Device for generating fluid pulses

Abstract

A method for generating fluid pulses is provided. The device comprises a first channel with a first fluid inlet and a second channel with a second fluid inlet, in which the first fluid inlet and second fluid inlet are substantially situated opposite each other. The first channel comprises a first control outlet at the height of the first fluid inlet, and the second channel comprises a second control outlet at the height of the second fluid inlet, in which the respective control outlet is located in front of the respective fluid inlet in relation to the inflowing direction of the fluid inlet.

Claims

1. A device for generating fluid pulses, comprising: a first channel with a first fluid inlet, a first working outlet, a second working outlet, and a first control outlet, the first control outlet located in front of the first fluid inlet in relation to an inflowing direction of fluid to the first fluid inlet, the first channel including at least one working outlet through which a portion of the inflowing fluid is removable; and a second channel with a second fluid inlet and a second control outlet, the second fluid inlet substantially situated opposite the first fluid inlet and the second control outlet located in front of the second fluid inlet in relation to an inflowing direction of fluid to the second fluid inlet, wherein, during operation, a fluid flowing in through the first fluid inlet passes through the first channel, and after running through the first channel, at least a portion of the introduced fluid exits the first channel through the first control outlet, thereby causing the inflowing fluid to be diverted toward the second fluid inlet, and a fluid flowing in through the second fluid inlet passes through the second channel, and after running through the second channel, at least a portion of the introduced fluid exits the second channel through the second control outlet, thereby causing the inflowing fluid to be diverted toward the first fluid inlet, wherein, in the fluid direction subsequent to the last working outlet of the first channel, the remaining portion of the introduced fluid exits the first channel through the first control outlet, wherein the cross sectional surface of the first channel is abruptly reduced between the first working outlet and the second working outlet and subsequent to the first working outlet, and wherein the first channel expands subsequent to the abrupt reduction and ahead of the second working outlet between the abrupt reduction and the second working outlet.

2. The device according to claim 1, wherein the first and second working outlets branch away from the first channel at an angle to a primary channel direction or substantially perpendicular to the primary channel direction.

3. The device according to claim 1, wherein the first and second working outlets comprise different cross sectional surfaces.

4. The device according to claim 1, wherein the second channel is structured symmetrically to the first channel.

5. The device according to claim 1, wherein the second channel is structured asymmetrically relative to the first channel.

6. The device according to claim 5, wherein the cross sectional surface of the second channel differs from the cross sectional surface of the first channel.

7. The device according to claim 5, wherein the time it takes to pass through the first channel differs from the time it takes to pass through the second channel given an identical fluid supply.

8. The device according to claim 1, wherein the device is a control stage of a fluid actuator for influencing a fluid flow along a flow surface.

9. The device according to claim 1, wherein the device directly influences a fluid flow along a flow surface.

10. The device according to claim 1, wherein the device provides a pulsed liquid jet.

11. The device according to claim 1, wherein the device provides a pulsed fluid stream comprising a fuel or a fuel-air mixture for subsequently burning the pulsed fluid stream.

12. The device according to claim 1, wherein the device provides a pulsed fluid stream for cooling turbine blades or combustion chamber walls.

13. The device according to claim 1, wherein the first channel and the second channel comprise a different capacity for fluid flow.

14. The device according to claim 2, wherein the primary channel direction is not a straight line.

15. A device for generating fluid pulses, comprising: a first channel with a first fluid inlet and a first control outlet, the first control outlet located in front of the first fluid inlet in relation to an inflowing, direction of fluid to the first fluid inlet, the first channel including at least one working outlet through which a portion of the inflowing fluid is removable; and a second channel with a second fluid inlet and a second control outlet, the second fluid inlet substantially situated opposite the first fluid inlet and the second control outlet located in front of the second fluid inlet in relation to an inflowing direction of fluid to the second fluid inlet, wherein, during operation, a fluid flowing in through the first fluid inlet passes through the first channel, and after running through the first channel, at least a portion of the introduced fluid exits the first channel through the first control outlet, thereby causing the inflowing fluid to be diverted toward the second fluid inlet, and a fluid flowing in through the second fluid inlet passes through the second channel, and after running through the second channel, at least a portion of the introduced fluid exits the second channel through the second control outlet, thereby causing the inflowing fluid to be diverted toward the first fluid inlet, wherein, in the fluid direction subsequent to the last working outlet of the first channel, the remaining portion of the introduced fluid exits the first channel through the first control outlet, and wherein the at least one working outlet further comprises at least two working outlets, wherein each of the at least two working outlets comprise different cross sectional surfaces.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The various embodiments will hereinafter be described in conjunction with the following drawing figures, wherein like numerals denote like elements, and wherein:

(2) FIG. 1 is a first schematic arrangement according to an exemplary embodiment of the present disclosure;

(3) FIG. 2 is a schematically represented detail of various embodiments of the present disclosure; and

(4) FIG. 3 is a second schematic arrangement according to another exemplary embodiment of the present disclosure.

