JP5117771B2 - Combustion device - Google Patents

Description

  The present invention relates to a fan that blows out an oxygen-containing gas for combustion, a diffusion path that is connected to a blow-out port of the fan and diffuses an oxygen-containing gas stream blown out by the fan, and an oxygen-containing gas that is fed from the diffusion path The present invention relates to a combustion apparatus provided with a burner that mixes and burns fuel and hydrocarbon fuel.

  For ease of explanation, in the home, combustion air (an example of combustion oxygen-containing gas) is forcibly blown by a fan, and the combustion air and city gas (an example of hydrocarbon fuel) are mixed. A combustion apparatus provided in a hot water supply facility of a type that supplies water by heating water by combustion of the mixed gas will be described as an example.

  The conventional combustion apparatus is as shown in FIGS. 1 and 2 (these drawings show the structure of the combustion apparatus according to the present application, but the basic configuration is the same as the conventional one, so these drawings are used. The structure of a conventional apparatus will be described), and a box-type combustor having a plurality of burners arranged side by side is provided on the upper side, and a sirocco fan as a blower is disposed below the combustor. Combustion air is sent to a combustor, mixed with separately supplied fuel, and burned by a burner (Patent Document 1).

  The path of the combustion air from the sirocco fan to the box-type combustor will be described. In this example, the blower outlet of the fan is installed so as to open upward (corresponding to the first direction D1). The combustion air blown out by is introduced into a substantially rectangular diffusion path and directed in the lateral direction (corresponding to the second direction D2).

  As shown in FIG. 2, this diffusion path is formed as a substantially rectangular transverse duct. As shown in FIG. 1, the plane cross-sectional area of this transverse duct is larger than the area of the outlet, so that the combustion air Hits the top of the transverse duct and is diffused in the horizontal direction of FIG. And in the part which reaches the connection path provided in the right end in FIG. 2, in the rectangular cross section composed of the front and back sides of the paper and the vertical sides, the flow is almost equal to the right direction (second direction D2). Become.

  The flow that enters the connecting path from the diffusion path, which is a transverse duct, is a flow path in the vertical direction. After being mixed with the hydrocarbon-based fuel, the burner is directed toward the left in FIG. 2 (in the direction opposite to the second direction D2) from the connection path, through the inlet, and mixed with the hydrocarbon fuel. Burned in.

Japanese Patent Laying-Open No. 2005-076931

In a combustion apparatus having this type of structure, many attempts have been made to reduce noise generated from the combustion apparatus as much as possible. In the technique described in Patent Document 1 described above, one object is to reduce noise.
However, although the technique disclosed in Patent Document 1 is effective mainly in a relatively high frequency region of 1000 Hz or higher, it cannot be said that the effect in a low frequency region below that is sufficient, and there is room for improvement. there were.
An object of the present invention is to obtain a technique capable of reducing as much as possible noise generated in a combustion apparatus for burning hydrocarbon fuel.

To achieve the above object, a fan for blowing out oxygen-containing gas for combustion, a diffusion path connected to a blow-out port of the fan and diffusing an oxygen-containing gas flow blown out by the fan, and fed from the diffusion path A first characteristic configuration of a combustion apparatus including a burner that mixes and burns an oxygen-containing gas and a hydrocarbon-based fuel,
The diffusion path connected to the blower outlet of the fan and guiding and diffusing the oxygen-containing gas flow blown out by the fan in the second direction, and supplied through the diffusion path at the second direction end of the diffusion path A connection path for guiding the oxygen-containing gas flow in the first direction through the bent portion, and the oxygen-containing gas flow from the connection path through the introduction port in a direction opposite to the second direction, and mixing with the hydrocarbon-based fuel And burner to burn,
The introduction port is provided on the downstream side from the reattachment point of the separation flow formed in the bent portion connected to the connection path from the diffusion path, and an extension wall extending in a direction away from the introduction port, Provided in the connection path side part of the diffusion path, the separation flow is formed at the tip of the extension wall,
With respect to the oxygen-containing gas flow from the fan to the burner, the peak frequency of the time-dependent fluid vibration (time-dependent fluid fluctuation) generated at the portion where the flow is bent is the frequency range of the combustion sound generated by the combustion of the mixed gas It is to be set outside.

It is known that when a hydrocarbon-based fuel and a combustion oxygen-containing gas are mixed and burnt, combustion noise in a specific frequency range is generated along with this combustion. The frequency range of the combustion noise is approximately in the range of 70 to 250 Hz (particularly 100 to 200 Hz).
On the other hand, in a structure in which the flow of the oxygen-containing gas from the fan to the burner is bent and directed as in the combustion apparatus of the present application, from the outlet that determines the flow of the oxygen-containing gas flow There is a case in which a certain time-dependent fluid vibration is generated at a bent portion provided at any portion reaching the introduction port. If the peak frequency of the combustion noise generated by the combustion of the mixed gas overlaps the frequency range of the temporal fluid vibration, the combustion noise and the temporal fluid vibration resonate to increase the noise generated from the combustion device. To do.

