EP0321379A2 - Gebogene Platte mit Wirbelgenerator - Google Patents

Gebogene Platte mit Wirbelgenerator Download PDF

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Publication number
EP0321379A2
EP0321379A2 EP88630118A EP88630118A EP0321379A2 EP 0321379 A2 EP0321379 A2 EP 0321379A2 EP 88630118 A EP88630118 A EP 88630118A EP 88630118 A EP88630118 A EP 88630118A EP 0321379 A2 EP0321379 A2 EP 0321379A2
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EP
European Patent Office
Prior art keywords
downstream
diffuser
troughs
conduit
cross
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
EP88630118A
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English (en)
French (fr)
Other versions
EP0321379A3 (de
EP0321379B1 (de
Inventor
Walter Michael Presz, Jr.
Robert William Paterson
Michael Joseph Werle
Robert Herman Ealba
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
RTX Corp
Original Assignee
United Technologies Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from US07/132,395 external-priority patent/US4971768A/en
Application filed by United Technologies Corp filed Critical United Technologies Corp
Publication of EP0321379A2 publication Critical patent/EP0321379A2/de
Publication of EP0321379A3 publication Critical patent/EP0321379A3/de
Application granted granted Critical
Publication of EP0321379B1 publication Critical patent/EP0321379B1/de
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15D—FLUID DYNAMICS, i.e. METHODS OR MEANS FOR INFLUENCING THE FLOW OF GASES OR LIQUIDS
    • F15D1/00—Influencing flow of fluids
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL-COMBUSTION ENGINES
    • F01N3/00—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust
    • F01N3/08—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous
    • F01N3/10—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust
    • F01N3/24—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust characterised by constructional aspects of converting apparatus
    • F01N3/28—Construction of catalytic reactors
    • F01N3/2892—Exhaust flow directors or the like, e.g. upstream of catalytic device
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
    • B01F25/00—Flow mixers; Mixers for falling materials, e.g. solid particles
    • B01F25/40—Static mixers
    • B01F25/42—Static mixers in which the mixing is affected by moving the components jointly in changing directions, e.g. in tubes provided with baffles or obstructions
    • B01F25/43—Mixing tubes, e.g. wherein the material is moved in a radial or partly reversed direction
    • B01F25/432—Mixing tubes, e.g. wherein the material is moved in a radial or partly reversed direction with means for dividing the material flow into separate sub-flows and for repositioning and recombining these sub-flows; Cross-mixing, e.g. conducting the outer layer of the material nearer to the axis of the tube or vice-versa
    • B01F25/4322—Mixing tubes, e.g. wherein the material is moved in a radial or partly reversed direction with means for dividing the material flow into separate sub-flows and for repositioning and recombining these sub-flows; Cross-mixing, e.g. conducting the outer layer of the material nearer to the axis of the tube or vice-versa essentially composed of stacks of sheets, e.g. corrugated sheets
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15D—FLUID DYNAMICS, i.e. METHODS OR MEANS FOR INFLUENCING THE FLOW OF GASES OR LIQUIDS
    • F15D1/00—Influencing flow of fluids
    • F15D1/0015—Whirl chambers, e.g. vortex valves
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F28—HEAT EXCHANGE IN GENERAL
    • F28F—DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION
    • F28F13/00—Arrangements for modifying heat-transfer, e.g. increasing, decreasing
    • F28F13/06—Arrangements for modifying heat-transfer, e.g. increasing, decreasing by affecting the pattern of flow of the heat-exchange media
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
    • B01F25/00—Flow mixers; Mixers for falling materials, e.g. solid particles
    • B01F2025/91—Direction of flow or arrangement of feed and discharge openings
    • B01F2025/913—Vortex flow, i.e. flow spiraling in a tangential direction and moving in an axial direction

