US3881701A

US3881701A - Fluid mixer reactor

Info

Publication number: US3881701A
Application number: US398031A
Authority: US
Inventors: Leonard Schoenman; Robert C Schindler
Original assignee: Aerojet General Corp
Current assignee: Aerojet Rocketdyne Inc
Priority date: 1973-09-17
Filing date: 1973-09-17
Publication date: 1975-05-06
Anticipated expiration: 1992-05-06

Abstract

An improved fluid mixing device comprised of a plurality of stacked, relatively thin plates having fluid passage means therein to allow two or more fluids to pass therethrough and to be mixed with each other yet at least one of the fluids, in the form of a liquid, can be atomized to enhance the mixing action between the two fluids. The device is constructed so that one or both fluids can be used to cool the face plate of the device such as when the latter is adjacent to a combustion chamber. Various embodiments of the device are disclosed.

Description

United States Patent [1 1 Schoenman et al.

[451 May 6,1975

[ FLUID MIXER REACTOR [7 51 Inventors: Leonard Schoenman, Citrus Heights;

Robert C. Schindler, Fair Oaks,

[21] Appl. No.: 398,031

[52] US. Cl 259/4; 23/252 [51] Int. Cl. B011 5/02; B01f 5/18 [58] Field of Search 259/4, 18, DIG. 30, 36, 259/60; 138/38; 48/180 R, 180 H, 180 B; 23/252 R [56] References Cited UNITED STATES PATENTS 3,206,170 9/1965 Schippers 259/4 3,325,150 6/1967 Broders 259/4 11/1973 Schmitt.... 259/4 3,770,249 4/1974 Clasen 25 9/4 Primary ExaminerRobert W. Jenkins Attorney, Agent, or Firm-John L. McGannon; J. Georg Seka; John S. Bell [5 7 ABSTRACT An improved fluid mixing device comprised of a plurality of stacked, relatively thin plates having fluid pas sage means therein to allow two or more fluids to pass therethrough and to be mixed with each other yet at least one of the fluids, in the form of a liquid, can be atomized to enhance the mixing action between the two fluids. The device is constructed so that one or both fluids can be used to cool the face plate of the device such as when the latter is adjacent to a combustion chamber. Various embodiments of the device are disclosed.

15 Claims, 7 Drawing Figures PATENTEB W5 3.881.701

SHEET 18! 3 FIG. 2

PATENTED 51975 3.881 .701

SHEET 2 UP 3 FIG. 4

PATENTEDIEAY 61975 3, 1,701

SHEET 3 GF 3 FIG. 5

FIG. 6

FLUID MIXER RIC/\("IOR This invention relates to improvements in the mixing of two different fluids prior to utilization of the mixture and, more particularly. to an improved fluid mixing device adapted to mix and atomize fluids as well as to utilize one of a number of fluids for cooling of the device itself.

The present invention is directed to a self-cooled device which achieves the efficient atomization and mix ing of two or more either inert or reactive fluids. lt accomplishes liquid stream atomization and/or vapor phase mixing by hydraulic or mechanical means or a combination of both. Mixing of two different fluids can be concurrent with the atomization process or can follow atomization. The mixer device can operate using a plurality of fluids and can be designed to stage the mixing processes through controlled variation in mass and mixture ratio and primary and secondary mixing and/or reaction.

The fluid mixer device of this invention is comprised of a plurality of thin plates which contain fluid-flow passages or channels. Depending upon the composition of the fluids and the platelet material, the plates can be joined in any one of a number of different ways, such as by diffusion bonding, a brazing, or adhesive. Platelet flow passages can be arranged so that a selected fluid is routed to provide cooling of the mixer wall.

The device provides efficient mixing control by dividing the total fluid flow into a very large number of precisely metered, very small streams which are atomized prior to or during their mixing with adjacent streams. All control of liquid flow, and indirectly of liquid atomization. and mixing is by means of the laminate or channel shape and depth. The fluid discharge from the device is through apertures which are normal to an end plate of the device, resulting in the outer face of the end plate being a continuous member and the platelet bond lines not being exposed to the reaction which follows mixing.

The quantity of outlets on the outer face of the device can be up to several hundred per square inch, with each discharging a stream of finely atomized fluid. Var iation in the design of the device allows these streams to consist of singular fluids or mixtures resulting from impingement of unlike streams. These sprays of atomized fluid can be directed to impinge on each other to acheive a controlled primary mixing zone exteriorly or interiorly of the device or, if directed axially, will experience secondary mixing by virtue of their proximity.

