JPH109522A - Combustion device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate horizontal vibration of film of a heat-resistant fiber mat, which causes resonance, and restrain pulsating combustion by fixedly attaching a damping steel plate formed of a steel plate and damping resin integrally to the rear side of the heat-resistant fiber mat. SOLUTION: When the concentration of premixed gas becomes an air-excess concentration, which often causes a lifted flame, for some reason, instability of the premixed flames increases fluctuation of reaction, such as temperature or pressure fluctuation. And a large pressure fluctuation gives rise to horizontal vibration of film of 100-250Hz in a heat-resistant fiber mat 14. The horizontal vibration of the mat 14 is transmitted to a damping resin layer 30 from bolts and nuts 27 through steel plate 28, 29 and the energy of vibration of the mat 14 is absorbed by the shearing deformation of the layer 30. That is, horizontal vibration of the mat, which causes resonance, is eliminated, and hence pulsating 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 combustion apparatus having a heat-resistant fiber mat constituting a combustion surface and a supporting steel plate.

[0002]

2. Description of the Related Art Heretofore, this type of combustion apparatus has been disclosed in
What was described in 35508 gazette was common. As shown in FIG. 4, the apparatus comprises a heat-resistant fiber mat 1 composed of heat-resistant fibers,
The casing 3 is provided on the back side of the peripheral edge of the heat-resistant fiber mat 1 to form a mixed gas chamber 4. The mixed gas chamber 4 contained a multi-port uniform plate 5. An opening 6 opened on the bottom surface of the casing 3 faces a nozzle 7 for supplying fuel, and is connected to a fan 8 for sending combustion air. Further, a combustion wall 9 is provided on the front side of the heat resistant fiber mat 1.
Are provided to form the combustion chamber 10. The flame holding wall 11 made of ceramic is provided on the periphery of the heat resistant fiber mat 1 and adjacent to the combustion wall 9. Heat resistant porous metal plate 12
Are fixed to the back surface of the heat-resistant fiber mat 1 by bolts and nuts 13. The heat-resistant fiber is a sintered body of a long fiber made of porous ceramics or an alloy such as iron, chromium, silicon, aluminum, and yttrium.
A so-called metal fiber mat having a heat resistance of not less than ° C is used. Since the long fibers of the metal fiber mat are stacked in the thickness direction, the heat conduction in the fiber direction is very good, but the heat conduction in the thickness direction is very poor.

Next, the combustion operation will be described. The fuel ejected from the nozzle 7 and the air discharged from the fan 8 flow into the mixed gas chamber 4 through the opening 6 and mix to form a premixed gas. This premixed gas is mixed with the uniform plate 5 and the heat-resistant porous metal plate 1.
Due to the homogenization with 2, the premixed gas flows into the heat resistant fiber mat 1 almost uniformly, and then the premixed gas is blown out from the flame port 2 and ignited to form a premixed flame. The flame holding wall 11 heated by the premixed flame and heated to a high temperature
Since the base of the premixed flame formed in the flame port 2A on the peripheral edge of the premixed flame is heated, the holding power of the premixed flame is improved, and the premixed flame is stabilized.

[0004]

However, in the conventional combustion apparatus, since the peripheral edges of the heat-resistant fiber mat 1 and the heat-resistant porous metal plate 12 are fixed by the casing 3 and the flame-holding wall 11, the heat resistance is high. A so-called lateral vibration of the film may occur in the fiber mat 1. In other words, the heat-resistant fiber mat 1 corresponds to a drum membrane. For example, if for some reason the concentration of the premixed gas becomes too high for the premixed flame to lift easily, the instability of the premixed flame will increase the reaction volume fluctuations, followed by temperature fluctuations and pressure fluctuations. Let it.
And, although the heat-resistant porous metal plate 12 suppresses the fluctuation of the heat-resistant fiber mat 1 through the bolt and nut 13, a large pressure fluctuation induces the lateral vibration of the film in the heat-resistant fiber mat 1. Let it. Furthermore, this heat resistant fiber mat 1
When the transverse frequency of the film becomes equal to the natural frequency of a certain portion of the combustion device, there is a problem in that the film resonates and oscillating combustion occurs.

