CN104549805A - Self-oscillation jet flow generation device - Google Patents

Abstract

A self-excited oscillating jet generating device of the present invention comprises an inlet section, an oscillation chamber, a feedback loop and a nozzle; the inlet section is located at the left end of the device, the oscillation chamber is located in the middle of the device, and the nozzle is located at the right end of the device, and the three are in sequence Connection; that is, the entrance section is connected to the oscillation chamber, the oscillation chamber is connected to the nozzle, and there are a plurality of feedback loops connected to the entrance of the oscillation chamber near the exit of the oscillation chamber. The device can generate self-excited oscillating jets for liquid and gas working medium, and does not need any movable parts. It is easy to use, simple and compact in structure, and is used for liquid atomization, enhanced heat exchange, flow control, cleaning, cutting, and crushing. tools etc.

Description

A self-excited oscillating jet generator

technical field

The invention relates to a self-excited oscillating jet flow generating device, which utilizes the Coanda effect and fluid logic feedback to make the fluid generate periodic oscillation and eject it through a nozzle to generate a self-excited oscillating jet. This device is mainly used in the field of liquid oscillating atomization and heat exchange enhancement, and can also be used in flow control, cleaning, cutting, breaking tools and other fields.

Background technique

Oscillating jets have important applications in liquid atomization, enhanced heat transfer, cleaning, cutting and other fields. When the jet is ejected from the nozzle, the self-excited oscillation will accelerate the stabilization of the jet, thereby promoting the breakage and atomization of the jet. For enhanced heat transfer, the oscillating jet will destroy the boundary layer, increase the convective heat transfer coefficient, and enhance the heat transfer. In the field of jet cutting and cleaning, the oscillating jet improves the impact effect. In the past, the method of making the jet oscillate was to add a reciprocating mechanism to forcibly disturb the jet, and the reciprocating mechanism is often complicated in structure, which will increase a lot of extra weight and maintenance costs.

Therefore, the present invention utilizes the property that the fluid will change its motion direction when it approaches the protruding solid surface, that is, the Coanda effect, and the fluid feedback loop to realize the self-excited oscillation of the jet. The device of the invention has small volume, simple structure, obvious self-excited oscillation and large amplitude. The frequency of self-oscillation can be adjusted by changing the length of the feedback loop.

Contents of the invention

The invention relates to a self-excited oscillating jet flow generating device. Figures 1a-c are schematic diagrams of the present invention. The principle of the present invention is described as follows with reference to Figs. 1a-c: the fluid flows into the device from the inlet section, and forms a jet after entering the oscillation chamber. This jet has a bistable state—that is, under the Coanda effect, the jet has the possibility of deflecting to either the upper or lower surface of the oscillating cavity, and the probability of deflecting to the upper surface and the lower surface is equal. Assuming that the jet is deflected to the upper surface of the oscillation cavity (as shown in Figure 1.a), a small part of the jet will flow to the entrance of the oscillation cavity along the feedback loop near the upper surface near the exit of the oscillation cavity (as shown in Figure 1.b) . The small jet flowing along the feedback loop to the entrance of the oscillating cavity interacts with the main jet, causing the main jet to deviate from the upper surface of the oscillating cavity and turn to the lower surface of the oscillating cavity (as shown in Figure 1.c). At the position close to the exit of the oscillation cavity, a small part of the jet flows to the entrance of the oscillation cavity along the feedback loop close to the lower surface, so that the main jet is deflected to the upper surface of the oscillation cavity. This process repeats itself, causing periodic pressure oscillations in the oscillating chamber. When the main jet is ejected from the nozzle, a self-oscillating jet is formed.

A self-excited oscillating jet flow generating device of the present invention specifically includes an inlet section, an oscillating cavity, a feedback loop and a nozzle. The position connection relationship between them is: the inlet section is located at the left end of the device, the oscillation chamber is located at the middle of the device, and the nozzle is located at the right end of the device; the three are connected to each other in sequence, that is, the inlet section is connected with the oscillation chamber, and the oscillation chamber is connected with the nozzle. Several feedback loops are connected to the entrance of the oscillation cavity near the exit of the oscillation cavity.

Wherein, there is a part protruding into the cavity at the outlet of the oscillation cavity, which makes the jet flow deflected under the action of the Coanda effect.

Wherein, a wedge-shaped object can be arranged at the nozzle to form a double-strand self-excited oscillating intermittent jet.

Wherein, the mobile working medium can be either liquid or gas.

Advantages and effects: The advantage of a self-excited oscillating jet flow generating device of the present invention is: no additional reciprocating mechanism is required, only relying on the arrangement of the fluid passages in the device, self-oscillating single or multiple jets can be generated, and the oscillation The amplitude is large, and the oscillation frequency can be adjusted by adjusting the structural parameters of the fluid channel.

Description of drawings:

Figure 1a: The process of deflecting the main jet to the upper surface after entering the oscillating cavity.

Figure 1b: The process of a small jet flowing along the feedback loop to the entrance of the oscillating chamber.

