DE102006001319A1 - Two-fluid nozzle with Lavalcharekteristik and with pre-division in the liquid supply - Google Patents

Abstract

This invention relates to two-component nozzles with an internal mixture. Through a targeted gradation of the pressure drop in the atomizing gas to the mixing chamber in or in the two-phase fluid from the mixing chamber to the nozzle mouth, a much finer tropical spectrum is generated with the same amount of energy expenditure. Furthermore, the average droplet size is considerably reduced by pre-dividing the liquid flow which is fed to the mixing chamber.

Description

was standing of the technique

In Many process engineering plants distribute liquids in a gas. It is common crucial that the liquid in as possible sprayed fine drops becomes. The finer the drops, the greater the specific drop surface area. from that can There are considerable procedural advantages. For example, hang the size of a reaction vessel and its manufacturing cost significantly from the average droplet size. But In many cases, it is by no means sufficient for the average droplet size to be one certain limit value. Just a few much larger drops can to considerable malfunctions to lead. This is especially the case when the drops due to their Not size evaporate fast enough so that drops or doughy particles in subsequent components, e.g. B. on fabric filter bags or on fan blades, be deposited and disrupted by incrustations or lead to corrosion.

Around liquids to spray fine, come either high-pressure single-fluid nozzles or medium-pressure two-fluid nozzles Commitment. An advantage of two-fluid nozzles is that they, in comparison with the single-fluid nozzles, relatively large Flow areas so that even coarse particles or precipitates Tending fluids sprayed can be. The invention described below relates to such two-fluid nozzles.

There most dual-fluid nozzles be operated with compressed air, the following is often followed instead of the term "compressed gas" Designation "compressed air" used.

Characters:

1 : Two-fluid nozzle with internal mixing according to the prior art.

2 : Basic variant of a two-fluid nozzle according to the invention with a Lavalcharakteristik.

3 : Two-fluid nozzle according to the invention with pre-division of the liquid by internals in the liquid supply line.

4 : Two-fluid nozzle according to the invention with pre-division of the liquid by introducing a small amount of atomizing gas into the liquid before entering the mixing chamber.

5 : Unfavorable allocation of film flow direction and supply holes in the mixing chamber.

6 : Favorable allocation of the flow direction of the liquid films and the arrangement of Zuluftbohrungen in the mixing chamber according to the invention. Shown is the development of the here conically executed mixing chamber wall with the Zuluftbohrungen and with arrows, which represent the flow direction of the liquid film on the mixing chamber wall.

1 shows an example of the axis 19 essentially symmetrical two-fluid nozzle 3 According to the state of the art. The liquid to be sprayed 1 is via a central lance tube 2 at the bottleneck 10 into the mixing chamber 7 initiated. The compressed gas 15 is over an outer lance tube 4 an annular chamber 6 fed, which surrounds the mixing chamber annular; over a certain number of holes 5 the compressed gas is in the mixing chamber 7 initiated. In this mixing chamber a first division of the liquid takes place in drops, so here is a drop-containing gas 16 is formed. Also at the exit from the mixing chamber 7 there is a bottleneck 14 , It closes a divergent exit part 11 on, which with the nozzle mouth 8th ends. The one in the mixing chamber 7 formed drop-containing gas stream 16 is strongly accelerated in the convergent-divergent nozzle, so that here a further division of the drops is effected.

A fundamental problem with these nozzles results from the fact that the walls in the mixing chamber 7 are wetted with liquid. The liquid which wets the wall in the mixing chamber becomes a film of liquid due to shear stress and compressive forces 17 Driven to the nozzle mouth. It is tempting to assume that the walls are blown dry towards the nozzle mouth due to high flow rates of the gas phase and that only very fine droplets are formed from the liquid film.

theoretical and experimental work of the inventors / 1-9 / have, however, shown that liquid films on walls even then exist as stable films without dripping could be, if the gas flow, which the liquid films to the nozzle mouth drives, supersonic speed reached. And that is the reason why it is possible in rocket thrusters to apply a liquid film cooling. Particularly critical is the film flow in the spray Ver high viscosity Liquids, which at the same time have a high surface tension, e.g. B. of glycol in refrigeration dryers from natural gas pumping stations or from solid suspensions in spray absorbers.

The liquid films, which are driven by the gas flow to the nozzle mouth, can even move around a sharp edge on the nozzle mouth due to the adhesion forces; they then form on the outside of the nozzle mouth a Wasserwulst 12 . 1 , From this Wasserwulst dissolve edge drops 13 whose diameter is a multiple of the average droplet diameter in the jet core. And although these large edge drops contribute only a small mass fraction, they are ultimately determining the dimensions of the container, in which, for example, the temperature of a gas to be lowered by evaporative cooling from 350 ° C to 120 ° C, without causing an entry of drops comes in downstream components such as fans or fabric filters.