DETAILED DESCRIPTION

(5) The following detailed description is merely exemplary in nature and is not intended to limit the present disclosure or the application and uses of the present disclosure. Furthermore, there is no intention to be bound by any theory presented in the preceding background or the following detailed description.

(6) FIG. 1 shows a first schematic arrangement according to one of various exemplary embodiments of the present disclosure.

(7) A device for generating fluid pulses comprises a first channel C.sub.1 with a first fluid inlet R.sub.1 and a second channel C.sub.2 with a second fluid inlet R.sub.2. The first fluid inlet and second fluid inlet are substantially situated opposite each other. The first channel C.sub.1 has a first control outlet CP.sub.1 at the height of the first fluid inlet R.sub.1, and the second channel C.sub.2 has a second control outlet CP.sub.2 at the height of the second fluid inlet R.sub.2, wherein the respective control outlet CP.sub.1, CP.sub.2 is located in front of the respective fluid inlet in relation to the inflowing direction of the fluid inlet. During operation, a fluid flowing in through the first fluid inlet R.sub.1 passes through the first channel C.sub.1, and after running through the first channel C.sub.1, at least a portion of the introduced fluid exits the first channel C.sub.1 through the first control outlet CP.sub.1, thereby causing the inflowing fluid to be diverted toward the second fluid inlet R.sub.2, or a fluid flowing in through the second fluid inlet R.sub.2 passes through the second channel C.sub.2, and after running through the second channel C.sub.2, at least a portion of the introduced fluid exits the second channel C.sub.2 through the second control outlet CP.sub.2, thereby causing the inflowing fluid to be diverted toward the first fluid inlet R.sub.1. The first channel C.sub.1 has a working outlet WP.sub.1 or several working outlets WP.sub.1, WP.sub.2, . . . , WP.sub.n1, WP.sub.n, through which a portion of the inflowing fluid may be removed. The number of working outlets is assumed to be n on FIG. 1, wherein n stands for a natural number. Subsequent to the last working outlet of the first channel C.sub.1, the remaining portion of the introduced fluid exits the first channel C.sub.1 through the first control outlet CP.sub.1. In other words, the fluid does not escape, but is rather completely available for control purposes or passage through the second channel.

(8) Without delving into the above any further for now, the second channel C.sub.2 may have the same shape as channel C.sub.1, or channel C.sub.2 may have a design differing from channel C.sub.1. For example, channel C.sub.2 may have a differently configured length L.sub.1, L.sub.2 and/or cross sections for the channels, and a varying number of working outlets may additionally or alternatively be involved. For example, channel C.sub.1 may comprise a plurality of working outlets, while channel C.sub.2 has only one or even no working outlets.

(9) The sequence will be briefly outlined below, wherein individual locations on FIGS. 1 and 3 are numbered in chronological sequence, and circled in the drawings for delineation from device features.

(10) When a fluid flows in during operation, the fluid stream gravitates toward one of the two sides for reasons of no greater interest, and consequently flows into one of the fluid inlets. This is the case at fluid inlet R.sub.1 on FIG. 1, and the location is correspondingly marked 1. Subsequent thereto, the fluid stream passes location 2. Situated at location 2 is an exemplary first working outlet WP.sub.1, from which a certain portion of fluid is now removed. As depicted at locations 3 and 4, one or more additional optional working outlets WP.sub.+1 and WP.sub.n may then follow. A respective portion of fluid may be removed at these additional optional working outlets as before. Arranging various working outlets spatially close to each other may ensure that fluid exits the respective working outlet in a nearly synchronous manner, i.e., that only a slight phase shift arises. The still present fluid then continues flowing through the remainder of the channel (location 5) and is routed to the control outlet CP.sub.1. In other words, the fluid does not escape, but rather is completely available for control purposes or passage through the second channel, depending on the degree of modulation. Given a 100% degree of modulation, i.e., the inflowing fluid is completely diverted into the second fluid inlet R.sub.2, fluid no longer enters into the first fluid inlet R.sub.1 previously receiving the inflow. By contrast, given less than a 100% degree of modulation, at least a small portion of the inflowing fluid continues to flow into the previous first fluid inlet R.sub.1. The still present fluid exits channel C.sub.1 at location 6, and now diverts the fluid still flowing toward fluid inlet R.sub.1 to fluid inlet R.sub.2 of channel C.sub.2 (location 7). The fluid then passes through channel C.sub.2, and at least a portion of the fluid is routed toward the control outlet CP.sub.2. It also holds true here that all fluid remaining after removal through a possibly present working outlet or several possibly present working outlets of the second channel C.sub.2 is available for control purposes in the same way as described for channel C.sub.1. At location 8, the still present fluid exits channel C.sub.2, and now diverts the fluid still flowing toward fluid inlet R.sub.2 back to fluid inlet R.sub.1 of channel C.sub.1 (location 1). This concludes the cycle, which then begins anew. The length of the line between the last working outlet and ensuing control outlet is critically important in determining the switching frequency of the actuator.