The advantage of this device over other microelement platelet-type mixers is that the following can be achieved without an increase in stream size or flow per element:

(l) Fewer plates are needed, resulting in reduced structural complexity and fewer bonded interfaces (2) The outer face of the surface can be a single, continuous member so that bond joints between the stacked plates of the device need not be exposed.

(3) Atomization can be accomplished by stream impingement against an integral splash plate, like-onlike stream impingement, or like-on-unlike stream impingement. Since droplet size is not totally dependent upon orifice size, larger, less easily plugged passages and orifices can be utilized.

(4). Mixing is achieved by directed impingement or unlike sprays following their atomization.

(5). The outer face of the device can be flat or can have a simple or compound curvature. The face boundary can be polygonal or circular.

The invention, in providing a means of atomizing and mixing reactive or nonreactive fluids proximate to the surface of a flat or curved plate, is suitable for use in the following applications but is not limited thereto:

l. Propellant injection on both liquid and gaseous propellant rocket engines.

2. Fluid injection to provide jet interaction for maneuverable reentry bodies.

3. Liquid propellant injection for very low thrust liquid propellant rocket engines.

4. Gas turbine propellant injection.

5. Chemical process mixing with both reactive and inert fluids.

6. Gas-liquid mixing for internal combustion engines,

7. Exhaust reactors.

8Chemical laser devices.

The primary object of this invention is to provide an improved fluid mixer device of the type comprised of a plurality of stacked, relatively thin plates arranged with certain fluid passages therein so that the stack of plates can provide a fluid manifold and distribution system, a coolant, system, and an atomizing and'mixing system tailored to accommodate two or more different fluids, such as a fuel and atomizing agent, in an efflcent manner. 1

Another object of this invention is to provide a device of the type described wherein the mixing of two different fluids can occur interiorly or exteriorly of the device during or after atomization to provide flexibility in the use of the device yet the device is highly efficient irrespective of its particular use.

A further object of this invention is to provide a fluid mixing device of the aforesaid character wherein the device has a working end face adapted to be placed near a reaction zone at which heat is generated, the device having fluid passage means for directing a fluid in proximity to the working face so that the fluid will be in heat exchange relationship to such face and maintain the same in a relatively cool condition to thereby minimize erosion of the face due to the deteriorating effects of the heat generated thereto. Other objects of this invention will become apparentas the following specification progresses, reference being had to the accompanying drawings for several embodiments of the invention:

In the drawings:

FIG. 1 is a fragmentary, perspective view of a fluid mixing device of this invention, showing the fluid passages therein and the working end face thereof, arrows indicating the directions of flow of fluids therethrough;

FIG. 2 is a cross-sectional view of the device of FIG. 1;

FIG. 2a is an enlarged, fragmentary, perspective view of the embodiment of FIGS. 1 and 2, showing the way in which two fluid stream impinge upon each other exteriorly of the device;

FIG. 3 is a view similar to FIG. 2 but showing another embodiment of the device; and

FIGS. 4, 5 and 6 are additional embodiments of the device with each of the latter embodiments utilizing a swirl chamber for generating a fluid stream in the form of a vortex to enhance mixing of fluids. A first embodiment of the fluid mixing device of this invention is broadly denoted by the numeral I0 and is illustrated in FIGS. 1 and 2. Device is formed of a plurality of stacked

plates

12, 14, 16, 18, 20, 22 and 24, which are all of the same shape. For purposes of illustration, each such plate is rectangular but could have other shapes as well. Plates 12 -24 may be of any suitable material, such as metal. The plates are bonded to each other in any suitable manner, such as by diffusion bonding, by brazing or by use of an adhesive. Plate 12 comprises the outer end plate of the device and is adapted to be placed adjacent to the region at which fluids emanating from device 10 are further utlilized, such as a combustion chamber of a rocket engine.

The various plates of device 10 are relatively thin and, while they are shown as being of the same thickness, they could vary in thickness from each other to suit specific requirements. A typical range of thicknesses for such plates is 0.002 inch to 0.030 inch. Since the plates are so thin, fluid channels or passages formed therein are preferably formed by a conventional photoetching technique to achieve the relatively fine dimensions of the passages. Typical dimensions of such passages are of the order of magnitude of the plate thicknesses.

