CN116351590A - Asymmetric single-port self-excitation pulse jet device - Google Patents
Asymmetric single-port self-excitation pulse jet device Download PDFInfo
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- CN116351590A CN116351590A CN202310242602.7A CN202310242602A CN116351590A CN 116351590 A CN116351590 A CN 116351590A CN 202310242602 A CN202310242602 A CN 202310242602A CN 116351590 A CN116351590 A CN 116351590A
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- jet
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- snail
- pulse jet
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- 239000012530 fluid Substances 0.000 claims abstract description 10
- 241000237858 Gastropoda Species 0.000 claims description 6
- 230000002401 inhibitory effect Effects 0.000 claims description 4
- 230000000903 blocking effect Effects 0.000 claims description 3
- 230000000694 effects Effects 0.000 description 8
- 238000000926 separation method Methods 0.000 description 4
- 238000010408 sweeping Methods 0.000 description 4
- 238000010586 diagram Methods 0.000 description 3
- 238000005516 engineering process Methods 0.000 description 3
- 238000000034 method Methods 0.000 description 3
- 230000009977 dual effect Effects 0.000 description 2
- 230000005284 excitation Effects 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 238000011160 research Methods 0.000 description 2
- 230000009471 action Effects 0.000 description 1
- 230000002411 adverse Effects 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000008901 benefit Effects 0.000 description 1
- 230000001427 coherent effect Effects 0.000 description 1
- 238000004891 communication Methods 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000013461 design Methods 0.000 description 1
- 230000001687 destabilization Effects 0.000 description 1
- 230000000670 limiting effect Effects 0.000 description 1
- 230000007246 mechanism Effects 0.000 description 1
- 230000008569 process Effects 0.000 description 1
- 230000000452 restraining effect Effects 0.000 description 1
- 238000004088 simulation Methods 0.000 description 1
- 238000011144 upstream manufacturing Methods 0.000 description 1
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Classifications
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05B—SPRAYING APPARATUS; ATOMISING APPARATUS; NOZZLES
- B05B1/00—Nozzles, spray heads or other outlets, with or without auxiliary devices such as valves, heating means
- B05B1/02—Nozzles, spray heads or other outlets, with or without auxiliary devices such as valves, heating means designed to produce a jet, spray, or other discharge of particular shape or nature, e.g. in single drops, or having an outlet of particular shape
- B05B1/08—Nozzles, spray heads or other outlets, with or without auxiliary devices such as valves, heating means designed to produce a jet, spray, or other discharge of particular shape or nature, e.g. in single drops, or having an outlet of particular shape of pulsating nature, e.g. delivering liquid in successive separate quantities ; Fluidic oscillators
- B05B1/083—Nozzles, spray heads or other outlets, with or without auxiliary devices such as valves, heating means designed to produce a jet, spray, or other discharge of particular shape or nature, e.g. in single drops, or having an outlet of particular shape of pulsating nature, e.g. delivering liquid in successive separate quantities ; Fluidic oscillators the pulsating mechanism comprising movable parts
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- Jet Pumps And Other Pumps (AREA)
Abstract
The invention discloses an asymmetric single-port self-excitation pulse jet device, which comprises a drainage port, a mixing cavity and a snail-shaped jet port which are positioned on the central axis of the device in sequence to form a main flow path; the left and right sides of the central axis of the device are respectively provided with a left feedback loop and a right feedback loop, and the overall configuration of the device is left-right asymmetric; wherein: when the device drainage port is given with high pressure, the snail-shaped jet port is given with low pressure, the device can spontaneously generate pulse jet flow with certain frequency and duty ratio at the outlet of the snail-shaped jet port for fluid flow control.
Description
Technical Field
The invention relates to an asymmetric single-port self-excitation pulse jet device, and belongs to the technical field of unsteady flow control.
Background
Current fluid machines are moving toward high aerodynamic loads, and when the fluid machine load increases significantly beyond the current aerodynamic design level, flow separation phenomena are typically caused by high back pressure gradients or shock-boundary layer interference, causing dramatic drop in fluid machine efficiency and even destabilization. Therefore, researchers at home and abroad are always focusing on flow control technology and corresponding flow control devices capable of inhibiting or even eliminating flow separation. The unsteady flow control technique is an advanced flow control technique that produces unsteady excitations that take advantage of flow instabilities that interact with the proposed structure in the separated flow. Related researches show that the same flow control effect is achieved, and the consumption energy of the unsteady flow control technology can be saved by 1-2 orders of magnitude compared with the corresponding unsteady flow control technology, namely the flow control device has the effect of 'four-two jack pulling'.
The self-exciting jet oscillator can be used as an unsteady flow control device. If the inlet and the outlet of the self-excited jet oscillator are respectively connected with a high-pressure gas source and a low-pressure gas source, the self-excited jet oscillator can rely on flow instability, so that the outlet can generate unsteady jet and can be used as unsteady excitation required by unsteady flow control. The self-excited jet oscillator has a simple structure and no movable parts, so that the self-excited jet oscillator has a good application prospect.
