JP2678466B2 - Housing device for diffuser and catalytic converter - Google Patents

Description

FIELD OF THE INVENTION The present invention relates to a diffuser and a housing device for a catalytic converter.

PRIOR ART Diffusers are well known in the art.
In the Webster's New Collegiate Dictionary (1981), a diffuser is defined as "a device that reduces the velocity of a fluid passing through a system and increases its static pressure." The present invention relates to the most typical diffuser having a smaller flow passage cross-sectional area at the inlet than the flow passage cross-sectional area at the outlet. Diffusers may be used specifically to reduce the velocity of the fluid or to increase the pressure of the fluid, but the diffuser has the physical need to increase the cross-sectional flow area of the passage, such as when connecting conduits of different diameters. Often used by sex.

In the present specification, the "diffuser" has a smaller flow passage cross-sectional area at the inlet than the flow passage cross-sectional area at the outlet, reduces the velocity of the fluid in the main flow direction, and increases the static pressure thereof. Means

If the diffuser wall slope is too steep with respect to the main flow direction, the boundary layer separates two-dimensionally in the flow direction. In the present specification, "the boundary layer two-dimensionally separates in the flow direction" means that the fluid bulk is separated from the surface of the object, and as a result, the fluid bulk near the wall of the object is in the direction opposite to the flow direction of the fluid bulk. It means that a moving flow occurs. Such delamination of the boundary layer increases loss, reduces pressure recovery, and reduces velocity reduction. When such a phenomenon occurs, the diffuser is said to have stalled. Stall occurs in the diffuser when the momentum of the boundary layer cannot overcome the pressure rise as it moves downstream along the wall, causing the fluid flow in the vicinity of the wall to actually go in the opposite direction. Become. The boundary layer cannot remain attached to the wall downstream from such a point, and a peeling region is formed downstream from the point.

To prevent stall, the diffuser must be long enough to reduce the required divergence angle. However, increasing the length of the diffuser is not acceptable in some applications, for example due to space limitations or weight limitations, and thus does not necessarily solve the above problem in all cases. It is therefore possible to diffuse the fluid more quickly without stall, i.e. over a relatively short distance, or conversely, a flow path that can be achieved with a conventional diffuser for a given diffuser length. It is highly preferred to be able to diffuse the fluid to a flow passage cross sectional area that is larger than the cross sectional area.

Conventional diffusers are two-dimensional or three-dimensional diffusers. A two-dimensional diffuser generally has four sides, two opposite sides being parallel to each other and the other two opposite sides diverging toward the diffuser outlet. Further, the conical diffuser and the annular diffuser are sometimes called a two-dimensional diffuser. Annular diffusers are often used in gas turbine engines. The three-dimensional diffuser may, for example, have two pairs of opposite side surfaces which are divergent with respect to each other.

One use of diffusers is in catalytic converter equipment for passenger cars, trucks, and the like. Converters are used to reduce exhaust emissions (nitrogen oxides) and oxidize carbon monoxide and unburned hydrocarbons. Currently, platinum is selected as the catalyst. Platinum is very expensive, so it is important to use platinum efficiently, which exposes the high surface area of platinum to gas and performs acceptable functions using as little catalyst as possible. Therefore, it means that the residence time is sufficiently long.

Currently, the exhaust gas is about 2.5 to 5.0 in ² (16 to 32 cm ² )
Is conveyed to the converter by a circular conduit having a flow passage cross-sectional area of. The catalyst (in the form of a platinum-coated ceramic monolith or a bed of coated ceramic pellets) is, for example, an elliptical channel cross-sectional area which is 2 to 4 times that of a circular inlet conduit. Is disposed in the conduit having. The inlet conduit and the conduit containing the catalyst therein are connected to each other by a diffusing section that changes the cross-sectional shape from circular to elliptical. Due to space limitations, the diffuser is very short and half its divergence angle is at most 45 °. When half of the divergence angle exceeds about 7 °, the fluid flow separates from the wall, so the flow of exhaust gas from the inlet conduit tends to maintain a circular cross section, most of which is an elliptical cross section of the catalyst. Only the tiny portion of the inlet area of the shape is impacted. Thus, due to insufficient diffusion in the diffusion section, the exhaust gas flow in the catalyst bed is non-uniform. These issues were addressed by the International Fuels and Lubricants Meeting in Philadelphia, PA, USA, October 6-9, 1986.
and Exposition SAE Paper No.86155 submitted
4 Daniel W. Wendland, William R. Matthes `` Vis
ualization of Automotive Catalytic Converter Inter
It is discussed in a paper entitled "nal Flows". There is a need to better diffuse the exhaust gas flow within such short diffusions so that platinum catalysts can be used more efficiently and thereby reduce the amount of catalyst required.