On the other hand, as described in the above characteristic configuration, the peak frequency of the temporal fluid vibration generated in the bent flow portion of the oxygen-containing gas flow is set outside the frequency range of the combustion sound generated by the combustion of the mixed gas. If so, the occurrence of such resonance can be prevented, and the noise generated from the combustion apparatus can be reduced as a whole. The occurrence of such a problem becomes conspicuous when the crossing angle in both directions at the bent portion forming such a bent flow is particularly 0 to 120 degrees. When the crossing angle is 0 degree, the flow flowing in the specific direction can be changed in the reverse direction at the bent portion. When the crossing angle is 90 degrees, the crossing angle is 120 degrees. In this case, the current flows from the specific direction in an oblique direction by 60 degrees with respect to that direction. In the example shown in FIG. 1, the crossing angle between the first direction and the second direction is 90 degrees.

As described above, it is known that when a hydrocarbon-based fuel and a combustion oxygen-containing gas are mixed and burned, a combustion noise in a specific frequency range is generated along with the combustion. The frequency range of the combustion noise is approximately in the range of 70 to 250 Hz (particularly 100 to 200 Hz).
On the other hand, as in the combustion apparatus of the present application, the flow of the oxygen-containing gas from the fan to the burner is oriented in the second direction, the first direction, and further in the direction opposite to the second direction. Thus, the structure of any part from the outlet to the inlet that determines the flow of the oxygen-containing gas flow may be configured to generate a certain fluid vibration over time. If the frequency range of the combustion sound generated by the combustion of the mixed gas and the peak frequency of the temporal fluid vibration overlap, the combustion sound and the temporal fluid vibration resonate to increase the noise generated from the combustion device. To do.

On the other hand, as described in the above characteristic configuration, the peak frequency of the temporal fluid vibration generated in any part of the oxygen-containing gas flow is outside the frequency range of the combustion sound generated by the combustion of the mixed gas. If set, the occurrence of such resonance can be prevented, and the noise generated from the combustion apparatus can be reduced as a whole. The occurrence of such a problem becomes remarkable when the crossing angle in both directions at the bent portion is 60 to 120 degrees.
Moreover, in this structure, an inlet is provided downstream from the reattachment point of the separated flow. Therefore, even if a separation flow (separation vortex) is generated at the bent portion, a part of the separation flow flows in the direction opposite to the second direction from the inlet and does not become a strong vortex. That is, it is possible to reduce the influence of the separated flow from the flow state at the inlet, to adjust the frequency of fluid vibration over time, and to suppress the generation of noise accompanied by resonance.
Furthermore, in this configuration, since an extension wall is provided and a separation flow is formed at the tip, the formation region of the separation flow (separation vortex) is from the introduction port by the amount of the extension wall. The reattachment position of the separation flow can be kept away. As a result, it is possible to avoid an influence between the flow on the inlet side and the separation flow, and it is possible to prevent the generation of noise from the principle described above.
The combustion apparatus having this configuration includes a fan that blows out oxygen-containing gas for combustion, a diffusion path that is connected to a blow-out port of the fan and guides and diffuses the oxygen-containing gas flow blown out by the fan in a second direction, A connection path that guides the oxygen-containing gas flow supplied through the diffusion path in the first direction at the second direction end of the diffusion path through the bent portion; and the oxygen-containing gas flow from the connection path through the inlet. A combustion apparatus including a burner that is guided in the opposite direction to the two directions and is mixed with a hydrocarbon fuel and burned;
The introduction port is provided on the downstream side from the reattachment point of the separation flow formed in the bent portion connected to the connection path from the diffusion path, and an extension wall extending in a direction away from the introduction port, The separation flow is formed at the connection path side portion of the diffusion path, and the separation flow is formed at the tip of the extension wall.

Now, in a combustion apparatus having a upper Kitoku symptoms configuration, the over time fluidic oscillator formed with the bent portion continuous to the connecting passage from the diffusion path starting, repetitive vibration of the separated flow repeating predetermined variation it is preferable that.

As in the present application, in a combustion apparatus that introduces a combustion oxygen-containing gas from an inlet through a fan, a diffusion path, and a connection path to the mixing unit to obtain a mixed gas and burns it, the space between the diffusion path and the connection path Thus, the flow direction of the main flow of the oxygen-containing gas is changed from the second direction in the diffusion path to the first direction in the connection path through the bent portion. Therefore, there is a case where a predetermined fluctuation of the separation flow (vortex) is repeated because the path is interposed between the two paths. Depending on the positional relationship between the diffusion path and the introduction port existing across the connection path or the condition of the connection path, a relatively strong vortex is formed as the separation vortex, and the repetition frequency of the predetermined fluctuation May overlap the frequency of the combustion sound. However, as in the present application characteristic configuration, the peak of the repetition frequency of the predetermined variation of the separated flow, by removing the frequency range of the combustion noise, occurrence of excessive noise accompanied by resonance can be suppressed.