However, the currently prevailing self-exciting fluidic oscillators have certain problems as unsteady flow control devices. The first type is a symmetrical single port self-exciting swept jet as shown in fig. 1, which produces a swept jet at the outlet (i.e. the jet velocity is substantially constant but the jet angle varies continuously over a range, such as between 40 ° and 140 °). However, control of the separation flow typically exists at optimum jet angles (typically between 10 ° and 45 °). Therefore, the control effect of the sweeping jet is often poor or even negative. The second type is a symmetrical dual port self-exciting pulsed jet as shown in fig. 2, which produces two pulsed jets (jet angle unchanged, velocity changed) at two outlets in opposite phase (180 deg. out of phase). However, related studies show (see Li Qiufeng, research on mechanism of a passive double-pulse jet), that double-pulse jets with similar positions and opposite phases can produce coherent action, and their control effects cancel each other, so that the flow control effect of the jet is also poor.
Disclosure of Invention
The invention aims to overcome the defects in the prior art and provide an asymmetric single-port self-excitation pulse jet device which can be used for inhibiting flow separation in fluid machinery and improving the fluid mechanical performance.
In order to achieve the above purpose, the invention is realized by adopting the following technical scheme:
in a first aspect, the invention provides an asymmetric single-port self-excitation pulse jet device, which comprises a drainage port, a mixing cavity and a snail-shaped jet port which are positioned on the central axis of the device in sequence to form a main flow path; the left and right sides of the central axis of the device are respectively provided with a left feedback loop and a right feedback loop, and the overall configuration of the device is left-right asymmetric; wherein:
when the device vent is given a high pressure and the snail vent is given a low pressure, the device can spontaneously produce a pulsed jet with a frequency and duty cycle at the outlet of the snail vent for fluid flow control.
Furthermore, the shape of the snail-shaped jet orifice is formed by splicing an ellipse and a parallelogram, and the shape of the snail-shaped jet orifice is similar to that of a snail.
Further, in the snail-shaped jet port, the oval structure is used for reversing the jet originally swept leftwards, inhibiting and blocking the jet and forming a trough of the pulse jet; the parallelogram structure is used for smoothly guiding out the jet flow swept rightward to form the wave crest of the pulse jet flow.
Further, the lengths of the left feedback loop and the right feedback loop are not equal.
Further, the right feedback loop length is greater than the left feedback loop length.
Further, the ratio of the right feedback loop length L1 to the left feedback loop length L2 has a value between 1.05 and 2.
Compared with the prior art, the invention has the beneficial effects that:
the invention provides an asymmetric single-port self-excitation pulse jet device, which can generate pulse jet with certain frequency and duty ratio by designing a snail-shaped jet port, thereby avoiding the adverse control effect of the single-port self-excitation sweep jet device and the double-port self-excitation pulse jet device which are widely adopted at present in actual flow control application and having more engineering practicability.
Drawings
FIG. 1 is a schematic view of a symmetrical single port self-exciting sweeping jet;
FIG. 2 is a schematic diagram of a symmetrical dual port self-energizing pulsed jet;
FIG. 3 is a schematic diagram of an asymmetric single port self-energizing pulsed jet;
FIG. 4 is a schematic illustration of an asymmetric single port self-energizing pulsed ejector plugging mode;
fig. 5 is a schematic diagram of a jet pattern of an asymmetric single port self-exciting pulse jet.
In the figure: 1. a drainage port; 2. a mixing chamber; 3. snail-shaped jet port; 4. a left feedback loop; 5. and a right feedback loop.
Detailed Description
The invention is further described below with reference to the accompanying drawings. The following examples are only for more clearly illustrating the technical aspects of the present invention, and are not intended to limit the scope of the present invention.
In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, are merely for convenience in describing the present invention and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a specific orientation, be configured and operated in a specific orientation, and thus should not be construed as limiting the present invention. Furthermore, the terms "first," "second," and the like, are used for descriptive purposes only and are not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first", "a second", etc. may explicitly or implicitly include one or more such feature. In the description of the present invention, unless otherwise indicated, the meaning of "a plurality" is two or more.
In the description of the present invention, it should be noted that, unless explicitly specified and limited otherwise, the terms "mounted," "connected," and "connected" are to be construed broadly, and may be either fixedly connected, detachably connected, or integrally connected, for example; can be mechanically or electrically connected; can be directly connected or indirectly connected through an intermediate medium, and can be communication between two elements. The specific meaning of the above terms in the present invention can be understood by those of ordinary skill in the art in a specific case.