DISCLOSURE OF THE INVENTION One object of the present invention is to provide a diffuser having improved operating characteristics.

Another object of the present invention is to provide a diffuser which can achieve the same amount of diffusion in a short length as compared with the conventional diffuser.

Yet another object of the present invention is to provide a diffuser that can achieve greater diffusion than a conventional diffuser for a given length.

Accordingly, the invention includes a thin wall member disposed in the conduit upstream of the diffuser portion and having substantially two sides spaced apart from the wall surface of the conduit, the wall member adjacent the member. It has a corrugated downstream portion that produces a plurality of adjacent vortices in the diffuser portion that rotate in opposite directions about a corresponding axis extending in the flow direction of the flowing fluid bulk.

In one embodiment, the corrugated member is positioned upstream of the diffuser inlet and is supported spaced from and near the surface of the diffuser inlet conduit. The corrugated portion of the member includes a plurality of alternating U-shaped ridges and valleys extending in the direction of flow of the fluid bulk proximate the member and ending in a corrugated downstream edge. . The depth of these valleys and the height of the ridges increase in the downstream direction, and the shapes and dimensions of the valleys and ridges are such that each valley has a pair of ridges on the downstream side of the downstream edge of the member having the wavy portion. The shape and dimensions are such that vortices adjacent to each other are generated. The swirl forces the boundary layer closer to the diffuser wall and delays or prevents the boundary layer from separating from the diffuser wall. Thus, the diffuser can provide equal diffusion over shorter distances (ie, can effectively operate at larger divergence angles), or some given relative to that with conventional diffusers. More diffusion can be done in length. Proper orientation of the corrugated member and its troughs and ridges causes the fluid to exit the troughs with some momentum that carries it toward the diffuser wall. The eddies generated from each side wall at the outlet of the valley are considered to be large-scale vortices (in this case, "large-scale" means that the vortex has a diameter approximately equal to the total depth of the valley. Means that). These two vortices, one from each side wall, rotate in opposite directions, causing the fluid from the valley and the fluid from the nearby fluid to flow in the vicinity of the diffuser wall just downstream of the member containing the corrugations. Create a flow field to mix with. Due to such a phenomenon, the fluid bulk is guided outward toward the wall surface of the diffuser, and the fluid bulk is mixed in the diffuser member, which urges the boundary layer along the wall surface of the diffuser, thereby improving the performance of the diffuser. Is improved. A member containing corrugations may not be close enough to the diffuser wall to urge the boundary layer and delay boundary layer separation, or the diffuser wall may be too steep to avoid boundary layer separation. Even if this is not possible, mixing of the fluid bulk in the diffuser caused by large scale vortices improves the diffuser's overall performance.

The troughs and ridges of the members of the present invention are preferably shaped so that fluid can flow through them sufficiently (ie, there is no two-dimensional boundary layer separation in the flow direction within the troughs). Thus, it is important that the boundary layer of the fluid flowing on the member immediately upstream of the valley of the member including the wavy portion is not separated two-dimensionally in the flow direction. This is because otherwise the separated flow of fluid flows into the trough, which hinders the formation of strong vortices. Preventing flow-direction two-dimensional boundary layer separation in the valley is one important consideration for the valley structure. For example, if the slope of the bottom of the valley is too steep with respect to the flow direction of the fluid bulk in the vicinity thereof, two-dimensional boundary layer separation may occur.

The valleys and ridges are preferably U-shaped when viewed in a cross section perpendicular to the downstream direction, and are smoothly curved so that the loss is reduced (for example, at the position where the side wall surface of the valley meets the bottom surface of the valley). (There are no sharp angles). In particular, it is preferable that the valleys and ridges form a smoothly undulating surface that is corrugated when viewed in a cross section perpendicular to the downstream direction.

According to another aspect of the invention, the fluid exiting each trough preferably has a lateral velocity component that is as small as possible to reduce secondary flow losses. For this reason, the sidewalls of the valley are preferably parallel to the flow direction of the bulk of the fluid entering the valley over a considerable distance upstream of the exit of the valley.

One important advantage of the present invention is that the presence of the diffuser in the flow field can improve the performance of the diffuser without incurring substantial flow loss.

