CA2312425A1

CA2312425A1 - Device for increasing the power of media flowing along a body at a high speed or a very fast moving body in a medium and use thereof as a high pressure nozzle

Info

Publication number: CA2312425A1
Application number: CA002312425A
Authority: CA
Inventors: Charles Loegel
Original assignee: Individual
Current assignee: MORTIZ HELMUT
Priority date: 1998-05-13
Filing date: 1999-02-23
Publication date: 1999-11-18
Also published as: KR20010032484A; AU3253899A; ATE239553T1; JP2002514500A; DE19821449A1; DE59905470D1; WO1999058250A1; AU745411B2; EP1079935B1; EP1079935A1

Abstract

In order to increase the power of fast flowing media, the wall surface (2) of a solid body (1) along which the medium flows, is provided with a plurality of recesses (3; F1, F2, F3) that extend by at least one length (1) in the direction of flow (SR) at a depth (t) that is substantially lower than the length thereof (1). At least parts of the recesses (3) have a depth (t) that diminishes in the direction of flow (SR) along said wall surface and the recesses form at least one interruption in the wall surface (2) in the direction of flow. The device can be used to particularly advantageous effect in high pressure nozzles in order to produce a high pressure liquid jet in pipelines, suction tubes for carburettors, exhaust gas tubes and in projectiles such as rockets which can move very quickly through a medium.

