JP2011206751A - Fluid mixing apparatus and denitrification apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fluid mixing apparatus having a simple structure and capable of uniformly mixing a second fluid with a first fluid over the whole flowing passage when mixed by jetting the second fluid from a jetting port to the first fluid flowing in the flowing passage.SOLUTION: The fluid mixing apparatus mixes the second fluid B to the first fluid A by jetting the second fluid B from the jetting port 5 arranged in a flowing passage 4 where the first fluid A flows. This fluid mixing apparatus has a spiral guide vane 1 formed by projecting to the inner diameter side from a wall surface of the flowing passage 4 and having a spiral shaft in the communicating direction of the flowing passage 4, and this spiral guide vane 1 is constituted as a spiral guide vane of multiple rows provided in a plural number at the same position in the axis direction of the flowing passage 4, and in circumferentially different phases. A communicating opening area 7 continuing in the communicating direction of the flowing passage 4 is formed in the inner diameter side part of this plurality of spiral guide vanes. The jetting port 5 is arranged on the wall surface of the flowing passage 4 upstream of a position of the spiral guide vane 1.

Description

The present invention is directed to a fluid mixing device that ejects a second fluid from a jet port disposed in the flow passage to the flow passage through which the first fluid flows, and mixes the second fluid with the first fluid, and
The present invention relates to a denitration apparatus that includes a fluid mixing device that mixes a reducing agent with exhaust gas discharged from a combustion engine and that flows through a flow passage, and denitrates the mixed gas mixed by the fluid mixing device by a catalytic reaction.

As a device equipped with such a fluid mixing device, a reducing agent such as ammonia or urea is jetted in a gas or mist form into a flow passage through which exhaust gas discharged from a combustion engine such as an engine flows, and the reducing agent is discharged into the exhaust gas. There is a denitration device configured to decompose nitrogen oxides contained in exhaust gas into nitrogen and water by a catalytic reduction action.
In such a denitration device, if the exhaust gas and the reducing agent are not mixed uniformly in the fluid mixing device, sufficient decomposition performance of nitrogen oxides cannot be obtained, or catalyst deterioration becomes local, resulting in a short catalyst life. Problems such as becoming. Furthermore, in the denitration apparatus, if the pressure loss generated with respect to the first fluid in the flow passage is large, the operation of the combustion engine on the upstream side of the flow passage may be hindered.

  The inventors have proposed a fluid mixing apparatus described in Patent Document 1 as a fluid mixing apparatus that can be used in such a denitration apparatus. In the technique described in this document, a baffle portion is arranged in a part of the flow path cross section of the flow passage, and the ejection port is an open area other than the area where the baffle portion is arranged in the flow passage cross section of the flow passage or the It arrange | positions upstream (for example, refer patent document 1).

In this technique, the second fluid can be diffused well over the entire flow path, and the second fluid can be uniformly mixed with the first fluid. In addition, when the spout and the baffle are arranged in this way, the second fluid can be uniformly mixed with the first fluid even if the baffle is relatively small. The increase in pressure loss with respect to can be suppressed.
However, it has been found that the following problems occur in the fluid mixing apparatus configured as described above.

  That is, in the technique described above, in order to provide the ejection port, the supply pipe 5 is provided in the fluid flow path of the flow path so as to cross the flow path, and the second fluid is ejected from the ejection port 6 provided in the supply pipe 5. To do. Therefore, when the first fluid is corrosive gas such as exhaust gas discharged from the engine, the supply pipe 5 may be corroded. Further, depending on the types of the first fluid and the second fluid, the jet port 6 provided in the supply pipe 5 may be clogged with a corrosion product or a reaction product.

  In order to solve such a problem, it is conceivable to eliminate the supply pipe itself provided across the flow passage. In this case, the jet outlet is opened on the wall surface of the flow passage. However, when the outlet is opened in the wall surface of the flow passage in this way, the distribution of the second fluid is biased to the vicinity of the side wall surface of the outlet of the flow passage, and a good mixed state cannot be obtained.