[0005] Even if lateral vibration of the membrane is not induced in the heat-resistant fiber mat 1, if the frequency of the large pressure fluctuation itself becomes equal to the natural frequency of a certain portion of the combustion device, resonance occurs and vibration combustion occurs. There was also a problem of occurrence.

When the concentration of the premixed gas becomes close to the theoretical air ratio for some reason, the premixed flame moved to the vicinity of the flame port 2 heats the heat resistant fiber mat 1 by radiation or convection. The surface of the conductive fiber mat 1 rises in temperature and glows red. Then, thermal stress is generated in the heat resistant fiber mat 1 due to thermal expansion, but the resistance of the heat resistant porous metal plate 12 via the bolt and nut 13 prevents large deformation such as warpage of the heat resistant fiber mat 1. However, since the bolt and nut 13 only act locally on the resistance of the heat-resistant fiber mat 1 to the heat-resistant porous metal plate 12, there is a problem that wrinkles of the heat-resistant fiber mat 1 are generated in the gap between the bolt and nut 13. Was. On the other hand, fixing the heat-resistant porous metal plate 12 on the back surface of the heat-resistant fiber mat 1 with the bolts and nuts 13 has a problem that the number of steps is increased. Further, there is a problem that the bolt / nut 13 itself is deteriorated by heat.

[0007]

In order to solve the above-mentioned problems, the present invention provides a mixed gas chamber for mixing air and fuel to form a mixed gas, a casing surrounding the mixed gas chamber, and a downstream of the mixed gas chamber. The heat-resistant fiber mat that is installed on the side and forms the combustion surface, the damping steel sheet that is integrated with the back of the heat-resistant fiber mat to suppress the vibration of the heat-resistant fiber mat, and the heat-resistant fiber mat and the vibration-damping steel sheet And a flame opening which is opened therethrough.

[0008] According to the above invention, the instability of the premixed flame increases the reaction amount fluctuation, and subsequently causes the temperature fluctuation and the pressure fluctuation. And large pressure fluctuations induce lateral vibration of the membrane in the heat resistant fiber mat. The lateral vibration of the heat-resistant fiber mat film is transmitted to the vibration-damping resin layer via a steel plate integrally fixed to the heat-resistant fiber mat, and the transverse vibration energy of the heat-resistant fiber mat film is transmitted to the vibration-damping resin layer. Absorbed by shear deformation. That is, since the lateral vibration of the film of the heat resistant fiber mat which causes the resonance is eliminated, the vibration combustion can be suppressed.

Further, even if lateral vibration of the membrane is not induced in the heat-resistant fiber mat, the vibration combustion that occurs when the frequency of the pressure fluctuation becomes equal to the natural frequency of a certain part of the combustion device is a mixture of large pressure fluctuations. When transmitted to the gas chamber, the damping steel plate absorbs the energy of the pressure fluctuation, so that it can also be suppressed.

[0010] Subsequently, if for some reason the concentration of the premixed gas becomes excessive air which is likely to lift the premixed flame,
As the premixed flame leaves the flame outlet, the surface of the heat resistant fiber mat does not rise in temperature as much as it glows red. However, if the concentration of the premixed gas becomes close to the theoretical air ratio for some reason, the premixed flame moves to the vicinity of the flame outlet, and the surface of the heat-resistant fiber mat rises in temperature and glows red. However, in any case, since the heat resistance of the heat resistant fiber mat is very poor in the thickness direction, the temperature of the back surface of the heat resistant fiber mat is small and the temperature is low. Therefore, the damping steel sheet does not decrease in damping ability due to temperature dependency, and can also prevent thermal deterioration by employing a damping resin for high temperature.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention comprises a mixed gas chamber for mixing air and fuel to form a mixed gas, a casing surrounding the mixed gas chamber, and a downstream side of the mixed gas chamber to form a combustion surface. Heat-resistant fiber mat, a damping steel plate integrated with the back of the heat-resistant fiber mat to suppress the vibration of the heat-resistant fiber mat, and a flame opening that is opened through the heat-resistant fiber mat and the vibration-damping steel plate. Have