According to another aspect of the present invention, the valley wall at the exit is preferably steep. This is because it is considered that the steepness of the sidewall enhances the strength of the vortex flow generated by the sidewall. In the present specification, "steep" means that the tangent line at the steepest point on each side wall as seen in a cross section perpendicular to the length direction of the valley intersects at an intersection angle of about 120 ° or less. means. In particular, the side walls are preferably parallel to each other. In the present specification, when the side walls are parallel, the intersection angle is regarded as 0 °.

Japanese Patent Application No. SHO 62- filed by the same applicant as the applicant of the present application
No. 107920 describes a trailing edge region of an airfoil having streamwise valleys and ridges (wavy portions) that define a corrugated thin trailing edge. The valleys on one side define ridges on the other side. These valleys and ridges retard the two-dimensional separation of the boundary layer at the suction side of the airfoil by releasing the low momentum boundary layer flow in three dimensions, or Prevents serious effects from two-dimensional peeling. The present invention is intended to improve the performance of the diffuser arranged immediately downstream of the member including the wavy portion.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings with reference to the accompanying drawings.

BEST MODE FOR CARRYING OUT THE INVENTION As will be described in more detail below, the wall member including the corrugated portion of the present invention assists in diffusing the fluid and also urges the boundary layer along the wall of the diffuser. Is used immediately upstream of the diffuser inlet or at the diffuser inlet to create a flow downstream of the wall member, which improves the performance of the diffuser. This hydrodynamic mechanism is similar to the hydrodynamic mechanism described in Japanese Patent Application No. 63-164067 filed by the applicant of the present application. Figures 14 and 14A of this patent application are reproduced herein as Figures 1 and 1A. In the above patent application, a plate containing corrugations is used to reduce the base drag by forming a hydrodynamic flow pattern downstream of the plate to reduce the non-streamlined end face of the moving object. It was placed upstream. In Figures 1 and 1A, an article having a non-streamlined base is shown generally at 200. Article 200 has a smooth and relatively flat top surface 2
02, and the fluid has a top surface 2 as indicated by arrow 204.
It flows on 02 substantially in the downstream direction. The article 200 has a non-streamlined base or trailing end face 206. It is assumed that the flow of fluid along the upper surface 202 separates from the article along the line 208, unless the plate containing the corrugations is provided. For purposes of describing the invention, separation line 208 is considered to be the starting point, or upstream edge, of non-streamlined end face 206.

A corrugated wall member or plate 210 is disposed on the upper surface 202 and is spaced from the upper surface 202 by a support member 212 (one of which is shown in the drawing). Plate 210 has an upstream or leading edge 214
And a downstream edge or trailing edge 216. Although the plate is fairly thin, the leading edge 214 is as rounded as the leading edge of the airfoil so that a uniform flow of fluid begins to flow over them on the upper surface 218 and the lower surface 220 of the plate. There must be. For example, to reduce the weight of the plate or the base drag of the plate itself, the plate may be trailing edge 216 if desired.
The thickness may decrease progressively toward.

A plurality of U-shaped grooves 222 and ridges 224 are formed in the plate. Adjacent valleys and ridges are smoothly connected to each other, thereby forming the undulating or wavy downstream portion of the corrugated plate at the trailing edge 216. The depth of the valley must increase in the downstream direction so that a vortex is formed, but the depth of the valley reaches its maximum value upstream from the exit of the valley, and then the valley It may be a constant value until the exit of. First
In the figure, the leading edge 214 of the plate is straight and the plate is flat over the first short distance. The valleys and ridges are smoothly connected to the flat part. As shown, the depth of the valleys (and the height of the ridges) is preferably 0 at their upstream ends and maximum at their downstream edges 216, but is not the leading edge of the plate. 214 has a waveform with a small amplitude, and the depth of the valley may gradually increase from the leading edge toward the trailing edge. The shapes of the valleys and ridges are
The valleys are chosen to allow sufficient fluid flow over their entire length.

Since the plate 210 is attached to the article 200, the plate itself also causes a loss (drag), which must therefore be reduced. First, considering a plate that has no corrugations and is virtually parallel to the plane on which it is arranged, the valley bottom and the ridge peaks are of such a virtual plane. It is preferred that they extend equidistantly up and down.