Definitions

  • This invention relates to diffusers.
  • Diffusers are well known in the art.
  • Webster's New Collegiate Dictionary (1981) defines diffusers as "a device for reducing the velocity and increasing the static pressure of a fluid passing through a system".
  • the present invention is concerned with the most typical of diffusers, those having an inlet cross-sectional flow area less than their outlet cross-sectional flow area. While a diffuser may be used specifically for the purpose of reducing fluid velocity or increasing fluid pressure, often they are used simply because of a physical requirement to increase the cross-sectional flow area of a passage, such as to connect pipes of different diameters.
  • diffuseuser shall mean a fluid carrying passage which has an inlet cross-sectional flow area less than its outlet cross-sectional flow area, and which decreases the velocity of the fluid in the principal flow direction and increases its static pressure.
  • Streamwise, two-dimensional boundary layer separation means the breaking loose of the bulk fluid from the surface of a body, resulting in flow near the wall moving in a direction opposite the bulk fluid flow direction. Such separation results in high losses, low pressure recovery, and lower velocity reduction.
  • the diffuser is said to have stalled. Stall occurs in diffusers when the momentum in the boundary layer cannot overcome the increase in pressure as it travels downstream along the wall, at which point the flow velocity near the wall actually reverses direction. From that point on the boundary layer cannot stay attached to the wall and a separation region downstream thereof is created.
  • a diffuser may have to be made longer so as to decrease the required diffusion angle; however, a longer diffusion length may not be acceptable in certain applications due to space or weight limitations, for example, and will not solve the problem in all circumstances. It is, therefore, highly desirable to be able to diffuse more rapidly (i.e., in a shorter distance) without stall or, conversely, to be able to diffuse to a greater cross-sectional flow area for a given diffuser length than is presently possible with diffusers of the prior art.
  • Diffusers of the prior art may be either two- or three-dimensional.
  • Two-dimensional diffusers are typically four sided, with two opposing sides being parallel to each other and the other two opposing sides diverging from each other toward the diffuser outlet.
  • Conical and annular diffusers are also sometimes referred to as two-dimensional diffusers.
  • Annular diffusers are often used in gas turbine engines.
  • a three-dimensional diffuser can for example, be four sided, with both pairs of opposed sides diverging from each other.
  • a diffuser is in a catalytic converter system for automobiles, trucks and the like.
  • the converter is used to reduce exhaust emissions (nitrous oxides) and to oxidize carbon monoxide and unburned hydrocarbons.
  • the catalyst of choice is presently platinum. Because platinum is so expensive it is important to utilize it efficiently, which means exposing a high surface area of platinum to the gases and having the residence time sufficiently long to do an acceptable job using the smallest amount of catalyst possible.
  • the catalyst in the form of a platinum coated ceramic monolith or a bed of coated ceramic pellets
  • the inlet conduit and the catalyst containing conduit are joined by a diffusing section which transitions from circular to elliptical. Due to space limitations the diffusing section is very short; and its divergence half-angle may be as much as 45 degrees.
  • One object of the present invention is a diffuser having improved operating characteristics.
  • Another object of the present invention is a diffuser which can accomplish the same amount of diffusion in a shorter length then that of the prior art.
  • Yet another object of the present invention is a diffuser which can achieve greater diffusion for a given length than prior art diffusers.
  • the present invention includes a thin, essentially two sided wall member disposed within the conduit upstream of a diffuser section inlet and spaced from the conduit wall surface, the member having a convoluted downstream portion which generates a plurality of adjacent vortices within the diffuser section rotating in opposite directions about respective axes extending in the direction of bulk fluid flow adjacent the plate-like member.
  • the convoluted member is disposed upstream of a diffuser section inlet and is supported in closely spaced relation to the surface of the diffuser inlet conduit.
  • the convoluted portion of the member comprises a plurality of adjoining, alternating, U-shaped lobes and troughs extending in the direction of bulk fluid flow near the member and terminating at a downstream edge, which is wave shaped.
  • the trough depth and lobe height increase in the downstream direction, and the troughs and lobes are contoured and dimensioned such that each trough generates a pair of adjacent vortices downstream of the downstream edge of the member.
  • the vortices energize the boundary layer adjacent the diffuser section wall and delay or eliminate its separation therefrom.