  In view of this, a spiral guide vane is formed that protrudes from the wall surface of the flow passage toward the inner diameter side, and has a spiral axis in the communication direction of the flow passage, and at the inner diameter side portion of the spiral guide blade, A communication open region continuous in the communication direction is formed, and the jet port is provided on the wall surface of the flow path upstream of the position of the spiral guide vane, and the first fluid and the second fluid are mixed. It is considered to improve the state (see Patent Document 2).

JP 2005-118622 A JP 2009-127451 A

  However, when the configuration as described above is adopted, the mixing state of the first fluid and the second fluid can be improved, but the pressure loss generated by the guide vanes hinders the fluid supply. There is a limit to the reduction, and there are limitations on the design, and the tube structure of the fluid mixing apparatus is complicated, and problems such as an increase in manufacturing cost tend to occur. Further, there is a demand for improving the mixed state of the first fluid and the second fluid.

  An object of the present invention is to have a simple configuration and when the second fluid is jetted from the outlet into the first fluid flowing through the flow passage and mixed with the second fluid configuration over the entire flow passage. In particular, by providing such a fluid mixing device, there is provided a denitration device that improves the decomposition performance and catalyst life of nitrogen oxides and does not hinder the operation of the combustion engine. In the point.

〔Constitution〕
In order to achieve the above object, the characteristic configuration of the fluid mixing apparatus of the present invention is as follows:
When the second fluid is ejected from the jet port arranged in the flow passage to the flow passage through which the first fluid flows, and the second fluid is mixed with the first fluid,
A plurality of spiral guide blades that protrude from the wall surface of the flow passage toward the inner diameter side and have a spiral axis in the communication direction of the flow passage are provided at the same position in the axial direction of the flow passage and in different phases in the circumferential direction. It is configured as a multi-row spiral guide vane, and forms a communication open region continuous in the communication direction of the flow passage at the inner diameter side portion of the plurality of spiral guide vanes, than the position of the spiral guide vane The jet port is provided on the wall surface of the upstream flow passage.

[Function and effect]

  In this fluid mixing apparatus, the second fluid jet port and the spiral guide vane are provided from the upstream to the downstream of the flow passage. And by providing the jet outlet on the wall surface of the flow passage, as described above, the pipe for supplying the second fluid is corroded, and its function cannot be exhibited, or the jet outlet is clogged. There is no problem.

  However, there is a possibility that the second fluid is unevenly distributed by providing the jet outlet on the wall surface as described above. However, by providing the spiral guide blade, the wall surface side on which the jet outlet is provided is provided. While the second fluid that is unevenly distributed is redirected by the blade, it is guided to the entire surface of the flow passage to promote diffusion and the uneven distribution can be eliminated. Furthermore, by forming a communication open region at the inner diameter side portion of the spiral guide vane, the second fluid diffused in the circumferential direction by the vane flows into the open region, and sufficient diffusion is achieved while reducing pressure loss. Mixing can be realized.

  Here, since the spiral guide vanes are multi-striped, the swirling flow that has received an acting force that changes the direction of the first and second fluids flowing through the flow passage is at the same position in the axial direction of the flow passage. A plurality of the directions are changed at the same time, and the first second fluid flows downstream while being particularly efficiently stirred. Therefore, it contributes to the improvement of mixing efficiency, and sufficient mixing is possible and pressure loss can be suppressed only by receiving a mixing action at a short distance from the position of the spiral guide vane to the downstream side.

〔Constitution〕
In addition, it is preferable that the multiple spiral guide blades are provided without overlapping over the entire circumference in the axial direction view of the flow passage.