[0012] The instability of the premixed flame increases the fluctuation in the reaction amount, and causes fluctuations in temperature and pressure. Subsequently, large pressure fluctuations induce lateral vibration of the membrane in the refractory fiber mat. The lateral vibration of the heat-resistant fiber mat film is transmitted to the vibration-damping resin layer via a steel plate integrally fixed to the heat-resistant fiber mat, and the transverse vibration energy of the heat-resistant fiber mat film is transmitted to the vibration-damping resin layer. Absorbed by shear deformation. That is, since the lateral vibration of the film of the heat resistant fiber mat which causes the resonance is eliminated, the vibration combustion can be suppressed.

On the other hand, even if lateral vibration of the membrane is not induced in the heat-resistant fiber mat, large pressure fluctuations are mixed in the vibration combustion that occurs when the frequency of the pressure fluctuation becomes equal to the natural frequency of a part of the combustion device. When transmitted to the gas chamber, the damping steel plate absorbs the energy of the pressure fluctuation, so that it can also be suppressed.

Subsequently, if for some reason the concentration of the premixed gas becomes excessive air which is likely to lift the premixed flame,
As the premixed flame leaves the flame outlet, the surface of the heat resistant fiber mat does not rise in temperature as much as it glows red. However, if the concentration of the premixed gas becomes close to the theoretical air ratio for some reason, the premixed flame moves to the vicinity of the flame outlet, and the surface of the heat-resistant fiber mat rises in temperature and glows red. However, in any case, since the heat resistance of the heat resistant fiber mat is very poor in the thickness direction, the temperature of the back surface of the heat resistant fiber mat is small and the temperature is low. Therefore, the damping steel sheet does not decrease in damping ability due to temperature dependency, and can also prevent thermal deterioration by employing a damping resin for high temperature.

[0015] The vibration damping resin has a vibration damping steel sheet which is sandwiched between the back surface of the heat resistant fiber mat and the steel sheet and adhered.

[0016] The instability of the premixed flame increases the fluctuation of the reaction amount, and causes the fluctuation of temperature and the fluctuation of pressure. Subsequently, large pressure fluctuations induce lateral vibration of the membrane in the refractory fiber mat. The lateral vibration of the film of the heat resistant fiber mat is directly transmitted to the vibration damping resin layer, and the energy of the lateral vibration of the film of the heat resistant fiber mat is efficiently absorbed by the shear deformation of the vibration damping resin layer. That is, since the heat-resistant fiber mat and the vibration damping resin are directly bonded, lateral vibration of the film of the heat-resistant fiber mat which causes resonance can be reliably eliminated, and vibration combustion can be prevented.

Also, a mixed gas chamber for mixing air and fuel to form a mixed gas, a casing surrounding the mixed gas chamber, and a heat resistant fiber mat installed downstream of the mixed gas chamber and constituting a combustion surface And a steel plate stitched and joined to the back surface of the heat resistant fiber mat, and a flame opening penetrating through the heat resistant fiber mat and the steel plate.

The work of stitching the heat-resistant fiber mat and the steel plate can be easily and efficiently performed using, for example, an industrial sewing machine. Moreover, since the heat-resistant fiber mat and the steel sheet are in line contact, that is, the seam acts on the resistance of the steel sheet over a wide range of the heat-resistant fiber mat, so that wrinkling of the heat-resistant fiber mat can be suppressed.

Alternatively, when the heat-resistant fiber mat induces the lateral vibration of the film, the damping steel sheet absorbs the energy of the lateral vibration of the film of the heat-resistant fiber mat and suppresses the vibration.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. (Embodiment 1) FIG. 1 is a sectional view of a combustion apparatus according to Embodiment 1 of the present invention.