Device 10 operates in a threefold manner, namely, it defines a fluid manifold and distribution system; it defines a coolant system wherein heat input from the region adjacent to end plate 12 is conducted to one or several of the fluids passing through the device; and it serves as an atomization and mixing system tailored to accommodate selected fluids.

As shown in FIG. 1, plate 12 has a plurality of pairs of

openings

26 and 28, each pair of openings being adjacent to each other and arranged so that the fluid streams issuing therefrom will be in the form of sprays directed toward each other in the manner shown in FIG. 1. Plate 12 has a plurality of such pairs of

openings

26 and 28. Typically, there are about 10 to 100 or so pairs of

openings

26 and 28 per square inch of plate 12. For purposes of illustration, each opening is trapezoidal in shape with the longer sides of the openings being adjacent to each other so that the sides of one opening diverge as the other opening is approached as shown in FIG. 1.

Plate 14 immediately adjacent to plate 12 has a number of fluid channels 30 (FIG. 1) for delivering a fluid, such as a liquid, from one side of device 10 across the device and along and in heat exchange relationship to the inner surface of plate 12. In the downstream end of each channel 30, plate 16 has a circular hole 32 placing the corresponding channel 30 in fluid communication with a fluid passage 34 in plate 18 transverse to channel 30.'Thus, fluid passing from channel 30 into opening 32 and through passage 34 can flow into a second opening 36 in plate 16, then up through an opening 38 in plate 14 and out of device 10 through a corresponding opening 26. Serpentive arrow 39 (FIG. 2) illustrates the path of flow of fluid from a channel 30 to the corresponding opening 26. Opening 38 in plate 14 is larger in size than opening 36 of plate 16 as shown in FIG. 2. Also, opening 26 is partially aligned with opening 38 so that a portion 40 of plate 12 overhangs opening 38 to present a lip or projection causing a fluid stream passing from

holes

36 and 38 to bent laterally as shown in FIG. 2. Furthermore, portion 40 causesatomization of the fluid passing the same before the fluid exits from device 10. The fluid exits from opening 26 along an inclined path as shown in FIG. 1, 2 and 3.

A second fluid directed toward each opening 28 flows upwardly through aligned

holes

44, 46, 48, 50v

and 52 in

plates

24, 22, 20, 18 and 16, respectively. Plate 14 has an enlarged hole 54 in fluid communication with holes 52 and the corresponding opening 28 partially overlies on end of opening 54 to define an over-hanging or projecting portion 56 which serves the same purpose as portion 40, namely to atomize the fluid before it exits from device 10. The fluid leaving each opening 28 is directed along an inclined path extending toward the fluid path extending away from the corresponding opening 26. Serpentive arrow 57 (FIG. 2) represents the flow of the second fluid through device 10 toward a corresponding opening 28. While the second fluid is shown in FIG. 2 as coming from a chan-v nel 59 remote from end plate 12, it is possible to form plate 14 so that the second fluid can be moved into heat exchange relationship to plate 12 so that both fluids operate to cool such plate.

The sprays issuing from each pair of

opening

26 and 28 are denoted by arrows 58 and 60 (FIG. 2a). The two sprays, both of which have been previously atomized, mix together at a zone 62 substantially midway between each pair of

openings

26 and 28. After mixing together, the mixture is ready for use, such as the fueloxidizer source for a combustion chamber. Thus, device 10 allows atomization of at least one of the fluids within the device, whereas, mixture of the two fluids occurs exteriorly of the device. Device 10 is adapted for use when direct impingement of liquids to be mixed within device 10 is not desired, i.e., when an exothermic reaction occurs upon impingement. Variations in the shapes of the holes in

plates

12 and 14 and the spacing of

openings

26 and 28 allow the spray character (spray shape and droplet size) -as well as the position of impingement zone 62 to be varied.

The second embodiment of the fluid mixer device of this invention is shown in FIG. 3 and is denoted by the numeral 110. Device includes a stack of

plates

112, 114, 116, 118, 120, 122 and 124, such stack being arranged to operate in a manner to cause a direct impinging mixing action of two fluid streams within the device itself to cause atomization. Also, mixing of two different fluids occurs within the device.

A first fluid enters device 110 along a pair of paths denoted by

arrows

126 and 128 and passes through

respective holes

130 and 132 in

plates

124 and 122, respectively. I-Ioles 132 communicate with respective fluid passages 134 in plate 120, passages 134 being opposed to each other and terminating at a central opening 136 aligned with a shaped slot 138 in plate 118 and with shaped

slots

140, 142 and 144 in

plates

116, 114 and 112, respectively.

