US3753304A

US3753304A - Pressure wave generator

Info

Publication number: US3753304A
Authority: US
Inventors: N Hughes
Original assignee: Energy Sciences Inc
Current assignee: Energy Sciences Inc; VORTRAN CORP
Priority date: 1971-02-02
Filing date: 1971-02-02
Publication date: 1973-08-21
Anticipated expiration: 1990-08-21

Abstract

First and second shock wave generating cells are separated by a first resonant cavity. Third and fourth shock wave generating cells are arranged transverse to the first and second cells at opposite sides of and in communication with the first cavity. The shock waves from the cells collide in the first cavity. A second resonant cavity, which is terminated by a reflective strip of material, communicates with the outlet of the second cell. A plurality of cubicle auxiliary resonant cavities are formed around the side of the second cavity to intersect the plane in which the strip lies. A fifth shock wave generating cell is arranged transverse to the second cell in communication with the second cavity. Preferably, the shock waves generated by all the cells and the dimensions of the cavities are multiply related.

Description

United States Patent -i191 1 Hughes Aug. 21, 1973 PRESSURE WAVE GENERATOR 3,514,956 6/1970 Bray 60/270 X 3,568,703 3/1971 Warren et a1... 137/815 [75] Inventor gz Hughes Ronmg 3,595,022 7/1971 Radebold et a1 60/270 R I 3,379,204 4/1968 Kelley et'al 137/81.5 3,398,758 8/1968 Unfried 137/815 31 ssignee: Energy Sciences, Inc., Costa Mesa, 3,456,668 7 1969 WheelenJr. 137/815 Calif, 3,614,961 10/1971 Nekrasov et a1.... 137/81.5 3,665,949 5/1972 Rivard 137/8l.5 [22] Filed: Feb. 2, 1971 Primary Examiner-Samuel Scott U Appl L995 Attorney-Christie, Parker & Hale Related US. Application Data [63] Continuation-impart of Ser. No. 855,321, Sept. 4, 7 ABSTRACT 1969, abandoned, and a conunuation-m-part of Ser. No. 13,977, Feb. 25, 1970, abandoned. First and second shock wave generating cells are sepa- 3 I rated by a first resonant cavity. Third and fourth shock [52] US. Cl 1. 137/823, 137/827, 235/201 ME wave generating cells are arranged transverse to the [51] Int. C1,... FlSc l/l4 first'and second cells at opposite sides of and in com- [58] Field of Search 239/4; 235/201 ME; munication with the first cavity. The shock waves from 60/249, 247, 270 R; 137/815, 13 the cells collide in the first cavity. A second resonant cavity, which is terminated by a reflective strip of mate- [56] References Cited I rial, communicates with the. outlet of the second cell. UNITED STATES PATENTS A plurality of cubicle auxiliary resonant cavities are 3,175,357 3/1965 Klein 60/249 x fmmFd Slde 'tersect 2.805545 9/1957 wilmanw 60/247 the plane 1n which the strip lies. A fifth shock wave gen- 3,005,310 10,19 Red" t I I 60/249 crating cell is arranged transverse to the second cell in ,3 0 12/1962 Riordan 137/815 communication with the second cavity. Preferably, the 3,371,869 3/1968 Hughes 239/4 X shock waves generated by all the cells and the dimen- 3,389,97l 6/1968 Alliger 239/4 sions of the cavities are multiply related. 3,393,964 7/1968 Donnelly 239/4 X 3,503,408 3/1970 Metzger 17 Claims, 7 Drawing Figures Patented Aug. 21, 1973 3,753,304

5 Sheets-Shoet ll.

'9 55 i H55 w 3 INVENTOR.

I Patented Aug. 21, 1973 5 Sheets-Sheet Patented Aug. 21, 1973 3 3,153,304

' 3 Sheets-Sheet 3 H5. 7

1 PRESSURE WAVE GENERATOR CROSS REFERENCE TO RELATED APPLICATIONS This is a continuation-in-part of copending applications, Ser. No. 855,321, filed Sept. 4, .1969 and Ser. No. 13,977, filed Feb. 25, l970,'both of which are now abandoned.

BACKGROUND OF THE INVENTION This invention relates to the generation of pressure waves and, more particularly, to a pressure wave generator this is particularly well suited for the PCV system of an internal combustion engine.

In my Pat. No. 3,554,443, which issued Jan. l2, 1971, there is disclosed a shock wave generating cell in which a converging-diverging supersonic nozzle is formed by a fluid boundary layer. A primary inlet opening in the cell couples fluid from a source to the converging-diverging nozzle for conversion to supersonic flow and auxiliary inlet openings designed to form the boundary layer couple the source to the cell. As the pressure of the source varies, the boundary layer changes to adjust the throat area of the convergingwaves propagates along the longitudinal axis. The second cell is coupled to the cavity at the side wall such that the vertex of its shock waves propagates along an axis transverse to and intersecting the longitudinal axis. The distance between the point of intersection and each wall of the cavity and the other dimensions are also multiply related. Preferably, the mass flow rate of the fluid passing through the second cell is substantially less than the first cell and is balanced by a thrid cell coupled to the cavity at the side wall opposite the second cell. The transverse shock waves are introduced into the resonant cavity between two spaced shock wave generating cells arranged in series, as described in the preceding paragraph.