[Function and effect]
Since the stirring and mixing action of the swirl flow in which the first and second fluids are changed in direction from the spiral guide vane is sufficiently generated regardless of the overlap in the spiral axis direction of the spiral guide vane at the downstream position. , When viewed in the direction of the spiral axis of the flow passage, there is no overlap over the entire circumference (for example, if there are two strips, the two spiral guide vanes of 1/2 circumference are arranged 180 degrees out of phase in the circumferential direction) If it is 4, it is a state where four 1/4 spirals are arranged 90 ° out of phase in the circumferential direction). If provided, the spiral guide vanes are formed with an efficient and simple configuration. be able to.

〔Constitution〕
Further, according to the diffusion mixing distance to the uniform mixing condition satisfaction position, which is the position downstream of the multiple spiral guide blades, the number of the spiral guide blades of the multiple stripes, the shorter the diffusion mixing distance, It is preferable to determine so as to satisfy the uniform mixing condition at the position where the uniform mixing condition is satisfied in the form in which the number of spiral guide blades is increased.

[Function and effect]
As described above, the first and second fluids change from the state of colliding with the spiral guide blades to the stirring and mixing state, but a certain amount of mixing time is required for mixing to a state that can be regarded as uniform. On the other hand, when the mixed fluid reacts by the action of a catalyst or the like, it is required that the mixed fluid be in a uniform mixed state before the catalyst. The distance (diffusion mixing distance) to the position (uniform mixing condition satisfaction position) where the first and second fluids flow downstream from the spiral guide vanes for the mixing time and are considered to be uniform (uniform mixing conditions). ) Is considered to be preferable as it is shorter. However, in practice, it is preferable to mix by effectively using the pipe length according to the pipe length provided with the spiral guide vanes. Further, based on the description of the mixing efficiency described above, the mixing time can be reduced more efficiently as the number of the spiral guide blades increases, so that the mixing time can be shortened.

  Therefore, when reconstructing based on the diffusion mixing distance, the shorter the diffusion mixing distance is, the more the number of the spiral guide blades of the multiple stripes is increased, so that the uniform mixing condition at the uniform mixing condition satisfaction position is satisfied. Thus, a sufficiently mixed state can be formed while maximally effectively using the pipe length provided with the spiral guide blade.

〔Constitution〕
The number of the spiral guide blades of the multiple strips is 4, and the blade position at the rear end in the circumferential direction with respect to the pair of blades adjacent to each other in the circumferential direction around the axial center and the inner diameter Dx of the communication open region The ratio (Lx / Dx) of the separation distance Lx in the axial center direction of the said flow path with the blade | wing position of the circumferential direction front-end | tip is set to 0.05 or more and 0.5 or less. The fluid mixing apparatus according to the item.

[Function and effect]
If the number of spiral guide blades is four, the spiral guide blades having an appropriate size according to the diameter and length of the flow passage can be easily arranged, and the mixing efficiency is sufficiently high. It has been experimentally found that the number of stripes can be exhibited. When the number of strips is small, there may be a case where the mixing efficiency cannot be sufficiently improved. On the other hand, when the number of strips is large, it is difficult to form the arrangement of the spiral guide blades. Further, regarding the pair of blades adjacent to each other in the circumferential direction, the spiral guide blade has an inner diameter Dx of the communication open region, and the blade position at the rear end in the circumferential direction and the blade position at the front end in the circumferential direction. If the ratio (Lx / Dx) to the separation distance Lx around the axis in the axial direction of the flow path is set to be 0.05 or more and 0.5 or less, the area where the spiral guide blades are provided is reduced. In addition, it is possible to generate a large acting force that changes the direction of the first and second fluids flowing through the flow passage. That is, if the ratio (Lx / Dx) is too small, the difference from a mere baffle plate is reduced, the pressure loss is increased, and it is difficult to obtain an acting force that changes the direction of the first and second fluids. Therefore, it is difficult to obtain mixing ability. On the other hand, if the ratio (Lx / Dx) is too large, the region where the spiral guide vanes are provided extends long in the axial direction of the flow passage, and an acting force that changes the direction of the first and second fluids is obtained. It becomes difficult to obtain the mixing ability and the diffusion mixing distance becomes long.