Slots

140, 142 are of greater size than slot 138. Thus, within opening 136, the two streams of the first fluid flowing along the path denoted by

arrows

126 and 128 impinge upon each other to cause atomization of the first fluid. The resulting mixture is expelled through shaped slot 138 in plate 118.

Plate 116 has opposed fluid passages 146 formed therein which communicate with transverse passages 148 in plate 114. A second fluid entering passages 148 flows through the same to cool end plate 112. The fluid then flows through respective, opposed passages 146 in plate 116 along paths denoted by arrows 150 and 152. The two fluid streams exit from passages 146 and impinge against each other at the center of slot to cause atomization of the second fluid. Plate 1 14 can be constructed so that passages 148 can be fed from the edge of device 110 or by passages from one extremity thereof which penetrate through plates 116-124.

There is a mixing action within shaped

slots

140, 142 and 144 of the two different fluids, namely, the first fluid entering device 1 along

paths

126 and 128 and the second fluid entering along paths 150 and 152. The mixture occurs prior to exit from device 110. Before such mixing action, the first fluid will have been atomized by impingement of the two streams thereof within opening 136.

FIG. 4 illustrates a third emobidment of the device of this invention wherein mixing of two fluids is accomplished by a vortex action. The device of this embodiment, denoted by the numeral 210, is comprised of

plates

212, 214, 216, 218, 220, 222 and 224 arranged in a stack. As before, plate 212 will have a number of shaped slots or openings 226 per square inch. The vortex action occurs within device 210 when a first fluid, flowing along a path denoted by arrow 228, passes through a tangential port 230 at the inner end of a fluid passage 236 in plate 220 and enters a swirl chamber 232 also in plate 220. Plate 218 has a shaped slot 234 communicating with and defining the outlet of the swirl chamber. The fluid entering the swirl chamber initially reaches fluid passage 236 by way of openings 238 and 240 in

plates

222 and 224, respectively. Opening 240 is in fluid communication with a manifold 241 adapted to be coupled to a source of the first fluid.

Plate 216 contains a shaped slot 252 and a pair of

fluid passages

242 and 244 which communicate with transverse passages 246 in plate 214. A second fluid flowing through passages 246 toward

passages

242 and 244 will cool plate 212. The second fluid flows through

passages

242 and 244 along paths denoted by

arrows

248 and 250 and enters the vortex created by the first fluid because

passages

242 and 244 are on opposite sides of the vortex. The two fluids are thus mixed together within device 10 and flow out of the same in vortex fashion through shaped slots 252,254 and 266 in

plates

216, 214 and 212, respectively. Fluid can be fed to passages 246 in plate 214 from the edge of the stack or from a location thereon by means of passages through plates 216-224. While the vortex action within device 10 serves to mix the two different fluids with each other, it also serves to atomize the second fluid.

FIG. 5 illustrates still another embodiment of a fluid mixer device utilizing an internally generated vortex. In FIG. 5, the fluid mixer device 310 is comprised of stacked

plates

312, 314, 316, 318, 320, 322 and 324. A swirl chamber 326 is provided in plate 320 and has an outlet denoted by a shaped slot 328 in plate 318. A first fluid is supplied along a path 330 to the swirl chamber plate 320 after the fluid has passed through

openings

332 and 334 in

plate

324 and 322, respectively, and through a fluid passage 336 also in plate 320. Passage 336 has an exit port 338 which is tangential to swirl chamber 326 to create the vortex indicated by the spiral arrow 340 leaving device 310 through shaped

openings

342, 343 and 345 in

plates

312, 314 and 316, respectively. As before, face plate 312 has a plurality of openings 342 per unit area inasmuch as the relative sizes of the various openings and passages in each plate are quite small.

A second fluid is fed through transverse passage 344 in plate 314, there being a pair of passages 344 on each side of the vortex, respectively. Passages 344 serve to permit the second fluid to cool end plate 312 before mixing with the first fluid in the vortex. The two streams of the second fluid which leaves each pair of passages 344 enters a passage 346 whereby impingement of the two streams causes atomization of the second fluid before passing through shaped slot 348 which causes the atomized second fluid to leave device 310 in the form of a spray. Then the second fluid streams denoted by arrows 349 are directed toward and intersect the vortex of the first fluid to create a mixing action between the two fluids.