In FIG. 1, reference numeral 14 denotes a heat-resistant fiber mat of heat-resistant fibers constituting the combustion surface, and the heat-resistant fiber mat 14 has a large number of round holes 15 open. 16
Is a casing provided on the back side of the heat-resistant fiber mat 14 and forms a mixed gas chamber 17. Reference numeral 18 denotes a uniform plate having a large number of communication ports 19 opened, and is incorporated in the mixed gas chamber 17. Reference numeral 20 denotes an opening which is opened on the bottom surface of the casing 16, and a nozzle 21 for supplying fuel is provided in the opening 20.
And the fan 22 for sending the combustion air was connected. Reference numeral 23 denotes a combustion wall provided on the front side of the heat-resistant fiber mat 14, and forms a combustion chamber 24. Reference numeral 25 denotes a flame holding wall made of ceramics. 26 is a damping steel plate having a constrained damping structure,
The heat-resistant fiber mat 14 is fixed to the back surface of the heat-resistant fiber mat 14 by a bolt nut 27. This damping steel plate 26 is composed of two steel plates 28,
29 has a sandwich structure in which a damping resin 30 having a thickness of 100 μm or less having viscoelastic properties is sandwiched.

Next, the combustion operation will be described. First,
First, the fan 22 sends combustion air from the opening 20 to the mixed gas chamber 17, and then the nozzle 21 jets fuel to the discharge side of the fan 22 and supplies the fuel to the mixed gas chamber 17 from the opening 20. The combustion air and the fuel are sufficiently mixed in the mixed gas chamber 17 to form a premixed air. And the premixed gas is a uniform plate 18
The heat is homogenized when passing through the communication port 19, flows almost uniformly into the heat-resistant fiber mat 14, ignites downstream of the heat-resistant fiber mat 14, and starts combustion to form a premixed flame. . And, since the flame holding wall 25 heated by the premixed flame heats the base of the premixed flame formed in the flame opening 15A on the periphery of the heat resistant fiber mat 14, the flame holding power of the premixed flame is improved, The premixed flame stabilizes.

Next, a case where the concentration of the premixed gas becomes excessive for easy lifting of the premixed flame for some reason will be described. At this time, the instability of the premixed flame increases the variation in the reaction amount, and causes a variation in temperature and pressure. Then, in the experiment, a large pressure fluctuation induces a lateral vibration of the film of about 100 to 250 Hz in the heat resistant fiber mat 14. The lateral vibration of the film of the heat resistant fiber mat 14 is transmitted from the bolt and nut 27 to the 30 layers of the vibration damping resin via the steel plates 28 and 29, and the energy of the lateral vibration of the film of the heat resistant fiber mat 14 is Absorbed by shear deformation. That is, since the lateral vibration of the film of the heat resistant fiber mat 14 which causes the resonance is eliminated, the vibration combustion can be suppressed.

The case where the frequency of the pressure fluctuation itself becomes equal to the natural frequency of a certain portion of the combustion device will be described. At this time, in the experiment, the resonance
Oscillating combustion of about Hz is induced. However, when the pressure fluctuation is transmitted to the mixed gas chamber 17, the damping steel plate 26 absorbs the energy of the pressure fluctuation, so that the oscillating combustion can be suppressed.

Next, the operating temperature of the damping steel sheet 26 will be described. If for some reason the concentration of the premixed gas becomes excessive air that makes it easy for the premixed flame to lift, the premixed flame separates from the flame port 15, so that the surface of the heat-resistant fiber mat 14 does not increase in temperature so as to glow red. On the other hand, if the concentration of the premixed gas becomes close to the stoichiometric air ratio for some reason, the premixed flame moves to the vicinity of the flame outlet 15, so that the surface of the heat-resistant fiber mat 14 rises in temperature and glows red. . However, in any case, since the heat resistance of the heat resistant fiber mat is very poor in the thickness direction, the temperature of the back surface of the heat resistant fiber mat 14 is small and the temperature is low. Therefore, the damping steel sheet 26 does not decrease in damping ability due to temperature dependency, and adopts a high-temperature damping resin 30, for example, a thermosetting resin (polyester-based) or a thermoplastic resin (olefin-based film). Thermal degradation can be prevented.