  • a diffuser can accomplish the same amount of diffusion in a shorter length (i.e., can operate effectively with greater diffusion angles) or can achieve a greater amount of diffusion for a given length than was possible with prior art diffusers.
  • the proper orientation of the member and its troughs and lobes can also result in the fluid leaving the troughs with a direction of momentum that carries it toward the diffuser wall surface.
  • the vortices generated from each side wall surface at the trough outlet are large-scale vortices.
  • Large-scale it is meant the vortices have a diameter about the size of the overall trough depth.
  • These two vortices rotate in opposite directions and create a flow field which tends to cause fluid from the trough and also from the nearby bulk fluid to mix with the fluid near the diffuser wall surface immediately downstream of the member.
  • the net affect of these phenomenon is to direct bulk fluid outwardly toward the diffuser wall surfaces and also to create bulk fluid mixing within the diffuser section, all of which energize the boundary layer along the diffuser wall thereby improving diffuser performance.
  • the troughs and lobes of the present invention are preferably contoured such that they flow full (i.e., no streamwise, two-dimensional boundary layer separation occurs within the troughs).
  • the prevention of streamwise, two-dimensional boundary layer separation within the troughs is an important consideration in their design. For example, two-dimensional boundary layer separation may occur if the slope of the bottom of a trough is too steep relative to the nearby bulk fluid flow direction.
  • the troughs and lobes are U-shaped in cross section taken perpendicular to the downstream direction and are preferably smoothly curved (e.g., no sharp angles where trough sidewall surfaces meet the trough floor) to minimize losses.
  • the troughs and lobes form a smoothly undulating surface which is wave-shaped in cross section perpendicular to the downstream direction.
  • the fluid exiting from each trough have a lateral component of velocity as small as possible to minimize secondary flow losses.
  • the trough sidewalls, for a significant distance upstream of the trough outlet are preferably parallel to the direction of bulk fluid flow entering the trough.
  • One important advantage of the present invention is its ability to improve diffuser performance without introducing substantial flow losses as a result of its own presence in the flow field.
  • the trough sidewalls at the outlet be steep. This is believed to increase the intensity of the vortex generated by the sidewall.
  • the word "steep" as used herein and in the claims means that, in cross section perpendicular to the direction of trough length, lines tangent to the steepest point on each sidewall intersect to form an included angle of no more than about 120°. Most preferably the walls are parallel to each other. For purposes of this application, when the walls are parallel the included angle shall be considered to be 0°.
  • the convoluted wall member of the present invention is used immediately upstream of or at a diffuser inlet to create fluid flow downstream of the member which help diffuse the fluid and also energize the boundary layer along the diffuser wall, whereby the diffuser performance is improved.
  • the fluid dynamics is similar to the fluid dynamics involved in commonly owned U.S. patent application serial number 117,770 entitled Convoluted Plate to Reduce Base Drag , by Robert W. Paterson et al. filed on November 5, 1987 and of which this application is a continuation-in-part.
  • Figs. 14 and 14A of U.S.S.N. 117,770 are reproduced in this application as Figs. 1 and 1A.
  • a blunt based article is generally represented by the reference numeral 200.
  • the article 200 has a smooth, relatively flat upper surface 202 over which fluid flows in the generally downstream direction represented by the arrows 204.
  • the article 200 has a blunt base or end surface 206. Without the convoluted plate the flow along the surface 202 is assumed to separate from the article along the line 208.
  • the separation line 208 shall be considered the beginning or upstream edge of the blunt end surface 206.
  • a convoluted wall member or plate 210 is mounted on and spaced from the surface 202 by means of support members or standoffs 212, only one of which is shown in the drawing.
  • the plate 210 has an upstream or leading edge 214 and a downstream or trailing edge 216. While the plate may be fairly thin, the leading edge 214 should be rounded, like the leading edge of an airfoil, to assure that attached uniform flow is initiated on both the upper surface 218 and lower surface 220 of the plate.
  • the plate may then taper to a smaller thickness, if desired, toward the trailing edge 216, such as to save weight or to minimize base drag of the plate itself.
  • a plurality of U-shaped troughs 222 and lobes 224 are formed in the plate. Adjacent troughs and lobes blend smoothly into each other forming an undulating or convoluted downstream portion of the plate which terminates as a wave-shape at its trailing edge 216. For vortices to be generated trough depth must increase in the downstream direction, although trough depth could reach its maximum upstream of the trough outlet and thereafter remain constant to the outlet.