FIG. 6 illustrates a modification of the embodiment of FIG. 5 in that plate 314 is provided with only a single passage instead of a pair of such passages on each side of the vortex, respectively. The single passage, denoted by the numeral 344a communicates with a passage 346a the latter being in fluid communication with slot 348a to cause atomization of the fluid flowing along a path denoted by the numeral 350a. Atomization occurs because of the. overhanging portion 3520 of plate 312 with respect to passage 346a The second fluid then flows along an inclined path as it leaves device 310 through each slot 348a and intersects the vortex of the first fluid whereby the two fluids are mixed together. As before, the second fluid passing through passages 344a cools end plate 312.

We claim:

1. A fluid mixing device comprising: a plurality of relatively thin plates arranged in a stack to form a platelet assembly, one of the plates being at the end of the stack and provided with an outlet opening, the plate next, adjacent to said end plate having an elongated channel for receiving a first fluid and for placing the latter in heat exchange relationship to the end plate, said assembly having first passage means coupled with the channel for directing the first fluid from the latter to said opening, a second passage means for directing a-secondfluid into mixing relationship to the first fluid,-and means defined by said passage means and employing the kinetic energy of the flowing fluid for atomizing at least one of the fluids as it flows through said assembly and prior to its being mixed with the other fluid.

2. A device as set forth in claim 1, wherein said end plate has a second opening adjacent to said first opening, the second passage means communicating with the second opening, said first passage means and said second passage means defining respective first and second passages oriented to cause the first and second fluids leaving the assembly through the openings to traverse inclined paths converging toward each other as the flu- I ids flow away from said end plate, whereby the fluids are mixed together exteriorly of said assembly.

3. A device as set forth in claim 1, wherein said atomizing means comprises a lip extending partially across the path of said one fluid for engaging the same and for reducing the particle size thereof as the fluid flows past the lip.

4. A device as set forth in claim 1, wherein the end plate has a plurality of pairs of shaped outlet slots, there being a first passage means and a second passage means for each pair of slots, respectively, one of the slots of each pair communicating with the corresponding first passage means and the other slot of each pair communicating with the corresponding second passage means, the slots of each pair being arranged to present a fluid spray therefrom with the sprays being directed toward each other for mixture at a zone exteriorly of the stack and between said pair of slots.

5. A device as set forth in claim 1, wherein a first of said plates of said assembly has a pair of opposed fluid passage therein communicating with said outlet opening, and wherein the atomizing means comprises means for directing one of the fluids through said opposed fluid passages and toward and into impinging relationship to each other to cause atomization ofsaid one fluid prior to flow thereof out of said assembly through said outlet opening.

6. A device as set forth in claim 1, wherein each of a pair of said plates has a pair of opposed fluid passages therein communicating with said outlet opening. and wherein the atomizing means comprises means coupled with each pair of fluid passages, respectively. for directing a respective fluid thereto whereby the fluid will pass therethrough in a pair of streams and the streams will impinge upon each other and atomize the fluid before the fluid passes out of the assembly through said outlet opening.

7. A device as set forth in claim 6, wherein the zone of impingement of the first fluid is disposed between the outlet opening and the zone of impingement of the second fluid.

8. A device as set forth in claim 1, wherein said atomizing means is defined by a swirl chamber.

9. A device as set forth in claim 1, wherein one of the plates has means defining a swirl chamber. the latter forming a part of said second passage means. whereby the second fluid entering the swirl chamber will be caused to form a vortex which advances toward. through and out of said outlet opening. said first passage means including an outlet slot adjacent to said outlet opening and disposed to permit said first fluid to leave said assembly and to travel toward and into intersecting relationship to the vortex at a location exteriorly of said assembly.

10. A device as set forth in claim 9, wherein said atomizing means includes means defined by said plate adjacent to said end plate for dividing the first fluid into two streams and for directing the two streams into impingement with each other upstream of said outlet slot to effect atomization of the first fluid. said dividing and directing means being disposed to permit the first fluid to leave the assembly through said outlet port along a path substantially perpendicular to said end plate.

11. A device as set forth in claim 9, wherin said plate adjacent to said end plate includes a fluid passage defining said first passage means. said fluid passage being oriented in partial underlying relationship to said end plate and in partial fluid communication with said outlet slot to cause the first fluid to pass out of the assembly through said outlet slot along an inclined path extending toward the path of the vortex.

12. A device as set forth in claim 11, wherein said atomizing means presents a projection defined by said end plate at one side of said outlet slot in the inclined path of said first fluid to cause atomization hereof.