Another problem is that at the bottleneck 10 into the mixing chamber 7 Incoming liquid forms a massive jet in most dual-fluid nozzles of this type, which can be divided into sufficiently small drops only with a relatively large amount of energy, ie with a relatively large atomizing air flow and atomizing air pressure. In the competitive product, the one-component pressure atomizer, the energy consumption is relatively low, but only at very high atomization pressures to drop sizes, as can be achieved with two-fluid nozzles even at much lower pressures. Therefore, in the interests of minimizing the energy expenditure, the initial phase of liquid atomization in two-substance nozzles should not be dispensed with with the aid of a high compressed-air consumption. In the interest of producing a particularly fine droplet spectrum with the least possible expenditure of energy, the pressure potential of the compressed gas should for the most part only be used in the final phase of the atomization in the mixing chamber and in the supersonic jet.

In a recent one already filed by the same inventors far-reaching suggestions for the optimization of two-fluid nozzles described. This application concerned jets with an additional one Ringspaltverdüsung at the nozzle mouth. With these nozzles is already at a relatively low pre-pressure of the atomizing air and thus with low energy consumption a fairly fine droplet spectrum to achieve. However, the pressure of the atomizing air is sufficient then no longer in the nozzle orifice supersonic speed to reach. An even finer drop spectrum is in design the two-fluid nozzle as functional Laval in any case, if you have such a high pressure in the atomizing air builds up that the two-phase mixture accelerates to supersonic speed will and if you have the formation of large drops of wall-fluid films and in particular avoids water accumulation at the nozzle mouth.

aim The invention is, with the aid of novel two-fluid nozzles at preferably low energy consumption, a particularly fine droplet spectrum generate and in particular the formation of isolated large drops to avoid.

2 shows a basic variant according to the invention.

In this novel nozzle concept, the grading of the sum of the bore cross-sectional areas for the atomizing air at the inlet 5 into the mixing chamber and the cross-sectional areas at the mixing chamber outlet 14 or in the divergent part of the nozzle orifice chosen so that at the given form the atomizing air in the holes 5 at the entrance to the mixing chamber approximately reaches the speed of sound and that at the nozzle mouth 8th without consideration of the drop content of the flow supersonic speed is achieved. This means that the cross-sectional widening in the divergent nozzle exit part 11 only so large may be chosen that a steady acceleration of the supersonic flow up to the nozzle mouth 8th actually takes place. If the crosscut widening is set too large, compression impacts already occur in the divergent nozzle part, and a fall back into the subsonic velocity range occurs. If, on the other hand, the cross-sectional widening is dimensioned too small, a bursting free jet is created at the nozzle mouth. In both cases, the divergent nozzle part points 11 no Lavalcharakteristic in the true sense of the word, because the cross-sectional shape is not adapted to the available pressure gradient.

To step but in the divergent section of the nozzle exit part, compression shocks, so leads this is great for education Drops. This is due to the fact that the pressure jump in the compression shock with the flow boundary layer along the Wall of the nozzle exit part interacts. This leads to the formation of a more or less extended flow separation zone with a liquid film occupied wall. In such detachment zones The wall shear stress is inevitably very low, so only low shear forces on the liquid film act; are accordingly large the drops formed here. For this reason, there is a disadvantage the Laval nozzle in that they respect the air supply not operated advantageous in the partial load range can be. At one for a big pressure drop designed Laval nozzle the outlet cross section at the nozzle mouth is relatively large and for a smaller one available pressure drop in any case, too large. At partial load operation occur in the divergent exit part of such Nozzle compression shocks on and the flow velocity is reduced to subsonic speeds. At subsonic speeds but then finds itself in the divergent part of the nozzle, as in any subsonic diffuser, a delay the flow velocity instead, associated with a pressure increase. This pressure increase causes a strong thickening of the flow boundary layer and thus a serious reduction of the wall shear stress in said divergent nozzle section. If a nozzle in terms of the atomizing air to be driven in a wide pressure range, so that with subsonic speeds at the nozzle mouth is to be expected, is recommended, the nozzle without a divergent outlet part to build or an annular gap atomization at the nozzle mouth provided. Because about this annular gap atomization can the liquid film even then sprayed into small drops when the shear stress on the inside of the divergent nozzle exit part relatively low is. However, it must not be too low; especially must have a flow separation in the divergent nozzle part be avoided at all costs.

Also an unmatched Laval nozzle with too small cross-sectional widening and consequently with a bursting free jet does not cause optimal atomization, because the way for the energy supply into the drops in the expansion fan then too short. And further, the shear stress on the wall fluid films in the nozzle exit part acts lower at subsonic velocities within this nozzle exit part, as if actually at supersonic speeds already within the nozzle exit part would be accelerated.