  • the plate leading edge 214 is straight and the plate is initially flat for a short distance. The troughs and lobes blend smoothly into the flat portion.
  • trough depth (and lobe height) are zero at their upstream ends and are maximum at the downstream edge 216; however, the plate leading edge 214 could have a low amplitude wave shape, and the trough depth would increase from that initial amplitude.
  • the contour and shape of the troughs and lobes is selected such that the troughs flow full throughout their length.
  • the plate 210 Since the plate 210 is attached to the article 200, the plate itself creates losses (i.e. drag) which should be minimized. If one initially considers an imaginary, smooth plate without convolutions and which is generally parallel, locally, to the surface above which it is disposed, the peaks and valleys of the troughs and lobes preferably extend an equal distance above and below such "imaginary" plate.
  • the vortices generated by the troughs and lobes on each side of the plate are shown schematically in the drawing.
  • a vortex having its axis in the bulk fluid flow direction, is generated off of each sidewall of each trough.
  • the trough 226 generates a clockwise rotating vortex 228 from its right sidewall (as viewed in Fig. 1) and a counter clockwise rotating vortex 230 from its left sidewall.
  • An adjacent trough 232 on the opposite side of the plate to the left of the trough 226 also generates a counter clockwise rotating vortex 234 from its right wall which combines with and reinforces the counter clockwise rotating vortex 230 to form what is effectively a single, stronger vortex.
  • the left sidewall of the trough 236 generates a clockwise rotating vortex 238 which combines with the clockwise rotating vortex 228 from the trough 226.
  • the vortices generated therefrom will energize the boundary layer flow on the surface 202 downstream of the plate thereby resulting in the flow remaining attached to the article surface beyond the imaginary separation line 208. Furthermore, it is believed the bulk fluid flowing from the troughs and over the surface 202 is directed downwardly (in Fig. 1) into the space behind the blunt end surface 206 to further reduce the separation bubble which would otherwise be formed and thereby further reduce base drag.
  • P is the peak to peak wave length at the plate trailing edge 216;
  • A is the peak to peak wave height or amplitude (and may also be referred to as the trough depth);
  • H is the distance between the surface 202 and the closest wave peaks of the trailing edge 216; and
  • D is the distance between the trailing edge 216 and the upstream edge of the blunt end surface which is the separation line 208 as discussed above.
  • the peak to peak wave length P is constant over the full length of the troughs.
  • the trailing edge 216 be located a distance D equal to one to two wave amplitudes A upstream of the blunt end surface 206. This does not mean that no benefit would be achieved if D were less than A or even zero; however, it is believed the advantages would be lessened. Similarly, if the plate is situated too far upstream from the end surface 206 the vortices might significantly or completely dampen out before reaching the end surface 206 and thereby provide little or no benefit.
  • the distance H should be sufficiently great to avoid creating secondary flow fields or blockage adjacent the surface 202 which might disrupt and cause separation of the boundary layer on the surface 202 before it reaches the line 208. It is believed that H should be at least about the thickness of the boundary layer. Concurrently, the distance H should be small to keep the vortices as close to the surface 202 as possible.
  • the slope ⁇ of the trough bottom relative to the bulk fluid flow direction adjacent the plate cannot be too shallow or too steep. If the slope is too shallow, the strength of the vortices generated will be too weak or they may not be generated at all as a result of losses from surface friction. It is believed that ⁇ should be at least about 5°.
  • the steepness of the sidewalls may be represented by the included angle C (depicted in Fig. 1), which is the angle between lines tangent to the steepest points along the opposed sidewalls of a trough. As stated above, the closer the angle C is to 0°, the better; however, the angle C should be no greater than about 120° at the trough outlet.
  • the overall length of the plate from its leading edge 214 to its trailing edge 216 is equal to or slightly greater than the length L of the troughs and ridges. Excessive length, while not devastating, will also not provide any advantage and will simply add unnecessary surface drag, cost and weight.
  • the leading edge 214 should be rounded and the troughs and lobes should be shaped and sized along their entire length to assure that the troughs flow full throughout their length and generate vortices which are sufficiently strong to provide a benefit (i.e., drag reduction) deemed to be worthwhile considering the needs of the particular application.