The vortices generated by the valleys and ridges on both sides of the plate are shown diagrammatically in FIG. A vortex flow having an axis extending in the flow direction of the fluid bulk is generated from each sidewall of each valley. Thus, the valley 226 forms a swirl 228 which rotates clockwise from the side wall on the right side thereof and a swirl 230 which rotates counterclockwise from the side wall on the left side thereof as viewed in FIG. The left side valley 232 in the figure of the valley 226 provided on the opposite side of the plate also forms a vortex flow 234 rotating counterclockwise from the right side wall in the figure, and this vortex flow rotates in the counterclockwise direction. Combined with 230, it strengthens the vortex, thereby forming one more powerful vortex.
Similarly, the sidewall on the left side of the valley 236 in the figure forms a clockwise swirling flow 238 which is combined with the clockwise swirling flow 228 formed by the valley 226.

When the plate 210 is properly positioned and oriented with respect to both the upper surface 202 and the non-streamlined end surface 206, the vortices formed by them cause the boundary layer flow to flow to the upper surface 20 downstream of the plate.
It is urged against 2, so that the fluid flow remains attached to the surface of the article beyond the virtual separation line 208. In addition, the bulk of the fluid flowing over the upper surface 202 above the groove is guided downward into the space behind the non-streamlined end surface 206, as seen in FIG. 1, which reduces the delamination bubbles otherwise generated. Further reduce the base drag.

For purposes of the following description, in FIG. 1, P is the peak-to-peak wavelength at the trailing edge 216 of the plate, and A is the peak-to-peak wave height, or amplitude (valley). H is the distance between the top surface 202 and the wave peak of the trailing edge 216 closest to the top surface 202, and D is the trailing edge 216 and upstream of the non-streamlined end surface. Let it be the distance to the edge (which is the peel line 208 as described above). The wavelength P from peak to peak is preferably constant over the entire length of the valley.

The eddy current is not well formed over a range of distance downstream of the trailing edge 216 of the plate,
Further, since it is preferable to urge the boundary layer upstream of the separation line 208 by the vortex flow, the trailing edge 216 has a distance D equal to 1 to 2 times the amplitude A in the upstream direction from the non-streamlined end surface 206. It is preferable to be arranged in the position. This does not mean that no effect is obtained when the distance D is smaller than A or 0.
It is believed that the effect is only reduced. Similarly, if the plate is located farther upstream than the end face 206, the vortex will be significantly or completely dampened before it reaches the end face 206, with little or no effect.

The distance H avoids the occurrence of secondary flow fields or obstacles near the upper surface 202 that disturb or delaminate the boundary layer on the upper surface 202 before the boundary layer reaches the separation line 208. Must be large enough to Also the distance H
Is considered to be at least approximately equal to the thickness of the boundary layer. At the same time, the distance H must be small so that the vortex stays as close to the upper surface 202 as possible. The tilt angle θ of the bottom surface of the valley with respect to the direction of flow of the liquid bulk close to the plate must not be too small or too large. If this inclination angle is too small, the strength of the vortex flow formed will be too weak, or no vortex flow will be formed due to the loss due to surface friction. It is believed that the tilt angle θ should be at least about 5 °. On the other hand, if the inclination angle is too steep, the fluid does not flow sufficiently in the valley (that is, two-dimensional boundary layer separation occurs in the valley). This hinders the formation of eddies. It is considered that the larger the inclination angle, the higher the strength of the eddy current as long as the fluid flows sufficiently in the valley. However, it is considered that the fluid does not sufficiently flow into the valley when the inclination angle exceeds about 30 °.
The optimum tilt angle for any particular application needs to be determined empirically.

As far as the slope angle of the sidewalls of each valley is concerned, it is preferred that the sidewalls are substantially parallel to each other over the trailing edge 216 and some distance upstream. The angle of inclination of the sidewalls is represented by the intersection angle C (see FIG. 1) which is the angle between the tangents at the steepest points along the mutually opposing sidewalls of the valley. As mentioned above, the closer the angle C is to 0, the better, but the angle C should be less than about 120 ° at the valley exit.

The total length of the plate from the leading edge 214 to the trailing edge 216 is preferably equal to or slightly greater than the length L of the valleys and ridges. If this length is too long, there will be no flow turbulence, but it will not provide any benefit, only surface drag, cost,
And the weight is only increased. As mentioned above, the leading edge 214 must be rounded so that the valleys and ridges have sufficient fluid flow over their entire length in the valleys to provide benefits (ie, drag force) that may be beneficial in view of the requirements of the particular application. Must be set over their entire length in shape and size to generate vortices that are strong enough to obtain a.

Generally, in order to form a strong vortex without causing excessive pressure loss, the wavelength P should be about half the amplitude A or more and about four times the amplitude or less. The sum of the flow path cross-sectional areas projected downstream of the valley exit is sufficient to effectively reduce the base drag relative to the total area projected downstream of the non-streamlined end face. Must be a large value. Practical considerations such as physical limitations, cost, weight, and even aesthetics affect the final selected shape to varying degrees.

