JPS61252412A - Circulation flow generating device - Google Patents

Abstract

PURPOSE:To reduce the amount of leakage of fluid and enable an efficient production of circulation flow by a method wherein movable guide vanes are fixed and at least one of the walls corresponding to a bottom surface of a cylindrical space is composed of a sliding wall which may be moved toward a central axis of the cylindrical space. CONSTITUTION:Fixed guide vanes 13 are arranged at the inlet port of a circulation flow producing device passage 18, the fluid flowed into the guide vanes is varied in its direction with the angle of each of the fixed guide vanes 13 and then a circulation force is applied to it. Since a width of the flow passage 18 can be set optionally if the movable wall 14 is slid axially under operation of an operating rod 17, a fluid-flowing speed can be varied optionally and also the circulation force can be varied. Further, since no clearance is found between the fixed guide vanes 13 and the side walls 12a, 12b, no leakage of fluid is found. Since they are arranged such that a flowing direction of the fluid is coincided with the tangential direction of an inscribed circle at the extremity end of each of the vanes 13, almost of all the speed vector of fluid can be changed into a circulation force, with the result that a better efficiency of production of circulation flow can be attained.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a swirling flow generating device, which is mainly used in combustion devices, and has a so-called radius that is suitable for imparting swirling force to a fluid such as combustion air. This invention relates to a flow-type swirling flow generator.

[Conventional technology]

In combustion equipment for oil, gas, pulverized coal, etc., combustion air is swirled to control its mixing with fuel. Proper swirling strengthens the flame-holding function by forming a backflow area, and improves the fuel flow. Nitrogen oxides and unburned substances can be reduced by controlling the mixing condition of the fuel and air.

In other words, the reduction of nitrogen oxides and the suppression of unburned matter are contradictory, and normally, when the mixture of fuel and air is improved to suppress unburned matter, the temperature locally increases. Conversely, if the mixing of fuel and air is delayed, nitrogen oxides will decrease but unburned matter will increase.

However, if proper swirl is given to the combustion air, a backflow area is formed near the burner outlet, and the main flow of the combustion air is directed outwards, delaying mixing with the fuel, resulting in the generation of nitrogen oxides. is suppressed. On the other hand, when you leave the burner,
Since the backflow region has disappeared, the main flow of combustion air heads toward the center, making it possible to completely burn the unburned matter generated in the previous combustion region near the burner. In other words, applying an appropriate swirling force to the combustion air is extremely important from the viewpoint of environmental protection and high efficiency combustion. Especially when using pulverized coal, etc., which has poor combustibility, as fuel, the subtle swirling force is extremely important. This requires adjustment.

Conventionally, there are two types of swirl flow generation devices used in combustion devices and the like: an axial flow type and a radial flow type. The former axial flow type is
The inlet flow path and the outlet flow path of the fluid form a cylindrical space (i.e.
This system exists on the same linear axes of a cylindrical or regular polygonal space, and a spiral guide vane is placed between the inlet and the outlet to apply swirling force to the fluid passing through. On the other hand, in the latter radial flow type, fluid flows in from a portion corresponding to the side surface of the cylindrical space and flows out from the bottom surface of at least one side of the cylindrical space. Usually, the fluid flows radially from the inlet to the center. After that, it turns in the direction of the central axis of the cylindrical space and heads toward the bottom exit. At this time, by providing a guide vane in the injection part, a swirling force is applied to the inflowing fluid in the circumferential direction, so that the fluid heads toward the center in a spiral shape at one end, then reverses direction and spirals. It is heading for the exit.

FIGS. 6 and 7 show an example of a combustion apparatus equipped with a conventional radial swirl flow generating device. In the same figure, the swirl flow generator 24, 24' is a burner port 1 provided on the furnace wall 2.
It is attached around the central axis of 1. This example is for a pulverized coal burner. /(-Navot 11 is provided with a pulverized coal nozzle 8, a secondary air nozzle 9, and a tertiary air passage 10 from the center to the outside, and a swirling flow The pulverized coal nozzle 8 is housed in the wind box 3 together with the generator 24, 24'.
is installed, and an air dust 4 having a damper 5 is connected to the wind box 3.

The swirl flow generator 24, 24' is located at the bottom 11i of the cylindrical space.
lit' rotating device side walls 12a, 12b, multiple movable blades (guide blades) 25, rotating shaft 26, link 27°30
, an operating shaft 28 and an operating handle 29.