〔Constitution〕
Moreover, it is preferable that the area ratio of the said communication open area | region with respect to the whole cross-sectional area of the said flow path shall be the range of 3: 11-4: 5 by the communication direction view of the said flow path.

[Function and effect]
As described above, the communication fluid release region is formed in the inner diameter side portion of the spiral guide vane, so that the second fluid diffused in the circumferential direction by the vane flows into the open region, thereby reducing the pressure loss. Sufficient diffusive mixing can be achieved.
Here, in the region where the spiral guide vane covers the flow passage, between the portion of the first and second fluids whose direction is changed in the circumferential direction and the portion which passes through the communication open region without being changed in direction. On the other hand, there is one aspect in which the turbulence of the generated gas flow occurs and mixing is promoted. On the other hand, if the ratio of the gas flow to be redirected is excessively increased, the pressure loss is increased. Specifically, when the ratio is larger than 4: 5, it tends to be difficult to obtain the mixing ability by the spiral guide blades, and when it is smaller than 3:11, the pressure loss increases.

〔Constitution〕
The characteristic configuration of the denitration device of the present invention includes a fluid mixing device that mixes a reducing agent with the exhaust gas discharged from the combustion engine and flowing through the flow passage, and the mixed gas mixed by the fluid mixing device is denitrated by catalytic reaction. A denitration device that
As the fluid mixing device, the fluid mixing device is characterized in that the first fluid is the exhaust gas and the second fluid is the reducing agent.

[Function and effect]
As the fluid mixing device, the fluid mixing device described above is provided in a form in which the first fluid is the exhaust gas and the second fluid is the reducing agent, thereby mixing the first fluid and the second fluid. Can be obtained sufficiently and stably, and the mixed gas can be guided to the catalyst part to perform denitration well.

The figure which shows schematic structure of the denitration apparatus which concerns on this application Elevated sectional view showing schematic configuration of fluid mixing device The figure which shows the detail of the helical guide blade used for the fluid mixing apparatus of this invention The figure which shows the mixing state of the fluid by a spiral guide blade The figure which shows the guide blade 1b used as a comparative example The figure which shows the mixing state of the fluid by the guide blade 1b The figure which shows the guide blade 1c used as a comparative example The figure which shows the mixing state of the fluid by the guide blade 1c The figure which shows the guide blade 1d used as a comparative example The figure which shows the mixing state of the fluid by the guide blade 1d Graph showing fluid mixing state by each guide vane

Hereinafter, a denitration apparatus 200 including the fluid mixing apparatus 100 according to the present application will be described with reference to the drawings.
FIG. 1 is a diagram showing a configuration of a denitration apparatus 200 according to the present application, and FIG. 2 is a diagram schematically showing a configuration of a fluid mixing apparatus 100 according to the present application incorporated in a part of the denitration apparatus 200. It is.
As shown in FIG. 1, the denitration apparatus 200 includes a fluid mixing apparatus according to the present application for exhaust gas discharged from a combustion engine 201 (in the illustrated example, an engine 203 for rotating the generator 202). 100 is used to mix the reducing agent, and the mixed gas uniformly mixed by the fluid mixing apparatus 100 is guided to the catalyst unit 205 where the catalyst 204 (reduction catalyst and oxidation catalyst) is disposed, and the exhaust gas is harmless. It is to become. Therefore, in this configuration, the exhaust gas from the combustion engine 201 corresponds to the first fluid A in the present application, and the reducing agent mixed with the exhaust gas becomes the second fluid B. Here, the exhaust gas contains nitrogen oxides to be rendered harmless, and the reducing agent for rendering the nitrogen oxides harmless is specifically a mixture of urea and water. These reducing agents may be supplied to the flow passage in a gas state, or may be supplied to the flow passage in a mist state.