2 and 3 show another application of the corrugated wall member or corrugated plate shown in FIGS. 1 and 1A, which application is the subject of the present invention. The conduit is shown generally at 300 in FIGS. 2 and 3. The conduit 300 includes a fluid supply 302 and a diffuser 304. These portions have a rectangular cross-sectional shape when viewed in a cross section perpendicular to the fluid flow direction, which is the direction indicated by arrow 306. The supply part 302 and the diffuser part 304 have flat and parallel side walls 308. Thus, the diffuser portion 304 diffuses the fluid only in two dimensions.
The flat surface 310 is located at the interface between the supply section 302 and the diffuser section 304, and is located at the same position as the inlet 312 of the diffuser section.

A corrugated plate 314 is located within the conduit feed 302. One plate is attached to the top wall 316 of the feed by legs 320 and the other plate is attached to the bottom wall 318. The large scale vortex formed by these plates is illustrated by the helix 322 and has an axis substantially parallel to the downstream direction 306.

The above description of FIGS. 1 and 1A regarding the size, shape, and location of the corrugated plate 210 applies equally to the corrugated plate 314, with the plate 310 of FIG. 2 having a boundary layer in the absence of the corrugated plate. 1 corresponds to the line 208 in FIG. 1 showing the peeling position. Thus dimensions L, D, H,
A, P and angle θ must be selected in the same way as described with reference to FIGS. 1 and 1A. First
In the application of Figures and 1A, the corrugated plate reduces the base drag of a moving object, but the present invention biases the boundary layer along the walls of the diffuser, and the fluid in the diffuser section 304. It improves the performance of the diffuser by totally mixing and diffusing the bulk flow.

A two-dimensional diffuser similar to the diffuser shown in FIGS. 2 and 3 was tested both with and without the corrugated plate. 2 and 3, the diffuser had the following dimensions.

B = 21.1in (53.6cm) F = 32.7in (83.1cm) E = 5.4in (14cm) For the corrugated plate, D = 2.3in (5.8cm) L = 6.3in (16cm) H = 0.25in (0.64) cm) A = 2.3 in (5.8 cm) P = 1.7 in (4.3 cm) Wi = 0.5 in (1.3 cm) W ₀ = 1.2 in (3.0 cm) θ ₁ = 11 ° θ ₂ = 15 °. As shown in Figure 3, the sidewalls of each valley were parallel to each other. Although FIGS. 2 and 3 have a test apparatus having the above-described dimensions, the present invention is not limited to such dimensions and their relative relationship. For example, the valleys on both sides of each plate may be the same (ie, Wi = Wo, θ ₁ = θ ₂ ). The optimum configuration for a particular application can only be determined empirically using guidelines such as those mentioned above.

In both of these series of tests (ie with and without corrugated plates), the diffuser's divergence angle equals the diffuser's figure of merit equal to the ratio of inlet area to outlet area of about 1.4-3.1. Half α is about 2
Measured over a 10 ° range. The results of these tests are shown in the graph of FIG. 4, where curve A shows the case without the corrugated plate and B shows the case with the corrugated plate. ing. For the range of half the divergence angle of the diffuser above about 6 ° (at least up to the maximum tested angle), the present invention is more efficient than the same diffuser without the corrugated plate. Was excellent. In the case where half of the divergence angle is 10 °, the present invention has a higher coefficient of performance than the highest coefficient of performance of the diffuser without the corrugated plate (the coefficient of performance when half of the divergent angle is 6 °). The half of the divergent angle is 10 °, which is about 25% higher than the performance coefficient of the same diffuser without the corrugated plate. In the present invention, it was also found that the separation of the boundary layer started slowly even when the half of the divergence angle was higher.

5 and 6 show an axially symmetric three-dimensional diffuser 400.
Is shown to use the present invention. In this case, the corrugated thin wall member 402 is axisymmetric, the ridges and valleys extend along the axis in the downstream direction 404, and also in the radial direction at the height and depth points. Existence

The present invention may also be used in a diffuser having a step as shown in FIGS. 7 and 8. A diffuser having a step may be regarded as a diffuser in which half of the divergence angle is very steep such as 90 °. This kind of diffuser is generally a conduit including a portion in which the flow passage cross-sectional area of the passage changes stepwise (that is, increases rapidly). In FIGS. 7 and 8, the fluid flowing in the conduit 502 in the downstream direction is indicated by arrow 500. Conduit 502
Is an outlet section 5 with a rectangular cross section like the inlet section 501 with a rectangular cross section
03. The inlet portion has a side wall 504 parallel to each other and parallel to the downstream side, and an upper wall 507 and a lower wall 507 also parallel to the downstream side and parallel to each other. The flow passage cross-sectional area of the passage changes in a plane on the plane 508. This discontinuity exists only in the upper wall and the lower wall 507. The talk wall 504 maintains a parallel state over the entire length of the outlet portion 503 even in a region beyond the discontinuous portion.

