KR100745149B1 - Superonic ejector having minimum pressure load and driving method thereof - Google Patents

Abstract

The present invention relates to a supersonic ejector, and more particularly, to a supersonic ejector having a minimum pressure load and a driving method thereof. To this end, drive fluid supply means for supplying a drive fluid; First valve means (72) for controlling the flow rate of the drive fluid supplied by the drive fluid supply means; A driving fluid part 32 connected to the first valve means 72 and formed in a central region of the driving fluid part 32 and a suction fluid part 30 to which suction fluid is introduced, the driving fluid part An ejector 100 composed of a mixing part 34 and a second neck part 36 formed integrally with one end of the mixing part 34 and a diffusion part in which the fluid introduced through the 32 and the suction fluid part 30 are mixed; A second valve means 90 is provided which is connected to the suction fluid part 30 and controls the flow rate of the suction fluid.

Ejector, Supersonic, Working Pressure, Expanding Neck, Nozzle, Secondary, Mixing, Suction Fluid, Driving Fluid

Description

Supersonic ejector having minimum pressure load and its driving method

1 is a schematic side cross-sectional view of a conventional supersonic ejector,

2 is a graph showing a performance curve of the conventional supersonic ejector shown in FIG. 1;

3 is a schematic side cross-sectional view of a supersonic ejector in which the driving fluid has a minimum pressure load in accordance with the present invention;

4 is a schematic block diagram of a driving system using the supersonic ejector shown in FIG. 3;

5 is a configuration diagram showing the installation position of the pressure sensor for measuring the pressure change in the axial direction in the supersonic ejector shown in FIGS.

6 is a pressure line graph for characterizing the flow inside the ejector according to the change of the inlet condition of the suction fluid in the supersonic ejector shown in FIGS. 3 and 4;

7 is a graph of an experiment for determining whether sound pressure is generated in the suction fluid unit by applying the conventional driving method and the driving method of the present invention to the supersonic ejector shown in FIGS. 3 and 4, respectively.

8 is a graph of an experiment for determining the operating pressure when the pressure of the driving fluid is changed with respect to the supersonic ejector shown in FIGS. 3 and 4 and the conventional driving method is applied.

FIG. 9 is an experimental graph for confirming whether the supersonic ejector shown in FIGS. 3 and 4 operates as a supersonic ejector when the driving method of the present invention is applied under the operating pressure.

<Description of the symbols for the main parts of the drawings>

10: driving fluid part,

20: suction fluid part,

23: mixing unit,

24: secondary neck,

26: diffusion part,

30: suction fluid part,

32: driving fluid part,

33: primary neck,

34: mixing section,

36: secondary neck,

40: diffusion part,

50: the first compressor,

52: first dryer,

54: main air tank,

60: second compressor,

62: second dryer,

64: service air tank,

70: setting chamber,

72: the first valve,

80: measuring computer,

82: data acquisition device,

90: second valve,

100: supersonic ejector.

The present invention relates to a supersonic ejector, and more particularly, to a supersonic ejector having a minimum pressure load and a driving method thereof.

In general, an ejector injects a high flow rate and high pressure fluid, that is, a primary flow into a nozzle, and inhales and inhales a low energy fluid by exchanging momentum with a surrounding low pressure gas using the kinetic energy. It is a kind of pump that gets the flow of (secondary flow). Ejectors are classified into subsonic, sonic and supersonic ejectors according to the speed of the driving fluid, and are divided into air, steam and water ejectors according to the type of driving fluid. In addition, it is divided into central injection method and annular injection method according to injection method of driving fluid in axisymmetric ejector.

Since the ejector is a device that only depends on aerodynamics, it does not need any external power source and does not have any rotating or active parts of the system, so it is possible to obtain a small and large suction fluid, and to have a low trouble element and a simple structure. It has the advantages of constant operating performance, long life and easy maintenance.

This advantage has long been widely used in vacuum drying, concentration, distillation, deodorization, crystallization, exhaust, impregnation, mixing, cooling, conveying, thrust enhancement of V / STOL aircraft, combustion testing, noise reduction, and various chemical industries. Recently, it has been applied to the pressure recovery system of high power chemical lasers, the high-flying environment simulation device, and the RBCC (Rocket Based Combined Cycle) engine which is the next generation propulsion concept.

