CN102716827B - Gas-liquid two-phase pressure-balanced wide-angle uniformly-distributed mist nozzle - Google Patents

Abstract

The invention discloses a gas-liquid two-phase pressure-balanced wide-angle uniformly-distributed mist nozzle. The gas-liquid two-phase pressure-balanced wide-angle uniformly-distributed mist nozzle comprises a nozzle shell and a Venturi ejector, wherein the nozzle shell is provided with a liquid inlet pipe and a gas inlet pipe; the a Venturi ejector is formed by a Venturi rotating body and a spiral groove type inner core and is fixedly embedded in an inner cavity of the nozzle shell; the spiral groove type inner core is fixedly inserted in a middle cavity of the Venturi rotating body; the Venturi rotating body is provided with a ring-shaped pressure equalizing chamber which is communicated with the liquid inlet pipe; a liquid discharging ring seam is formed on the inner side of the ring-shaped pressure equalizing chamber; a ring-shaped reducing section, a ring-shaped throat pipe section and a ring-shaped divergent section are sequentially formed between the spiral groove type inner core and the Venturi rotating body from inside to outside; the ring-shaped reducing section is communicated with the gas inlet pipe; the ring-shaped throat pipe section is communicated with the liquid discharging ring seam; and the ring-shaped divergent section is communicated with the outside. The gas-liquid two-phase pressure-balanced wide-angle uniformly-distributed mist nozzle disclosed by the invention has the advantages of simple structure, good atomizing distribution uniformity, wide ejection area and the like.

Description

Gas-liquid two-phase pressure balance wide-angle uniform distribution fine mist nozzle

technical field

The invention relates to a gas-liquid two-phase flow atomizing nozzle suitable for the fields of smoke and dust purification, desulfurization and denitrification, gas cooling, spraying and fire protection, especially a gas-liquid two-phase pressure balanced wide-angle uniformly distributed fine mist nozzle.

technical background

There are two types of atomizing nozzles: single-liquid atomizing nozzles and gas-liquid two-phase atomizing nozzles.

The atomization mechanism of the single-liquid atomizing nozzle is mainly filiform splitting. The liquid is ejected from the nozzle hole at a high speed. Under the action of surface tension and friction between the liquid and the still air outside, the liquid column becomes a snake-like vibration. Liquid filaments, then break into mist. The atomization effect of the single-liquid atomizing nozzle is poor. If you want to produce droplets with an average diameter of less than 100 microns, you must use small nozzle holes and high hydraulic pressure. The problem with this structure of the single-liquid atomizing nozzle is: the orifice is easy to Blockage, poor atomization quality.

The gas-liquid two-phase atomizing nozzle mainly uses compressed air to impact the liquid flow to improve the atomization quality and greatly reduce the hydraulic pressure. Because gas-liquid two-phase atomizing nozzles have better atomization performance than single-liquid atomizing nozzles, gas-liquid two-phase atomizing nozzles are more and more widely used.

The atomization mechanism of the gas-liquid two-phase atomizing nozzle is mainly film splitting. When the gas-liquid mixed flow is ejected from the pressure nozzle at a relatively high speed, it can form a film-like droplet group with gas in the liquid, and the gas expands to make it The liquid film breaks into fog, increasing the air pressure and reducing the liquid volume can further improve the atomization effect. There are two types of gas-liquid two-phase atomizing nozzles: ejection type and gas-liquid collision type.

The hydraulic pressure required by the injection nozzle is extremely low, which can be normal pressure (ambient atmospheric pressure), and the negative pressure generated by the high-speed airflow at the throat of the Venturi tube may suck the liquid into the Venturi tube, making the gas and liquid mix to form a mist drop. The main problem with ejector nozzles is that the atomization quality is not stable for two reasons:

One is that the liquid cannot be sucked into the injection nozzle, so that the liquid mist cannot be formed: according to the diffusion law of the gas jet, when the distance between the throat and mouth is too large, the cross-sectional area of the gas jet has diffused to be larger than the area of the throat before entering the throat, and the throat is relatively large. The jet flow becomes a mere drag, so that the injector cannot pump the liquid and form a liquid mist. In addition, there is a lower limit to the gas flow velocity of the jet flow gas injection. If the nozzle gas velocity is lower than the lower limit, the negative pressure generated is not enough, the liquid cannot be sucked into the nozzle, and the liquid mist cannot be formed (see: Wu Weifeng, Feng Quanke, Xiang Qingjiang, Lu Junxian. Analysis of the two-phase flow flow pattern in the gas-liquid injector. Kernel Power Engineering. 2007, 28(6), 34-37).

