JPH045899Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field] The present invention relates to a combustor, and more particularly to a combustor equipped with an evaporator tube on the upstream side in which pre-evaporation and premixing is performed.

[Prior art and its problems]

Conventional combustors of this type include, for example, the one shown in Fig. 4, which is currently being filed by the applicant in Japanese Patent Application No. 58-224257, and the one shown in Fig. 4, which is currently being filed by the applicant in Japanese Patent Application No. 59-194296, although it is not of the reverse flow can type.
There are applications pending for some issues. In FIG. 4, 1 is a cylindrical pre-evaporation and premixing chamber (hereinafter referred to as evaporation chamber), and 2 is a combustion chamber arranged in parallel. In this example, these outer cylinders 3 are formed as an integral molded block using a heat insulating material, and a communication chamber 5 communicating from the evaporation chamber 1 to the combustion chamber 2 is provided on the side of the head casing 4A.

Furthermore, 6 is a cross full board, and this cross full board 6
A space between the communication chamber 5 and the combustion chamber 2 is defined by this, and an annular nozzle 8 to the combustion chamber 2 is formed by the baffle plate 6 and the flame stabilizer 7. 9 is an auxiliary fuel injection valve, 10 is a main fuel injection valve inserted into the evaporation pipe 1 from the outside of the casing 4B, 11 is an ignition plug, and 12 is a dilution duct provided on the downstream side of the combustion chamber 2. .

In the combustor configured in this way, the air A led from the outer circumference of the duct 12 is first mixed with the atomized fuel F injected from the main fuel injection valve 10 in the evaporation chamber 1, which is also a premixing chamber. , and is guided to the communication chamber 5 as a premixture M. In this way, the premixture M is formed into a swirling flow around the flame stabilizer 7, is reversed and guided to the combustion chamber 2, and is combusted there, becoming a diluted mixture in the duct 12 further downstream, where combustion occurs. It continues and becomes high temperature gas.

In other words, this example has a cylindrical evaporation chamber 1 and a combustion chamber 2 formed into a compact integral body, so there is no need for a cylindrical combustion tube, and an inexpensive and ideal premixture is created. It has the characteristics that can be obtained.

However, in the case of a combustor like this example, although air A is sent from around the duct 12 to the evaporation chamber 1 and is made into the premixture M here, there is no inflow of air from around the wall surface. In some cases, the temperature distribution tends to be uneven between the wall surface closer to the combustion chamber 2 and the wall surface not in contact with the combustion chamber 2, and furthermore, the outer cylinder 3 is made of an inflexible heat insulating material. As a result, thermal stress is generated within the outer cylinder 3 and at the joint between the outer cylinder 3 and the duct 12, and when severe, damage occurs in these parts.

In addition, as illustrated in the example of Utility Application No. 194296, the outer cylinder of the evaporation chamber is formed of a porous material, and backfire is prevented by the inflow of air from the surrounding area. be. However, even in this example, since the outer cylinder wall is made of an inflexible porous material, the occurrence of thermal stress due to non-uniform temperature cannot be avoided.

[Purpose of invention]

The purpose of this invention is to focus on the above-mentioned problems, and to solve them, the wall temperature of the evaporation chamber is made uniform by introducing air from around the evaporation chamber, and the walls of the evaporation chamber are made flexible. It is an object of the present invention to provide a combustor in which damage to the wall due to thermal stress can be prevented by forming the combustor with a flexible material, and furthermore, the premix ratio can be changed.

[Summary of the idea]

In order to achieve such an object, the present invention comprises an evaporation chamber that prevaporizes atomized fuel and introduces air to premix it, and a combustion chamber that combusts the premixture obtained in the evaporation chamber. In the combustor, the evaporation chamber is formed into a cylindrical shape using flexible ceramic fibers, and air can flow from around the evaporation chamber to the evaporation chamber through the ceramic fibers. It is characterized by

[Effect]

In a combustor constructed in this way, the wall of the evaporation chamber is formed into a tube shape using ceramic fiber cloth that allows air to flow, and there is a gap between the periphery of the tube-shaped wall and the heat-insulating outer cylinder wall. Since air is drawn from the space provided in the pipe, a uniform flow and temperature distribution are maintained within the pipe, which has the effect of suppressing flashbacks and efficiently cooling the insulated outer cylinder wall. It is possible to suppress the occurrence of thermal stress,
Furthermore, by changing the cross-sectional area of the evaporation chamber from the outside, it became possible to change the air distribution ratio.

〔Example〕

Embodiments of the present invention will be specifically described below with reference to the drawings. FIG. 1 shows an embodiment of the present invention, where 20 is an evaporation chamber (hereinafter referred to as an evaporation tube) formed into a cylindrical shape using, for example, silicon carbide SiC fiber cloth; A bell mouth part 20A is formed on the air introduction side of the evaporation gap 20 so that a gap 21 is maintained between the heat insulating material and the outer cylinder 3. A part of the air is guided into the gap 21 from between the space and the wall surface. Note that the downstream end 20B of the evaporation tube 20 is fixed to the outer cylinder 3.