1 is a schematic side cross-sectional view of such a conventional supersonic ejector. As shown in FIG. 1, the supersonic ejector has a driving fluid part 10 in which a driving fluid is injected into one end. The drive fluid portion 10 is circular in cross section, and a nozzle (or primary neck portion) is formed at the end.

In addition, the suction fluid flows in from the side of the ejector, and the mixing part 23 is a nozzle end of the driving fluid part 10 and is a part where the driving fluid and the suction fluid start to mix.

Secondary neck portion 24 has a narrower cross-sectional area than the mixing portion 23, which is a region in which the flow rate is fast and the pressure is low. The diffuser 26 is formed continuously after the secondary neck 24 and is configured to be exposed to the atmosphere.

FIG. 2 is a graph showing a performance curve of the conventional supersonic ejector shown in FIG. 1. As shown in FIG. 2, the performance curve is a curve of the pressure change of the driving fluid-suction fluid obtained when the supersonic ejector is driven by changing the pressure of the driving fluid, and thus the performance of the supersonic ejector can be confirmed at a time.

In FIG. 2, when the driving fluid pressure increases further after starting to operate as a subsonic ejector in the region a, the suction fluid pressure suddenly decreases as in the region b, and the vertical shock wave is placed in the diffuser 26. The driving fluid pressure at this time is referred to as starting pressure. After the supersonic ejector is activated, the supersonic ejector remains active, as in the c region, even if the operating fluid pressure is reduced.

If the pressure of the driving fluid is further reduced, the ejector stops as shown in the region d at a certain pressure and shows the performance of the subsonic ejector. The driving fluid pressure at this time is called an unstarting pressure.

In order to drive a supersonic ejector, the driving fluid must initially be supplied and injected at a pressure higher than the operating pressure. However, there is a hysteresis in the actual operating range that can be maintained at lower pressures but higher than the stopping pressure.

Accordingly, the present invention has been made to solve the above problems, an object of the present invention, by using the hysteresis such that the drive fluid is to minimize the drive fluid to start the operation even under the operating pressure of the supersonic ejector It is to provide a supersonic ejector having a pressure load and a driving method thereof.

Other objects, specific advantages and novel features of the invention will become more apparent from the following detailed description and the preferred embodiments described in conjunction with the accompanying drawings.

An object of the present invention as described above, drive fluid supply means for supplying a drive fluid;

First valve means (72) for controlling the flow rate of the drive fluid supplied by the drive fluid supply means;

A driving fluid part 32 connected to the first valve means 72 and formed in a central region of the driving fluid part 32 and a suction fluid part 30 to which suction fluid is introduced, the driving fluid part An ejector 100 composed of a mixing part 34 and a second neck part 36 formed integrally with one end of the mixing part 34 and a diffusion part in which the fluid introduced through the 32 and the suction fluid part 30 are mixed;

The drive fluid, which is connected to the suction fluid part 30 and constitutes a second valve means 90 for controlling the flow rate of the suction fluid, can be achieved by a supersonic ejector having a minimum pressure load.

In addition, it is preferable that the primary neck part 33 is further formed on the inner surface of the annular drive fluid part 32.

In addition, the driving fluid is preferably any one of air, water and steam.

In addition, the drive fluid supply means,

A first compressor (50) for sucking and compressing air from the atmosphere;

A main air tank 54 connected to the first compressor 50;

It may be suitable to further include a; setting chamber 70 is connected to the main air tank 54 to maintain a constant discharge pressure.

And, the drive fluid supply means,

A second compressor (60) for sucking and compressing air from the atmosphere;

Further comprising a; service air tank 64 connected to the second compressor (60),

More preferably, the first valve means 72 is driven at the pressure of the service air tank 64.

The main air tank 54 may have a maximum pressure of 30 bar, and the service air tank 64 may have a maximum pressure of 5 bar.

In addition, the first compressor 50 and the second compressor 60 preferably further include a first dryer 52 and a second dryer 62, respectively.

The object of the present invention as described above, as another category of the present invention, the suction fluid portion 32 is formed in the center region of the drive fluid portion 32, the drive fluid portion 32 having an annular inlet ( 30), the mixing unit 34 and the secondary neck portion 36 formed integrally with one end of the mixing portion 34 is mixed with the driving fluid 32 and the fluid introduced through the suction fluid portion 30 and the diffusion portion In the driving method of the ejector 100,

Closing the suction fluid part 30 (S10);

Spraying the driving fluid through the driving fluid part 32 to form a predetermined sound pressure in the suction fluid part 30 area (S20);

The driving fluid, which comprises the step (S30) of opening the suction fluid part 30 and supplying the suction fluid, may be achieved by a method of driving a supersonic ejector having a minimum pressure load.

