RU1787221C - Gas ejector - Google Patents

Abstract

SUMMARY OF THE INVENTION: The slotted exit openings of the active nozzle are formed by partitions directed from the axis of the ejector, a leading edge of a smaller diameter is located inside the nozzle, a larger diameter is located in the mixing chamber. The inner face of each partition is adjacent to a fairing that is continuous and symmetrical with respect to the axis of the ejector in each longitudinal section thereof, with its tip facing the opposite direction to the movement of the active medium. The back face of each partition is located in the mixing chamber. The thickness of the partition increases in two directions - towards the diffuser and from the axis of the ejector. The peripheral face of the baffle outside the nozzle is located outside the cylindrical surface described by the radius of the nozzle exit section. The front edges of the partitions are made with a sharp edge and stepped. In the active nozzle are partitions of a larger diameter step, made streamlined. 4 s.p. f-ly, 4 ill. ate with

Description

The invention relates to inkjet technology and can be used when pumping various media.

An ejector is known for removing a vapor-air mixture from a condenser of a steam turbine plant and maintaining the necessary vacuum, comprising a receiving chamber, a narrowing nozzle, a mixing chamber, a narrowing part of the channel and a diffuser. The nozzle is used to convert the potential pressure energy of the active medium entering the nozzle from the receiving chamber into the kinetic energy of the jet, which, flowing out of the nozzle at a high speed, entrains the vapor-air mixture from the chamber connected to the vapor space of the condenser into the narrowing part of the channel

of variable cross section and then enters the diffuser, in which the flow is decelerated and the kinetic energy is converted to potential, as a result of which the pressure at the outlet of the diffuser exceeds atmospheric pressure and the vapor-air mixture is constantly removed from the condenser.

The disadvantage of such an ejector is its low efficiency due to the fact that the active jet captures the passive medium only by its surface, while the internal part of the jet does not come into contact with the passive medium.

Structurally, the closest to the proposed one is a jet pump (ejector), comprising a distribution chamber, a multi-barrel active nozzle with trunks installed in it, made

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in the form of concentrically placed double-walled nozzles with slit outlet openings located relative to each other with the formation of annular channels for supplying a passive medium, and a mixing chamber with a neck, the active nozzle having a diameter exceeding the diameter of the neck of the mixing chamber, one of the three walls of the nozzle is made cylindrical, another conical and located at an acute angle to the axis of the mixing chamber, and the channels for supplying a passive medium are communicated with each other by means of radial nozzles.

The disadvantages of such a jet pump are low efficiency due to the large hydraulic resistance in the multi-barrel active nozzle, large hydraulic losses in the annular channels for supplying a passive medium, and ineffective conditions for the interaction of two media directly behind the nozzle exit section when using gas as an active medium, i.e. e. non-drip liquid., design complexity and low reliability of its operation when pumping contaminated liquids,

The aim of the invention is to increase the efficiency of the ejector by improving the conditions for mixing the active and passive media while significantly reducing the hydraulic resistance in the active nozzle and when the passive medium is mixed in the chamber, simplifying the design and increasing the reliability of operation.

The goal is achieved in that in an ejector (jet pump) containing an active multi-barrel nozzle with slotted outlet holes, a mixing chamber with a diffuser, the slotted outlet holes being formed by partitions, the front edges of which are stepped, directed from the axis of the ejector, the front sharp edge of the step is smaller the diameter is located inside the nozzle, and the larger diameter step is streamlined and located in the mixing chamber, the rear face of each partition is located in the mixing chamber, while The thickness of each baffle increases in two directions — to the diffuser and from the axis of the ejector, the peripheral face of each baffle outside the nozzle is located outside the cylindrical surface described by the radius of the exit section of the nozzle, and the inner face of each baffle is adjacent to the solid and symmetrical relative to the axis of the ejector in each longitudinal section of the fairing, the tip facing the opposite direction to the movement of the active medium.

Figure 1 shows a longitudinal section of a gas ejector; figure 2 is a section

A-A in FIG. 1;. In FIG. 3 - section A-A, variant; figure 4 - section aa, option

In a gas ejector (FIGS. 1, 2) containing a multi-barrel active nozzle 1 with slotted outlet openings 2, a chamber 3

0 mixing with the diffuser 4, the slotted outlet openings 2 are formed by partitions 5, the leading edges 6 of which are made stepped, directed from the axis of the ejector, with the front sharp edge of the step 5 of smaller diameter located inside the nozzle 1, and the step of larger diameter made streamlined and located in the chamber 3 mixes, and the rear face 7 of each partition 5 is located in the chamber 3

0 mixes. In this case, the thickness of each baffle 5 increases in two directions - to the diffuser 4 and from the axis of the ejector, the peripheral face 8 of each baffle 5 outside the nozzle 1 is located outside

5. The cylindrical surface described by the radius r of the exit section of the nozzle 1, and the inner face of each partition is closely adjacent to a solid and symmetrical axis of the ejector in

0 each of its longitudinal sections of the fairing 9, with an ostrium facing in the opposite direction to the movement of the active medium. The length of the fairing 9 may be equal to the length of the partitions 5, counted

5 along the axis of the ejector, the rear face 10 of the fairing can be located in one section with the rear face 7 of each partition, and the length of the first is less than the length of the partition counted along the axis of the ejector. In each cross section of the cowling 9 in the direction of the diffuser 4, the outer diameter of the former may increase; in the area adjacent to the tip of the cowling 9, the outer diameter of the latter may increase by

5 of each section in the direction of the diffuser, and then remain constant.