According to another aspect of the invention, a resonant cavity for converting shock waves into coherent sonic waves is arranged in series with and downstream of one or more converging-diverging supersonic nozzles. In a preferred embodiment, the cavity has first and second spaced ends and a longitudinal, preferably cy- I lindrical side wall extending about an axis between the diverging nozzle so the wavelength of the principal shock waves tends to remain constant. The dimensions I of the cell are selected so the wavelengths of the secondary pressure pulsations produced by the auxiliary openings and the cavities formed within the cell andthe wavelength of the principal shock waves are multiply related. Thus, substantially coherent shock wave energy emanates from the cell.

SUMMARY OF THE INVENTION The invention is concerned with techniques for enhancing the'coherent pressure wave energy produced by converging-diverging supersonic nozzles, particulary the shock wave generating cell disclosed in US. Pat. No. 3,554,443.

According to one aspect of the invention, a plurality of converging-diverging supersonic nozzles are arranged in spaced apart series relationship. The princi pal wavelength of the shock waves produced by the nozzles and the space between the nozzles are multiply related. In a preferred embodiment, an annular resonant spacer is disposed in a housing between first and second shock wave generating cells. The fluid stream flows from an inlet of the housing through the first cell, the spacer, and the second cell to the outlet of the housing.

According to another aspect of the invention, a plu-' rality of converging-diverging supersonic nozzles are arranged transverse to each other so the shock waves they produce collide and interact. In a preferred embodiment, the energy from a first shock wave generating cell is coupled to a resonant cavity for transverse resonant interaction with the energy from a second shock wave generating cell. The resonant cavity has a pair of spaced ends, a longitudinal side wall extending between the ends, a longitudinal axis extending between the ends, and an exit and a solid reflective wall at one of the ends. The principal wavelength of the shock waves produced by the first and second cells, the length of the cavity, and the width of the cavity are all multiply related. The first cell is coupled to the cavity at the other end wall such that the vertex of its shock ends. At the first end, there are introduced shock waves having a vertex that propagates along the axis. The principal wavelength of the shock waves and the length of the cavity are multiply related to promote resonant action in the cavity. An exit from the cavity is formed at the second end to permit the sonic wave energy to leave the cavityafter reflection from the second end.

Preferably, the exit from the second end comprises two identical chordal openings a solid reflective strip, the width of which is multiply related to the wavelength. To enhance the intensity of the coherent sonic wave energy, hexahedral, preferablycubical, auxiliary cavities are formed around the side wall to intersect the plane in which the second strip lies. The auxiliary cavities intercept the energy as it is reflected outwardly from the second end, thereby providing additional resonant action.

A compact sonic wave generator capable of producing coherent sonic waves having a high intensity can be formed by incorporating into a common housing the structural features described in the two preceding paragraphs. Such a generator is particularly well suited for insertion in a PCV return line.

BRIEF DESCRIPTION OF THE DRAWINGS The features of several specific embodiments of the best mode contemplated of carrying out the invention are illustrated in the drawings, in which:

FIG. 1 is a side veiw of a shock wave generator incorporating the principals of the invention;

FIG. 2 is a side view of a sonic wave generator incorporating the principals of the invention;

FIG. 3 is a sectional view of the sonic wave generator of FIG. 2;

FIG. 4 is an exploded view of a sonic wave generator that incorporates the'elements of FIGS. 1 and 2 into a common housing;

FIG. 5 is a side sectional view of the spacer of FIG. 1 showing the dimensions of the resonant cavity;

FIG. 6 is a side sectional view of the spacers of FIG. 2 showing the dimensions of the resonant cavity; and

FIG. 7 is a schematic diagram of a PCV system incorporating a pressure wave generator in accordance with the invention.

In FIG. 1, a housing comprises a cylindrical tube 11, a cylindrical outer jacket 12, and tubular fittings 13 and 14. Fittings .13 and 14 are fixed to tube 11 by swaging or other means. Jacket 12, which surrounds tube 11, has a force fit therewith. A shock wave generating cell 15, an annular spacer 16, and a shock wave generating cell 17 are disposed within tube 11 along its cylindrical axis 18 in abutting relationship between the ends of fittings 13 and 14, as shown in FIG. 1. Thus,

cells

15 and 17 and spacer 16 fit snugly inside housing 10 as a single cylindrical unit without being able to move. The space enclosed by spacer 16 between

cells

15 and 17 comprises a resonant cavity 27. Cylindrical counterbores 19 and 20 are formed at diametrically opposite sides of jacket 12. Cylindrical shock wave generating cells 20, respectively, by force fits. A circular hole 23 through tube 11 and a circular hole 24 through spacer 16 couple cell 21 to cavity 27. A circular hole 25 through tube 11 and a circular hole 26 through spacer 16 couple cell 22 to cavity 27. Counterbores 19 and 20, cells 21 and 22, and holes 23 through 26 are all centered about a transverse axis 28 that is perpendicular to axis 18 and intersects axis 18 at a point 29 within cavity 27.