Then, the closing step (S10) of the suction fluid portion 30 includes the step of closing the second valve 90 connected to the suction fluid portion 30,

More preferably, the opening step S30 of the suction fluid part 30 includes opening the second valve 90.

And, the negative pressure forming step (S20) is preferably such that the negative pressure of less than 50 torr is formed in the suction fluid portion 30 region.

In the negative pressure forming step (S20), the driving fluid is most preferably injected below the operating pressure.

The invention will now be described in detail with reference to the accompanying drawings, in which preferred embodiments are shown. 3 is a schematic side cross-sectional view of the supersonic ejector 100 in which the drive fluid has a minimum pressure load in accordance with the present invention. As shown in FIG. 3, a suction fluid part 30 is formed at one side of the supersonic ejector 100, and an annular drive fluid part 32 is formed around the suction fluid part 30. In addition, a primary neck part 33 serving as a nozzle is formed in the driving fluid part 32.

In the mixing section 34, the suction fluid and the driving fluid are mixed with each other, and the taper shape is reduced in cross-sectional area as it progresses in the axial direction.

The secondary neck portion 36 is connected to the mixing portion 34 and has a narrow cross section equal to the minimum cross-sectional area of the mixing portion 34.

The diffusion portion 40 is integrally connected to one end of the secondary neck portion 36 and has a shape in which the cross section gradually increases along the axial direction, and the end thereof is exposed to the atmosphere.

Specific dimensions of the supersonic ejector 100 produced and tested as an example in the present invention are described in Table 1.

sign Dimension (mm) sign Dimension (mm) R _S 56.57 R _throat 68.19 R _max 68.94 R ₂ 41.72 R _exit 72.34 R _p 12.37 L _m 389.26 L ₂ 666.0 L _d 350.0 L _s 100.0 H 54.44 h 61.24

As shown in FIG. 3 and [Table 1], the supersonic ejector 100 of the present application is an annular ejector, in which a driving fluid is injected along the wall of the mixing part 34 to be mixed with the suction fluid, and the mixed fluid is a secondary neck part. It is discharged into the atmosphere through the 36 and the diffusion 40. Where D is the diameter of the secondary neck portion 36, d is the diameter of the suction fluid portion (30).

FIG. 4 is a schematic block diagram of a driving system using the supersonic ejector shown in FIG. 3. As shown in FIG. 4, the first compressor 50 and the first dryer 52 and the main air tank 54 for removing moisture (or moisture) in the air are connected in series. The main air tank 54 has a discharge pressure of up to about 30 bar.

The second compressor 60 and the second dryer 62 and the service air tank 64 for removing moisture (or moisture) in the air are connected in series. The service air tank 64 has a discharge pressure of up to about 5 bar and is for driving the first valve 72.

The main air tank 54 and the service air tank 64 are connected to the setting chamber 70, and the setting chamber 70 is configured to set the pressure target value by the user. The set chamber 70 discharges constant compressed air without fluctuation in pressure. That is, the setting chamber 70 functions as a pressure regulator. Since the compressor, dryer, air tank, and setting chamber disclosed in the present invention are mechanical component parts widely used in the pneumatic art, the construction is easy for those skilled in the art, and detailed description thereof will be omitted.

Compressed air at a constant pressure discharged from the set chamber 70 becomes a driving fluid and is injected into the driving fluid part 32 of the supersonic ejector 100 through the first valve 72. At this time, the injection amount may be adjusted according to the opening and closing degree of the first valve (72).

The second valve 90 is connected to the suction fluid part 30 of the supersonic ejector 100. The second valve 90 may control the flow rate of the suction fluid according to the degree of opening and closing.

In the case of the actual supersonic ejector 100 of the present invention, the main air tank 54 has a volume of 11 m ³ and a maximum pressure of 30 bar, and the service air tank 64 has a volume of 1 m ³ and a maximum pressure of 5 bar. It is a small compressed air tank that is.

The first valve 70 used a pneumatic automatic valve for this purpose 5 bar service air tank (64). The area ratio of the drive fluid nozzle is 15, the design Mach number is about 4.39 and the design flow rate is 1.35 kg / s.