In the combustion apparatus having the above Kitoku symptoms arrangement further
A connection path portion from reattachment point of the separated flow to said inlet port, it is preferable to provide a rectifying unit for rectifying the oxygen-containing gas stream flowing through the connection path.
In this characteristic configuration, the flow accompanied by the separation flow is rectified by the rectification unit after reattachment, and then flows into the introduction port. Therefore, it is possible to further reduce the influence of the predetermined fluctuation of the separation flow formed at the bent portion from the flow state at the inlet, to adjust the frequency of fluid vibration over time, and to form a strong separation vortex. Can be avoided further. As a result, generation of noise accompanied by resonance can be suppressed.

The combustion apparatus having this configuration includes a fan that blows out oxygen-containing gas for combustion, a diffusion path that is connected to a blow-out port of the fan and guides and diffuses the oxygen-containing gas flow blown out by the fan in a second direction, A connection path for guiding the oxygen-containing gas flow supplied through the diffusion path in the first direction at the second direction end of the diffusion path through the bent portion; and the oxygen-containing gas flow from the connection path through the inlet. A combustion apparatus including a burner that is led in a direction opposite to the second direction and mixed with a hydrocarbon-based fuel and burned;
The introduction port is provided on the downstream side from the reattachment point of the separation flow formed in the bent portion connected to the connection path from the diffusion path, and an extension wall extending in a direction away from the introduction port, Provided in the connection path side part of the diffusion path, the separation flow is formed at the tip of the extension wall,
The combustion apparatus is provided with a rectification unit that rectifies the oxygen-containing gas flow flowing through the connection path at a connection path portion from the reattachment point of the separation flow to the introduction port.
Here, a rectification unit that rectifies the oxygen-containing gas flow that flows through the connection path is provided in a connection path portion downstream from the reattachment point of the separation flow formed in the bent portion that is connected to the connection path from the diffusion path, The combustion apparatus is provided with the introduction port that is downstream from the rectifying unit .

More specifically, the configuration that makes the relationship between the inlet opening provided in the connection path and the separation flow (separation vortex) favorable for reducing noise can be as follows.
The extension wall extending in a direction away from the guide inlet provided at the connection roadside site of diffusion path, and configured to separated flow is formed in the tip of the extension wall.
In this configuration, an extension wall is provided, and a separation flow is formed at the tip of the extension wall. Therefore, the separation flow (separation vortex) is formed in the separation flow from the introduction port by an amount corresponding to the extension wall. The reattachment position of can be kept away. As a result, it is possible to avoid an influence between the flow on the inlet side and the separation flow, and it is possible to prevent the generation of noise from the principle described above.

Connection roadside site expansion Ciro, or the connection passage portion from the inlet connection roadside site to at least the connecting channel of the diffusion path down to the inlet port, a third direction intersecting the directions of the first and second directions In addition, a partition for dividing the flow path is provided.
In this configuration, the partition is in the third direction (in the example shown in FIG. 2, the depth direction that is the front and back of the paper surface) in the state where the diffusion path itself or the diffusion path and the connection path are continuous. These flow paths are partitioned in a direction orthogonal to the first direction and the second direction. As described above, when the flow in the flow path is divided with respect to the diffusion path or the diffusion path and the connection path connected thereto, only a weak separation vortex can be formed and the separation flow is weakened. As a result, by providing such a partition, generation of noise can be prevented.

  If such a partition has a thickness in the third direction, a vortex having an axis intersecting with the axis of the separation vortex (axis in the third direction) can be formed. The formed separation flow can be further weakened.

Hereinafter, the combustion apparatus 1 used for the hot water supply facility will be described.
The hot water supply facility is a hot water supply facility that is used by being installed on the wall surface of each household, etc., and the combustion device 1 forcibly blows the combustion air by the blower 2, and the combustion air and city gas (hydrocarbon fuel) 1 type) is mixed and heated by the combustion of a mixed gas to supply hot water.

[First embodiment]
As shown in FIG. 1, the combustion apparatus 1 is configured by disposing a box-shaped combustor 4 having a plurality of burners 3 arranged in parallel on the upper side of the apparatus and a sirocco fan 2 as a blower on the lower side of the apparatus. The combustion air sucked and blown out by the sirocco fan 2 is sent to the combustor 4 through the duct 5 to generate a mixed gas and burned in the burner 3.
Hereinafter, the combustor 4, the sirocco fan 2, and the duct 5 connecting the two will be described in this order.