Example 1
As shown in fig. 3, this embodiment introduces an asymmetric single-port self-excitation pulse jet device, which includes a drainage port 1, a mixing cavity 2, and a snail-shaped jet port 3, forming a main flow path; the left feedback loop 4 and the feedback loop with different lengths are respectively arranged on the left side and the right side of the device, and the whole structure of the device is left-right asymmetric. When the device is given a high pressure for the vent 1 and a low pressure for the snail vent 3, the device can spontaneously produce a pulsed jet with a frequency and duty cycle at the outlet of the snail vent 3, which can be used for fluid flow control. The self-excitation ejector is internally provided with a left feedback loop and a right feedback loop 5, and is characterized in that the lengths of the left feedback loop 4 and the right feedback loop 5 are unequal. The length of the right feedback loop 5 is generally longer than that of the left feedback loop 4, because the flow resistance is larger when the jet flows through the oval structure of the snail-shaped jet orifice 3, so that the stay time of the mode is shorter, the duty ratio of the pulse jet is influenced, and the longer right feedback loop 5 can compensate the problem, so that the duty ratio of the pulse jet is close to an ideal value of 0.5; wherein the ratio of the length of the right feedback loop 5 to the length of the left feedback loop 4 has a value between 1.05 and 2.
The technical principle of the invention is as follows: the main channel MC in the mixing chamber 2 is attached to one of the left or right walls of the mixing chamber 2 due to the coanda effect. If the main flow path MC is stuck to the right wall surface of the mixing chamber 2, the jet flows back to the upstream along the left wall surface of the snail-shaped jet port 3, so as to form an effect of restraining and blocking the jet flow, and meanwhile, a right feedback loop is formed (see fig. 4), and the right feedback loop RC pushes the main flow path MC at the inlet of the mixing chamber 2 to be stuck to the left wall surface of the mixing chamber 2, so that the main flow finally forms a jet flow from the snail-shaped jet port 3, and forms a feedback flow path LC (see fig. 5) in the left feedback loop. The two processes are alternated to form a pulsed jet with a duty cycle.
The description of the above embodiment will be made with reference to a preferred embodiment.
In the implementation of the asymmetric single-port self-excitation pulse jet device, firstly, the required pulse jet frequency F0 and the jet speed V0 are determined according to the specific application scene of the fluid machinery. Secondly, on the basis of the existing mature symmetrical single-port self-excitation sweeping jet device, the jet sweeping frequency of the jet device at the jet speed V0 is F0 through the scaling; through numerical simulation or experimental means, the snail-shaped jet orifice 3 is designed, and the length of the long axis and the short axis of the oval configuration in the snail-shaped jet orifice 3 and the ratio of the length L1 of the right feedback loop 5 to the length L2 of the left feedback loop 4 are optimized, so that the asymmetric single-orifice self-excited pulse jet device generates a single pulse jet with the frequency F0, the jet speed of about V0 and the duty ratio of about 0.5, thereby realizing the pulse jet flow control function on a flow field.
The foregoing is merely a preferred embodiment of the present invention, and it should be noted that modifications and variations could be made by those skilled in the art without departing from the technical principles of the present invention, and such modifications and variations should also be regarded as being within the scope of the invention.
Claims (6)
1. An asymmetric single-port self-excitation pulse jet device is characterized by comprising a drainage port (1), a mixing cavity (2) and a snail-shaped jet port (3) which are positioned on the central axis of the device in sequence to form a main flow path; the left and right sides of the central axis of the device are respectively provided with a left feedback loop (4) and a right feedback loop (5), and the whole configuration of the device is left and right asymmetric; wherein:
when the device conduction port (1) is given with high pressure, the snail-shaped jet port (3) is given with low pressure, and the device can spontaneously generate pulse jet with certain frequency and duty ratio at the outlet of the snail-shaped jet port (3) for controlling the flow of fluid.
2. The asymmetric single port self-exciting pulse jet device according to claim 1, wherein the shape of the snail-shaped jet port (3) is formed by splicing an ellipse and a parallelogram, and the shape of the snail-shaped jet port is similar to the shape of a snail.
3. The asymmetric single port self-exciting pulse jet device according to claim 1, wherein in the snail-shaped jet port (3), an elliptic structure is used for reversing the jet originally swept leftwards, inhibiting and blocking the jet itself, forming the trough of the pulse jet; the parallelogram structure is used for smoothly guiding out the jet flow swept rightward to form the wave crest of the pulse jet flow.
4. The asymmetric single port self-exciting pulse jet device according to claim 1, characterized in that the lengths of the left feedback loop (4) and the right feedback loop (5) are not equal.
5. The asymmetric single port self-exciting pulse jet device according to claim 1, wherein the right feedback loop (5) length is greater than the left feedback loop (4) length.
6. The asymmetric single port self-exciting pulse jet device according to claim 1, wherein the ratio of the length L1 of the right feedback loop (5) to the length L2 of the left feedback loop (4) has a value between 1.05 and 2.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202310242602.7A CN116351590A (en) | 2023-03-14 | 2023-03-14 | Asymmetric single-port self-excitation pulse jet device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202310242602.7A CN116351590A (en) | 2023-03-14 | 2023-03-14 | Asymmetric single-port self-excitation pulse jet device |
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| Publication Number | Publication Date |
|---|---|
| CN116351590A true CN116351590A (en) | 2023-06-30 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202310242602.7A Pending CN116351590A (en) | 2023-03-14 | 2023-03-14 | Asymmetric single-port self-excitation pulse jet device |
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| CN (1) | CN116351590A (en) |
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- 2023-03-14 CN CN202310242602.7A patent/CN116351590A/en active Pending
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