(11) The first control outlet CP.sub.1 is generally arranged in such a way that a fluid flowing out of the first control outlet CP.sub.1 substantially flows into the second fluid inlet R.sub.2 (location 6), and that the second control outlet CP.sub.2 is arranged in such a way that a fluid flowing out of the second control outlet CP.sub.2 substantially flows into the first fluid inlet R.sub.1 (location 8). This increases efficiency, and also enables reliable switching even given a high restrictive effect.

(12) FIG. 2 depicts a schematically represented detail of various embodiments of the present disclosure. This detail corresponds to the frame denoted with dashed lines on FIGS. 1 and 3.

(13) As depicted, the cross sectional surface of the first channel C.sub.1 is abruptly reduced subsequent to a working outlet WP.sub.n+1, W.sub.Pn. For example, the cross section Q.sub.2 is smaller before the working outlet WP.sub.n than the cross section Q.sub.3 after the working outlet WP.sub.n. Due to the abrupt reduction, the resultant damming effect in the feed lines to the fluid outputs may make fluid with an overall pressure exceeding the reference pressure of the environment available to a downstream recipient. As further shown on FIG. 2, the first channel C.sub.1 again expands subsequent to the abrupt reduction. For example, the cross section Q.sub.2 before the working outlet WP.sub.n is larger than the cross section Q.sub.1 after the working outlet WP.sub.n+1. The expansion counteracts the thickening of the boundary layers. In addition, this contouring makes it possible to favorably route the fluid to the working outlets in terms of flow mechanics, and enables an extremely homogeneous distribution of the fluid to be removed among a plurality of outlet openings.

(14) In one of various embodiments of the present disclosure, the fluid flows into the first channel or the second channel substantially from a rectangular access channel. Rectangular cross sections and in particular quadratic cross sections are beneficial from the standpoint of flow mechanics.

(15) In another exemplary embodiment of the present disclosure, at least one working outlet branches away from the first channel at an angle to the primary channel direction or substantially perpendicular to the primary channel direction. For example, the working outlet or the working outlets, as denoted by crosses in the working outlets on FIGS. 1 and 3, may branch off perpendicular to the channel plane, i.e., normal to the drawing plane. This enables a very compact design that economizes on material. It is also possible to provide the channel C.sub.1, C.sub.2 itself with a curvature, i.e., the primary channel direction is not necessarily a straight line. This may be targeted at further reducing the installation size, or permit use in systems that were not straight from the very outset, e.g., for cooling turbine blades or combustion chambers.

(16) In one of various embodiments of the present disclosure, at least one working outlet branches away from the first channel at an angle to the primary channel direction or substantially perpendicular to the primary channel direction. For example, the working outlet or the working outlets, as denoted by crosses in the working outlets on FIGS. 1 and 3, may branch off perpendicular to the channel plane, i.e., normal to the drawing plane. This enables a very compact design that economizes on material. It is also possible to provide the channel C.sub.1, C.sub.2 itself with a curvature, i.e., the primary channel direction is not necessarily a straight line. This may be targeted at further reducing the installation size, or permit use in systems that were not straight from the very outset, e.g., for cooling turbine blades or combustion chambers.

(17) The present disclosure further provides that the working outlets comprise differing cross sectional surfaces. This makes it possible to optimally adjust the removal of fluid at different working outlets to the respective intended purpose.