The second is that the backflow effect in the mixing chamber makes it impossible to spray normally: there is a gas-liquid mixing chamber between the gas nozzle and the Venturi tube, and the outside of the high-speed jet area generated by the gas nozzle is the backflow zone, and the backflow zone continues to flow with the increase of back pressure. The entrance of the mixing chamber moves, and when the back pressure exceeds a certain level, serious backflow will occur at the entrance, resulting in the termination of the injection nozzle (see: Wang Houqing, Shen Chao, Wang Xiaojuan, Chen Binglu, Zhang Hefei. Gas-liquid two-phase flow introduction Numerical simulation and experimental research of injector. Petroleum Machinery. 2005, 33(9), 21-23).

Gas-liquid collision nozzles mainly rely on high-speed gas-liquid collisions to generate atomization. Gas-liquid collision nozzles have better atomization stability, but there are also shortcomings:

1. The liquid phase nozzle is easy to block. Since the gas-liquid collision nozzle is atomized by the collision between gas and liquid at high speed, the diameter of the liquid phase nozzle is required to be small (usually less than 1mm), so that the spray liquid becomes a very fine liquid column, so that it is easy to spray at high speed. Under the impact of the airflow, it breaks into fog (see: Yang Lijun, Wang Wei. Research on atomization characteristics of two-phase flow emulsified water mist nozzle, Journal of Beijing University of Aeronautics and Astronautics, 2002, 28 (4), 413-416). If the liquid has impurities (such as solid particles in the wet desulfurization spray alkali solution, oily dirt in the oil spray mist, etc.), the fine nozzles are easily blocked.

2. The gas-liquid two-phase atomization effect has not been fully exerted. Collision nozzles only have the collision effect between high-speed gas and liquid, and do not use the shear force between gas and liquid two-phase flow.

3. The hydraulic pressure required by the gas-liquid collision type nozzle is higher than that of the ejection type nozzle.

In order to overcome the problem of unstable atomization quality of ejection nozzles and effectively utilize the atomization potential of gas-liquid collision nozzles, Chinese invention patent ZL 2009 1 0063156.3 discloses a method that uses down-swirling compressed airflow and uses high-speed airflow to The impact of the liquid column, combined with the shearing effect of the high-speed rotating air flow on the liquid column, makes the liquid column more easily broken to form a liquid mist. Although the two-phase swirl large-diameter fine mist nozzle has greatly improved the atomization effect, there are still some defects:

1. The required hydraulic pressure is high (usually greater than 0.2MPa).

2. Due to the unequal pressure on the contact surface between the air flow and the liquid, the amount of liquid ejected from each nozzle hole at the end of the nozzle is unequal.

3. For all porous nozzles, whether it is a porous single-liquid atomizing nozzle or a porous gas-liquid two-phase atomizing nozzle, there is always a phenomenon of uneven spray distribution between the two atomizing jets. This problem has not been well understood so far. well resolved.

Contents of the invention

The purpose of the present invention is to overcome the above-mentioned technical defects and provide a gas-liquid two-phase pressure balanced wide-angle uniform distribution fine mist nozzle with good atomization distribution uniformity, simple structure and no clogging.