  As schematically shown in FIG. 2, the fluid mixing apparatus 100 according to the present application sends the second fluid B from the jet port 5 provided on the wall surface of the flow passage 4 into the flow passage 4 through which the first fluid A flows. The second fluid B is mixed with the first fluid A by being ejected. Here, the quantity ratio (mass ratio) of the second fluid B to the first fluid A is approximately 1: 100000 to 5: 1000. As described above, since the amount of the second fluid B is extremely small, when the active mixing / stirring is not performed on the downstream side of the ejection port 5, the extreme uneven distribution of the second fluid B may occur at the inlet portion of the catalyst unit 205. Will remain.

  The flow path 4 is a flow path formed in a pipe having a circular cross section, and after the first fluid A received from the upstream side is circulated and mixed with the second fluid B, the mixed gas is transferred to the downstream side. (To be specific, the catalyst section inlet 205a having a square cross section is discharged).

  The jet outlet 5 is formed in the wall surface 6 of the flow passage, and the second fluid B is jetted into the flow passage 4 from the opening. The ejection direction of the second fluid B is the radial direction of the flow passage 4 substantially orthogonal to the wall surface 6. Here, the opening direction of the jet nozzle 5 may be a radial direction as shown in the embodiment, or may be a direction inclined from the radial direction to the upstream side or the downstream side. When the structure is inclined to the upstream side, the second fluid B is ejected to face the first fluid A, thereby promoting the mixing of both fluids. On the other hand, when the structure is inclined to the downstream side, the second fluid B can be sucked by the first fluid A and sucked into the flow passage 4. In this configuration, the power required for the ejection of the second fluid B can be reduced. In the present application, since both the fluids can be reliably mixed by the spiral guide blade 1 provided on the downstream side of the jet port 5, even when the jet port 5 is directed to the downstream side in this way, there is no problem of mixing. It can be surely solved.

  Moreover, although the said jet nozzle 5 is provided in one place of the circumferential direction of the flow path 4, it is also possible to provide the jet nozzle 5 in multiple numbers in the circumferential direction, and to disperse | distribute it. For example, when the outlets 5 are provided at 90 ° pitches at four locations in the circumferential direction, the distribution of the second fluid B can be ensured to some extent at the ejection locations in the circumferential direction.

  In the fluid mixing device 100, the spiral guide vane 1 is arranged in a partial region in the flow passage 4 (that is, on the wall surface 6 of the flow passage upstream of the position of the spiral guide blade 1) The configuration in which the jet nozzle 5 is provided), and the spiral guide blade 1 makes it possible to give a swirling component to the first fluid A flowing through the flow passage 4 and to easily flow along the wall surface 6 of the flow passage 4. The second fluid B is swung along the wall surface 6 of the flow passage 4 and dispersed in the circumferential direction, and is mixed with the first fluid A.

  As shown in FIG. 3, the spiral guide blade 1 is formed so as to protrude from the wall surface 6 of the flow passage 4 toward the inner diameter side, and the spiral guide blade 1 having a spiral axis in the communication direction of the flow passage 4 is passed through the flow passage. Four spiral guide vanes in the same region in the spiral axis direction of the path 4 are configured as members that cover ¼ circumference of the flow path as viewed in the spiral axis direction of the flow path 4, and are 90 They are arranged at a pitch and are provided so as not to overlap in the axial direction of the flow passage 4.

  In addition, a communication open region 7 that is continuous in the communication direction of the flow passage 4 is formed in the inner diameter side portion of the plurality of spiral guide vanes 1. In the communication open region 7, the fluid flows to the downstream side without resistance. In this embodiment, the spiral guide vane 1 is a part of a coiled plate-like body that is thin with respect to the spiral axis direction and has a rectangular cross-sectional shape that is long in the inner diameter direction. The cross-sectional shape of the constituent material that constitutes can be a spiral flow whose spiral axis is the communication direction of the flow passage 4 in the mixed flow that flows along the wall surface 6 of the flow passage 4, and a part of the spiral flow is a communication open region. The shape is not limited to the plate-like body.