Combustor 4
The combustor 4 shown in the figure is a so-called combustor 4 capable of performing lean combustion, and includes a first burner 3a having a rich mixed gas flame port 6a and a second burner 3b having a light mixed gas flame port 6b. Are provided in the box-shaped casing 7.
Each burner 3 includes a flame port 6 at the upper end thereof, and includes a substantially U-shaped mixed gas flow path 8 connected to the flame port 6 on the downstream side. The mixed gas flow path 8 has an inlet 10 for receiving city gas discharged from the gas nozzle 9 and combustion air at the base end side.
Between the introduction port 10 and the flame port 6, the mixing unit 8 a located on the lower side of the apparatus in the installed state, and located above the mixing unit 8 a, the flame port 6 is provided on the top surface. The mixing unit 8a receives the combustion air from the periphery of the city gas discharged from the gas nozzle 9 and mixes both gases. On the other hand, in the distribution unit 8b, the mixed gas flowing in from the mixing unit 8a is distributed to each flame port. As shown in the figure, the mixing section 8a is configured to form a transverse flow path that extends in the left direction in the figure, and the distribution section 8b is a mixed gas that is once guided in the mixing section 8a to the left side. The flow is distributed upward while being guided in the opposite direction and guided to each flame outlet 6.
In the example shown in FIG. 2, the second burner 3b for light combustion is drawn on the front side, and the first burner 3a for rich combustion is drawn on the rear side.

Sirocco fan 2
The sirocco fan 2 includes a fan case 21, a rotary blade 23 that is housed and held rotatably around the rotation shaft 22 in the fan case 21, and a plurality of blade portions arranged side by side in the circumferential direction. An electric motor 24 that rotates around is provided. And the sirocco fan 2 was taken in from the taking-in part 25 formed in the one end side of the rotating shaft 22 of the rotating blade 23 by rotating the rotating blade 23 to the surroundings of the rotating shaft 22 by the drive of the electric motor 24. Air is sent out to the outlet 26 formed along the substantially tangential direction of the rotation trajectory of the plurality of blade portions.
As shown in FIG. 2, the air outlet 26 is disposed so as to face vertically upward (first direction D <b> 1) in the installed state.

Duct 5
Between the outlet 26 of the sirocco fan 2 and the inlet 10 provided in the combustor 4, a diffusion path 11 that is a transverse duct and a connection that is an upstream duct connected to the diffusion path 11 on the upstream side. A passage 12 is provided, and the introduction port 10 is connected to a predetermined portion of the connection passage 12 in communication.
The outlet 26 of the sirocco fan 2 opens vertically upward in the installed state, and the diffusion path 11 is formed on the upper side. The diffusion path 11 has a relatively short vertical length, and its top surface 11a and bottom surface 11b are substantially rectangular transverse ducts made of a rectangular plate-like body. Therefore, the blown-out combustion air hits the top surface 11a of the duct and is diffused in the right direction (second direction D2) in FIG. And it guide | induces to the inflow port 12a of the connection path 12 connected to the right end in FIG. That is, at the right end portion of the diffusion path 11, the flow blows out almost evenly in the right direction in a square cross section composed of the front and back sides of the paper surface and the vertical sides.

  The connecting path 12 is configured as an ascending duct, and the cross-sectional area of the flow path is substantially the same as the cross-sectional area of the right end portion 11 c of the diffusion path 11. Accordingly, the flow that enters the connection path 12 from the diffusion path 11 that is a transverse duct is directly directed from the horizontal direction to the vertical upward direction. Furthermore, as shown in the figure, the diffusion path 11 and the connection path 12 are connected via a substantially orthogonal road wall. After the air flow is once separated, the flow direction is changed to the upward direction, the reattachment point A accompanied with the formation of the separation vortex e is formed, and the air flow rises in the connection path 12. And it changes into the left direction from the inlet 10 formed in the downstream part of this connection path 12, and flows in into the combustor 4 demonstrated previously.

The above is the schematic configuration of the hot water supply facility 1 according to the present application. Hereinafter, the characteristic configuration of the hot water supply facility 1 will be described.
FIG.3 (b) is drawing which shows the structure of the site | part from the diffusion path 11 in the conventional hot water supply equipment 1 to the connection path 12, and Fig.3 (a) is a figure of the applicable site | part of the hot water supply equipment 1 which concerns on this application. The configuration is shown.
Comparing both figures, it can be seen that in the hot water supply facility 1 according to the present application, the connection path 12 is longer than the conventional one (the length in the vertical direction is about 1.5 times). Therefore, in the present application, the inlet 10 that leads the combustion air to the combustor 4 side is vertically upward.