As described in more detail in U.S. Pat. No. 3,554,443 the disclosure of which is incorporated herein by

reference cells

15, 17, 21, and 22 each comprise a cylindrical nozzle open at its downstream end and bounded at its upstream end by an end wall. The end wall has a large center hole that serves as a primary inlet for the nozzle and a plurality of smaller, equally spaced peripheral holes disposed about the center hole. The cylindrical side wall of the nozzle has a plurality of oppositely disposed pairs of holes lying in a common plane near the downstream end of the nozzle for throat plane stabilization. The smaller peripheral holes and the throat plane stabilization holes serve as the secondary inlets for forming the converging-diverging boundary layer. A cylindrical cell cover surrounds the nozzle to form with the cylindrical side wall of the nozzle an annular cavity. The cell cover completely enclosesthe nozzle except for an opening at its upstream end that communicates with the holes of the nozzle. Forthe purpose of discussion, it is assumed that

cells

15 and 17 each have the dimensions and hole diameters specified in U.S. Pat. No. 3,554,443 and cells 21 and 22 each have the dimensions and hole diameters specified in U.S. Pat. No. 3,554,443 except for the diameter of the opening at the upstream end of the cell cover, which is assumed to be 0.097 inches. In other words, openings 30 and 31 of

cells

15 and 17 respectively are twice as big in diameter as opening 32 of cell 22 and the corresponding opening of cell 21 (not shown). As used in this specification, the term boundary layer formed shock wave generating cell refers to the type of device disclosed in U.S. Pat. No. 3,554,443, and the term boundary layer formed supersonic nozzle refers to a device based upon the principles taught in my U.S. Pat. No. 3,531,048, which issued Sept. 29, 1970, and is referenced in U.S. Pat. No. 3,554,443.

It is further assumed that fitting 13 is connected to an atmospheric air source at a temperature of 528 R and at atmospheric pressure, the openings at the upstream 21 and 22 are maintained in counterbores l9 and end of the cell covers of cells 21 and 22 are exposed to atmospheric air, and fitting 14 is connected to an air receiver at a lower than atmospheric pressure. The pressure difference across

cells

15, 17, 21, and 22 induces a subsonic flow of air into the cells where'the air is converted to a supersonic airstream at the outlet that produces coherent shock waves having a wavelength of 0.194 inches as a principal energy component. As used in this specification, the term coherent shock waves means a series of pressure waves all having substantially the same difference between successive peaks, i.e., the same wavelength. The pressure waves are positive and unipolar, i.e., the pressure at a given point varies between ambient pressure and a large positive pressure. In other words, the pressure of coherent shock waves varies essentially in the same manner as a rectified, base-clipped electrical sine wave signal. In addition to the principal wavelength, the cells also produce other pressure wave components discussed in U.S. Pat. No. 3,554,443, which have secondary wavelengths that are multiples and/or submultiples of the principal wavelength e.g., 0.194 inches. Cells 21 and 22 have a particularly large energy component at the submultiple wavelength of 0.097 inches because of the diameter of the openings at the upstream ends of their cell covers. In summary,

cells

15, 17, 21, and 22 all produce coherent shock waves having principal and secondary wavelengths that are multiply related.

Cavity 27 is cylindrical. The inside surface of spacer 16 defines the cylindrical side wall of cavity 27, the upstream end of the cover of cell 17 defines the reflective end wall of cavity 27, and axis 18 is the longitudinal axis of cavity 27. FIG. 5 is an isolated view of spacer 16 in which the dimensions of cavity 27 are labelled. The distance along axis 18 from the upstream end of cavity 27 to intersection point 29 is X,, the distance along axis 18 from intersection point 29 to the downstream end of cavity 27 is X the distance along axis 28 from the side wall of cavity 27 at the point where hole 24 is formed to intersection point 29 is Y,, and the'distance along axis 28 from the side wall of cavity 27 at the point where hole 26 is formed to intersection point 29 is Y In the disclosed embodiment, cavity 27 is cylindrical and holes 24 and 26 are spaced midway between the ends of cavity 27. Thus, distances Y and Y, are the same, their sum equalling the diameter of the cylinder, and distances X, and X, are the same, their sum equalling the length of the cylinder. The structure involving housing 10, cell 15, spacer 16, and cell 17, without cells 21 and 22, was disclosed in application Ser. No. 13,977, but is claimed herein.