  The angle of the spiral guide vane 1 is the above-described blade position at the rear end in the circumferential direction and the blade position at the front end in the circumferential direction with respect to the inner diameter Dx of the communication opening region and the pair of blades adjacent in the circumferential direction. The ratio (Lx / Dx) to the separation distance Lx around the axial center in the axial direction of the flow path is set to 0.05 or more and 0.5 or less, and the flow path is completely disconnected in the communication direction view of the flow path. The area ratio of the communication open region 7 to the area is set to about 3:11 to 4: 5. In the following embodiment, the angle of the spiral guide blade 1 is set to Lx / Dx = 0.11. (See Figure 3)

FIG. 3 is a view of the spiral guide blade 1 as viewed in the spiral axis direction from the upstream side. As can be seen from this drawing, the spiral guide blade 1 is annular when viewed in the spiral axis direction. Thus, a communication open area 7 is formed on the inner diameter side.
Now, when the length from the wall surface 6 of the flow passage 4 to the inner diameter end of the spiral guide blade 1 is referred to as the protrusion height h1 of the blade, the protrusion height h1 is the second fluid B ejected from the ejection port 5. The diffusion region is configured to have at least a majority of the height (referred to as diffusion height) hz (refer to FIG. 4) in the channel crossing direction. By setting the protruding height h1 of the spiral guide blade 1 in this way, a majority of the second fluid B ejected from the ejection port 5 is taken into the spiral flow path to give a turn, and the second The fluid can be guided to a phase portion on the opposite side to the circumferential phase of the flow passage 4 in which the jet nozzle 5 is provided, so that the second fluid B can be evenly distributed in the flow passage 4.

FIG. 4 shows a simulation of the mixing state of the fluid mixing device 100 of the present embodiment by a numerical analysis method, and shows a cross section at a point 100 mm downstream of the spiral guide blade 1 in the flow path 6. The concentration distribution of the 2nd fluid in a 200 mm point cross section is shown. (It is shown that the second fluid is present at high concentration in the dark)

  As shown in FIG. 4, when the spiral guide vane 1 of the present invention is used, the second fluid B is guided to the side opposite to the side where the jet nozzle 5 is disposed, and the second fluid B is cross-sectioned at the inlet of the catalyst unit 205. It can be seen that it is distributed almost uniformly throughout.

Further, in place of the fluid mixing device 100 provided with the spiral guide blade 1, the fluid mixing device 100b (see FIG. 5) using one spiral guide spiral blade 1b having a slit portion in the axial direction is used as a comparison. A fluid mixing device 100c (see FIG. 7) provided with guide blades 1c in which guide blades are arranged so as to form a spiral around one line, and a fluid mixing device 100d (see FIG. 9) provided with a ring-shaped baffle plate 1d. FIG. 6 shows the concentration distribution of the second fluid in the cross section at the point of 100 mm downstream of the spiral guide blade 1 and the cross section at the point of 200 mm in the flow passage 6 when using the fluid mixing devices 100b, 100c and 100d. Shown in 8,10. In each fluid mixing device, the flow passage 4 is formed of a pipe having an inner diameter of 51 mm, and the swirl vane and the baffle plate are each provided with a communication open region 7 having an inner diameter of 34 mm. In addition, the results of examining the relationship between the pressure loss and the concentration distribution at that time are shown in Table 1 and are shown in a graph in FIG.
Here, the angle of the spiral guide vane 1b and the guide vane 1c with respect to the spiral axis and the area ratio of the communication open area to the entire cross-sectional area of the flow passage in the direction of communication of the flow passage are the spiral. It is designed to be the same as the shape guide blade 1.