Description

DEVICE FOR INCREASING THE POi~IER OF MEDIA FLOWING ALONG
A BODY AT A HIGH SPEED OR A VERY FAST MOVING BODY IN A MEDIUM
AND USE THEREOF AS A HIGH PRESSURE NOZZLE
The invention relates to a device for increasing the power of media f lowing fast along the wall surfaces of a body or, con-versely, bodies moving very fast in a medium as well as uses of the device.
Such devices have already been known for high pressure nozzles in order to produce a high pressure liquid jet (US 1,703,029, EP-A-0 121 951 and DE-A-3 443 263). It is often desirable not to spread the so-called "jet angle" of the medium jet exiting from the nozzle too far, but to keep it as narrow as possible.
In narrow high pressure jets, the energy content per surface unit of the jet area is, as a rule, higher than in a very far spread or, respectively, an atomizing jet. The efficiency of the fast flowing gas or liquid is improved by channels extend-ing axially along the nozzle opening in the lateral area or, respectively, the inner wall surface of the nozzle bore.
It is the object underlying the invention to further improve the power or, respectively, efficiency. It is not only the im-provement of the "energetic" efficiency of the jet impinging on an object which is considered, but other efficiencies of media flowing fast in tubes and hoses, for instance, or of bodies moving very fast in media are to be improved as well; this makes it possible to improve the energy expenditure for the transport of the flowing medium or a rocket, for instance, or to increase the velocity thereof, respectively.
The invention is characterised in claims 1 and 14; further con-figurations are claimed in the subclaims. Preferred conf igura-tions of the invention are explained in detail upon reference to the following specification and the drawings.
The invention makes it possible to improve the power of the me-dium flowing along the wall surface at high speed or the effi-ciency of a body moving very fast through a medium in a sur-prising manner: although the wall surface in the direction of flow is not smooth, but definitely uneven (since recesses are disposed therein), the power is improved.
According to the general principle of the present invention, at least one wall surface of a solid body, laterally limiting the fast flowing medium and guiding it in a specific direction, is provided with a plurality of recesses extending at least over a length or, respectively, distance in the direction of flow, whose depth is substantially smaller than their length. The depth of the recesses is preferably 0.01 to 2 mm, more particu-larly 0.1 - 0.8 mm. Such recesses are preferably formed as groove-shaped recesses in the manner of axial grooves which do, however, not extend over the whole length of the wall surface in the direction of flow, but whose length is substantially smaller than the length of the respective wall surface so that several such recesses are spaced apart from each other "one be-hind the other". The depth of part of the recesses, at least, diminishes in the direction of flow. The recesses may lead to a retaining site in the flow channel or may form certain "retaining sites" themselves so that the flow resistance of the medium changes in the direction of flow and, more particularly, alternates several times between different values.
If the wall surface of the solid body is formed as the inner lateral area of a tube, it is recommended to form the recesses into the lateral tube area such that they constitute marked guiding edges substantially in the direction of flow and are distributed as uniformly as possible over the periphery of the flow channel. It has been shown that at least four, better five or six such axial grooves should be disposed in the flow chan-nel for high pressure water jet nozzles having a small passage - cross-section whereas even more, e.g. twelve axial grooves should be provided for f ire extinguishing lances having higher passage cross-sections.
It has been shown that the sum of the surface portions on the respective wall surface, Which are constituted by recesses, should be higher than 1 in proportion to the sum of the wall surface portions which do not correspond to recesses. The pro-portion of the surfaces associated with the recesses is pref-erably 0.7, more particularly 0.8 and 0.9 with respect to the overall surface, whereby the "roughness" of the wall surface becomes very strong.
Moreover, it is recommended to make the flow area of the flow channel diminish in the direction of flow so that there results an opening angle a between 1° and 13°, more particularly be-tween 2.8° and 3.8° against the direction of flow of the me-dium.
A substantially greater improvement may be achieved if an addi-tional abrupt flow resistance is generated at the end of the flow channel by a small retaining or impact shoulder before the medium flowing from said flow channel enters a passage opening, having a substantially smaller cross-section, of a nozzle in-sert of a hard material, in particular, through which the jet then exits from the nozzle.
An arrangement of the axial grooves having a star-shaped cross-section leads to favourable results.
Thus, it has been shown that the power of a narrow high pres-sure water jet produced according to the invention could be im-proved, completely surprisingly, by approximately 350 % over a water jet produced with conventional high pressure nozzles at the same water pressure of 1200 bar. For instance, if a slot is provided in rock formations with a conventional high pressure nozzle having a cylindrical inner cross-section of the flow channel under the above-mentioned pressure and with a flow rate of 10 1/min water, a "cutting power" of 2 m2/h is achieved at a specific slot depth. If this known nozzle is replaced with a nozzle formed according to the invention, there not only re-sults a higher flow rate between 11 and 11.5 1/min water at the same pressure, but also a cutting power of 7 m2/h is achieved for the same rock and under the otherwise same conditions. In comparison with the conveying rate of 2 m2/h in the case men-tioned first, this means a multiplication by 3.5.
However, the invention may also be applied to other ffields, e.g. for pipeline tubes and turbines whose inner jacket is pro-vided, around the periphery, with such flat recesses extending in the axial direction and being spaced apart from each other in said direction. The invention is also applicable to turbine blades and guide blades of other turbo-machines.