The shock waves produced by cell 15 have a vertex that propagates along axis 18. The distances X, and X, are each equal to one half of the principal wavelength; thus the length of cavity 27 is 0.194 inches. As a result, some of the shock waves produced by cell 15 are reflected from the upstream end of the cover of cell 17 and resonate in cavity 27 to enhance the intensity. It is believed the shock waves are converted to coherent sonic wave energy by the resonant action.

In this specification, the term coherent sonic wave energy" means pressure waves in which the energy is concentrated in terms of its frequency spectrum into a principal component with or without a number of other components, and the pressure waves are bipolar, i.e., the pressure varies both positively and negatively from the ambient pressure so that concentration and rarifiare a plurality of components, the 'multicomponent sonic wave energy is coherent in that the wavelengths of all the components are multiples or submultip'les of the principal component wavelength. Since the wavelengths of the components comprising the coherent sonic wave energy are all essentially multiply related, these components reinforce each other to form standing waves in an enclosed area and to-produce extremely large pressure gradients. The described coherent sonic wave energy produces much higher pressure gradients and, therefore, atomizing power, than comparable shock waves due to the bipolar nature of the sonic pressure wave.

Holes 23 and 24 and holes 25 and 26 have a-diameter equal to one half of the principle wavelength, i.e., 0.097 inches, so the shock waves from cells 21 and 22 are coupled to cavity 27 by holes 23 through 26 without any appreciable attenuation. Thus, cells 21 and 22 have a virtual or apparent outlet at the side wall of cavity '27. The shock waves produced by cells 21' and 22 have vertices that propagate along transverse axis 28 and collide with the vertex of the shock waves produced by cell l5at intersection point 29. The distances Y, and Y, are each equal to the principal wavelength; thus the radius of cavity 27 is 0.194 inches. The relationship of the distances X,, X,, X, X,,.Y,, and Y,, to the shock wave wavelength further'enha'nces the resonant action in cavity 27 and increases the intensity of the pressure wave energy. In a sense, fluidic reflective surfaces are formed at point 29 by the colliding of the shock waves travelling along axis 18 and along axis 28. Since the distances from these fluidic reflective surfaces to the side wall and the ends of cavity 27 are multiples or submultiples of the wavelength of the shock waves, these fluidic reflective surfaces promote with the sidewall and ends further resonant action in cavity 27.

The coherent sonic wave energy produced in cavity 27 is drawn into cell 17 where it is reconverted to coherent shock waves having a principal component wavelength of 0.194 inches. The intensity of these shock waves is appreciably higher than the intensity of the shock waves produced by the device disclosed in application Ser. No. 13,977. This fact is attributable to the resonant interaction that takes place between shock waves from cells 21 and 22 and the shock waves from cell 15.

The small diameter of theopenings at the upstream end of the cell covers of cells 21 and 22 reduces the mass flow rate of air through cells 21 and 22 vis-a-vis the mass flow rate of air through cell 15. This prevents the shock waves produced by cells 21 and 22 from swamping the shock waves produced by cell and from disrupting the propagation of shock waves along axis 18 to cell 17.

Although the preferred dimensions of distances X,, and Y, relative to the principal wavelength are as stated above, the described increase in the intensity of the shock waves can be realized with other specific dimensions. The basic rule to follow is that distances X,, X,, Y,, and Y, and the principal wavelength are all multiply related. It is believed the fluidic, reflective surface formed at the colliding shock waves enhances the resonant action due to the solid reflective surfaces at the upstream end of the cover of cell 17 and around the inside of spacer 16. Although the optimum enhancecation of the fluid molecules alternately occurs If there ment occurs when the above described multiple relationship exists between the principal wavelength and the distance from the outlets of

cells

15 and 21 to intersection point 29, the pressure wave intensity is also enhanced to some extent when the multiple relationship does not exist. Thus, the structure disclosed in FIG. 12 of application Ser. No. 13,977 insofar as it relates to transversely arranged cells is also claimed herein.

In FIG. 2, a resonant cavity 40 is enclosed'within a housing 41, which comprises a cylindrical tube 42, a cylindrical outer jacket 43, and tubular fittings 44 and 45. Fittings 44 and 45 are fixed to tube 42 by swaging or other means. Jacket 43, which surrounds tube 42, has a force fit therewith.

Annular spacers

46, 47, 48, and 49 are disposed within tube 42 along its cylindrical axis 50in abutting relationship between the ends of fittings 44 and 45, as shown in FIG. 2. Thus, spacers 46 through 49 fit snugly inside housing 41 as a single cylindrical unit without being able to move. A strip 51 of material is attached to spacer 49 so it extends diametrically across spacer 49 (see FIG. 3) flush with the end thereof. The space enclosed by

spacers

46, 47, and 48 between fitting 44 and-strip 51 comprises cavity 40.