Corrugated plates 510, similar to the corrugated plates shown in FIGS. 2 and 3, are located proximate and supported by upper and lower walls 507. Flatter than corrugated plate
The distance D to 508 should be substantially in the range of 0 to twice the depth of the valley, preferably 1 to 2 times the depth of the valley.

In a stepped diffuser such as that shown in FIG. 7, the corrugated plate cannot keep the fluid flow attached to the diffuser walls, but the plate has a fluid flow above plane 508. It is possible to reduce the distance to the position where the wall and the lower wall are redeposited. That is, the loss of the step diffuser is at least smaller than the loss when the corrugated plate is not used. Also, in this embodiment, two corrugated plates are located close to the top and bottom walls, but one large (in terms of amplitude) plate can also be effective.

Japanese Patent Application No. SHO 62- filed by the same applicant as the applicant of the present application
No. 336823 describes a corrugated plate similar to the corrugated plate of the present application and used in a heat transfer device to improve heat transfer across a fluid flow wall on both sides. FIGS. 9 and 10 of the present application correspond to FIGS. 8 and 9 of the above-mentioned patent application, respectively, and are indicated by arrow 804.
Figure 7 shows a corrugated wall member 800 positioned within a conduit 802 that carries fluid in the direction of. As best shown in FIG. 10, plate 800 extends diametrically in a direction substantially transverse to the conduit. The ridges and valleys in the downstream portion of the plate 800 form vortices 806 and 808 adjacent to each other and rotating in opposite directions downstream of the plate 800, which rub off the thermal boundary layer from the inner wall surface 810 of the conduit. , Mixing the fluid flowing in the central portion of the conduit with the fluid flowing close to the wall of the conduit. This ultimately increases the heat transfer coefficient between the fluid in the conduit 802 and the wall of the conduit 802 for the purpose of effecting heat energy exchange between the fluid in the conduit 802 and the fluid surrounding the conduit. As shown in FIG. 9, a plurality of corrugated plates 800 are spaced within the conduit along the axis of the conduit at a distance that improves the heat transfer coefficient over the length of the conduit. To be done. Of course, this means that each plate 800
It is necessary for the eddy current formed by the vanishing to disappear due to friction with the wall and viscous effects.

The present invention does not relate to heat transfer devices, but uses the same corrugated plate located in the conduit for the purpose of affecting the dynamic flow of fluid in the diffusion of the conduit downstream of the corrugated plate. It is a thing. We have found that such a plate creates a large scale vortex, which urges the boundary layer to improve the performance of the diffuser and results in a fluid bulk in a direction perpendicular to the fluid bulk flow, i.e. transverse to the conduit. It has been found that the mixing is improved and this also improves the performance of the diffuser.

One particular application of the wall member of the present invention is in catalytic converter devices for automobiles and the like. Such a converter device is shown generally at 900 in FIGS. 11 and 12. The converter device 900 is a cylindrical gas supply conduit 902.
And a gas receiving conduit 904 having an elliptical cross section and a diffuser 906 which is a transition conduit provided therebetween. The flow direction of the fluid bulk is indicated by the arrow 905 and is parallel to the axis 907 of the supply conduit 902. The diffuser 906 receives a conduit 90 from a circular outlet 908 of the supply conduit.
4 extends to an inlet 910 that is substantially oval in cross section. The receiving conduit holds a catalyst bed (not shown) therein. The catalyst bed is preferably a honeycomb-shaped monolith, and the honeycomb cells are parallel to the downstream direction. The inlet end face of the monolith is located at the inlet 910, although this inlet end face may be moved further downstream to provide additional diffusion distance between the outlet 908 of the feed conduit and the catalyst. Good. Catalyst and catalyst bed morphologies for catalytic converters are well known in the art.