  As shown in FIGS. 2 and 3A, in this structure, the reattachment point A of the separation flow accompanied by the formation of the separation vortex e formed in the bent portion 14 connected from the diffusion path 11 to the connection path 12. By providing an extension of the connection path 12 on the further downstream side (upper side in the vertical direction), this portion becomes the rectification unit 15 for the combustion air flow, and the introduction port 10 is located on the upper side that is the downstream side of the rectification unit 15. Is provided. Specifically, the rectifying unit 15 is merely an ascending duct. However, by extending the connection path 12 to the upper side as compared with the conventional case, the influence of the strong separation vortex e that causes resonance on the inlet 10 can be reduced. it can.

FIG. 4 shows a flow state in the structure in which the rectifying unit 15 is provided in the upper part of the connection path 12.
As can be seen from this figure, separation occurs in the inflow from the diffusion path 11 to the connection path 12, a separation vortex e is formed along the left wall surface 12b of the connection path 12, and the separation wall surface 12b. It can be seen that redeposition to This reattachment point is indicated by A. Further, in the rectifying unit 15, the velocity vector is a flow that faces substantially upward, and it can be seen that the flow does not reach the introduction port due to the separation caused by the bending.

  FIG. 5 shows the spectral distribution of the fluid vibration over time at the point B in FIG. In the figure, the horizontal axis represents the frequency f (Hz), and the vertical axis represents the spectral intensity (notation is made dimensionless). As can be seen from this figure, the spectrum has a relatively gentle convex shape, and it can be seen that there is no spectrum peak in the range of 70 to 250 Hz, which is a problem in the present application.

Corresponding to FIGS. 4 and 5, FIGS. 14 and 15 show the examination results in the conventional structure (without extending the connection path and without the rectifying unit).
As can be seen from FIG. 14, in the conventional structure, separation occurs when the diffusion channel 11 flows into the connection channel 12 and a separation vortex e is formed, and the reattachment point of the separation flow is the introduction port. It can be seen that it is located around 10.
FIG. 15 shows the spectral distribution of the fluid vibration over time at the point B in FIG. As can be seen from this figure, it can be seen that the spectrum has a clear peak in the range of 70 to 250 Hz (especially 100 to 200 Hz).

  FIG. 6 is a diagram comparing spectra of noise generated from hot water supply facility 1 according to this embodiment and noise generated from a hot water supply facility having a conventional structure. The thick solid line shows the result of the hot water supply facility 1 according to the present application, and the thin solid line shows the result of the conventional structure of the hot water supply facility. In this figure, the horizontal axis indicates the frequency (0 to 300 Hz), and the vertical axis indicates the noise value (dB). Since this measurement result involves actual combustion in the combustor 4, there will be a noise peak in the range of 70 to 250 Hz. However, the noise level is lower by about 2 dB in the structure of the present application. Thus, it can be seen that a further significant reduction effect is obtained in the combustion apparatus having the conventional structure in which the noise reduction which is almost close to the limit is achieved.

In the above embodiment, regarding the combustion air flow from the outlet 26 to the inlet 10, the combustion fluid generated by the combustion of the mixed gas has the peak frequency of the fluid vibration with time generated in the bent portion 14. Can be set outside the frequency range. In this embodiment, the influence of the separation vortex e that may be formed from the bent portion 14 to the inlet 10 is reduced by extending the connection path 12 vertically upward and rectifying the flow at the extended portion. It was.
As a structure capable of reducing the influence of the separation vortex e as described above, the flow path from the bent portion 14 to the introduction port 10 is extended as described above, and in the conventional structure as shown in FIG. A hanging wall 14a (an example of an extending wall) that hangs down from the position of the bent portion 14 is provided, the diffusion path 11 is projected downward, and the flow is once guided downward from the introduction port 10, and the hanging wall A connection path 12 through which fluid flows upward may be provided on the back side of 14a, and a separation vortex e may be formed from the tip of the hanging wall. By doing in this way, even if the separation vortex e is formed, the vortex reattaches to the wall surface until it reaches the back surface of the hanging wall itself or reaches the inlet 10, so that it does not flow into the inlet 10. The purpose of the present application can be achieved.

  Further, as shown in FIG. 7 (b), a channel extension wall 14b (an example of an extension wall) extending leftward from the bent portion 14 is provided, and a portion in the vicinity of the bent channel 14 of the diffusion channel 11 is projected to the right side. The flow path is once guided to the right side away from the introduction port 10 and a flow path returning to the introduction port 10 side is provided, and a connection path 12 through which fluid flows upward is provided on the back side of the flow path extension wall 14b. A separation vortex e may be formed from the tip. By doing in this way, since the vortex reattaches to the wall surface until it reaches the back surface of the flow path extension wall itself or reaches the inlet 10, it is avoided that the separation vortex e flows into the inlet 10. Can serve the purpose.

