in the upper part and sparsely in the lower part. In particular, the upper peripheral wall surface is formed with, for example, a horizontal V-shaped protrusion 6, and a slit-shaped air hole 3 is formed in the protrusion 6.
Incidentally, the slit-shaped air hole 3 may be composed of a plurality of small hole groups, and the air flow ejected from the slit-like air hole 3 may be configured so that it becomes a radial or swirling flow when viewed from above with the combustion tube 2 as the central axis. It is. Reference numeral 7 denotes an auxiliary combustion tube which is lower than the combustion tube 2 and stands upright on the outer periphery almost concentrically with the combustion tube 2, and has a recirculation port 7 at the bottom and a fuel supply port 9 at one side. 10 is a mixing chamber, 11
1 is a combustion chamber, 12 is a recirculation path, and 13 is a combustion regulating plate having an opening 13' located at the top of the combustion tube 2. 14 is a fuel spray nozzle, 15 is an igniter, 16 is a primary air cylinder, 17 is a cylinder body, 18 is a fuel pump, 19 is a blower case, 20 is a combustion main flame,
21 is an arrow indicating the recirculation effect. Especially the third
As shown in the figure, it is necessary to process the slit so that the cross-sectional area of the slit-shaped air hole 3 is smaller on the inside and becomes larger on the outside.
Note that the air holes 5 may be formed so as not to create a swirling air flow. Furthermore, if the upper end of the auxiliary combustion cylinder 7 is narrowed slightly toward the inner diameter side, the degree of infiltration of the mixed gas into the three portions of the combustion hole will be more effective.

The operation will be explained using an embodiment configured as above. First, liquid or gaseous fuel is injected from the fuel pump 18 into the mixing chamber 10 through the fuel injection nozzle 14 . On the other hand, combustion air is supplied from the ventilation case 19 to the mixing chamber 1 through the plurality of air holes 3, 4, and 5 of the combustion tube 2.
0 and the combustion chamber 11, and some of the primary air 16
The fuel is supplied into the mixing chamber 9 and the combustion chamber 11 together with the injected fuel. At this time, when the igniter 15 generates, for example, a high-pressure spark, the injected fuel is ignited by its high-temperature heat, and this ignition flame moves into the mixing chamber 10 together with the injected fuel, performing high-speed swirl mixing and igniting the injected fuel. In order to vaporize by self-combustion and perform diffusion and homogeneous mixing, the slit-shaped air holes 3 are instantly released from the ignition stage.
At this point, the flame becomes fishtail-shaped with no soot and blue, and overlaps like a flower leaf, forming a quiet, short, and stable combustion main flame 20 for complete combustion. In particular, as described above in detail in FIG. 3, the shape of the air hole 3 is a slit-like hole formed in an outwardly protruding protrusion 6, and the protrusion 6 narrows the upper part of the mixing chamber 10. The cross-sectional area of the air hole 3 bored in the wall of the combustion tube 2 is larger on the outside than on the inside due to the thickness of the plate, so that the air jetting speed is The inner root of the root is early and the outer root is markedly lowered. Furthermore, the shape of the airflow spreads radially to form a fishtail shape, and the airflows overlap each other in the shape of flower leaflets, forming an air curtain as a whole at the tip of the fishtail shape.

Therefore, the rich mixed gas generated in the mixing chamber 10 is surrounded by the air curtain and the wall of the auxiliary combustion tube 7, and is forced to flow into the valleys between the plurality of slit-shaped air holes 3 as indicated by the arrow A in FIG. As the gas is sucked in all at once, a very high speed and smooth ejection air flow and diffusion homogeneous mixing are performed at the base of the air hole 3, and a sufficient amount of mixed gas is generated, just like a premix burner. A clean, soot-free blue flame with a fishtail-like shape and a short flower-leaf-like combustion main flame 2.
0 and complete combustion.

On the other hand, the mixing of air and mixed gas is promoted in a very stable manner, the ejection velocity of the main combustion flame 20 is lowered as a whole, the fishtail-shaped flames overlap each other, and the air holes 3 Since the combustion tube 2 has a protrusion 4 configuration, the lower part of the air hole 3 is blown out slightly downward and faces the rising mixed gas, so these conditions combine to significantly improve the flame holding effect. be done. As a result, there is no pulsating combustion, and the increase in combustion noise (especially infrasound (sound below 50 KHz)), which previously occurred due to unstable flame stability of the combustion main flame 20, has almost disappeared and the noise has been greatly reduced. Ta.
Furthermore, since the main combustion flame 20 has a fishtail-like flame shape compared to the conventional filament flame, the flame surface area per unit air hole area becomes larger and the flame becomes significantly shorter. Vessel body 1
As the width of the combustor body 1 is increased relative to the peripheral wall of the combustor, the height of the combustor tube 2 becomes lower in the former case, and the diameter of the combustor main body 1 is reduced by shortening the flame, making it possible to reduce the size of the combustor body 1. As a result, the heat exchange efficiency can be significantly improved, and there is also the prospect that the combustor main body 1 can be further downsized, which is of great practical importance.

Effects of the Invention As explained above, according to the configuration of the present invention,
For example, the air hole configuration that forms the main combustion flame in the upper part of the combustion cylinder is
By protruding in a letter shape and providing slit-like air holes in the protrusions, the air flow ejected from the air holes becomes fishtail-shaped and overlaps like a flower leaf, and an air curtain is formed above the air flow. Due to this action, the mixed gas rising from the mixing chamber is forcibly and smoothly sucked into the mutual valleys of the slit-shaped air holes, so the mixed gas and air are spread uniformly and efficiently at high speed. While this promotes the mixing of air quality, the airflow spreads outward in a fishtail shape, ensuring a sufficient combustion surface, resulting in a clean, soot-free fishtail with no short pulsations. Complete combustion with a stable combustion main flame. Therefore, the entire combustion chamber can be downsized in addition to significantly quieter combustion, and a practical combustion device can be realized.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of a conventional combustion device, FIG. 2 is a cross-sectional view of a combustion device showing an embodiment of the present invention, and FIG.
The figure is an enlarged sectional view of the main part of FIG. 2. 2... Combustion tube, 3... Slit-shaped air hole, 4
...Horizontal V-shaped protrusion, 5,5'...air hole,
6... auxiliary combustion tube, 7... recirculation port, 8... fuel supply port, 9... mixing chamber, 10... combustion chamber.

Claims (1)

[Claims] 1. A fuel and air supply means and an ignition means are faced into the combustion chamber, a combustion cylinder having a plurality of air holes is installed approximately in the center of the combustion chamber, and a mixing chamber and a recirculation path are formed around the outer periphery of the combustion cylinder. An auxiliary combustion cylinder having a recirculation port and a fuel supply port is erected so that the auxiliary combustion cylinder has a recirculation port and a fuel supply port, and the periphery of the upper side wall of the combustion cylinder is protruded to form a protrusion, and the air flow is ejected from an air hole drilled around the protrusion. A combustion device with air holes in a slit shape or in a group of small holes to produce a radial or swirling flow.