- Chordal openings 52 and 53 (see FIG. 3), which are defined by the edges of strip 51 and the inside wall of spacer 49, comprise the exit from cavity 40.

Auxiliary cubicle cavities

54, 55, 56, and 57 (see FIG. 3) are formed at 90 intervals around spacer 48 at the end abutting spacer 49. Thus,

cavities

54, 55, 56, and 57 communicate with cavity 40 and intersect the plane in which strip 51 lies. A cylindrical counterbore 58 is formed in jacket 43. A cylindrical shock wave generating cell 59, which is identical to cells 21 and 22 in FIG. 1, is maintained in counterbore 58 by a force fit. A circular hole 60 through tube 42 and a circular hole 61 through spacer 47 couple cell 59 to cavity 40. Counterbore 58, cell 59, and holes 60 and 61 are all centered about a transverse axis 62 that is perpendicular to axis 50 and intersects axis 50 at a point 63 within cavity 40.

' A shock wave generator 70, which is preferably the arrangement disclosed in FIG- 1, but could be the shock wave generator disclosed in one of the referenced applications, or even a conventional convergingdiverging supersonic nozzle, is coupled to cavity 40 by a connecting hose 71. A clamp 72 secures hose 71 to fixture 44 and a clamp 73 secures hose 71 to a fitting on shock wave generator 70. It is assumed for the purpose of discussion that generator produces shock waves having a principal component wavelength of 0.194 inches. The wavelength of the shock waves, the underformed diameter of hose 71, and the inside diameter of the fittings are all multiply related specifically, the diameter of the hose and the inside diameter of the fittings are both twice the wavelength of the shock waves, e.g., 0.388 inches. Accordingly, connecting hose 71 can be quite long without appreciably attenuating the shock waves.

Cavity 40 is cylindrical. The inside walls of spacers .46 through 47 define the cylindrical side wall of cavity 40, strip 51 defines the reflective end surface of cavity 40, and axis 50 is the longitudinal axis of cavity 40. FIG. 6 is an isolated view of

spacers

46, 47, and 48 in which the dimensions of cavity 40 are labelled. The distance along axis 50 from the upstream end of cavity 40 to intersection point 63 is X,, the distance along axis 50 from intersection point 63 to the downstream end of cavity 40 is X and the distance along axis 62 from the equals the radius of the cylinder and the sum of distances X and X is equal to the length of the cylinder.

The shock waves produced by generator 70 are coupled by connecting hose 71 to cavity 40 where they propagate along axis 50. The distance X is 2% times the principal wavelength, and the distance X is 1% times the principal wavelength; thus, the length of cavity 40 is 0.776 inches. Strip 51 reflects the vertex of the shock waves impinging upon it, thereby giving rise to resonant action due to the multiple relationship of distances X and X, to the wavelength of the shock waves. The portion of strip 51 closely surrounding axis 50 most effectively reflects the impinging shock waves, because it intercepts the protruding portion of the wavefront,'i.e., the vertex of the shock wave. Theoretically, the reflecting surface could be a circular piece of material centered as a target at the end of cavity 40. In practice a strip shaped reflecting surface is used to provide an easy to fabricate means for supporting the reflective surface at the end of cavity 40. The width of strip 50 is equal to a multiple or a submultiple of the principal wavelength, preferably one wavelength, i.e. 0.194 inches.

Holes 60 and 61 have a diameter equal to one-half of the principal wavelength, i.e., 0.097 inches, so the shock waves from cell 59 are coupled to cavity 40 by holes 60 and 61 without any appreciable attenuation. Thus, cell 59 has a virtual or apparent outlet at the side wall of cavity 40. The shock waves produced by cell 59 havea vertex that propagates along transverse axis 62 and collides with the vertex of the shock waves propagating along axis 50 at intersection point 63. Distance Y; is equal to the principal wavelength; thus, the radius of cavity 40 is 0.194 inches. The relationship of the distances X X X, X and Y to the shock wave wavelength further enhances the resonant action in cavity 40 in the manner described above in connection with FIG. 1, and increases the efficiency of the conversion to coherent sonic wave energy. As in the arrangement of FIG. 1, attention is given to the mass flow rate through cell 59 so the shock waves produced by cell 59 do not disrupt the propagation of shock waves along axis 50. If desired cell 59 could be balanced by an identical cell entering cavity 40 from a hole in its side wall opposite hole 61 and aligned with axis 62.

Cavities

54, 55, 56, and 57 intercept some of the energy reflected outwardly by strip 51. The sides of cavities 54 through 57 equal the principal wavelength. As a result, the intercepted energy is subjected to resonant action in cavities 54 through 57, which still further enhances the conversion to coherent sonic wave energy.