In the example shown in FIGS. 7A and 7B, the example in which the bent portion 14 is provided with the hanging wall 14a and the channel extending wall 14b is shown. However, in the present application, the separation vortex e formed by the bent portion 14 is shown. Therefore, a partition wall 10 a (an example of a blocking wall) that prevents the separation vortex e from extending to the introduction port 10 may be provided before the introduction port 10.
FIG. 7C shows such a reference example. In the first reference example, a partition wall 10a extending in the right direction is provided at the lower end of the introduction port 10, and as a result, the flow path cross-sectional area until the connection path 12 reaches the partition wall 10a is relatively large. A large lower connection path portion 12a and an upper connection path portion 12b having a channel cross-sectional area smaller than that of the lower connection path portion 12a and having the tip end position of the partition wall 10a substantially as the inlet side position of the flow channel. is doing.
Accordingly, the separation vortex e formed in the bent portion 14 is formed up to a region reaching the partition wall 10a in the lower connection path portion 12a. And in the form which goes around the front-end | tip of the partition wall 10a, a flow flows in in the inlet 10 through the upper connection path part 12b provided in the right side conventionally. In such a case, the separation vortex e is formed at the bending portion 14 so that the completed below the partition wall 10a.
FIG. 8 shows the spectral distribution of fluid vibration over time when these configurations are adopted, as in FIG.
In the figure, the broken line indicates the result when the conventional structure shown in FIG. 3B is adopted, the solid line corresponds to FIG. 7A, and the alternate long and short dash line corresponds to FIG. 7B. As a result, the alternate long and two short dashes line shows the result corresponding to FIG. In any case, it can be seen that the spectrum of 70 to 250 Hz (particularly 100 to 200 Hz) is lower than that of the conventional type.

In view of the fact that the fluid vibration with time, which is a problem in the present application, is caused by the separation vortex e formed in the bent portion 14 extending from the diffusion path 11 to the connection path 12, this structure is used instead of the above structure. You may employ | adopt the structure which prevents formation of the peeling vortex e itself.
That is, it is only necessary to provide an anti-separation means for preventing exfoliation of the combustion air flow at the bent portion 14 in the bent portion 14 that continues from the diffusion path 11 to the connection path 12.

[Second Reference Example ]
As this type of peeling prevention means, as shown in FIG. 9, in order to connect the diffusion path 11 and the connection path 12, the inner diameter side connection walls 11a and 12b are smoothly directed from the second direction D2 to the first direction D1. As the curved connecting wall 16 changes, the connection is made smoothly. By forming such a curved connection wall 16, the flow from the diffusion path 11 to the connection path 12 can be made smooth, and it is possible to suppress the occurrence of fluid vibration over time, and to reduce the combustion noise. Noise generated by resonance can be suppressed.

[Third and fourth reference examples ]
Further, as another peeling preventing means, as shown in FIGS. 10A and 10B, a rectifying portion 17 is provided in a bent portion 14 that extends from the diffusion path 11 to the connection path 12. The example shown in FIG. 10A is an example in which a rectifying portion 17a as a peeling preventing means is provided across the bent portion 14, and the example shown in FIG. 10B is a bending of the rectifying portion 17b as a peeling preventing means. This is an example provided in the connection path 12 on the downstream side of the section 14.
In these examples, the rectification unit 17 is provided with a honeycomb-shaped rectification member that forms a large number of flow paths along the rectification direction. By arranging such a rectifying member in the rectifying unit 17, formation of the separation vortex e can be suppressed, and an increase in noise accompanied by resonance with combustion noise can be suppressed.
Second Embodiment
In the third and fourth reference examples described above, the rectifying unit 17 is provided in the bent portion 14 that extends from the diffusion path 11 to the connection path 12, but basically in the depth direction of the diffusion path 11 (connection path 12 In this example, no special structure is proposed for the third direction: the third direction is orthogonal to the first and second directions. However, as shown in FIGS. 11A and 11B, a plurality of partitions 11 s that partition the flow paths in the depth direction may be provided in the diffusion path 11 itself or in the diffusion path 11 and the connection path 12. This partition 11s partitions the flow path in the depth direction in the connection path side part of the diffusion path 11 itself or in the connection path side part of the diffusion path 11 and the diffusion path side part of the connection path 12 in a continuous state. As described above, by dividing the flow in the flow path with respect to the diffusion path 11 or the diffusion path 11 and the connection path 12 connected thereto, the flow passing through the bent portion 14 described above forms only weak separation vortices. The separation flow is weakened. As a result, by providing such a partition, generation of noise can be prevented. Therefore, it also serves as a kind of peeling prevention means.

  In the configuration of this example, an example in which three partitions 11s are provided in the diffusion path 11 itself is shown in FIG. 11A, and an example in which three partitions 11s are provided in the diffusion path 11 and the connection path 12 connected thereto. Is shown in FIG. Further, FIG. 12 also shows the spectral distribution of the fluid vibration over time of the example shown in FIG. 11A by a solid line. In the drawing, the broken line shows the result of the conventional type. In the case of this example, the peak position of the fluid vibration with time escapes to the higher frequency side, and it can be seen that the spectrum of 70 to 250 Hz (especially 100 to 200 Hz) is lower than the conventional peak intensity.