  • the wave length P should be no less than about half and no more than about four times the wave amplitude A in order to assure the formation of strong vortices without inducing excessive pressure losses.
  • the sum of the downstream projected cross-sectional flow areas of the trough outlets should be large enough, relative to the total downstream projected area of the blunt end surface to have a worthwhile impact on base drag. Practical considerations such as physical constraints, cost and weight, and even aesthetics will also have various degrees of impact upon the final configuration selected.
  • Figs. 2 - 3 show another application for the convoluted wall member or plate described in Figs. 1 and 1A; and that application is the subject of the present invention.
  • a conduit is generally represented by the reference numeral 300.
  • the conduit 300 includes a fluid delivery section 302 and a diffuser section 304. Both are rectangular in cross section taken perpendicular to the flow direction, which is in the direction of the arrows 306.
  • the delivery section 302 and the diffuser section 304 both include flat, parallel sidewalls 308.
  • the diffuser section 304 provides only two-dimensional diffusion.
  • the plane 310 is at the interface between the delivery section 302 and the diffuser section 304 and is coextensive with the diffusion section inlet 312.
  • One is attached to the upper wall 316 and the other to the lower wall 318 of the delivery section by means of legs 320.
  • the large-scale vortices generated by the plates are illustrated by the spirals 322 and have axes generally parallel to the downstream direction 306.
  • the present invention improves the performance of a diffuser by energizing the boundary layer along the diffuser walls and by causing general mixing and diffusion of the bulk fluid flow within the diffusing section 304.
  • a two-dimensional diffuser like that of Figs. 2 and 3 was tested both with and without convoluted plates.
  • the sidewalls of each trough were parallel to each other, as shown in Fig. 3. While Figs.
  • the present invention had a coefficient of performance higher than the maximum coefficient of performance (i.e., at a 6° half-angle) of the diffuser without the convoluted plates and about 25 percent greater than that of the same diffuser with a 10° half-angle and no convoluted plates.
  • the present invention also delayed the onset of boundary layer separation to higher half-angles.
  • Figs. 5 and 6 illustrate the use of the present invention in conjunction with an axisymmetric three-­dimensional diffuser 400.
  • a convoluted thin wall member 402 is axisymmetric, with the lobes and troughs extending axially in the downstream direction 404 and radially (in height and depth).
  • a stepped diffuser may be considered one in which the diffuser half-angle is extremely steep, such as 90°.
  • This type of diffuser is typically a conduit which includes a step change (i.e., sudden increase) in passage cross sectional flow area.
  • fluid flowing a conduit 502 in the downstream direction is represented by the arrows 500.
  • the conduit has an inlet section 501 of rectangular cross sectional area and an outlet section 503, also of rectangular cross sectional area.
  • the inlet section has sidewalls 504 parallel to each other and the downstream direction, and upper and lower walls 507 also parallel to the downstream direction and to each other.
  • a step change in the passage cross sectional area occurs at the plane 508.
  • the discontinuity is only in the upper and lower walls 507.
  • the sidewalls 504 remain parallel past the discontinuity for the entire length of the outlet section 503.
  • a convoluted plate 510 Disposed adjacent and supported from each of the upper and lower sidewalls 507 is a convoluted plate 510 similar to that shown in Figs. 2 and 3.
  • the distance D of the plate upstream of the plane 508 should be anywhere from about zero to twice the trough depth and most preferably one to two times the trough depth.
  • a stepped diffuser such as shown in Fig. 7 the convoluted plates cannot keep the flow attached to the walls, they can reduce the distance downstream of the plane 508 where reattachment of the flow to the upper and lower walls occurs.
  • the bottom line is that the stepped diffuser will have lower losses than would occur without the use of the convoluted plates.
  • a convoluted plate is disposed adjacent each of the upper and lower walls, a single, perhaps larger (in terms of wave amplitude) plate disposed in the center of the conduit would also provide benefits.
  • the lobes and troughs in the downstream portion of the plate 800 generate adjacent counterrotating vortices 806, 808 downstream thereof which scrub the thermal boundary layer from the internal wall surface 810 of the tube and mix the core flow with the fluid flowing adjacent the wall.
  • the net effect is to increase the coefficient of heat transfer between the fluid and the wall of the conduit 802 for the purpose of ultimately exchanging heat energy between the fluid within the conduit and fluid surrounding the conduit.