The coherent sonic wave energy produced in cavity 40 leaves through

chordal openings sections

52 and 53 and propagates along the interior of spacer 49 and fitting 45 to the point where it is utilized. Although the preferred dimensions of distances X X and Y relative to the principal wavelength are as stated above, the efficient conversion of shock waves to sonic waves can be realized with other dimensions. The basic rule to follow is that the principal dimensions i.e., distances X X and Y,, the wavelength, the sides of cavities 53 through 57, and the width of strip are all multiply related. As a result, the described types of resonant action occur within cavity 40. Under some circumstances some .of these dimensions are not significant. For example, in the embodiment disclosed in FIG. 2, fitting 44 and hose 71 have the same diameter as cavity 40. The entrance to cavity 40 merely appears as an extension'of hose 71 and fitting 44. Accordingly, distance X, of cavity 40 is not important. Distance X, only becomes significant when the shock wave generator is very close to its cavity, i.e., a distance of several wavelengths. An embodiment where X, is significant is described below in connection with FIG. 4.

The arrangement of FIG. 1 is a highly efficient shock wave generator; the arrangement of FIG. 2 is a highly efficient converter of coherent energy from shock waves to sonic waves. In the arrangement of FIG. 4, the components of FIGS. 1 and 2 are combined in a common housing having

tubular fittings

71 and 72. The components of FIGS. 1 and 2.bear the same reference numerals in FIG. 4. Cell 59 has been rotated 90 in FIG. 4 so it is disposed midway between cells 21 and 22, the latter of which is not visible in FIG. 4. The arrangement of FIG. 4 is a compact sonic wave generator capable of producing coherent sonic wave energy of high intensity.

The cells, housings, and spacers of FIGS. 1, 2, and 4 are functionally integral with each other. They are physically separate units only to facilitate fabrication and assembly. Therefore, different physical divisions of the arrangements of FIGS. 1, 2, and 4 could be made depending upon the particular mode of fabrication and assembly used.

In practice, resonance is not completely destroyed until the wavelength of the shock waves deviates by one quarter wavelength from its prescribed value relative to the dimensions of the cavities, i.e., from the multiple relationship. As a design guide, when the actual dimensional relationships between shock wave wavelength and cavities are met to within 2 10 percent of the prescribed values, the described results are in fact achieved. Beyond a i 10 percent deviation, the results drop off, but may still be usable.

FIG. schematically represents a conventional PCV system in' an internal combustion engine and a pressure wave generator constructed according to the invention functioning with the PCV system. The engine has an air cleaner 75, a carburetor 76 with a butterfly throttle valve 77, and an engine enclosed within a crankcase manifold 78. The combustible crankcase emissions produced in the course of the operation of the engine comprise blowby gases, i.e., incompletely combusted substances that escape from the combustion cylinders via the piston rings, and oil particles that become suspended in the air within the crankcase manifold. The PCV system returns these crankcase emissions to the intake system of the engine, at the base of the carburetor as shown or at the intake manifold, for recombustion in the engine. Clean air is coupled from cleaner by a connecting hose 80 to the crankcase manifold through an oil filler cap 81. This clean air, represented by arrows 82, mixes with and carries the blowby gases, represented by arrows 83, out of crankcase manifold 78 through a PCV valve 84 as represented by arrows 85. PCV valve 84 is coupled to the intake system by a connecting hose 86, which serves as the PCV or oil gallery return line. The described PCV system is conventional. The only modification that is desirable is to provide a spring having a smaller spring constant for PCV valve 84. This enables PCV valve 84 to operate normally, i.e., to close during idling and deceleration, de-' V spite. the smaller pressure drops that have been found to exist in'the presence of a pressure wave generator. To install a pressure wave generator 87, which is one of the devices disclosed in FIGS. 1 through 4, hose 86 is simply cut and the two ends formed by the cut are joined to the respective fittings of pressure wave generator 87.

As the mixture of combustible crankcase emissions and air passes through pressure wave generator 87, this mixture is energized, thereby becoming directly atomized. In addition, the pressure waves propagate into the intake system, as represented by the dots between pressure wave generator 87 and carburetor 76, and atomize indirectly the combustible mixture entering the intake manifold from the carburetor. This indirect atomization is particularly effective when pressure wave generator 87 is a sonic wave generator that produces coherent sonic wave energy. In such case, the coherent sonic waves propagate into the intake system in an orderly fashion to form a standing wave veil across the outlet of carburetor 76 through which the combustible mixture formed in the carburetor must pass before entering the intake manifold. The result is that the combustible mixture from the carburetor is finely atomized. Although a shock wave generator is also an effective pressure wave generator, it is not as efficient as acoherent sonic wave generator. The shock waves are reflected haphazardly from the first obstruction in their path and then dissipate. Thus, their range is substantially less than the range of coherent sonic waves. The arrangement of FIG. 7 is claimed in application Ser. No. 158,915, filed July 1, 1971.