The shape of this type of partition 11s is to avoid the formation of a uniform separation vortex e in the depth direction of the apparatus (equivalent to the third direction in the present application and the left-right direction in FIG. 11). For this reason, it is preferable that the vortex has a flow velocity component in the depth direction. FIG. 13 shows such an example, and the partition 11 s is provided only in the diffusion path 11.
In the example shown in FIG. 13A, each partition 11s is formed in a rectangular parallelepiped shape having a thickness in the depth direction, and each flow divided at a position flowing out from the divided flow path divided by the partition 11s is depth. This is an example in which mixing occurs in the direction and the strong separation vortex e weakens.
In the example shown in FIG. 13B, each partition 11s is formed in a triangular prism shape having a triangular cross section that extends in the depth direction toward the downstream side in the flow direction, and flows out from the divided flow path divided by the partition 11s. This is an example in which each flow divided at the position spreads in the depth direction and mixing occurs, and the strong separation vortex e weakens.
In the example shown in FIG. 13 (c), each partition 11s is formed in a triangular shape that narrows in the depth direction toward the downstream side in the flow direction, and further has a shape in which the lower end side is narrowed, and is divided by the partition 11s. This is an example in which mixing of each flow divided at a position flowing out from the divided flow path occurs and the strong separation vortex e weakens.

[Another embodiment]
(1) In the above embodiment, the configuration in which the fan blows out the oxygen-containing gas for combustion in the first direction (upward) has been described. However, the second direction (horizontal direction) or the direction opposite to the first direction is described. You may employ | adopt the structure which blows out (downward) and is introduce | transduced into a diffusion path.
Further, when the fan blows out the oxygen-containing gas for combustion in the first direction (upward), and the diffusion path has a structure for directing the oxygen-containing gas for combustion in the second direction (horizontal direction), it is bent between both directions. A flow is formed. In this case, the site of penetration into the diffusion path may be a site where fluid vibration is generated over time, and it is also preferable that the frequency of fluid vibration generated at the bent portion is outside the range of 70 to 250 Hz described above. It is an aspect, and it is also a preferable aspect to provide the peeling prevention means referred to in the present application at this portion.
(2) In the above embodiment, the case where the first direction and the second direction are orthogonal to each other has been described, but the first direction and the second direction are bent within a range of 60 to 120 degrees. In addition, it is effective to adopt the characteristic configuration of the present application.
In the above embodiment, the example in which the third direction is orthogonal to the first direction and the second direction has been described. However, the intersection of the third direction, the first direction, and the second direction is similarly 60. The partition of the present application is effective when intersecting at an angle in the range of ˜120 degrees.
(3) In the above-described embodiment, the case where the combustion device includes the light and dark combustion burner has been shown. However, the characteristic configuration according to the present application can be adopted for the combustion device that performs combustion at a specific mixing ratio.
(4) The combustion apparatus according to the present application can be employed not only in the hot water supply equipment described in the embodiment, but also in a steam generator and an absorbent regenerator of an absorption chiller.

Exploded perspective view of combustion apparatus according to the present application Vertical section of the combustion device Explanatory drawing which shows the positional relationship with respect to the burner of a diffusion path and a connection path The figure which shows the flow state of the connection path site | part which concerns on this application The figure which shows the spectrum distribution of the time-dependent fluid vibration generate | occur | produced from the combustion apparatus which concerns on this application Diagram showing noise reduction effect in low frequency range The figure which shows another embodiment (a, b) which makes the position of the reattachment point in the combustion apparatus which concerns on this application an appropriate position, and the 1st reference example (c) . The figure which shows the spectrum distribution of the time-dependent fluid vibration generate | occur | produced from the structure shown in FIG. The figure which shows the 2nd reference example of the combustion apparatus which concerns on this application The figure which shows the 3rd reference example (a) and 4th reference example (b) of the combustion apparatus which concerns on this application The figure which shows 2nd Embodiment which provides the partition which divides | segments the diffusion path in the combustion apparatus which concerns on this application, or a connecting path following it. The figure which shows the spectrum distribution of the time-dependent fluid vibration generate | occur | produced from the structure shown to Fig.11 (a). The figure which shows another embodiment of the partition shown in FIG. The figure which shows the flow state of the connection path site | part of a conventional structure A diagram showing the spectral distribution of noise generated from a conventional combustion device

DESCRIPTION OF SYMBOLS 1 Combustion device 2 Sirocco fan 3 Burner 4 Combustor 5 Duct 9 Gas nozzle 10 Inlet 11 Diffusion path 12 Connection path 13 Duct casing 14 Bending part 15 Rectification part 16 Curved connection wall 17 Rectification part 26 Outlet A Reattachment point e Separation vortex (Peeling flow)

