JPH0315491B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a mixing atomizer for atomizing liquids using gas. Furthermore, the invention relates to a device for liquid atomization comprising a plurality of such mixing atomizers.

The term liquid as used throughout this specification also includes dispersions and emulsions containing solid particles in the liquid.

Atomizers are used on a large scale, especially to atomize heavy liquid fuels during the combustion process, in order to promote intense contact between the liquid and the combustion air for proper combustion. In the atomizer, the liquid fuel is dispersed into very small droplets, which can then be mixed with oxygen or an oxygen-containing gas, such as air, in a combustion chamber to combust the fuel. Atomization is typically accomplished by ejecting liquid under pressure through one or more orifices of specific shape and size. Adding a gas, such as steam, to the liquid within the atomizer itself facilitates atomization of the liquid. In this specification and claims, an atomizer that adds gas to the liquid to be atomized is referred to as a mixing atomizer. When attempting to atomize fuel, it is important to generate a spray of liquid particles that is substantially uniformly distributed over the exit area of the atomizer to promote optimal combustion of the liquid within the combustion chamber. That's true.

Although the following description of the invention deals primarily with steam atomization of liquids such as oil, the application of the proposed atomizer is not limited to steam atomization of liquids. Steam may be replaced by air or refinery fuel gas, for example. It can also be saturated with steam for moistening. In addition to applications in combustion devices, the proposed type of atomizer can also be used, for example, in atomization devices for evaporating volatile components.

It is an object of the present invention to provide a mixing atomizer for atomizing liquids using a gas, the device being capable of controlling the velocity and flux of liquid leaving the atomizer during operation in order to produce a uniform liquid atomization. is configured to be substantially uniformly distributed throughout the exit area of the atomizer to facilitate maximum utilization of the liquid for combustion or other uses.

The mixing atomizer for atomizing a liquid with a gas according to the invention comprises a first mixing chamber with inlet means for supplying the liquid and the primary gas to form a mixture of the liquid and the gas; means for supplying a secondary gas tangentially around the liquid and gas mixture passing through the second mixing chamber; and an outlet nozzle having a cross-sectional area substantially smaller than the cross-sectional area of the second mixing chamber. a second mixing chamber having a cross-sectional area substantially larger than the cross-sectional area of the first mixing chamber; The two mixing chambers and the outlet nozzle have substantially coincident longitudinal axes.

In a suitable embodiment of the invention, a plurality of the above-mentioned atomizers are combined in a single device for atomizing liquid, said device comprising a single liquid supply supplying a plurality of mixing atomizers. A single gas supply section.

The invention therefore also relates to a device for atomizing liquids using gas, which device comprises a member having a longitudinal axis and comprising a plurality of inventive mixing atomizers terminating in the outer surface of the head of the member. a first member forming a fluid communication section between the liquid supply channel and the first mixing chamber of the mixing atomizer; a passage, a second passage for supplying primary gas from the gas supply passage to the first mixing chamber, and a second passage for supplying secondary gas tangentially from the gas supply passage to the second mixing chamber of the mixing atomizer; and a third passage.

The invention will now be explained in more detail by way of examples with reference to the accompanying drawings.

FIG. 1 shows a mixing atomizer for atomizing liquid such as heavy liquid fuel using gas,
This atomizer is generally designated by the numeral 1.
The mixing atomizer 1 has as its main components a first mixing chamber 2, a second chamber 3 in fluid communication with the first mixing chamber 2, and an outlet nozzle 4 connected to the second mixing chamber 3.
and has. Although these three components have substantially coincident longitudinal axes, the cross-sectional area of the second mixing chamber 3 and the cross-sectional area of the outlet nozzle 4 are both smaller than the cross-sectional area of the first mixing chamber 2. substantially larger. Furthermore, the cross-sectional area of the outlet nozzle 4 is selected to be smaller than the longitudinal area of the second mixing chamber 3. Channels 5 and 6 are provided in the atomizer for supplying the liquid to be atomized at or near the free end of the first mixing chamber 2 and for atomizing the gas at or near the free end of the first mixing chamber 2. will be placed in Channels 5 and 6 are arranged at an angle with respect to each other to facilitate vigorously dispersing the flow of liquid exiting channel 5 by the gas flow from channel 6.

Channel 7 for supplying gas to the second mixing chamber 3
An annular channel 7 is provided in the mixing atomizer with a passage 8 forming fluid communication between the mixing chamber 3 and the mixing chamber 3 .
These passages 8 are arranged evenly across the outer circumference of the second mixing chamber 3 and are arranged in such a way that the gas from the annular passage 7 is introduced tangentially into said mixing chamber 3. disposed relative to the second mixing chamber.

Downstream of the annular channel 7, the second mixing chamber 3 is provided with a substantially frustoconical side wall 9, which tapers towards the outlet nozzle 4, so that the fluid flows through the channel 7 and the channel 8. from there toward the outlet nozzle 4.