There also result considerable improvements when the inner sur-faces of suction tubes and manifolds of car or other carburet-tors are provided with corresponding recesses which are not too deep. The invention is also applicable to exhaust gas tubes and exhaust elbows so that there surprisingly result improvements of several percent in view of reduced fuel consumption with better output power in the field of internal combustion engines of motor vehicles, in particular. This result is completely surprising since one had hitherto considered that the wall and baffle surfaces exposed to the flowing medium should be config-ured to be as even as possible.
The reason for the surprising results has not been analysed sufficiently yet in theory nor science. It is assumed that there occur boundary layer effects, i.e. that the invention in-fluences the boundary layer between the flowing medium in the region near the lateral area, on the one hand, and in regions more remote from the lateral area on the other hand such that there occurs a more efficient distribution between the laminar and turbulent flows and that less energy is withdrawn from the medium flowing along the lateral area or, respectively, the baffle and flow surface although one had to assume prima facie that such "interruptions" of the wall surfaces or, respec-- tively, the lateral areas achieve the opposite. Surprisingly, less kinetic energy, for instance, is withdrawn from the flow-ing medium in the invention. It is assumed that the so-called transition line may be displaced far downstream by the inven-tion, which helps in promoting the discontinuity surface in po-tential flows. Turbulent effects are reduced.
It is correspondingly recommended to use the invention for flow surfaces of aircraft and, above all, very fast flying missiles like rockets wherein the medium surrounding these bodies cer-tainly need not flow fast itself, but may stand still. However, since the fast moving body has a high velocity, there also re-sults a corresponding effect at the boundary layer between the medium liquid or gas, on the one hand, and the body on the other hand.
Embodiments of the invention will be explained in detail upon reference to the drawing; therein:
Fig. 1 is a schematic part-longitudinal section through a high pressure water jet nozzle in the longitudinal direction and fig. la shows part of a cross-section through the nozzle in respectively enlarged representation;
Fig. 2 is a schematic aspect of an inner lateral tube area serving as a wall surface and comprising a system of lozenge-like flat recesses in the wall surface;
Fig. 3 is a longitudinal section through a high pressure noz-zle;
Fig. 4 is a cross-section according to A-A of fig. 3 and ' 6 Fig. 4a is an enlarged part-section thereof;
Fig. 5 is an enlarged detail of the transition between an at-tachment bushing and a following hard material insert of the HP nozzle under flow conditions;
Fig. 6 is another cross-section of the flow channel of the at-tachment bushing;
Fig. 7 is a schematic cross-section through a pipeline tube and a partial aspect of its inner lateral area; and Fig. 8 is a schematic cross-sectional drawing of an aircraft wing.
Fig. 1 shows the longitudinal section through a part of a solid body 1 configured as a nozzle tube, which may consist of hard steel, for instance. The inner lateral area of tube 1 having the diameter D constitutes the wall surface 2 for the medium, e.g. water, flowing very fast through the tube cross-section.
In contrast to the conventional configuration of the wall sur-face 2 which is smooth or merely interrupted by axial longitu-dinal grooves, the wall surface 2 according to the invention is interrupted by numerous recesses 3 spaced one behind the other in the direction of flow (SR), which have, in this example, an approximately lens-shaped cross-section and extend into the ma-terial of tube 2 with a maximum depth t = 0.3 mm, namely not over the whole axial length of tube 1, but merely over a length being about five to fifty times the depth t. According to fig.
la, these recesses 3 may be configured in the form of a notch having an approximately triangular cross-section with a notch angle ~3 of between 80 and 100°, in particular. The base or, re-spectively, the bottom of notch-like recesses 3 extends, as bottom line 4, substantially in the axial direction or, respec-tively, the flow direction SR of tube 1 and adopts, in the lon-gitudinal section, the lens-shaped form shown in fig. 1, whereby respectively part of the respective recess comprises a depth t diminishing in the direction of flow SR along wall sur-face 2. Therefore such recesses 3 are disposed to be spaced apart in the direction of flow on wall surface 2, one behind the other. Also, such recesses 3 are distributed over the pe-riphery of the inner lateral area or, respectively, wall sur-' face 2; these recesses are indicated merely symbolically in fig. 1 by recess lines 3' .
According to fig. 2, the inner lateral tube area 2 is consti-tuted by a net-like system of webs 2' which, in an aspect seen from the tube interior, keep lozenge-like recesses 3 spaced apart from each other, which in their turn comprise bottom lines 4 substantially extending in the direction of flow SR;
these bottom lines 4 respectively connect those lozenge corners of each lozenge which are spaced farthest apart. In this con-figuration of the invention, the greater part of the wall sur-faces is occupied by recesses 3 Whereas the sum of webs 2*, which constitute the actual wall surface 2, is substantially smaller in comparison. Since very narrow webs 2' are used, the sum of the recesses 3 projected onto the wall surfaces becomes substantially larger, with about 80 to 95 % of the overall in-ner lateral tube area, than the remaining wall surface 2 con-stituted by webs 2'.
According to fig. 3, high pressure water nozzle D comprises a screw insert 10 made of INOX, i.e. stainless steel, for in-stance, into which an annular insert 5 of a hard material like sapphire, in particular, is glued, whose passage opening 6 com-prises a diameter d of about 1 mm. In the direction of flow, an attachment bushing 7 is disposed before insert 5, which is to be considered a body 1 whose wall surface 2 diverts the flow of the liquid, water in the present case, led through it under high pressure. The diameter D of flow channel 8 is substan-tially larger, i.e. 1.5 mm, than diameter d in the region of the transition towards the cylindrical passage opening 6 of in-sert 5 so that a retaining or, respectively, impact shoulder 9 is formed at that transition, which prima facie further in-creases the flow resistance.