22 is the main fuel injection nozzle, 23 is the injection nozzle 2
A bench lily 24 is provided around the bench lily 2, and a rotating wing 24 is arranged between the bench lily 23 and the bell mouth portion 20A. Further, in this example, the duct 12 is provided separately from the heat insulating wall 3A of the combustion chamber 2, and air is introduced into the duct 12 from between the end of the duct 12 and the end of the combustion chamber heat insulating wall 3A and is diluted. Make it. The other configurations are the same as in Figure 4.

In the combustor configured in this way, the combustion air A flows around the injection nozzle 22 and around the swirler blade 24.
A part of the air A is guided into the evaporation tube 20 through the evaporation tube 20 , and a part of the air A is also introduced into the air gap 21 , from where it is drawn into the evaporation tube 20 through the cross-hole of the evaporation tube 20 .

This suppresses the non-uniformity of the flow within the evaporator tube 20 and achieves sufficient pre-evaporation and premixing, which contributes to preventing flashback and evenly cools the wall surface of the outer cylinder 3. This prevents the outer cylinder wall from being damaged due to thermal stress generated from the temperature distribution of the outer cylinder wall, and provides a durable evaporation chamber due to the heat resistance and flexibility of the evaporation tube 20 itself. can be provided.

FIGS. 2 and 3 show an example in which the present invention is applied to change the cross-sectional area of the evaporator tube 20 midway to vary the ratio of air to fuel in the premixture to be sent to the combustion chamber 2. In this example, an actuator 26 is provided with a push rod 25 near the longitudinal center of the evaporator tube 20 shown in FIG.
As shown in FIG. 2, the evaporation tube 20 is held between the press plates 25A of the push rod 25 facing each other.

FIG. 2 shows the state before the evaporator tube 20 is deformed. Therefore, in this example, when the air-fuel ratio becomes extremely large when the engine is under partial load or idling, and it is necessary to reduce the proportion of air flowing into the evaporator tube 20, the actuator 26 is actuated to reduce the air-fuel ratio. The push rod 25 is extended, and the flexible evaporation tube 20 is deformed by the pressure plate 25A as shown in FIG.
The amount of air flowing into the air can be reduced.

Although the above example has been described for the case of a backflow tube type combustor, the application of the present invention is not limited to the backflow can type, but can be widely applied to combustors of the type equipped with an evaporation chamber. Not even.

[Effect of idea]

As explained above, according to the present invention, in a combustor that includes an evaporation chamber that pre-evaporates and premixes atomized fuel and a combustion chamber that combusts the premixture obtained in the evaporation chamber, The chamber is formed into a cylindrical shape using flexible ceramic fiber cloth, and air can be supplied from around the cylindrical evaporation chamber through the wall of the evaporation chamber, thereby suppressing backfire. Not only that, it can uniformly cool itself and the surrounding wall surfaces, obtain a uniform premixture, and furthermore prevent damage by suppressing the thermal stress generated on the surrounding wall surfaces. .

In addition, since the evaporation chamber has a flexible cylindrical shape, it is possible to change the flow rate of air by deforming its cross-sectional shape by external force. It has become possible to control the air-fuel ratio by changing it accordingly.

[Brief explanation of the drawing]

Figure 1 is a sectional view showing an example of the configuration of the combustor of the present invention, and Figure 2 is a configuration diagram showing an example of the evaporation chamber deformed by applying the present invention, taken along the line B-B in Figure 1. , FIG. 3 is an explanatory diagram showing a state in which the evaporation chamber is deformed in the example of FIG. 2, and FIG. 4 is a sectional view showing an example of the configuration of a conventional combustor. 1...Evaporation chamber, 2...Combustion chamber, 3...Outer cylinder, 3
A...insulation wall, 4A, 4B...casing, 5...
...Communication chamber, 6...Full plate, 7...Flame stabilizer, 8
... Annular nozzle, 9, 10 ... Fuel injection valve, 11
... Spark plug, 12 ... Duct, 20 ... Evaporation pipe,
20A... Bell mouth part, 20B... End part, 21
... air gap, 22 ... fuel injection nozzle, 23 ... bench lily, 24 ... swirling wing, 25 ... push rod, 25A ... press plate, 26 ... actuator.

Claims (1)

[Claims for Utility Model Registration] A combustor comprising an evaporation chamber that prevaporizes atomized fuel and introduces air to premix it, and a combustion chamber that combusts the premixed mixture obtained in the evaporation chamber. The evaporation chamber is formed into a cylindrical shape using flexible ceramic fibers, and air can flow into the evaporation chamber from around the evaporation chamber through the ceramic fibers. combustor.