  • the present invention is not a heat transfer device, it does utilize the same convoluted plates disposed in a conduit for the purpose of influencing the fluid flow dynamics in a diffusion section of the conduit downstream of the plate. we have discovered that such plates generate large-scale vortices to 1) energize the boundary layer to improve diffuser performance, and 2) increase mixing of the bulk fluid across the duct in directions perpendicular to the bulk fluid flow, which also improves diffuser performance.
  • a specific application for the wall members of the present invention is in a catalytic converter system, such as for an automobile.
  • a converter system is generally represented by the reference numeral 900 in Figs. 11 and 12.
  • the converter system 900 comprises a cylindrical gas delivery conduit 902, an elliptical gas receiving conduit 904, and a diffuser 906 which is a transition duct or conduit between them.
  • the bulk fluid flow direction is represented by the arrows 905 and is parallel to the axis 907 of the delivery conduit 902.
  • the diffuser 906 extends from the circular outlet 908 of the delivery conduit to the essentially elliptical inlet 910 of the receiving conduit 904.
  • the receiving conduit holds the catalyst bed (not shown).
  • the catalyst bed is preferably a honeycomb monolith with the honeycomb cells parallel to the downstream direction.
  • the inlet face of the monolith is at the inlet 910; however, it could be moved further downstream to allow additional diffusion distance between the delivery conduit outlet 908 and the catalyst.
  • Catalysts for catalytic converters and catalyst bed configurations are well known in the art.
  • the diffuser 906 of this embodiment is effectively a two-dimensional diffuser.
  • Disposed within the delivery conduit 902 is a convoluted plate 914 having a plurality of parallel troughs therein.
  • the plate 914 extends across the conduit 902 along approximately a diametral plane which is perpendicular to the major axis 912 of the elliptical gas receiving conduit 804.
  • the plate 914 is attached at its side edges 920 to the conduit 902.
  • the trough sidewalls 924 are preferably parallel to each other at the downstream wave-shaped edge 922 of the plate and are also preferably parallel to the ellipse major axis 912. Although optimum plate size and configuration will need to be determined by experimentation, using the teachings of the present invention as a guide, it is believed there should be at least two complete troughs on one side of the plate (there are three in the embodiment of Fig. 12) and the troughs should have a depth at their downstream edge which is a large percentage of the available space within the conduit.
  • conduit 902 of Figs. 11 and 12 has a diameter of 2.0 inches
  • one possible set of dimensions for the plate 914 is a trough slope ⁇ of 15°; a wave amplitude A of 1.0 inch; a trough width W of about 0.30; and a plate thickness of about 30 mils.
  • Figs. 13 and 14 show another embodiment of a catalytic converter system.
  • This system is generally represented by the reference numeral 950 and comprises a cylindrical gas delivery conduit 952, an elliptical gas receiving conduit 954, and a diffuser 956 which is a transition duct or conduit between them.
  • the bulk fluid flow direction is represented by the arrows 958 and is parallel to the axis 960 of the delivery conduit.
  • the diffuser 956 extends from the circular outlet 962 of the delivery conduit and smoothly transitions to the elliptical inlet 964 of the receiving conduit, which holds the catalyst bed (not shown) whose inlet face corresponds with the plane of the inlet 964.
  • the converter system is considered to be analogous to the two-dimensional diffuser described in Figs. 2 and 3.
  • a pair of slightly curved convoluted plates 966 are disposed within the delivery conduit 952, both extending across the duct in a direction substantially parallel to a diametral line which is parallel to the minor axis 968 of the elliptical receiving conduit and perpendicular to the major axis 970.
  • the plates 966 are positioned close to, but are spaced from, the surfaces of the delivery conduit which are disposed above and below the diametral line or axis 968.
  • the plane 972 represents the axial location along the diffuser 956 where two-dimensional streamwise boundary layer separation would normally occur without the use of the convoluted plates 966.
  • the downstream wave-shaped edges 974 must be spaced upstream of the plane 972 in order to delay separation of the flow beyond the plane 972. It is believed that best results will be obtained if the distance D is about one to two times the maximum wave amplitude of the plates 966. This allows some downstream distance for the large-scale vortices generated by the convoluted plates to become more fully developed before reaching the location of the plane 972.
  • the wave forms of the upper and lower plates 966 are out of phase.
  • the wave forms could also be in phase as shown in the embodiment of Figs. 7 and 8, which may produce coupling of the generated vortices, and thereby further improve mixing. Assuming a two-inch diameter for the delivery conduit 952, it is recommended that the maximum wave amplitude for each plate 966 be between about 0.5 and 0.75 inch.