Furthermore, flow channel 8 comprises an opening angle a against the direction of f low SR. This opening angle should be between 2 and 13°; an especially preferred opening angle is 3-4°.
_ Moreover, the flow channel 8 is configured to have a hexagonal cross-section according to fig. 4, meaning that it comprises six axial grooves (Fl, F2, F3 ...) having relative sharp guide edges 4 which extend in the axial direction or, respectively, the direction of flow SR. According to the length 1 of flow channel 8, the depth t of these axial grooves is about 0.1 to 0.8 mm at the entrance end of flow channel 8 so that the above-mentioned opening angle is respected, and diminishes to zero towards retaining shoulder 9 at insert 5.
Fig. 4a represents a schematic cross-section of the upper half of attachment bushing 7 shown in fig. 4 in order to illustrate that axial grooves F1, F2 etc. are formed due to the hexagonal cross-sectional structure of the inner lateral areas, which are generated in the region of recesses 3 between the even portions of the inner lateral tube area and the imaginary semicircle which would be generated in the known cylindrical or, respec-tively, conical cross-sections of the flow channel 8 of such attachment bushings 7. This semicircle does not exist in the invention because recesses 3 are pressed or milled into body 1 of bushing 7 or carved out therefrom in any other manner.
Therefore the depth t of recesses 3 is measured from this semi-circle to the "groove base" which is constituted by edge 4 of the respective notch-shaped axial groove F1, F2, which extends in the longitudinal direction. The surfaces of axial grooves F1, F2, F3 preferably also comprise recesses 3 of the type shown in fig. 1 or 2, which is not shown in fig. 3, but indi-cated in fig. 4a.
Fig. 5 indicates the expected course of the flow pattern of the flowing medium which leaves the nozzle or, respectively, insert 4 as a jet S. It is assumed that a thin "boundary layer" is disposed about the "core" of jet S, which opposes a certain re-sistance to the widening of the "core" transversely with re-spect to the jet direction SR and thereby "holds" the energy of the liquid jet "together" in a small region with the above-mentioned effect of an improved efficiency and higher kinetic energy density.
According to fig. 6, the cross-section of flow channel 8 is not hexagonal, but star-shaped. The axial grooves or, respectively, recesses 3 have an approximately triangular cross-section; they protrude from the approximately conical clearance zone of flow channel 8 into the material of body 1, i.e. attachment bushing 7.
The cross-section of flow channel 8 selected according to the invention is for instance produced in that a polygonal tool is pressed or, respectively, driven into a bushing or sleeve 7 having a conical flow cross-section so far that there result the cross-sectional shapes of figs. 4 to 6 with the recesses 3 or, respectively, axial grooves F1, F2, F3 formed thereby.
Pocket-like recesses 3, which extend in a planar manner over a length 1 far in the axial direction or, respectively, flow di-rection SR of the tubular body 1 of fig. 7, constitute concave recesses, for instance, whose width b should be less than the length 1, but noticeably larger than their depth t.
Fig. 8 indicates that it is expedient to dispose the above-mentioned recesses 3 at least on that wall surface 2 of the body 1 serving as an aircraft wing where the air flow is di-verted in the direction of flow SR. Surprisingly, the flow about wall surface 2 on the respective part of the upper side of the wing is promoted such that, on the whole, a more effi-cient flow about the wing may be achieved in order to obtain a low-separation and, therefore, also a more eddy-free course of the air flow as it flows about the profile. The optimum depth, position, dimension and number of recesses may be determined by some tests in dependence upon the shape of the wing profile and 1~
the velocity at which the aircraft flies or, respectively, at which the air flowing about the wing moves.