Further, when the surface of the heat-resistant fiber mat 14 glows red due to a rise in temperature, thermal stress is generated in the heat-resistant fiber mat 14 due to thermal expansion. Large deformation such as warpage of the heat resistant fiber mat 1 can be prevented.

Note that spot welding may be performed by providing a bypass circuit on the damping steel plate 26 instead of the bolt and nut 27. In addition, by adding metal particles to make the vibration damping resin 30 conductive, direct spot welding can be performed.

The damping steel sheet may have an unconstrained damping structure composed of a single steel sheet and a thick damping resin, in which the heat-resistant fiber mat and the steel sheet are in contact. However, the damping action is not the shear deformation of the damping resin layer but the elongation deformation, which is different from the damping steel sheet having the constrained damping structure.

The damping steel sheet may be located at the place where the amplitude of the heat-resistant fiber mat is largest, and a sufficient effect can be expected even if it is not provided on the entire back surface of the heat-resistant fiber mat.

(Embodiment 2) FIG. 2 is a sectional view of a combustion apparatus according to Embodiment 2 of the present invention.

The difference from the first embodiment is that the vibration damping resin 31 is sandwiched between the back surface of the heat resistant fiber mat 32 and the steel plate 33 and adhered.
That is, the flame outlet 34 is opened through the heat resistant fiber mat 32, the vibration damping resin 31 and the steel plate 33.

The components having the same reference numerals as in the first embodiment have the same structure, and the description is omitted. Next, a case where the concentration of the premixed air becomes excessive for easy lifting of the premixed flame for some reason will be described. At this time, the instability of the premixed flame increases the variation in the reaction amount, and causes a variation in temperature and pressure. And a large pressure fluctuation induces lateral vibration of the film in the heat resistant fiber mat 32. This heat resistant fiber mat 3
2 is directly transmitted to the vibration damping resin 31 layer, and the vibration damping resin 31 layer is restrained by the heat resistant fiber mat 14 and the steel plate 33. Is efficiently absorbed by the shear deformation of the 31 layers of the damping resin. That is, since the heat-resistant fiber mat 32 and the vibration damping resin 31 are directly bonded, the lateral vibration of the film of the heat-resistant fiber mat 32 that causes the resonance is reliably eliminated, so that the vibration combustion can be prevented.

The heat resistant fiber mat 32 and the vibration damping resin 3
1 and the steel plate 33 are integrally formed by bonding, in other words, because they are substantially damped steel plates having a constrained damping structure, even if the number of bolt nuts 27 is reduced as compared with the first embodiment, the heat-resistant fiber Large deformation and wrinkles such as warpage of the mat 32 can be prevented.

(Embodiment 3) FIG. 3 is an enlarged perspective sectional view of a main part of a combustion apparatus according to Embodiment 3 of the present invention.

The difference from Example 1 is that the heat-resistant fiber mat 3
5 and penetrate the damping steel plate 36 to open a flame port 37,
The seam opening 38 for seam joining is also opened in the gap between the flame openings 37 in the damping steel plate 36. Then, a damping steel plate 36 is stitched to the back of the heat-resistant fiber mat 35 by using a sewing thread 39 according to a stitching opening 38 using an industrial sewing machine instead of the bolt and nut. Also, the sewing thread 39 is made of a heat-resistant material,
For example, a single wire of Kanthal which is an alloy of iron, chromium or the like, a twisted yarn or a single wire of ceramics fiber is used.