Gas ejector works as follows. . In multi-barrel active nozzle 1 s

An active medium (steam or water) enters from the receiving chamber through the slotted outlet openings 2, where the potential pressure energy of the latter is converted into kinetic energy of the jet,

5 which, due to the presence of baffles 5 in the nozzle 1, is divided into a series of jets.

Behind the exit section of nozzle 1, the pressure of the active medium decreases to the pressure at the suction of the ejector, as a result of which an increase in the volume of the active medium takes place behind the nozzle. Therefore, the presence of partitions 5, partially located in the mixing chamber 3, ensures the expansion of the active medium only in the direction from the axis of the ejector, which allows the creation of conditions for the formation of voids behind the rear faces 7 of each partition 5, as well as behind the fairing 9, into the indicated voids T a passive medium is generated, and the interaction surface of the two media increases sharply, which leads to the achievement of high values of the ejector efficiency. The presence of the fairing 9 allows more uniform distribution of the active medium in the volume of the mixing chamber.

The length of the portion I of the septum located in the mixing chamber 3 (Fig. 1) is determined experimentally by achieving maximum efficiency at the nominal operating mode of the ejector. In this case, the peripheral face 8 of each partition 5 in the radial direction should be located at such a distance from the axis of the ejector that the active medium at the exit from the nozzle 1 does not cover these faces 8. In this case, the passive medium is freely accessible into the resulting voids behind the rear faces 7 of each partition 5 and the rear face 10 of the fairing 9,

The implementation of the fairing 9 of various lengths and with a varying cross section along its length is determined by the size of the ejector and its other characteristics.

The ejector partitions can have a different shape, for example, for small values of the outlet (size) radius of the nozzle 1, the leading edges 6 of each partition 5 should be made straight (Fig. 2), and for large radii of the outlet section of the nozzle, an arc shape (Fig. 3) ), while both edges 11 and 12 of the rear face 7 can be made arc (Fig.Z, which provides an increase in the interaction surface of two media in the mixing chamber 3, in other words, leads to an increase in the ejector efficiency. Rotation of each front edge b of the partition 5 and both edges 11 12 each rear face 7 at an angle relative to each other around the axis of the ejector provides flow twist which under all conditions of claim 1 leads to an additional increase in the efficiency of the ejector.

In addition, to ensure reliable operation of the ejector, the partitions 5 can be made not rigidly connected to the nozzle 1, which, using a special device, allows the partitions to be removed from the nozzle to clean them of possible contaminants. It should be noted that the design

the proposed ejector is simpler than the design of the prototype.

The use of the invention in condensing units of steam turbines, as well as in other branches of technology, allows to reduce the energy consumption for the operation of the ejector due to a significant increase in its efficiency, as well as to reduce weight and dimensions, simplify its design compared to the 0 prototype and increase the reliability of operation.

Claims (4)

1. A gas ejector comprising a multi-barrel active nozzle with slit outlet openings and a mixing chamber 5 by a diffuser, while the slotted exit holes are formed by partitions directed from the axis of the ejector, the leading edge of a smaller diameter is located inside the nozzle, and the larger diameter is located in the mixing chamber, and the inner face of each partition is adjacent to a solid and symmetrical relative to the axis of the ejector in each longitudinal its cross section is flowed around with a tip pointing to the side opposite to the movement of the active medium, characterized in that the rear face of each partition is located in the mixing chamber Thickness of each partition 0 increases in two directions - to the diffuser and from the axis of the ejector, and the peripheral face of each partition outside the nozzle is located outside the cylindrical surface described by the radius of the outlet 5 nozzle sections, while the front edges of the partitions are made with a sharp edge and stepped, in the active nozzle are partitions of a step of smaller diameter, and in the mixing chamber, partitions 0 steps of larger diameter, the latter being streamlined, 2. The ejector according to claim 1, otT, and the fact that the length of the fairing is equal to the length of the partitions, counted along the axis of the ejector. 5 3. The ejector according to claim 1, with the fact that the rear face of the fairing is located in one section with the rear face of each partition, and the length of the fairing is less than the length of the partition counted 0 along the axis of the ejector. 4. The ejector according to claim 1, characterized in that in each section of the fairing in the direction of the diffuser, the outer diameter of the first increases. 55, The ejector according to claim 1, with the exception that in the area adjacent to the tip of the cowling, the outer diameter of the latter increases in each section in the direction of the diffuser, and then remains constant.