In order to achieve the above object, the gas-liquid two-phase pressure balance wide-angle uniform distribution fine mist nozzle designed by the present invention includes a nozzle housing, which is provided with a liquid inlet pipe and an air inlet pipe, and also includes a Venturi gyrator A Venturi injector composed of a spiral grooved inner core, the Venturi rotary body is embedded and fixed in the inner cavity of the nozzle housing, and the spiral grooved inner core is inserted and fixed in the middle cavity of the Venturi rotary body ; The Venturi gyrator is provided with an annular pressure equalizing chamber, the annular pressure equalizing chamber communicates with the liquid inlet pipe, and the inner side of the annular pressure equalizing chamber is provided with a liquid outlet annular seam; the spiral groove The annular tapering section, the annular throat section and the annular expanding section of the Venturi injector are sequentially formed between the inner core and the Venturi gyrator, and the annular tapering section communicates with the intake pipe. The annular throat section communicates with the liquid outlet annular seam, and the annular gradually expanding section communicates with the outside world.

In the above technical solution, the annular pressure equalizing chamber is enclosed by the annular groove on the Venturi gyrator and the inner wall of the nozzle housing.

In the above technical solution, the spiral groove type inner core includes an inner conical section, a middle stud section and an outer frustum section; the Venturi gyrator includes an inner inverted cone section, a middle cylinder section and an outer cone section; An annular tapering section is formed between the inner conical section and the inner inverted cone section, an annular throat section is formed between the middle stud section and the middle cylinder section, and the outer frustum section and the outer cone section are An annular gradually expanding segment is formed between them.

In the above technical solution, the nozzle housing is composed of a cone section casing and a cylinder section casing, the air inlet pipe is arranged on the top end of the cone section casing, and the Venturi rotator is embedded and fixed In the inner cavity of the cylinder section shell, the liquid inlet pipe is arranged on the side wall of the cylinder section shell.

In the above technical solution, the axis of the spiral grooved inner core coincides with the axis of the inlet pipe, is perpendicular to the axis of the liquid inlet pipe, and the axes of the three are located in the same plane.

The present invention adopts the above-mentioned technical scheme, and has the following significant technical progress and beneficial effects:

1. Combining Venturi injection atomization with hydrodynamic rotary cutting atomization, on the one hand, using the high-speed airflow negative pressure suction effect of the injection nozzle, effectively reducing the liquid supply pressure, using high-speed airflow in the Venturi The negative pressure injection in the inner injector sucks the liquid in the annular pressure equalizing chamber into the spiral groove through the liquid inlet annular gap, so that the liquid flow and the high-speed air flow are mixed and atomized, so the required hydraulic pressure is normal pressure Or low pressure, which has the effect of energy saving; on the other hand, the impact rotary cutting effect of the gas-liquid swirl nozzle is used to make the atomization of the liquid more sufficient and the particle size of the generated mist to be smaller.

2. The liquid inlet pipe of the present invention communicates with the annular pressure equalizing chamber, which is a large-section annular cavity. Because the cross-sectional area of the annular pressure equalizing chamber is much larger than the cross-sectional area of the liquid inlet annular seam, the The pressure on the entire gas-liquid circumferential contact surface at the entrance of the annular seam is equal, so that the flow rate of the liquid flowing from the liquid inlet annular seam into each spiral groove is the same. According to the principle of pressure balance, the gap between the annular pressure equalization chamber and the liquid inlet annular seam The pressure on the gas-liquid contact surface of the entire annular circumference is equal everywhere, which effectively solves the problem of unbalanced liquid inlet pressure and improves the uniformity of spraying.

3. The throat section of the Venturi injector adopts a spiral groove design, and the high-speed rotary cutting atomization effect of the air flow in the groove is used to shear and break the liquid flow, so that the liquid is atomized, and the atomization effect is good.

4. The liquid mist of the present invention is sprayed from the annular gradually expanding bell mouth at the end of the Venturi injector. The channel of the bell mouth is very wide, which effectively avoids the phenomenon of clogging, and the shape of the sprayed liquid mist is in the shape of a rotating umbrella. Improved atomization uniformity over the entire 360° angle range.

5. Among the parts composed of the nozzle of the present invention, the nozzle shell, the Venturi gyrator and the spiral groove inner core are all convoluted ring structures, which are easy to manufacture and easy to install.