The components having the same reference numerals as in the first embodiment have the same structure, and the description is omitted. Next, a case where the concentration of the premixed gas becomes close to the theoretical air ratio for some reason will be described. At this time, since the premixed flame moves to the vicinity of the flame port 37, the surface of the heat resistant fiber mat 35 rises in temperature and glows red. Then, thermal stress is generated in the heat resistant fiber mat 35 due to thermal expansion. However, the resistance of the damping steel plate 36 through the sewing thread 39 can prevent large deformation such as warpage of the heat resistant fiber mat 35. Further, the sewing thread 39 is in line contact with the heat-resistant fiber mat 35, that is, the sewing thread 39 acts on a wide range of the heat-resistant fiber mat 35 with the resistance of the steel plates 28 and 29. Mat 35
The generation of wrinkles can be suppressed. Similarly, the damping steel plate 36
The vibration damping ability of the first embodiment can be used more effectively than in the first embodiment. Further, the integration of the heat-resistant fiber mat 35 and the damping steel plate 36 can be performed more easily and efficiently by sewing using an industrial sewing machine than by bolts and nuts.

[0037]

As described above, the present invention has the following advantageous effects.

(1) Since the damping steel sheet composed of the steel sheet and the vibration damping resin is integrally fixed on the back surface of the heat resistant fiber mat, lateral vibration of the film of the heat resistant fiber mat which causes resonance is eliminated. As a result, vibration combustion can be suppressed.

(2) Since the vibration damping resin is sandwiched and bonded between the back surface of the heat resistant fiber mat and the steel plate, lateral vibration of the film of the heat resistant fiber mat which causes resonance can be reliably eliminated, and vibration combustion can be prevented.

(3) Since the steel sheet is stitched and joined to the back surface of the heat resistant fiber mat, the stitched portion allows the resistance of the steel sheet to act on a wide range of the heat resistant fiber mat, thereby suppressing wrinkles of the heat resistant fiber mat.

[Brief description of the drawings]

FIG. 1 is a sectional view of a combustion apparatus according to a first embodiment of the present invention.

FIG. 2 is a sectional view of a combustion device according to a second embodiment of the present invention.

FIG. 3 is an enlarged perspective sectional view of a main part of a combustion apparatus according to a third embodiment of the present invention.

FIG. 4 is a sectional view of a conventional combustion device.

[Explanation of symbols]

 14, 32, 35 Heat resistant fiber mat 15, 34, 37 Flame opening 16 Casing 17 Mixed gas chamber 26, 36 Damping steel plate 28, 29, 33 Steel plate 30, 31 Damping resin

Claims (5)

[Claims] 1. A mixed gas chamber which mixes air and fuel to form a mixed gas, a casing surrounding the mixed gas chamber, and a heat-resistant material which is installed downstream of the mixed gas chamber and constitutes a combustion surface. A fiber mat, a damping steel plate integrated with the back surface of the heat-resistant fiber mat, and suppressing vibration of the heat-resistant fiber mat, and a flame opening that is opened through the heat-resistant fiber mat and the vibration-damping steel sheet. Combustion device having. 2. The combustion apparatus according to claim 1, wherein the damping steel sheet is made of a steel sheet and a damping resin. 3. The combustion apparatus according to claim 1, wherein the damping resin is sandwiched between the back surface of the heat-resistant fiber mat and the steel sheet, and the damping steel sheet is bonded. 4. A mixed gas chamber which mixes air and fuel to form a mixed gas, a casing surrounding the mixed gas chamber, and a heat-resistant material which is installed downstream of the mixed gas chamber and forms a combustion surface. A combustion apparatus comprising: a fiber mat; a steel plate stitched and joined to a back surface of the heat resistant fiber mat; and a flame port opened through the heat resistant fiber mat and the steel plate. 5. The heat-resistant fiber mat according to claim 1, wherein when the lateral vibration of the film is induced, the damping steel sheet absorbs the energy of the lateral vibration of the film of the heat-resistant fiber mat to suppress the vibration. The combustion device according to claim 1.