During operation of the mixing atomizer shown in FIG. 1 for atomizing liquid fuel with steam, the liquid to be atomized and steam are introduced into the first mixing chamber 2 . Due to the impact force of the steam flow on the supplied liquid flow, the fluid flow is dispersed into small liquid fragments in the first mixing chamber 2. By bringing the steam from channel 6 into contact with the liquid flow from channel 5 at an angle, dispersion of the liquid flow is facilitated. The mixture thus formed from liquid fraction and steam enters a second mixing chamber 3 in which secondary steam is added to said mixture at sonic speed. Because the secondary steam is introduced tangentially at high speed into the enlarged second mixing chamber, the secondary steam is formed by a mixture of the liquid fraction from the first mixing chamber 2 and the primary steam. form a ring surrounding the central part. The majority of the tangentially introduced steam flows substantially along the frusto-conical wall 9 of the second mixing chamber 3 and follows a path along the wall of the outlet nozzle 4, so that Direct contact between the liquid and the wall is prevented. Such contact can easily reduce the velocity of liquid flowing close to said wall, resulting in an irregular outflow pattern of liquid throughout the outlet nozzle 4.

Because the cross-sectional area of the outlet nozzle 4 is substantially smaller than the cross-sectional area of the second mixing chamber 3, the velocity of the mixture of steam and liquid fractions is substantially increased in the outlet nozzle 4, so that the liquid fractions causing further dispersion of Owing to the presence of the shield consisting of the tangentially supplied secondary steam, the velocity and density of the liquid fragments are substantially uniform over the entire cross-section of the outlet nozzle 4, and this feature 4 allows effective combustion of the liquid in a combustion chamber (not shown) located downstream of 4. On exiting the mixing atomizer, the liquid/steam mixture expands rapidly, leading to the formation of a spray containing very fine liquid particles within the combustion chamber. In this space, the liquid particles are brought into contact with a blast of air to combust the fuel.

Figures 2 and 3 show a device for atomizing liquids.
Referring to the figures, the apparatus comprises a plurality of mixing atomizers of the type already discussed with reference to FIG.

The atomizing device comprises a central channel 11 for supplying atomizing liquid to a plurality of mixing atomizers 12 and a concentrically arranged annular channel 13 for supplying a liquid to be atomized, such as oil. Consisting of 10. A mixing sprayer 12 is placed in the head 14 of the device 10.

The distance between the outlet nozzles of adjacent mixing atomizers 12 must be selected to be sufficiently large so that no interference occurs between adjacent effluent liquid droplet streams. A suitable arrangement for the mixing atomizer 12 is that shown in FIG. In this case, the centers of the outlet nozzles of the mixing sprayer 12 are arranged in a circular manner,
Adjacent outlet nozzles are also spaced 120 degrees apart from each other. As shown in FIG. 2, the head 14 of the device 10 is frustoconically shaped, but the mixing atomizer 12 is positioned perpendicular to the outer surface of the head 14. This arrangement allows the application of more mixing sprayers than is possible with a device with a flat head and a mixing sprayer placed perpendicular to the flat outer surface of the head, and allows for the application of adjacent mixing sprayers. There is no risk of interference between sprayers.

Each mixing atomizer 12 comprises a first mixing chamber 15, a second mixing chamber 16 and an outlet nozzle 17, where the second mixing chamber 16 is substantially larger than the first mixing chamber 15. . The first mixing chamber 15, the second mixing chamber 16 and the outlet nozzle 17 of each mixing atomizer 12 have coincident longitudinal axes, such that each mixing atomizer is perpendicular to the frustoconical outer surface of the head 14. will be placed in

A plurality of passages 18 are provided forming fluid communication between the central channel 11 and the first mixing chamber 15 for supplying the primary atomizing fluid to the mixing atomizer 12 . A secondary atomizing fluid is supplied to the second mixing chamber 16 of the mixing atomizer 12 via a tangentially arranged passage 19 . These passages 19 form fluid communication between the mixing atomizer 12 and a substantially annular passage 20 which is connected to the central passage 11 via a passage 21 . An annular passage 20 surrounds the mixing atomizer 12 for supplying a secondary atomizing fluid to the mixing atomizer 12 via a tangentially arranged passageway 19 as shown in FIG.

The fluid to be atomized is supplied to the first mixing chamber 15 of the mixing atomizer 12 via a plurality of passages 22 which form a fluid connection between the liquid annular channel 13 and the first mixing chamber 15 .

The operation of the apparatus shown in FIGS. 2 and 3 is substantially the same as discussed with reference to the individual mixing atomizer shown in FIG. When using the apparatus shown in FIGS. 2 and 3 for atomizing oil with steam, a common liquid supply, i.e., annular passage 13, and a common steam supply, i.e., central passage 11, are used. Oil and steam are respectively supplied to the mixer atomizer 12 via the pump.