5 is a configuration diagram showing the installation position of the pressure sensor for measuring the pressure change in the axial direction in the supersonic ejector shown in FIGS. As shown in FIG. 5, three in the mixing section 34, six in the secondary neck section 36, three in the diffusion section 40, and an inlet for the driving fluid section 32 and the suction fluid section 30. The pressure was measured at 14 locations, one each at.

First, FIG. 6 is a pressure diagram illustrating the characteristics of the flow inside the ejector according to the change of the inlet condition of the suction fluid in the supersonic ejector shown in FIGS. 3 and 4. As shown in FIG. 6, when the suction fluid part 30 is exposed to atmospheric pressure before being closed, the supersonic ejector may be seen as vibrating without falling below 50 torr. 100) does not work.

In addition, after the experiment was started in the state exposed to atmospheric pressure, the suction fluid part 30 was blocked and the suction fluid part 30 pressure was lowered to less than 50 torr after 'closing', thereby maintaining a constant pressure, and the ejector 100 was supersonic. It worked as an ejector. Blocking the suction fluid part 30 is the same shape for any diameter ratio, so the ejector 100 operates unconditionally regardless. In this state, the suction fluid part 30 is again exposed to atmospheric pressure. However, it can be seen that the ejector 100 continues to maintain the state of the supersonic ejector 100. It is the effect of the secondary neck 36 that hysteresis occurs in this experiment in the closed-open mode of the suction fluid portion 30.

As described above, when the ejector 100 is operated, a vertical shock wave is formed at the end of the secondary neck part 36 and sucks a constant flow rate. When the suction fluid part 30 is blocked, P0p / Ps is increased. Shows the same result. In the case of the ejector 100 that does not operate at atmospheric pressure, it will operate on the same principle if the suction fluid portion 30 is blocked. At this time, if the suction fluid part 30 is exposed to atmospheric pressure again, P0p / Ps decreases, which acts as a effect of lowering the pressure of the driving fluid. As a characteristic of the ejector having a), the vertical shock wave formed at the end of the secondary neck portion 36 does not disappear, but stops working only after a pressure drop occurs over a certain limit.

FIG. 7 is a graph illustrating an experiment to determine whether sound pressure is generated in the suction fluid unit by applying the conventional driving method and the driving method of the present invention to the supersonic ejector shown in FIGS. 3 and 4, respectively. As shown in FIG. 7, the experiment (3) shows the operation of the ejector in a state in which the suction fluid part 30 is exposed to atmospheric pressure as in the conventional driving method.

① part is a state in which the driving fluid pressure does not reach the operating pressure in the state in which the suction fluid 30 is exposed to atmospheric pressure. As shown in the results, it is a region that vibrates without falling below the design requirement of 50 torr and shows no shock wave noise in the experiment.

However, when the driving method according to the present invention is applied, the suction fluid part 30 is blocked and then exposed to atmospheric pressure, and thus the pressure below 50 torr can be kept constant. In this experiment, shock wave noise is accompanied, which shows that the ejector 100 operates as a supersonic ejector. If the closed-open mode hysteresis phenomenon is used, it is not necessary to increase the operating pressure when the ejector 100 is operated, and the operating pressure of the ejector 100 can be lowered, which is a great advantage in many applications.

FIG. 8 is a graph of an experiment for determining an operating pressure when the pressure of the driving fluid is changed with respect to the supersonic ejector shown in FIGS. 3 and 4. As shown in FIG. 8, it can be seen that the pressure of the driving fluid starts to operate at 19 atm and does not operate at a pressure lower than 19 atm. That is, it can be seen that the operating pressure of the ejector 100 is 19 atm.

Hereinafter, in order to confirm that the ejector can be operated at a driving fluid pressure lower than the actual working pressure using the closed-open mode hysteresis according to the present invention, the pressure of the driving fluid with respect to the diameter ratio of the same suction fluid part 30 is determined. The experiment was carried out by changing. That is, FIG. 9 is an experimental graph for confirming whether the supersonic ejector shown in FIGS. 3 and 4 operates as a supersonic ejector when the driving method of the present invention is applied under the operating pressure. As shown in FIG. 9, the performance curve when operated using closed-open mode hysteresis at four driving fluid pressures lower than the operating pressure of 19 atm can be seen. In all four cases, after the driving fluid nozzle was opened while the suction fluid part 30 was blocked, the suction fluid part 30 was immediately exposed to atmospheric pressure when the operation state of the ejector 100 was confirmed. All four cases lower than the operating pressure starts with the supersonic ejector 100, and it can be seen that the ejector 100 can be operated at supersonic speed even at the pressure of the stop pressure level.