Description of drawings

Fig. 1 is a sectional structural view of a gas-liquid two-phase pressure balanced wide-angle uniformly distributed fine mist nozzle;

Fig. 2 is the A-A direction view of Fig. 1;

Fig. 3 is the schematic structural view of the spiral groove type inner core in Fig. 1;

In the figure, liquid inlet pipe 1; annular pressure equalizing chamber 2; liquid inlet annular seam 3; air inlet pipe 4; nozzle housing 5 (among them: conical section housing 5.1, cylindrical section housing 5.2); annular tapering section 6; annular throat section 7; annular expanding section 8; spiral groove inner core 9 (among them: inner conical section 9.1, middle stud section 9.2, outer frustum section 9.3); Venturi gyrator 10 (among them: The inner inverted cone section 10.1, the middle cylinder section 10.2, and the outer cone section 10.3).

Detailed ways

Below in conjunction with accompanying drawing and specific embodiment the present invention is described in further detail:

The gas-liquid two-phase pressure balance wide-angle uniform fine mist nozzle shown in the figure includes a nozzle housing 5, which is provided with a liquid inlet pipe 1 and an air inlet pipe 4, and also includes a Venturi gyrator 10 and a spiral A Venturi injector composed of a grooved inner core 9, a Venturi rotary body 10 is embedded and fixed in the inner cavity of the nozzle housing 5, and a spiral grooved inner core 9 is inserted and fixed in the middle cavity of the Venturi rotary body 10; The Venturi gyrator 10 is provided with an annular pressure equalizing chamber 2, the annular pressure equalizing chamber 2 is connected with the liquid inlet pipe 1, and the inner side of the annular pressure equalizing chamber 2 is provided with a liquid outlet annular seam 3; the spiral groove inner core Between 9 and the Venturi gyrator 10, the annular tapering section 6, the annular throat section 7 and the annular expanding section 8 of the Venturi injector are sequentially formed from the inside to the outside, and the annular tapering section 6 and the intake pipe 4 In communication, the annular throat section 7 communicates with the liquid outlet annular seam 3, and the annular expanding section 8 communicates with the outside world.

Specifically, the annular pressure equalizing chamber 2 is enclosed by an annular groove on the Venturi rotator 10 and the inner wall of the nozzle housing 5 . The spiral groove inner core 9 includes an inner conical section 9.1, a middle stud section 9.2 and an outer frustum section 9.3; corresponding to the three-section structure of the spiral groove inner core 9, the Venturi gyrator 10 is also provided with a three-section structure, including The inner inverted cone section 10.1, the middle cylindrical section 10.2 and the outer cone section 10.3. An annular tapered section 6 is formed between the inner conical section 9.1 and the inner inverted cone section 10.1, an annular throat section 7 is formed between the middle stud section 9.2 and the middle cylindrical section 10.2, and the outer frustum section 9.3 and the outer cone section An annular diverging section 8 is formed between the sections 10.3. There are spiral grooves distributed on the outer surface of the middle stud section 9.2, and the spiral grooves communicate with the annular pressure equalizing chamber 2 through the liquid inlet annular gap 3, and the spiral grooves and the Venturi rotor 10 are in static fit. Specifically, the spiral groove is spot-welded with the inner wall of the Venturi gyrator 10, and the structure is more stable.

In this embodiment, the axis line of the spiral groove type inner core 9 coincides with the axis line of the inlet pipe 4, is perpendicular to the axis line of the liquid inlet pipe 1, and the axis lines of the three are located in the same plane, so that not only It makes the air flow and liquid flow more smooth, and it is convenient for machining.

In this embodiment, the nozzle housing 5 is composed of a cone section casing 5.1 and a cylinder section casing 5.2, the air inlet pipe 4 is welded on the top of the cone section casing 5.1, and the Venturi gyrator 10 is embedded and fixed In the inner cavity of the cylinder section housing 5.2, the liquid inlet pipe 1 is welded on the side wall of the cylinder section housing 5.2.