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • Health & Medical Sciences (AREA)
  • Thermal Sciences (AREA)
  • Toxicology (AREA)
  • Combustion & Propulsion (AREA)
  • Dispersion Chemistry (AREA)
  • Devices And Processes Conducted In The Presence Of Fluids And Solid Particles (AREA)
  • Exhaust Gas After Treatment (AREA)
  • Exhaust Gas Treatment By Means Of Catalyst (AREA)
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EP88630118A 1987-12-15 1988-06-30 Gebogene Platte mit Wirbelgenerator Expired - Lifetime EP0321379B1 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US07/132,395 US4971768A (en) 1987-11-23 1987-12-15 Diffuser with convoluted vortex generator
US132395 1987-12-15

Publications (3)

Publication Number Publication Date
EP0321379A2 true EP0321379A2 (de) 1989-06-21
EP0321379A3 EP0321379A3 (de) 1991-07-10
EP0321379B1 EP0321379B1 (de) 1995-03-29

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Application Number Title Priority Date Filing Date
EP88630118A Expired - Lifetime EP0321379B1 (de) 1987-12-15 1988-06-30 Gebogene Platte mit Wirbelgenerator

Country Status (5)

Country Link
EP (1) EP0321379B1 (de)
JP (1) JP2678466B2 (de)
KR (1) KR960013199B1 (de)
DE (2) DE321379T1 (de)
YU (1) YU111888A (de)

Cited By (15)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0439226A1 (de) * 1990-01-24 1991-07-31 General Motors Corporation Abgasbehandlungsgerät mit geringer Einschränkung
EP0493302A1 (de) * 1990-12-24 1992-07-01 United Technologies Corporation Mechanismus zur Reduzierung von Druckverlusten in Rohrkrümmern
EP0410924A3 (en) * 1989-07-25 1992-10-21 United Technologies Corporation Diffuser
US5230369A (en) * 1990-12-24 1993-07-27 United Technologies Corporation Structure to reduce turning losses in angled conduit
EP0585194A1 (de) * 1992-08-05 1994-03-02 Carrier Corporation Misch- und Strömungverteiler
US5327940A (en) * 1992-03-09 1994-07-12 United Technologies Corporation Mechanism to reduce turning losses in angled conduits
WO1996023981A1 (de) * 1995-02-03 1996-08-08 Bmw Rolls-Royce Gmbh Strömungsleitkörper für eine gasturbinen-brennkammer
EP0999367A1 (de) * 1998-11-06 2000-05-10 ABB Alstom Power (Schweiz) AG Strömungskanal mit Querschnittssprung
EP0926356A3 (de) * 1997-12-22 2003-05-14 ALSTOM (Switzerland) Ltd Verfahren und Vorrichtung zur Energieanreicherung in einer an einer umströmten Oberfläche anliegenden Grenzschicht
US20110135541A1 (en) * 2008-08-12 2011-06-09 Mitsubishi Heavy Industries, Ltd. Air pollution control apparatus and air pollution control system
US20120128540A1 (en) * 2009-08-05 2012-05-24 Mitsubishi Heavy Industries, Ltd. Air pollution control device
EP2522912A1 (de) * 2011-05-11 2012-11-14 Alstom Technology Ltd Strömungsgleichrichter und Mischer
EP2522911A1 (de) * 2011-05-11 2012-11-14 Alstom Technology Ltd Gelappter Verwirbeler
DE102012221342A1 (de) * 2012-11-22 2014-05-22 Friedrich Boysen Gmbh & Co. Kg Strömungsleitvorrichtung
RU2692058C1 (ru) * 2018-06-08 2019-06-20 Акционерное общество "НИИ измерительных приборов - Новосибирский завод имени Коминтерна" (АО "НПО НИИИП-НЗиК") Способ защиты радиолокационной станции от малоразмерных беспилотных летательных аппаратов и устройство для его осуществления