Figure 1c: The process of deflecting the main jet to the downward surface due to the action of the small jet.

Figure 2: Self-excited oscillating jet generation device.

Figure 3: Device for generating self-oscillating dual-strand intermittent jets.

The symbols in the figure are explained as follows:

Inlet section 1; oscillation chamber 2; feedback loop 3; feedback loop 4; spout 5; wedge 6; entrance 21 of the oscillation chamber; exit 22 of the oscillation chamber; upper surface 23 of the oscillation chamber;

Detailed ways:

Figures 1a-c are schematic diagrams of the present invention.

Embodiment one:

An embodiment of a self-excited oscillating jet generator is shown in FIG. 2 , which is mainly composed of an inlet section 1 , an oscillating chamber 2 , a feedback loop 3 , a feedback loop 4 and a nozzle 5 . The working medium is liquid. The inlet section 1 is constricted and can accelerate the liquid. The end of the inlet section 1 is connected to the inlet 21 of the oscillation chamber 2 . The oscillation cavity is a cuboid square cavity with an upper surface 23 and a lower surface 24 . The outlet 22 of the oscillation chamber is connected to the nozzle 5 . Two upper and lower feedback loops 3 and 4 are arranged between the oscillating chamber outlet 22 and the oscillating chamber inlet 21 .

When the device is in operation, after the atomized liquid flows in, it is accelerated through the inlet section 1 to form a main jet that is sprayed into the oscillation chamber 2 from the entrance 21 of the oscillation chamber. According to the Coanda effect, the jet has a tendency to deviate from the original flow direction and flow along the surface of the protruding object instead. Therefore, when the jet flows in the oscillating cavity 2, it tends to deflect to the upper and lower surfaces of the oscillating cavity 2, and the probability of deflecting to the upper surface 23 and the lower surface 24 is equal, that is, the jet has bistability. Assuming that the jet is deflected to the upper surface 23 under the action of random factors, when it flows to the outlet 22 of the oscillation chamber, a small part of the liquid flows from the feedback loop 3 to the inlet 21 of the oscillation chamber. This small portion of liquid interacts with the main jet at the inlet 21 of the oscillating chamber so that the main jet is deflected towards the lower surface 24 . When the jet flows along the lower surface 24 to the outlet 22 of the oscillation chamber, a small part of liquid flows from the feedback loop 4 to the inlet 21 of the oscillation chamber, where it interacts with the main jet, causing the main jet to deflect to the upper surface 23 again, and this process can be cycled carried out, resulting in self-excited oscillation. The main jet is ejected from the nozzle 5, thereby generating a self-excited oscillating jet. Since the self-excited oscillating jet is very unstable, the atomization effect of the liquid is improved.

Embodiment two:

An embodiment of a self-oscillating double-strand intermittent jet flow generator is shown in Figure 3. The main difference between the second embodiment and the first embodiment is that a wedge-shaped object 6 is arranged at the nozzle 5. When the device is in operation, the fluid flows in and is accelerated through the inlet section 1 to form a main jet which is sprayed into the oscillation chamber 2 from the entrance 21 of the oscillation chamber. Assuming that the jet is deflected to the upper surface 23 under the action of random factors, when it reaches the outlet 22 of the oscillation cavity, the main jet is ejected from above the wedge-shaped object 6 to form a main jet with a phase of 0°. At the same time, a small portion of liquid flows from the feedback loop 3 to the inlet 21 of the oscillation chamber. This small portion of liquid interacts with the main jet at the inlet 21 of the oscillating chamber so that the main jet is deflected towards the lower surface 24 . When the jet flows along the lower surface 24 to the outlet 22 of the oscillation cavity, the main jet is ejected from below the wedge-shaped object 6 to form a second main jet with a phase difference of 180° from the previous main jet ejected from above the wedge-shaped object 6 . At the same time, a small part of the liquid flows from the feedback loop 4 to the inlet 21 of the oscillation chamber, where it interacts with the main jet, causing the main jet to deflect to the upper surface 23 again. Two jets of jets.

Claims (4)

1. a self-oscillation flow jet flow generating means, is characterized in that: it comprises entrance, vibration chamber, backfeed loop and spout; Entrance is positioned at this device left end, and vibration chamber is positioned in the middle of this device, and spout is positioned at this device right-hand member; Be linked in sequence each other between three, namely entrance connects vibration chamber, and vibration chamber connects spout, has a plurality of backfeed loops to be connected to vibration porch, chamber near the outlet of vibration chamber.

2. a kind of self-oscillation flow jet flow generating means according to claim 1, is characterized in that: the part that vibration oriented chamber, exit, chamber is projecting inward, and jet is deflected under the effect of Coanda effect.

3. a kind of self-oscillation flow jet flow generating means according to claim 1, is characterized in that: nozzle arranges a wedgeshaped object, forms bifilar self-oscillation intermittent jet.

4. a kind of self-oscillation flow jet flow generating means according to claim 1, is characterized in that: flow working medium can be liquid, also can be gas.