Working principle of the present invention is:

The liquid inlet pipe 1 communicates with the normal pressure water source through the plastic pipe, and the air inlet pipe 4 communicates with the compressed air supply device of 0.2MPa-0.4MPa through the plastic pipe. Water flows into the annular pressure equalization chamber 2 through the liquid inlet pipe 1. When the compressed air flow enters the annular tapering section 6 of the Venturi nozzle along the inlet pipe 4, the airflow gradually accelerates. When the airflow enters the annular throat section 7, the flow velocity reaches the maximum. The air flow flows at a high speed along the spiral grooves on the circumference of the spiral groove type inner core 9 . The high negative pressure generated by the high-speed air flow sucks the liquid in the annular pressure equalization chamber 2 into the spiral groove evenly along the liquid inlet annular gap 3. When the high-speed air flow and the liquid flow meet in the spiral groove, the high-speed air flow will The flow produces strong impact and rotary cutting, which breaks and atomizes the liquid flow to form a gas-liquid mixed flow. Subsequently, the gas-liquid mixed flow flows into the annular diverging section 8 (that is, the bell mouth) along the spiral groove, and the gas-liquid mixed flow is further expanded and atomized in the annular diverging section 8 . Finally, the liquid mist is sprayed from the annular diverging section 8 to form a fine mist with a wide angle and uniform distribution.

Claims (4)

1. A gas-liquid two-phase pressure balance wide-angle uniformly distributed fine mist nozzle, comprising a nozzle housing (5), said nozzle housing (5) is provided with a liquid inlet pipe (1) and an air inlet pipe (4), which Characterized by: It also includes a Venturi injector composed of a Venturi gyrator (10) and a spiral grooved inner core (9), the Venturi gyrator (10) is embedded and fixed in the inner cavity of the nozzle housing (5), The spiral groove type inner core (9) is inserted and fixed in the middle cavity of the Venturi rotor (10); The Venturi gyrator (10) is provided with an annular pressure equalization chamber (2), the annular pressure equalization chamber (2) communicates with the liquid inlet pipe (1), and the annular pressure equalization chamber (2) ) is provided with a liquid outlet annular seam (3); The annular tapered section (6), annular throat section (7) and annular Expanding section (8), the annular tapering section (6) communicates with the intake pipe (4), the annular throat section (7) communicates with the liquid outlet annular seam (3), and the annular gradually expanding Section (8) communicates with the outside world; The spiral groove type inner core (9) includes an inner conical section (9.1), a middle stud section (9.2) and an outer frustum section (9.3); the Venturi gyrator (10) includes an inner inverted cone section ( 10.1), the middle cylinder section (10.2) and the outer cone section (10.3); an annular tapered section (6) is formed between the inside cone section (9.1) and the inside inverted cone section (10.1), and the An annular throat section (7) is formed between the middle stud section (9.2) and the middle cylinder section (10.2), and an annular gradual expansion is formed between the outer frustum section (9.3) and the outer cone section (10.3). Paragraph (8). the 2. The gas-liquid two-phase pressure balanced wide-angle uniformly distributed fine mist nozzle according to claim 1, characterized in that: the annular pressure equalization chamber (2) is composed of the annular groove on the Venturi gyrator (10) and the The inner wall of the cylinder of the nozzle housing (5) is enclosed. the 3. The gas-liquid two-phase pressure balanced wide-angle uniformly distributed fine mist nozzle according to claim 1 or 2, characterized in that: the nozzle shell (5) is composed of a cone section shell (5.1) and a cylinder section shell body (5.2), the air inlet pipe (4) is set on the top of the cone shell (5.1), and the Venturi gyrator (10) is embedded and fixed in the cylinder shell (5.2) In the inner cavity of the cylinder, the liquid inlet pipe (1) is arranged on the side wall of the cylindrical section housing (5.2). the 4. The gas-liquid two-phase pressure balanced wide-angle uniformly distributed fine mist nozzle according to claim 1 or 2, characterized in that: the axis line of the spiral groove type inner core (9) and the axis of the air inlet pipe (4) The centerlines coincide and are perpendicular to the axis of the liquid inlet pipe (1), and the axes of the three are located in the same plane. the