In this type of radial flow type swirling flow generating device, combustion air flows through the movable vane 25, but the operating handle 29t-
When the operation shaft 28 is rotated, the link 27.30
The rotary shaft 26 can be rotated via. When the rotating shaft 26 rotates, the movable blade 25 attached to the rotating shaft 26 also rotates, and as shown in FIG. It is possible to change the inflow direction of the combustion air flowing into the swirl flow generating device. In addition, the movable blade 250 angle θ
At the same time, the change in t also changes the minimum flow path width t between the movable vanes. Therefore, if the movable blade angle θ becomes smaller, the inflow direction approaches the tangential direction, the circumferential component of the inflow velocity increases, and the inflow velocity itself also increases significantly, which should dramatically increase the turning force. It is.

[Problem that the invention seeks to solve]

However, as shown in FIG. 9, there is a gap 33 between the movable blade 25 and the side walls 12a, 12b of the swirl flow generator, so that some of the fluid leaks.

This gap 33 is created because it is necessary to move the movable blade 25 with as little power as possible, it is necessary to be able to move even if the device is subjected to thermal distortion due to radiant heat from the furnace wall 2, and it is also necessary to avoid mischief. For reasons such as increasing the manufacturing cost if the machining accuracy is increased, this gap will always exist as long as the blade has a movable blade structure.

As mentioned above, if the movable blade angle θ is made smaller to increase the swirling force and the minimum flow path +111t is made smaller, the cross-sectional area of the blade portion in the swirling flow generator decreases, and the area of the gap portion remains unchanged. As a result, the area ratio of the gap portion to the total flow path area increases. Therefore, the ratio of 1)-ri fluid that does not include a circumferential component increases, and even if the movable blade angle θ is reduced, the expected increase in swirling force cannot be obtained.

Moreover, this brings about the undesirable result that only the pressure loss increases without fail.

In addition, since a plurality of movable vanes are connected and moved by links, the vane angle θ of each movable vane is different, which may cause drift, and there is play in the links, so it is difficult to move the operating handle 29. movable blade 2
5 may not follow suit, which may lead to inconvenient situations when controlling the turning force appropriately.

SUMMARY OF THE INVENTION An object of the present invention is to provide a radial flow type swirling flow generation device that can eliminate the drawbacks of the prior art described above, reduce the amount of fluid leakage, and efficiently generate swirling flow.

[Means for solving problems]

In the radial swirl flow generating device, the movable guide vanes are fixed, and at least one of the walls corresponding to the bottom of the cylindrical space is connected to the central axis of the cylindrical space. It is composed of a sliding wall that can be moved in different directions.

Hereinafter, the present invention will be explained in detail based on illustrated embodiments.

〔Example〕

1 to 3 show an example in which a radial swirl flow generator 1.1' according to an embodiment of the present invention is applied to a pulverized coal burner.

In the figure, a burner boat 11 is provided on a furnace wall 2, and a pulverized coal nozzle 8, a secondary air nozzle 9, and a tertiary air flow path 10 are provided in the burner boat 11 from the center toward the outside. There is.

A radial swirl generator 1.1' is attached to the secondary air nozzle 9 and the tertiary air channel 10, respectively, and these are housed in the wind box 3. An air duct having a damper 5t is connected to the wind box 3, and an auxiliary combustion burner 6 to which an inopeller 7 is attached is provided in the pulverized coal nozzle 8.

The radial flow type swirl generating device 1, 1' has a swirl device side wall 12 which forms the bottom surface of a cylindrical space! 1, 12b, a plurality of fixed guide vanes 13, a movable side wall (sliding side wall) 14 having a notch through which the fixed guide vanes 13 can pass, and a cylindrical column with the movable side wall 14 as one bottom surface. A cylinder 15 corresponding to the side surface of the space and connected to the movable side wall 14, a packing 16 provided inside the cylinder 15, one end attached to the cylinder 15, and the other end attached to the wind box/3. It is constituted by an operating rod 17 penetrating the outer wall of.

The plurality of fixed guide vanes 13 are usually attached so as to be in contact with the inscribed circle of the tip of the vane, but depending on the case, they may be attached at an arbitrary angle with the tangent to the inscribed circle.

Next, the operation of the radial swirl flow generator 1°1' having the above structure will be described.

First, fluid such as combustion air supplied from the air duct 4 into the wind box 3 is supplied to the swirl flow generator 1.1'.

The air then passes through the 70 flow path 18 to reach the tertiary air flow path 10 and the secondary air nozzle 9, and further passes through the burner boat 11t and is ejected into the furnace.

A fixed guide vane 1 is installed at the inlet of the swirl flow generator flow path 18.
3, and the fluid flowing into the fixed guide vane 1
The direction of the flow is changed in the direction of an angle of 3 (usually in the circumferential direction), and a swirling force is applied.