It must be noted that the invention is not limited to mixing atomizers comprising a second mixing chamber with a frusto-conical wall downstream of the secondary steam inlet. If a smooth path exists for the secondary steam from the secondary steam inlet to the outlet nozzle of the mixing atomizer, it is ensured that the secondary steam forms a shield along the walls of the second mixing chamber and the outlet nozzle. If so, other shapes of tapered walls could be used in place of these walls.

Although in the illustrated embodiment the mixing atomizer is provided with a central inlet for the primary steam in combination with side inlets for the liquid, these inlets may be arranged in other ways, e.g. A combination of a central inlet for the primary steam and a lateral inlet for the primary steam may be selected.

Furthermore, the invention is not limited to devices with a mixing atomizer having a special arrangement of a central channel for steam and an annular channel for liquid, as shown in FIG.
Any other suitable arrangement may be applied, provided that steam and liquid can be supplied to the mixing atomizer from a common steam path and a common liquid path, respectively.

Finally, it is noted that the invention is not limited to liquid spray devices having a truncated conical head. Alternatively, the device can be provided with a flattened head. In the case of such a head, it is possible to arrange the mixing atomizers relative to each other in order to facilitate the arrangement of a relatively large number of mixing atomizers in the device without the risk of interference between the fluid flows exiting the active atomizers. Preferably, the mixing atomizer is arranged at an acute angle to the external surface of the head with outlet nozzles pointing in different directions.

[Brief explanation of the drawing]

Fig. 1 is a longitudinal sectional view of the mixing sprayer of the present invention, Fig. 2
3 is a longitudinal cross-sectional view of a device for liquid spraying comprising a plurality of mixing atomizers of the present invention, and FIG. 3 is a plan view of the device shown in FIG. 2. 1, 12... Mixing sprayer, 2, 15... First mixing chamber, 3, 16... Second mixing chamber, 4, 17... Outlet nozzle, 5... Liquid inlet means, 6... Gas inlet means, 7, 8... Secondary gas supply means, 10... Member (device), 11, 13... Supply path, 14... Head, 18... First passage, 19... Third passage,
22...Second passage.

Claims (1)

Claims: 1. A first mixing chamber with inlet means for supplying a liquid and a primary gas to form a mixture of liquid and gas, and a liquid and gas passing through a second mixing chamber during operation. a second mixing chamber leading to an outlet nozzle having a cross-sectional area substantially smaller than the cross-sectional area of the second mixing chamber; , the first mixing chamber extends into a second mixing chamber having a cross-sectional area substantially larger than the cross-sectional area of the first mixing chamber, and the first mixing chamber, the second mixing chamber and the outlet nozzle a mixing atomizer for atomizing a liquid with a gas, the atomizer having longitudinal axes substantially coincident with each other; 2. Mixing atomizer according to claim 1, characterized in that separate inlet means for liquid and primary gas are provided in the first mixing chamber, the inlet means being inclined with respect to each other. 3. The mixing atomizer according to claim 1 or 2, wherein the second mixing chamber is provided with a tapered wall portion for smoothly guiding the secondary gas to the outlet nozzle. 4. The mixing atomizer is provided with a plurality of tangentially arranged passages for tangentially supplying the secondary gas to the second mixing chamber, the passages traversing the outer periphery of the second mixing chamber. 4. A mixing atomizer according to any one of claims 1 to 3, characterized in that the atomizers are arranged substantially uniformly. 5. A mixing sprayer according to any one of claims 1 to 4, characterized in that the cross-sectional area of the outlet nozzle is substantially larger than the cross-sectional area of the first mixing chamber. 6. A member having a longitudinal axis, which is provided with a plurality of mixing sprayers according to any one of claims 1 to 5, and which terminates at the outer surface of the head of the member, and which is for liquid use. a first passage forming a fluid communication between the liquid supply passage and a first mixing chamber of the mixing atomizer; , a second passage for supplying the primary gas from the gas supply passage to the first mixing chamber, and a second passage for supplying the secondary gas tangentially from the gas supply passage to the second mixing chamber of the mixing atomizer. 3. A device for atomizing a liquid by means of a gas. 7. Apparatus according to claim 6, characterized in that the centers of the outlet nozzles are arranged in a circle with substantially equal distances from each other. 8. Claim 6, characterized in that the head of the member has a substantially frustoconical outer surface, and the mixing atomizer is arranged substantially perpendicular to said outer surface. The apparatus according to paragraph 7 or paragraph 7. 9. The head of the member has a substantially flat outer surface and the mixing atomizer is provided with outlet nozzles which are arranged at an acute angle to the outer surface of the head and which are oriented in mutually different directions. Apparatus according to claim 6 or 7, characterized in: 10. Claims characterized in that one of the feed channels is located substantially at the center of the member, the other feed channel is annular, and the feed channels have substantially coincident longitudinal axes. Apparatus according to any one of the ranges 6 to 9.