13. A fluid mixing and atomizing device for forming an atomized mixture of at least two fluids and for directing the fluids into a surrounding atmosphere comprising a plurality of relatively thin plates arranged in a stack to form a platelet assembly. a front of the assembly being defined by an end plate having at least one outlet opening. first fluid passage means for flowing a first fluid through the stack and to the outlet opening. second fluid passage means for flowing a second fluid through the stack into mixing relationship with the first fluid. and means for atomizing at least one of the fluids before its discharge from the stack and before being mixed with the other fluid. the atomizing means comprising means defined by at least one of the passage means for guiding the fluid flow through such passage means so that such fluid is atomized by virtue of its flow through the passage means.

14. A device according to claim 14 wherein the atomizing means includes means for impinging two fluid streams flowing in the stack.

15. A device according to claim 14 wherein the atomizing includes means for causing at least one fluid stream in the stack to abruptly change its flow direction to thereby atomize the fluid such streams.

Claims

1. A fluid mixing device comprising: a plurality of relatively tHin plates arranged in a stack to form a platelet assembly, one of the plates being at the end of the stack and provided with an outlet opening, the plate next adjacent to said end plate having an elongated channel for receiving a first fluid and for placing the latter in heat exchange relationship to the end plate, said assembly having first passage means coupled with the channel for directing the first fluid from the latter to said opening, a second passage means for directing a second fluid into mixing relationship to the first fluid, and means defined by said passage means and employing the kinetic energy of the flowing fluid for atomizing at least one of the fluids as it flows through said assembly and prior to its being mixed with the other fluid.

2. A device as set forth in claim 1, wherein said end plate has a second opening adjacent to said first opening, the second passage means communicating with the second opening, said first passage means and said second passage means defining respective first and second passages oriented to cause the first and second fluids leaving the assembly through the openings to traverse inclined paths converging toward each other as the fluids flow away from said end plate, whereby the fluids are mixed together exteriorly of said assembly.

5. A device as set forth in claim 1, wherein a first of said plates of said assembly has a pair of opposed fluid passage therein communicating with said outlet opening, and wherein the atomizing means comprises means for directing one of the fluids through said opposed fluid passages and toward and into impinging relationship to each other to cause atomization of said one fluid prior to flow thereof out of said assembly through said outlet opening.

6. A device as set forth in claim 1, wherein each of a pair of said plates has a pair of opposed fluid passages therein communicating with said outlet opening, and wherein the atomizing means comprises means coupled with each pair of fluid passages, respectively, for directing a respective fluid thereto whereby the fluid will pass therethrough in a pair of streams and the streams will impinge upon each other and atomize the fluid before the fluid passes out of the assembly through said outlet opening.

9. A device as set forth in claim 1, wherein one of the plates has means defining a swirl chamber, the latter forming a part of said second passage means, whereby the second fluid entering the swirl chamber will be caused to form a vortex which advances toward, through and out of said outlet opening, said first passage means including an outlet slot adjacent to said outlet opening and disposed to permit said first fluid to leave said assembly and to travel toward and into intersecting relationship to the vortex at a location exteriorly of said assembly.

10. A device as set forth in claim 9, wherein said atomizing means includes Means defined by said plate adjacent to said end plate for dividing the first fluid into two streams and for directing the two streams into impingement with each other upstream of said outlet slot to effect atomization of the first fluid, said dividing and directing means being disposed to permit the first fluid to leave the assembly through said outlet port along a path substantially perpendicular to said end plate.

11. A device as set forth in claim 9, wherin said plate adjacent to said end plate includes a fluid passage defining said first passage means, said fluid passage being oriented in partial underlying relationship to said end plate and in partial fluid communication with said outlet slot to cause the first fluid to pass out of the assembly through said outlet slot along an inclined path extending toward the path of the vortex.

13. A fluid mixing and atomizing device for forming an atomized mixture of at least two fluids and for directing the fluids into a surrounding atmosphere comprising a plurality of relatively thin plates arranged in a stack to form a platelet assembly, a front of the assembly being defined by an end plate having at least one outlet opening, first fluid passage means for flowing a first fluid through the stack and to the outlet opening, second fluid passage means for flowing a second fluid through the stack into mixing relationship with the first fluid, and means for atomizing at least one of the fluids before its discharge from the stack and before being mixed with the other fluid, the atomizing means comprising means defined by at least one of the passage means for guiding the fluid flow through such passage means so that such fluid is atomized by virtue of its flow through the passage means.