Therefore, the flow becomes a spiral and the swirling flow generator 1.1
Go to the center of '. By the way, since the central part of the side wall of the swirling device a is connected to the tertiary air flow path 10 or the secondary air nozzle 9, which is the outlet of the swirling flow generating device 1.1', the direction is changed again and a spiral shape is formed. Burna boat 11 becomes the flow
I will be heading to.

Here, the width of the swirling flow generator flow path 18 is the width of the operating rod 1
By the operation in step 7, the movable side wall 14t can be arbitrarily set by sliding in the axial direction, so that the inflow velocity of the fluid can be arbitrarily changed and the turning force can be changed. Moreover, since there is no gap between the fixed guide vane 13 and the side walls 12a, 12b, there is no leakage of fluid. Additionally, the fixed guide vanes 13 are usually arranged so that the inflow direction of the fluid coincides as much as possible with the tangential direction of the inscribed circle at the tip of the vane, so most of the velocity of the fluid is converted into swirling force. The efficiency of swirl flow generation is high.

Next, FIG. 4 shows a second embodiment of the present invention.

In this embodiment, a gasket 20 is provided in a notch or notch 19 provided in the movable side wall 14. This allows the notch 19 to be sealed, so the notch 19 can be sealed.
Even if the machining accuracy of No. 9 is poor, the airtightness of the sliding part can be maintained.

FIG. 5 shows a third embodiment of the present invention, in which an annular block 22 is slid by an operating rod 17 into a groove 23 into which a fixed guide vane 13 can be inserted, and a flow path 18 of the swirl flow generator is opened. The width is changed, and the effect is the same as that of the first embodiment.

Although each of the above-mentioned embodiments is an example applied to a pulverized coal burner, it goes without saying that it can be applied to any case that requires a swirling flow, such as a burner using other fuels or an after-air port.

〔Effect of the invention〕

As described in detail above, according to the present invention, in a radial flow type swirling flow generator, the guide vanes are fixed in the most efficient connection direction, and the movable side wall is slid to increase the flow path width of the swirling flow generator. The turning force can be adjusted by changing the
It is possible to eliminate leakage fluid that does not contribute to the turning force, which is seen when using conventional movable guide vanes, and since the angle of the guide vanes is constant, even when you want to obtain a large turning force, it is possible to eliminate the leakage fluid that does not contribute to the turning force. Due to the reduction in the effective root length due to the reduction of the blade angle of the movable guide vane, the amount of short passes increases, and if the specified turning force cannot be obtained, it will not happen at any time, and the range of change in the turning force can be greatly reduced. It can be made large.

Furthermore, it is possible to reduce deviations in the flow state due to variations in the vane angle of the movable guide vanes. Therefore,
There is less waste when generating a swirling flow, and the swirling force can be precisely controlled.

[Brief explanation of the drawing]

Figures 1 to #IJ3 are views showing an example of a pulverized coal burner equipped with a radial swirl flow generating device according to the first embodiment of the present invention, with Figure 1 being a sectional view and Figure 2 being a pulverized coal burner. 1, FIG. 3 is a partially enlarged view of section B in FIG. 2, and FIGS. 6 to 9 are views showing an example of a pulverized coal burner equipped with a conventional radial swirl flow generating device; FIG. 6 is a cross-sectional view;
FIG. 7 is a sectional view taken along line cc' in FIG. 6, and FIGS. 8 and 9 are partial views. 1.1'... Radial swirl flow generator, 3... Wind box, 4... Air duct, 5... Damper, 6...
- Auxiliary combustion burner, 8... Pulverized coal nozzle, 9... Secondary air nozzle, lO... Tertiary air flow path, 11...
Burner boat, 12a, 12b...Swivel device side wall,
13...Fixed circular inner blade, 14...Movable side wall (sliding side wall), 15...Cylinder, 16.20...Puttlekin, 17...Operation rod, 18...Swirling flow generator Flow path, 19... Notch, 21... Air flow, 22... Annular block, 23... Groove.

Claims (1)

[Claims] One bottom surface of the cylindrical space serves as a wall, the other bottom surface has a fluid outlet channel in its center, an annular portion on the outside thereof serves as a wall, and a fluid inlet channel is provided in a portion corresponding to the side surface. In a so-called radial flow swirling flow generating device in which a guide vane is provided in the inlet flow path, the guide vane is fixed, and the guide vane is fixed.
A swirling flow generating device characterized in that at least one of the walls forming both bottom surfaces of the cylindrical space is constituted by a sliding wall movable in the direction of the central axis of the cylindrical space.