The term fluid as used herein refers to gas and also refers to liquid to the extent applicable.

The described embodiments of the invention are only considered to be preferred and illustrative of the inventive concept; the scope of the invention is not to be restricted to such embodiments. Various and numerous other arrangements may be devised by one skilled in the art without departing from the spirit and scope of this invention as defined in the claims. For example, the disclosed pressure wave generators can be used in applications other than the PCV return line of an internal combustion engine; and the axes of the transversely arranged shock wave generating cells can be other than perpendicular; and cavities 54 through 57 can have unequal sides, i.e., they can be hexahedral.

Reference is made to my application Ser. No. 217,124, filed Jan. 12, 1972, which claims part of the subject matter disclosed herein.

What is claimed is:

l. A pressure wave generator comprising:

a first boundary layer formed shock wave generating cell having an outlet disposed about a longitudinal axis, the first cell producing at its outlet shock waves having a predetermined wavelength and a vertex that propagates along the longitudinal axis;

a second boundary layer formed shock wave generating cell having an outlet disposed about an axis transverse to and intersecting the longitudinal axis, the second cell producing at its outlet shock waves having a predetermined wavelength and a vertex that propagates along the transverse axis;

an enclosure forming a passage along the longitudinal axis, the outlets of the first and second cells being coupled to the passage so the shock waves produced by the first and second cells collide in the longitudinal passage at the point of intersection of the axes; the distance along the longitudinal axis between the outlet of the first cell and thepoint of intersection of the axes, along the transverse axis between the outlet of the second cell and the point of intersection of the axes, and the predetermined wavelengths of the shock wqves produced by the first and second cells all being multiples of a common divisor; and a reflective strip of material extending diametrically acrossthe passage in the path of the shock waves produced by the first cell, exits being formed by the spaces between the strip and the passage. 2. The pressure wave generator of claim 1, in which at least one hexahedral resonant cavity is formed in the enclosure in communication with the passage intersect- I ing the plane defined by the reflective strip, the sides of the cavity being multiples of the common divisor.

3. The pressure wave generator of claim 1, in which four cubicle resonant cavities are formed at 90 intervals around the enclsoure in communication with the longitudinal passage substantially in the plane defined by the reflective strip, the sides of the cavities being a multiple of the common divisor.

4. The pressure wave generator of claim 1, in which the longitudinal passage is cylindrical, the exit is a pair of semi-circular openings on either side of the strip, and the length and radius of the cylindrical passage are multiples of the common divisor.

5. The pressure wave generator of claim 4, in which the intensity of the shock waves produced by the first cell is higher than the shock waves produced by the second cell.

6. The pressure wave generator of claim 5, in which the predetermined wavelength of the shock waves produced by the first cell is a larger multiple than the predetermined wavelength of the shock waves produced by the second cell.

7. The pressure wave generator of claim 1, in which the enclosure comprises a'housing that surrounds the first cell and a spacer in the housing between the first cell and the reflective strip, the passage comprises a hole through the spacer, the second cell is fixed to the side of the housing, and the housing and the spacer have through them aligned radial holes that form the outlet of the second cell.

8. The pressure wave generator of claim 7, in which the mass flow rate through the second cell is more limited than the mass flow rate through the first cell.

9. A pressure wave generator comprising: a resonant cavity having a pair of spaced ends, a cylindrical side wall interconnecting the ends, and a longitudinal axis extending between the ends;

first means for introducing into the cavity atone of the ends shock waves having a vertex that propagates along the longitudinal axis and having a pre determined wavelength;

second means for introducing into the cavity at the side wall shock waves having a vertex that propagates along an axis transverse to and intersecting the longitudinal axis and having a predetermined wavelength, the distance between the point of introduction at the side wall and the longitudinal axis, the distance between the transverse axis and the other end of the cavity, and the predetermined wavelengths being multiples of the common divisor;

a reflective strip diametrically disposed at the other end of the cavity; and

an exit from the cavity at the other end for shock waves that collide at the point of intersection of the axes, the exit being formed between the strip and the adjacent portions of the side wall.

10. The pressure wave generator of claim 9, in which the distance between the ends is a multiple of the common divisor.

11. The pressure wave generator of claim 9, in which the shock waves introduced at the one end have a higher momentum than the shock waves introduced at the side wall.

12. The pressure wave generator of claim 9, in which the width of the strip is a multiple of the common divisor.

13. The pressure wave generator of claim 9, in which a plurality of hexahedral auxiliary cavities are formed in the side wall at the other end, the sides of the auxiliary cavities being multiples of the common divisor.

14. The pressure wave generator of claim 13, in which the resonant cavity comprises a plurality of adjacent annular spacers and a housing surrounding the spacers, the spacers defining the side wall of the cavity; the second means for introducing shock waves into the cavity comprises a boundary layer formed shock wave generating cell fixed to the side of the housing, the.

housing and the spacer adjacent to the cell having through them aligned radial holes to couple the cell to the cavity, the reflective strip is fixed to one of the spacers at one end, and .the auxiliary cavities are formed in another spacer at one end adjacent to the strip to intercept energy reflected from the strip.