Therefore, according to one embodiment of the present invention as described above, unlike the start of the conventional supersonic ejector, the pressure of the driving fluid must be increased up to the 'operating pressure' once, by simply operating the inlet of the suction fluid. The pressure can be operated at the minimum pressure of the ejector shape.

In the process of using an existing ejector or the development of a new product, it is expected that the effect of the operation fluid for starting can be reduced by simply attaching a simple device to the suction fluid inlet.

Supersonic ejector according to an embodiment of the present invention can be widely used in mechanical, aviation, chemical processes and the like. In addition, when the inlet of the inlet fluid is blocked and the inlet is exposed after starting, as in the driving method according to the present invention, the pressure of the driving fluid does not have to be increased above the operating pressure, and the limit of the inlet flow rate is increased. It is effective in reducing costs. Thus, not only supersonic ejectors but also all ejector applications used in industrial fields can be of great help.

Although the present invention has been described in connection with the above-mentioned preferred embodiments, it will be readily apparent to those skilled in the art that various other modifications and variations can be made without departing from the spirit and scope of the invention. It is obvious that all modifications fall within the scope of the appended claims.

Claims (12)

delete delete delete Drive fluid supply means for supplying a drive fluid; First valve means (72) for controlling the flow rate of the drive fluid supplied by the drive fluid supply means; A driving fluid part 32 connected to the first valve means 72 and having an annular inlet, a suction fluid part 30 formed at a central region of the driving fluid part 32 and into which suction fluid is introduced; Ejector composed of a mixing section 34 and a second neck portion 36 formed integrally with one end of the mixing section 34 and the fluid flowing through the driving fluid 32 and the suction fluid 30, 100; A second valve means 90 connected to the suction fluid part 30 to control the flow rate of the suction fluid, The drive fluid supply means, A first compressor (50) for sucking and compressing air from the atmosphere; A main air tank 54 connected to the first compressor 50; The supersonic ejector having a minimum pressure load is characterized in that the drive fluid is connected to the main air tank (54) comprising a set chamber (70) to maintain a constant discharge pressure. The method of claim 4, wherein the drive fluid supply means, A second compressor (60) for sucking and compressing air from the atmosphere; Further comprising a; service air tank 64 is connected to the second compressor (60), A supersonic ejector having a minimum pressure load on the drive fluid, characterized in that for driving the first valve means (72) at the pressure of the service air tank (64). 5. The supersonic ejector of claim 4, wherein the main air tank (54) has a maximum pressure of 30 bar. 6. The supersonic ejector of claim 5, wherein the service air tank (64) has a maximum pressure of 5 bar. The method of claim 5, The first compressor (50) and the second compressor (60) further comprises a first dryer (52) and a second dryer (62), characterized in that the drive fluid has a minimum pressure load supersonic ejector. A driving fluid part 32 having an annular inlet, a suction fluid part 30 formed in a central region of the driving fluid part 32, into which suction fluid flows, and the driving fluid part 32 and the suction fluid part 30. In the driving method of the ejector 100 composed of a mixing part 34 and a secondary neck part 36 and a diffusion part integrally formed with one end of the mixing part 34 through which the fluid introduced through the mixing part is mixed, Closing the suction fluid part 30 (S10); Spraying a driving fluid through the driving fluid part 32 to form a predetermined sound pressure in the suction fluid part 30 area (S20); Opening the suction fluid part 30 to supply a suction fluid (S30) characterized in that the drive fluid is a method of driving a supersonic ejector having a minimum pressure load. The method of claim 9, Closing step (S10) of the suction fluid part 30 includes closing a second valve 90 connected to the suction fluid part 30, The opening step (S30) of the suction fluid portion 30 includes the step of opening the second valve 90, characterized in that the drive fluid has a minimum pressure load driving method of the supersonic ejector. 10. The method of claim 9, wherein the negative pressure forming step (S20) is such that a negative pressure of less than 50 torr is formed in the suction fluid part (30). 10. The method of claim 9, wherein the driving fluid is injected below the operating pressure in the negative pressure forming step (S20).

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