As best shown in FIG. 12, diffusion occurs only in the direction of the major axis 912 of the ellipse. The minor axis of the ellipse has a constant length equal to the diameter of the outlet 908 of the feed conduit. Thus, the diffuser 906 in this embodiment is a two-dimensional diffuser. Within the supply conduit 902 is a corrugated plate 914 having a plurality of parallel valleys. The plate 914 extends transversely to the conduit 902 substantially along a radial plane perpendicular to the major axis 912 of the gas receiving conduit 804 having an elliptical cross section. Plate 914 is attached to conduit 902 at its side edge 920. The valley sidewalls 924 are preferably parallel to each other at the corrugated downstream edge 922 of the plate and are preferably parallel to the major axis 912 of the ellipse. The optimum size and morphology of the plate should be determined by experimentation using the teachings of the present invention as a guideline, but there must be at least two complete troughs on one side of the plate (12th (Three troughs are provided in the illustrated embodiment), the troughs must have a depth at their downstream edges equal to a relatively large proportion of the space in the conduit. Conceivable. It is also believed that best results are obtained when the valley depth direction is parallel to the principal direction of diffusion, but improved diffusion is obtained when the plate 914 is perpendicular to the direction shown in FIG. It is considered that it can be obtained even when it is oriented in almost any direction such as.

Assuming that the conduit 902 in FIGS. 11 and 12 has a diameter of 2.0 in (5.1 cm), the dimensions of the plate 914 are 15 ° valley inclination angle θ, 1.0 in (2.5 cm). Wave amplitude A, about 0.30
It has a valley width W of in (0.76 cm) and a plate thickness of about 30 mil (7.6 mm).

13 and 14 show another embodiment of the catalytic converter device. The converter system is generally designated by the numeral 950 in the figure and includes a cylindrical gas supply conduit 952, an oval cross-section gas receiving conduit 954, and a diffuser which is a transition conduit interposed therebetween. Includes 956 and. The flow direction of the fluid bulk is indicated by arrow 958 and is parallel to the axis 960 of the feed conduit. The diffuser 956 extends from the circular outlet 962 of the supply conduit,
The receiving conduit is smoothly connected to an inlet 964 having an elliptical cross section, and the receiving conduit holds therein a catalyst bed (not shown), the inlet end face of which corresponds to the plane of the inlet 964. doing.

In this embodiment, the converter arrangement is considered to be similar to the two-dimensional diffuser shown in FIGS. 2 and 3. Thus disposed within the supply conduit 952 is a pair of slightly curved corrugated plates 966 which are oriented parallel to the minor axis 968 of the receiving conduit of elliptical cross section and perpendicular to the major axis 970. It extends across the conduit in a direction substantially parallel to the line. Plates 966 are positioned proximate to and spaced from the surface of the feed conduit and are positioned above and below the contour line, or axis 968.

Plane 972 is a diffuser 95 where two-dimensional flow direction boundary layer separation occurs when corrugated plate 966 is not used.
The axial position along 6 is shown. The corrugated downstream edge 974 must be spaced upstream of plane 972 to delay separation of fluid flow beyond plane 972. Best results are believed to be obtained when the distance D is about 1-2 times the maximum amplitude of the plate 966. This provides a distance that allows the large scale vortices formed by the corrugated plates to reach their fully developed state before reaching the location of plane 972.

In this embodiment, the upper and lower plates
The waveforms of 966 are out of phase with each other. The corrugations may be in phase, as shown in the embodiment of FIGS. 7 and 8, in which case the vortices generated will couple to each other, further improving fluid mixing. . Assuming the supply conduit 952 has a diameter of 2 in (5.1 cm), the maximum amplitude of each plate 966 is about 0.5-0.75 in (1.3 cm).
˜1.9 cm) is preferred.

Although the present invention has been described in detail with reference to specific embodiments, the present invention is not limited to these embodiments, and various other embodiments are possible within the scope of the present invention. Some will be apparent to those skilled in the art.

[Brief description of the drawings]