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JP4788392B2 (ja) * 2006-02-24 2011-10-05 日立造船株式会社 脱硝反応装置におけるアンモニアガス均一混合装置
US10081429B2 (en) * 2014-07-21 2018-09-25 The Boeing Company Air diffuser systems, methods, and apparatuses

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Cited By (21)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0410924A3 (en) * 1989-07-25 1992-10-21 United Technologies Corporation Diffuser
EP0439226A1 (de) * 1990-01-24 1991-07-31 General Motors Corporation Abgasbehandlungsgerät mit geringer Einschränkung
EP0493302A1 (de) * 1990-12-24 1992-07-01 United Technologies Corporation Mechanismus zur Reduzierung von Druckverlusten in Rohrkrümmern
US5230369A (en) * 1990-12-24 1993-07-27 United Technologies Corporation Structure to reduce turning losses in angled conduit
US5327940A (en) * 1992-03-09 1994-07-12 United Technologies Corporation Mechanism to reduce turning losses in angled conduits
EP0585194A1 (de) * 1992-08-05 1994-03-02 Carrier Corporation Misch- und Strömungverteiler
WO1996023981A1 (de) * 1995-02-03 1996-08-08 Bmw Rolls-Royce Gmbh Strömungsleitkörper für eine gasturbinen-brennkammer
US5918465A (en) * 1995-02-03 1999-07-06 Bmw Rolls-Royce Gmbh Flow guiding body for a gas turbine combustion chamber
EP0926356A3 (de) * 1997-12-22 2003-05-14 ALSTOM (Switzerland) Ltd Verfahren und Vorrichtung zur Energieanreicherung in einer an einer umströmten Oberfläche anliegenden Grenzschicht
US6216644B1 (en) 1998-11-06 2001-04-17 Abb Alstrom Power (Schweiz) Ag Flow duct with cross-sectional step
EP0999367A1 (de) * 1998-11-06 2000-05-10 ABB Alstom Power (Schweiz) AG Strömungskanal mit Querschnittssprung
US20110135541A1 (en) * 2008-08-12 2011-06-09 Mitsubishi Heavy Industries, Ltd. Air pollution control apparatus and air pollution control system
US8840843B2 (en) * 2008-08-12 2014-09-23 Mitsubishi Heavy Industries, Ltd. Air pollution control apparatus and air pollution control system
US20120128540A1 (en) * 2009-08-05 2012-05-24 Mitsubishi Heavy Industries, Ltd. Air pollution control device
US9132391B2 (en) * 2009-08-05 2015-09-15 Mitsubishi Hitachi Power Systems, Ltd. Air pollution control device
EP2522912A1 (de) * 2011-05-11 2012-11-14 Alstom Technology Ltd Strömungsgleichrichter und Mischer
EP2522911A1 (de) * 2011-05-11 2012-11-14 Alstom Technology Ltd Gelappter Verwirbeler
US8938971B2 (en) 2011-05-11 2015-01-27 Alstom Technology Ltd Flow straightener and mixer
US9347663B2 (en) 2011-05-11 2016-05-24 General Electric Technology Gmbh Swirler having vanes provided with at least two lobes in opposite transverse directions with reference to a vane central plane
DE102012221342A1 (de) * 2012-11-22 2014-05-22 Friedrich Boysen Gmbh & Co. Kg Strömungsleitvorrichtung
RU2692058C1 (ru) * 2018-06-08 2019-06-20 Акционерное общество "НИИ измерительных приборов - Новосибирский завод имени Коминтерна" (АО "НПО НИИИП-НЗиК") Способ защиты радиолокационной станции от малоразмерных беспилотных летательных аппаратов и устройство для его осуществления

Also Published As

Publication number Publication date
EP0321379A3 (de) 1991-07-10
JPH01172603A (ja) 1989-07-07
KR960013199B1 (ko) 1996-09-30
EP0321379B1 (de) 1995-03-29
YU111888A (en) 1990-12-31
KR890010477A (ko) 1989-08-09
DE321379T1 (de) 1989-12-07
JP2678466B2 (ja) 1997-11-17
DE3853466D1 (de) 1995-05-04
DE3853466T2 (de) 1995-08-03

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