(18) As depicted on FIG. 1, the second channel C.sub.2 may be structured symmetrically to the first channel C.sub.1. In other words, channel C.sub.2 substantially has the same configuration as channel C.sub.1, i.e., the same length L.sub.1 and same number and positioning of working outlets, as well as a similar type of dimensioning for the cross sections.

(19) As an alternative hereto, the second channel C.sub.2 may also be structured asymmetrically to the first channel C.sub.1, as depicted on FIG. 3. For example, the cross sectional surface of the second channel C.sub.2 may differ from the cross sectional surface of the first channel C.sub.1, and/or the first channel C.sub.1 and second channel C.sub.2 comprise a varying capacity in terms of flow mechanics for other reasons. Furthermore, as shown on FIG. 3, the time it takes to pass through the first channel C.sub.1 may differ from the time it takes to pass through the second channel C.sub.2 given an identical fluid supply. For example, channel C.sub.2 has a distinctly shorter length L.sub.2 than channel C.sub.1 with a length L.sub.1. As a result, for example, a duty cycle may easily be provided. The work duration of the duty cycle is determined by flow mechanics-related characteristics of channel C.sub.1, while the idle duration of the duty cycle is determined by the flow mechanics-related characteristics of channel C.sub.2.

(20) The characteristics of the device according to the present disclosure make it especially suitable as a control stage of a fluid actuator, in particular a fluid actuator for influencing a flow along a flow surface. Critically important with regard to the latter are the stability even at a higher restrictive effect along with the enablement of small installation sizes and the rise in available weight associated therewith.

(21) Since the device according to the present disclosure may itself provide a pulsed fluid stream, the device is able to directly influence a flow along a flow surface.

(22) However, the present disclosure is not limited to these areas of application. Fluid pulses, in particular pulsed liquids, are also required in other areas. A first example involves the combustion of hydrocarbons for power or thermal purposes. A fuel or fuel-air mixture is frequently added to a combustion nozzle to ensure a good combustion, and thereby keep harmful gas emission low and efficiency high. The injected fluid is then burned via external or self ignition. Multiple injections are here used in addition to the multiple external ignitions. An adjustable self-induced vibration and/or provision of a duty cycle represent a possible embodiment for these systems as well.

(23) Another example involves the processing of metal materials. For example, the objective may be a roughening of the surface or separation.

(24) Another example has to do with medical technology. For example, pulsed liquid jets may be used as an alternative to lasers. This is especially advantageous, since as opposed to a laser, a pulsed water jet does not require that tissue be vaporized, but rather allows it to be separated out and transported away by the fluid jet itself. This decreases damage to surrounding tissue.

(25) The devices according to the present disclosure are suitable as independent systems for generating fluid impulses, and by comparison to prior art make it possible to provide a plurality of removal sites for pulsed fluid, substantially without any mutual phase shifting, which then may be released directly to the environment, e.g., via actuator chambers, or be used for flow control purposes. Furthermore, the present disclosure enables the provision of different amplitudes at the most varied of removal sites using a single fluidic switch and supply pressure. In addition, the present disclosure permits a duty cycle variation, wherein it must be noted that the fluid is not simply uselessly released to the environment in these duty cycles, but instead remains inside the device and is available in the next duty cycle.

(26) The present disclosure further permits a design in which up to and including rotationally symmetrical components may be integrated even along curved surfaces, e.g., turbine blades, combustion chamber diffusers, etc. As opposed to known actuators, the feedback loops are not present as an independent line, but instead the feedback loops are functionally integrated into the respective outlet line. Integrating the feedback loops into the outlet line makes it possible to achieve a distinct reduction in the required installation space. In comparison to previous systems, this reduction measures roughly about 50 percent. This yields additional advantages, since the devices according to the present teachings are tangibly less complex as a result, and a lower weight may also be realized due to the lower demand for material. Furthermore, this present disclosure also makes it possible to achieve outlet signal stability and increased efficiency.

(27) Let it be noted that neither moving nor electrical components are required for this purpose, thus making the present disclosure impervious to electrical or mechanical disruptions.

(28) While at least one exemplary embodiment has been presented in the foregoing detailed description, it should be appreciated that a vast number of variations exist. It should also be appreciated that the exemplary embodiment or exemplary embodiments are only examples, and are not intended to limit the scope, applicability, or configuration of the present disclosure in any way. Rather, the foregoing detailed description will provide those skilled in the art with a convenient road map for implementing an exemplary embodiment, it being understood that various changes may be made in the function and arrangement of elements described in an exemplary embodiment without departing from the scope of the present disclosure as set forth in the appended claims and their legal equivalents.