FIG. 1 is a solution showing the use of corrugated plates to reduce base drag. FIG. 1A is a cross-sectional view taken along line 1A-1A of FIG. FIG. 2 is a cross-sectional view showing a two-dimensional diffuser incorporating the features of the present invention. FIG. 3 is a cross-sectional view taken along line 3-3 of FIG. FIG. 4 is a graph showing the results of tests conducted on one embodiment of the present invention shown in FIGS. 2 and 3 and the prior art. FIG. 5 is a cross-sectional view of an axisymmetric diffuser incorporating features of the present invention. FIG. 6 is a view taken along the line 6-6 in FIG. FIG. 7 is a cross-sectional view showing a two-dimensional step diffuser incorporating the features of the present invention. FIG. 8 is a view taken along the line 8-8 in FIG. FIG. 9 is a solution diagram showing the use of a corrugated plate for heat exchanger applications according to Japanese Patent Application No. 63-63 filed by the same applicant as the present applicant. FIG. 10 is a view taken along the line 10-10 in FIG. FIG. 11 is a partial cutaway view of a catalytic converter device incorporating the features of the present invention. FIG. 12 is a sectional view taken along line 12-12 in FIG. FIG. 13 is a partial cutaway view showing another embodiment of the catalytic converter device incorporating the features of the present invention. FIG. 14 is a sectional view taken along the line 14-14 in FIG. 200 …… Article, 202 …… Top surface, 206 …… End surface, 208 …… Peeling line,
210 …… corrugated wall member (corrugated plate), 212 …… support member, 214 …… leading edge, 216 …… trailing edge, 218 …… upper surface, 220 …… lower surface, 222 …… valley, 224 …… ridge , 2
26 …… Valley, 228, 230 …… Eddy current, 232 …… Valley, 234 …… Eddy current, 23
6 …… Valley, 238 …… Vortex flow, 300 …… Conduit, 302 …… Fluid supply section,
304 …… Diffuser part, 308 …… Side wall, 312 …… Inlet, 314
...... Corrugated plate, 316 …… Upper wall, 318 …… Lower wall, 320 ……
Legs, 322 …… Eddy current, 400 …… Diffuser, 402 …… Wall member, 5
02 …… conduit, 501 …… inlet, 503 …… outlet, 504 …… side wall, 507 …… upper and lower walls, 800 …… corrugated plate, 802 ……
Conduit, 806, 808 ... Eddy current, 810 ... Inner wall surface, 900 ... Catalytic converter device, 902 ... Gas supply conduit, 904 ... Gas receiving conduit, 906 ... Diffuser, 908 ... Outlet, 910 ... Inlet , 9
12 …… long axis, 914 …… corrugated plate, 920 …… side edge, 922 ……
Downstream edge, 924 …… Valley side wall, 950 …… Catalytic converter device, 952 …… Gas supply conduit, 954 …… Gas receiving conduit, 956
...... Diffuser, 962 …… Outlet, 964 …… Inlet, 966 …… Corrugated plate, 968 …… Short axis, 970 …… Long axis, 974 …… Downstream edge

 ─────────────────────────────────────────────────── ———————————————————————————————————————————————————————————————————————–———————————————————————————————————————————————————————————————————−− Dec at at at 37 am・ Farms, Moran Road 136 (56) Reference JP-A-55-72901 (JP, A) JP-A-62-283203 (JP, A) JP-A-62-275896 (JP, A) Actual development Sho-56- 25002 (JP, U)

Claims (2)

(57) [Claims] 1. A wall device for defining a fluid flow path including an inlet part of a fluid having a first cross section and an outlet part having a second cross section larger than the first cross section; Fluid flowing in the inlet portion by being spaced apart from the inner wall surface of the wall device extending in the direction substantially along the flow of the fluid in the inlet portion and defining the inlet portion. A vortex generator including plate members configured to flow along both surfaces, said plate member comprising a plurality of alternating ridges each extending in the direction of fluid flow along both surfaces thereof. It has wavy parts that are formed in alternating U-shape to define the valley,
The height of the ridges and valleys of the corrugated portion gradually increases in the direction of fluid flow at least at a part of the extending length thereof, whereby the height of the valleys formed on one side of the plate member is increased. The fluid flow flowing through each laterally interferes with the fluid flow flowing through each of the valleys formed on the other side of the plate member at the outlet of the plate member and exits the plate member. A diffuser characterized by forming a vortex in a fluid flow. 2. A wall device for defining a fluid flow path including a fluid inlet portion having a first cross section and a catalyst storage portion having a second cross section larger than the first cross section, and the fluid flow path. Fluid flowing in the inlet portion of the wall device extending in a direction substantially along the flow of the fluid in the inlet portion and spaced from the inner wall surface of the wall device defining the inlet portion A vortex generator including plate members configured to flow along both surfaces, said plate member comprising a plurality of alternating ridges each extending in the direction of fluid flow along both surfaces thereof. The corrugation has alternating corrugated portions that define a valley, and the heights of the ridges and valleys of the corrugated portion gradually increase in the fluid flow direction in at least a part of the extending length thereof. Through each of the valleys formed on one side of the plate member The generated fluid flow laterally interferes with the fluid flow flowing through each of the valleys formed on the other side of the plate member at the outlet of the plate member, A housing device for a catalytic converter, which is adapted to form a vortex.