  From Table 1 and FIG. 11, according to the fluid mixing apparatus 100 using the multiple spiral guide vanes 1 of the present invention, the multiple spirals are compared to the examples of 1b, 1c, and 1d that can be regarded as the single spiral guide vanes. It can be read that the shape guide blade 1 is in a preferable state from the viewpoint of both pressure loss and mixing efficiency (concentration difference). Moreover, comparing the difference in the number of strips, it can be seen from the comparison of 1 and 1b that the pressure loss and the concentration difference are reduced as the number of strips of the spiral guide blades is increased. It can be seen that the diffusion mixing distance necessary for satisfying becomes shorter as the number of the spiral guide blades 1 increases, and the length of the flow path (the position downstream of the multiple spiral guide blades 1). According to the diffusion mixing distance L to the uniform mixing condition satisfaction position M (see FIG. 2), the shorter the diffusion mixing distance L is, the more the number of the spiral guide blades 1 is increased. When the number of strips of the spiral guide blade 1 is determined so as to satisfy the uniform mixing condition at the position M (specifically, the diffusion mixing distance L for which the fluid mixing device 100 is required to have a predetermined degree of mixing (concentration difference)). If you know, the degree of mixing The number of strips of the spiral guide blades 1 to be realized can be obtained from the broken line in Fig. 11.) While making the most effective use of the length of the pipe (flow passage 4) provided with the spiral guide blades 1, It has been found that a sufficiently mixed state can be formed.

1: spiral guide blade 2: guide blade portion 3: gap 4: flow passage 5: jet outlet 6: wall surface 7: communication open region 100: fluid mixing device 200: denitration device 201: combustion engine 205: catalyst portion 205a: catalyst Port A: First fluid B: Second fluid

Claims (6)

A fluid mixing device that ejects a second fluid from a jet port disposed in the flow passage to the flow passage through which the first fluid flows, and mixes the second fluid with the first fluid,
A plurality of spiral guide blades that protrude from the wall surface of the flow passage toward the inner diameter side and have a helical axis in the communication direction of the flow passage are provided in the same region in the axial direction of the flow passage, in different phases in the circumferential direction. It is configured as a multi-row spiral guide blade, and forms a communication open region continuous in the communication direction of the flow passage in the inner diameter side portion of the plurality of spiral guide blades,
The fluid mixing apparatus which provided the said jet nozzle in the wall surface of the flow path upstream from the position of the said helical guide blade.   The fluid mixing apparatus according to claim 1, wherein the multi-row spiral guide blades are provided without overlapping over the entire circumference in the axial direction of the flow passage.   According to the diffusion mixing distance to the uniform mixing condition satisfaction position, which is a position downstream from the multiple spiral guide vanes, the more the multiple mixing spiral guide vanes, the shorter the diffusion mixing distance, The fluid mixing apparatus according to claim 1, wherein the fluid mixing device is determined so as to satisfy the uniform mixing condition at the position where the uniform mixing condition is satisfied in a form in which the number of spiral guide blades is increased.   The number of the spiral guide blades of the multiple strips is 4, and the blade position at the rear end in the circumferential direction with respect to the pair of blades adjacent to each other in the circumferential direction around the axial center and the inner diameter Dx of the communication open region The ratio (Lx / Dx) of the separation distance Lx in the axial center direction of the said flow path with the blade | wing position of the circumferential direction front-end | tip is set to 0.05 or more and 0.5 or less. The fluid mixing apparatus according to the item.   The area ratio of the said communication open area | region with respect to the total cross-sectional area of the said flow path by the communication direction view of the said flow path shall be the range of 3: 11-4: 5. The fluid mixing device as described. A denitration apparatus comprising a fluid mixing device that mixes a reducing agent with exhaust gas discharged from a combustion engine and flowing through a flow passage, and denitrating the mixed gas mixed by the fluid mixing device by catalytic reaction,
A denitration apparatus comprising the fluid mixing apparatus according to any one of claims 1 to 4 as the fluid mixing apparatus, wherein the first fluid is the exhaust gas and the second fluid is the reducing agent.