Claims

1. A device for increasing the power of media flowing along the wall surfaces (2) of a solid body (1) and, more particularly, media being under high pressure and/or solid bodies (1) moving very fast in a medium, wherein at least one wall surface (2) of the a solid body (1) limits the relative flow (S) between the medium and the solid body (1) on at least one side and guides it in a specific direction, while forming a certain flow resistance, and wherein the wall surface (2) comprises a plurality of recesses (3) extending at least over a length (1) in the direction of flow (SR), whose depth (t) is substantially smaller than their length (1) characterised in that part at least of the recesses have a depth (t) diminishing in the direction of flow along the wall surface (2) and that the recesses (3) form at least one interruption of the wall surface in the direction of flow (SR).

2. A device according to claim 1, characterised in that the length (1) of the recesses (3) in the direction of flow (SR) along the wall surface (2) is substantially smaller than the overall length of the respective wall surface (2) limiting the flow.

3. A device acording to claim 1 or 2, characterised in that the body (1) is formed as a tube and the recesses (3) are formed as notches in the inner lateral tube area constituting the wall surface (2).

4. A device according to any of the preceding claims, characterised in that the recesses (3) comprise guiding edges (4) extending in the direction of flow (SR).

5. A device according to claim 4, characterised in that the recesses (3) are disposed in a star shape in the cross-section of the tube.

6. A device according to any of claims 1 to 5, characterised in that the depth (t) of the recesses is between 0.01 and 2 mm.

7. A device according to claim 6, characterised in that the depth (t) of the recesses is between 0.1 and 0.8 mm.

8. A device according to any of the preceding claims, characterised in that the opening angle (.alpha.) of a wall surface (2) conically tapered in the direction of flow (SR) is between 2.8 and 3.8°.

9. A device according to any of the preceding claims, characterised in that the sum (F a) of the surface proportions occupied by recesses (3) is larger than the sum of surface proportions not occupied by recesses (3) on the wall surfaces (3).

10. A device according to claim 9, characterised in that the sum ratio between the sum (F a) of the surface proportions occupied by recesses (3) and the sum (F b) of surface proportions not occupied by recesses (3) on the wall surfaces is higher than 0.7.

11. A device according to claim 10, characterised in that the sum ratio is between 0.8 and 0.95 and the recesses (3) on the wall surface (2) are substantially separated by small webs (2*) only.

12. A device according to any of the preceding claims, characterised in that the wall surface (2) is interrupted by a system of recesses (3) being offset with respect to each other and being lozenge-shaped in the surface layout on the wall surface (2).

13. A device according to any of the preceding claims, characterised in that the recesses (3) are formed to have a triangular cross-section with a notch angle (.beta.) between 80 and 100°.

14. A high pressure nozzle for producing a high pressure liquid jet (S) having an insert (5) of a hard material, in particular, whose passage opening (6) determines the jet of the exiting liquid, and an attachment sleeve or bushing (7) through the flow channel (8) of which the liquid being under high pressure may be supplied to the passage opening (6) of the insert (5), wherein the flow channel (8) comprises an average cross-section diminishing in the direction of flow (SR) with an opening angle (a) against the direction of flow (SR), characterised in that the flow channel (8) comprises axial grooves (F1, F2, F3) in the inner lateral area (2) which extend in the direction of flow (SR) and terminate at an interruption of the wall surface (2) in the direction of flow, in the form of a retaining shoulder (9) of the insert (5), and whose depth (t) diminishes in the direction of flow (SR).

15. A nozzle according to claim 14, characterised in that the opening angle (.alpha.) of the flow channel (8) of the attachment bushing (7) is between 2 and 4°.

16. A nozzle according to claim 14 or 15, characterised in that, in order to form the retaining shoulder (8), the diameter (d) of the passage opening (6) of the insert (5) is substantially smaller than the average cross-section (D) of the flow channel (8) at the transition to the insert (5).

17. Use of the device according to any of claims 1 to 13 for pipeline tubes.

18. Use of the device according to any of claims 1 to 13 for carburettors for internal combustion engines in the suction pipe or suction manifold.

19. Use of the device according to any of claims 1 to 13 for internal combustion engines in the exhaust gas tube or in exhaust manifolds.

20. Use of the device according to any of claims 1 to 13 for aircraft, on flow surfaces thereof, or for missiles like rockets.

21. Use of the device according to any of claims 1 to 13 for turbines.