SU1496826A2 - Injector for atomizing liquids - Google Patents

Abstract

The invention relates to the field of mechanical engineering and can be used for spraying a liquid with a stream of a spraying agent. The goal is to increase the efficiency of the nozzle. For this middle wing of the gas distribution device, it is inclined to the longitudinal axis of the chamber at an angle of 8 to 15 °. This wing installation improves the sensitivity of the oscillating system. 2 Il.

Description

The invention relates to mechanical engineering and can be used in devices for spraying a liquid in which a liquid under pressure is fed into a stream of a spraying agent.

The aim of the invention is to increase the efficiency of the nozzle.

FIG. 1 shows the nozzle section; in fig. 2 shows section A-A in FIG. one.

A nozzle for spraying a fluid comprises a housing 1 with a chamber 2 formed therein and an outlet opening 3, fluid supply means 4 placed in chamber 2 with lower 5 and upper 6 perforations and a source of a spray agent (not shown).

In addition, the nozzle contains a gas distribution device, which is made in the form of a wing 7 with a curved symmetric profile, installed with the possibility of oscillatory movement under the action of the flow of the spraying agent around the axis 8 located in the outlet part of the chamber 2 perpendicular to the center line of the wing profile 7. The middle line of the profile the wing 7 forms with the longitudinal axis of the nozzle body (with the direction of movement of the spraying agent) an angle a equal to 8-15 ° (angle of attack).

The chamber 2 has a narrowing in the upper 9 and lower 10 points, as well as a narrowing formed by the upper 11 and lower 12 forming the outlet opening 3. Between the housing 1 and the fluid supply means 4 there are upper 13 and lower 14 channels for the spraying agent, depending on the position wing 7.

The spray nozzle operates as follows.

In the initial state, when the spraying agent is not let down, the wing 7, under the action of the moment relative to the rotation axis 8, from the intrinsic gravity takes the position shown in FIG. 1. This is due to the fact that the center of gravity of the wing 7 is located to the right of the axis of rotation 8, therefore, the moment of gravity acts in the direction of rotation clockwise, therefore the wing 7 of the lower generatrix rests on the lower point 10 of the narrowed section of the chamber 2, covering with its stern a passage through the lower channel 14. In this position, the middle line of the wing profile 7 forms with the longitudinal axis of the nozzle (with the direction of movement of the spraying agent) an angle a (angle of attack) equal to 8-15 °.

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When applying the spraying agent, the latter passes the upper part of the wing 7, then into the channel 13 between the housing 1 and the means 4 and is directed to the outlet 3, the liquid discharged from the upper row of the perforation 6 of the means 4 is sprayed. less than the spreading agent, due to its covering by the aft part of the wing 7, the direction of flow after the outlet 3 is determined by the direction of the generatrix 11.

At the same time, when applying the spraying agent, due to the corner a, an asymmetrical flow of the wing 7 with this agent takes place. As a result, the speed of the agent above the wing 7 is greater than the speed of the agent under the wing 7. According to Bernoulli’s law, the pressure above the wing is less and under the wing more. Under the action of this pressure difference, the Zhukovsky lift force acts on the wing, equal to

where p is the density of the spraying agent,

W - speed of incident on the wing

spraying agent, m / s; g - velocity circulation around the wing,

1 - wing span in the transverse direction, m

This force is applied to the center of pressure of the wing 7, which, like its center of gravity, is located to the right of the axis of rotation 8.

However, the direction of this force is opposite to the direction of the force of gravity of the wing 7. Thus, on the wing 7 there are two moments of forces directed against each other. Upon reaching a certain value of the velocity of the spraying agent, the moment of Zhukovsky force exceeds the moment of gravity force. Wing 7 begins to rotate around axis 8 counterclockwise and approach its upper generator towards point 9.

The channel 13 is covered by the aft part of the wing 7, and the channel 14 is opened. The spraying agent passes through the channel 14 to the outlet 3, the sprayed liquid exiting from the bottom row of the perforation 5 of the means 4. Now the direction of flow after the outlet 3 is determined by the direction of the generatrix 12.

As soon as the channel 13 is covered by the wing 7, the pattern of the flow past the wing 7 is reversed. At the top of the wing 7, the flow pressure is greater than the bottom. Now the moment of difference of the forces of action of these pressures coincides with the moment of the own force of gravity of the wing 7, and the wing 7 returns to its original state.

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Then the cycle repeats automatically, and the wing 7 oscillates around the axis 8, like an indicator, directing the flow of the spraying agent into one or the other channels 13 and 14, thus creating an oscillating gas-liquid plume after the outlet 3.

Consequently, the wing periodically occupies two extreme positions at which the middle line of the wing profile 7 makes an angle of 8-15 ° both on one and the other side of the longitudinal axis of the nozzle.

The quality of the wing with is characterized by the ratio of the lifting force y to the frontal drag X of the wing 7 to the flow

c- v x

The higher this value is, the better the quality of the wing. The quality of the wing is maximum at an angle of attack and is 0.94. It falls slightly to the corner. If a is greater than 15 °, the quality c decreases sharply due to the disruption of the continuous separation of the wing by the flow, displacement and removal of the critical point from the exit edge of the wing (the critical point is the point where the current line above and below the wing in the sharp edge of the rear part of the wing 7 is merged).

Between the two extreme positions of the wing 7 there is an intermediate one when its median line coincides with the axis of the nozzle, i.e. when the angle of attack. In this short-term state, through which the wing moves to one of the two extreme positions by inertia, the flow of the spraying agent flows symmetrically around the wing 7 and passes in equal quantities through channels 13 and 14, and in the outlet 3, the flow moves with a direct flow along the nozzle axis without rejection.

Limiting the deflection of the wing 7 from the nozzle axis within the angles of attack of 8-15 ° allows reducing the size of the nozzle, the flow resistance from the wing 7, and thereby reducing the pressure loss on the blasting agent.

Improving the quality of the characteristics of the wing 7, caused by installing it at an angle of attack of 8–15 ° to the incident flow of the spraying agent, makes it possible to increase the sensitivity of the oscillatory system.

Claims (1)

Invention Formula Nozzle for spraying liquid according to ed. St. No. 1346265, characterized in that, in order to increase the efficiency of the nozzle operation, the centerline of the wing of the gas distribution device is inclined to the longitudinal axis of the chamber at an angle of 8-15 °. Phi.2.1