15. A pressure wave generator comprising:

an enclosure having spaced ends and a longitudinal cylindrical side wall extending between the ends about an axis; means for introducing into the enclosure at one end pressure waves having a vertex that propagates along the longitudinal axis and having a predetermined wavelength, the predetermined wavelength and the distance between the ends being multiples of a common divisor to promote resonant action in the enclosure; a reflective strip diametrically disposed at the other end; and

arcuate exits from the enclosure formed at the other end by 'the strip and the adjacent portions of the side wall to permit pressure wave energy to leave the enclosure at the other end.

16. The pressure wave generator of claim 15, in which the width of the strip is a multiple of the common divisor.

17. The pressure wave generator of claim 16, in which a plurality of hexahedral cavities are formed at the other end in communication with the energy reflected from the strip, the sides of the cavities being multiples of the common divisor.

Claims

1. A pressure wave generator comprising: a first boundary layer formed shock wave generating cell having an outlet disposed about a longitudinal axis, the first cell producing at its outlet shock waves having a predetermined wavelength and a vertex that propagates along the longitudinal axis; a second boundary layer formed shock wave generating cell having an outlet disposed about an axis transverse to and intersecting the longitudinal axis, the second cell producing at its outlet shock waves having a predetermined wavelength and a vertex that propagates along the transverse axis; an enclosure forming a passage along the longitudinal axis, the outlets of the first and second cells being coupled to the passage so the shock waves produced by the first and second cells collide in the longitudinal passage at the point of intersection of the axes; the distance along the longitudinal axis between the outlet of the first cell and the point of intersection of the axes, along the transverse axis between the outlet of the second cell and the point of intersection of the axes, and the predetermined wavelengths of the shock wqves produced by the first and second cells all being multiples of a common divisor; and a reflective strip of material extending diametrically across the passage in the path of the shock waves produced by the first cell, exits being formed by the spaces between the strip and the passage.

2. The pressure wave generator of claim 1, in which at least one hexahedral resonant cavity is formed in the enclosure in communication with the passage intersecting the plane defined by the reflective strip, the sides of the cavity being multiples of the common divisor.

3. The pressure wave generator of claim 1, in which four cubicle resonant cavities are formed at 90* intervals around the enclsoure in communication with the longitudinal passage substantially in the plane defined by the reflective strip, the sides of the cavities being a multiple of the common divisor.

7. The pressure wave generator of claim 1, in which the enclosure comprises a housing that surrounds the first cell and a spacer in the housing between the first cell and the reflective strip, the passage comprises a hole through the spacer, the second cell is fixed to the side of the hoUsing, and the housing and the spacer have through them aligned radial holes that form the outlet of the second cell.

9. A pressure wave generator comprising: a resonant cavity having a pair of spaced ends, a cylindrical side wall interconnecting the ends, and a longitudinal axis extending between the ends; first means for introducing into the cavity at one of the ends shock waves having a vertex that propagates along the longitudinal axis and having a predetermined wavelength; second means for introducing into the cavity at the side wall shock waves having a vertex that propagates along an axis transverse to and intersecting the longitudinal axis and having a predetermined wavelength, the distance between the point of introduction at the side wall and the longitudinal axis, the distance between the transverse axis and the other end of the cavity, and the predetermined wavelengths being multiples of the common divisor; a reflective strip diametrically disposed at the other end of the cavity; and an exit from the cavity at the other end for shock waves that collide at the point of intersection of the axes, the exit being formed between the strip and the adjacent portions of the side wall.

14. The pressure wave generator of claim 13, in which the resonant cavity comprises a plurality of adjacent annular spacers and a housing surrounding the spacers, the spacers defining the side wall of the cavity; the second means for introducing shock waves into the cavity comprises a boundary layer formed shock wave generating cell fixed to the side of the housing, the housing and the spacer adjacent to the cell having through them aligned radial holes to couple the cell to the cavity, the reflective strip is fixed to one of the spacers at one end, and the auxiliary cavities are formed in another spacer at one end adjacent to the strip to intercept energy reflected from the strip.

15. A pressure wave generator comprising: an enclosure having spaced ends and a longitudinal cylindrical side wall extending between the ends about an axis; means for introducing into the enclosure at one end pressure waves having a vertex that propagates along the longitudinal axis and having a predetermined wavelength, the predetermined wavelength and the distance between the ends being multiples of a common divisor to promote resonant action in the enclosure; a reflective strip diametrically disposed at the other end; and arcuate exits from the enclosure formed at the other end by the strip and the adjacent portions of the side wall to permit pressure wave energy to leave the enclosure at the other end.