Claims (7)

A fan that blows out oxygen-containing gas for combustion, a diffusion path that is connected to a blow-out port of the fan and diffuses an oxygen-containing gas stream blown out by the fan, and an oxygen-containing gas and a hydrocarbon system that are fed from the diffusion path A combustion apparatus comprising a burner for mixing and burning fuel,
The diffusion path connected to the blower outlet of the fan and guiding and diffusing the oxygen-containing gas flow blown out by the fan in the second direction, and supplied through the diffusion path at the second direction end of the diffusion path A connection path for guiding the oxygen-containing gas flow in the first direction through the bent portion, and the oxygen-containing gas flow from the connection path through the introduction port in a direction opposite to the second direction, and mixing with the hydrocarbon-based fuel And burner to burn,
The introduction port is provided on the downstream side from the reattachment point of the separation flow formed in the bent portion connected to the connection path from the diffusion path, and an extension wall extending in a direction away from the introduction port, Provided in the connection path side part of the diffusion path, the separation flow is formed at the tip of the extension wall,
Relates to the aforementioned oxygen-containing gas stream leading to the burner from the fan, the peak frequency of the time the fluid vibration generated at the site where the flow is bent is set outside the frequency range of the combustion noise generated by the combustion of the mixed gas Combustion device. The time the fluid vibration, the bent portion connected to the connecting passage from the diffusion path is formed as a starting point, a combustion apparatus according to claim 1, wherein the repeating vibration of the separated flow repeating fluctuations. Wherein the connection passage portion from the reattachment point of separated flow to said inlet port, said connecting passage combustion apparatus according to claim 1 or 2, wherein the rectifier is provided for rectifying the oxygen-containing gas stream flowing through. A fan that blows out oxygen-containing gas for combustion, a diffusion path that is connected to a blow-out port of the fan and diffuses an oxygen-containing gas stream blown out by the fan, and an oxygen-containing gas and a hydrocarbon system that are fed from the diffusion path A combustion apparatus comprising a burner for mixing and burning fuel,
The diffusion path connected to the blowout port of the fan and guiding and diffusing the oxygen-containing gas flow blown out by the fan in the second direction, and oxygen supplied through the diffusion path at the second direction end of the diffusion path A connecting path for guiding the contained gas flow in the first direction through the bent portion, and the oxygen-containing gas stream from the connecting path through the introduction port in a direction opposite to the second direction and mixed with the hydrocarbon-based fuel. And burner to burn
Crossing both the first direction and the second direction at the connection path side part of the diffusion path, or at the connection path side part of the diffusion path and at least the connection path part from the connection path entrance to the introduction port Providing a partition for dividing the flow path in the third direction,
Relates to the aforementioned oxygen-containing gas stream leading to the burner from the fan, the peak frequency of the time the fluid vibration generated at the site where the flow is bent is set outside the frequency range of the combustion noise generated by the combustion of the mixed gas Combustion device. A fan that blows out oxygen-containing gas for combustion, a diffusion path that is connected to the blow-out port of the fan and that guides and diffuses the oxygen-containing gas flow blown out by the fan in a second direction, and a second direction end of the diffusion path A connection path for guiding the oxygen-containing gas flow supplied through the diffusion path in a first direction through a bent portion, and a direction opposite to the second direction from the connection path through the inlet through the oxygen-containing gas flow A combustion apparatus comprising a burner for directing and mixing and burning with a hydrocarbon-based fuel,
Wherein said inlet port downstream of the reattachment of the separated flow formed in the bent portion continuous to the connecting passage from the diffusion path provided Rutotomoni, the extension wall extending in a direction away from the inlet, A combustion apparatus that is provided at a connection path side portion of the diffusion path and in which the separation flow is formed at a tip of the extension wall . Wherein the connection passage portion from the reattachment point of separated flow to said inlet port, a combustion apparatus according to claim 5, wherein having a rectifier for rectifying the oxygen-containing gas stream flowing through the connection path. A fan that blows out oxygen-containing gas for combustion, a diffusion path that is connected to the blow-out port of the fan and that guides and diffuses the oxygen-containing gas flow blown out by the fan in a second direction, and a second direction end of the diffusion path A connection path for guiding the oxygen-containing gas flow supplied through the diffusion path in a first direction through a bent portion, and a direction opposite to the second direction from the connection path through the inlet through the oxygen-containing gas flow A combustion apparatus comprising a burner for directing and mixing and burning with a hydrocarbon-based fuel,
The introduction port is provided on the downstream side from the reattachment point of the separation flow formed in the bent portion connected to the connection path from the diffusion path ,
Crossing both the first direction and the second direction at the connection path side part of the diffusion path, or at the connection path side part of the diffusion path and at least the connection path part from the connection path entrance to the introduction port The combustion apparatus which provided the partition which divides | segments a flow path in the 3rd direction .

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