As previous versions have already shown, the conditions in the design of a Laval nozzle fundamentally essential more complex when there is a two-phase flow. This is especially true then if in addition to the gas phase and wall liquid film there are still drops in the free flow. These Drops represent high-density mass accumulations of a gas flow must be accelerated with relatively low density. Acceleration forces act but only from the gas flow on the drops when the gas flow faster than the drops, d. h., if a slip between the two components occurs. In this case, every drop points dependent on from the slip speed a more or less extensive Caster "dead water" on, which with Filled gas phase is. The mean velocity of this dead water lies between that of the drop and that of the undisturbed gas phase. Consequently the sum of the dead water areas behind the drops for the gas phase a Querschnittsversperrung represents, whereby the effective cross-section is reduced in the divergent exit part of the nozzle. You could be too the conclusion that it is therefore necessary to a larger cross-sectional extension to provide an adapted Laval nozzle configuration. On the other hand, however, it has to be considered that the interaction between the driving gas flow and the braking drops is subject to pressure loss. The pressure gradient, which the gas phase for the acceleration available Accordingly, is less than that in a single-phase gas flow, so that the achievable final speed is generally lower than at pure gas phase flow. In addition, there is also a density change of the gas phase Evaporative cooling, because as atomizing medium usually dry air is used.

mit

• M = Machzahl = Strömungsgeschwindigkeit/Schallgeschwindigkeit
• κ = Isentropenexponent (≈ 1,4 für Luft)

With a low drop loading, most of the effects mentioned here are naturally lower than with a large drop load. Since such two-fluid nozzles are designed for a wide range of variations of the liquid loading, an exact vote is possible only for a very special operating condition. According to the observations of the inventors, it is advantageous for usual proportions of the mass flows of atomizing gas and liquid, the divergent nozzle part 11 actually approximately to be carried out such that this section represents an adapted Laval nozzle at the available pressure ratio in single-phase gas flow. The corresponding formula apparatus is known from gas dynamics. Thus, the diameter ratio of the divergent nozzle section D _{n, m} / D _{n, mc, e} 2 , for example, correspond to the following relationships:

With

• M = Mach number = flow velocity / speed of sound
• κ = isentropic exponent (≈ 1.4 for air)

The Mach number M, in turn, results from the pressure ratio of the "static pressure" in the mixing chamber p ₀ to the "final pressure" at the nozzle orifice "p _m as follows:

From the combination of both equations, the dimensioning rule for the diameter ratio D _{n, m} / D _{n, mc, e is derived} for a given pressure ratio p ₀ / p _m :

Should the nozzle not strictly rotationally symmetrical, would be here with the diameters of Circular cross sections to be calculated, with the orthogonal flow cross sections match the actual nozzle.

The detail optimization, taking into account the effect of the drops to be accelerated or divided in the Laval nozzle, can lead to the aspect ratio of the divergent nozzle section D _{n, m} / D _{n, mc, e} , 2 , must be modified in comparison to that of a matched Laval nozzle in single-phase flow. Thus, it may be advantageous to increase the difference in the diameter of the nozzle orifice and the constriction at the mixing chamber outlet by a factor of at most about 5, measured on the values resulting from the above design rule. In a closer examined nozzle with a diameter of 9 mm at the bottleneck of the mixing chamber outlet, for example, an increase in diameter of the nozzle mouth of calculated 9.4 mm to 11.5 mm has proved advantageous, which corresponds to a magnification factor of 3.75.

Here also plays the quality the pre-atomization in the mixing chamber and the physical properties of the liquid, in particular the toughness and surface tension a significant role because small droplets or their atomization products, a drop cloud, lower slip speeds and thus a lower displacement effect exhibit as big Drops.

Another very important aspect is the slimming degree of the Laval nozzle. Neglecting the flow boundary layers, it is possible to achieve end velocities of the same magnitude with the same cross-sectional ratios "bottleneck to mouth" but with different degree of slenderness of the nozzle. Despite the steady acceleration, of course, flow boundary layers also occur in Laval nozzles, which are thicker with long and slimmer nozzles than with short nozzles. Accordingly, high values of the wall shear stress can be achieved in short nozzles, so that smaller drops are formed from the decay of the wall liquid film than with slender nozzles. Theoretical considerations can be expected to create particularly favorable conditions with a slenderness of about 1-4. Here, as slenderness degree "S", the ratio of the length of the divergent section of the nozzle exit part I _{n, div} (n = nozzle / nozzle) to the difference ΔD from the diameter at the nozzle mouth D _{n, m} (m = mouth / mouth) to that defined at the exit from the mixing chamber D _{n, mc, e} (mc, e = mixing chamber, exit).

Furthermore, in 2 the use of sheath air 20 shown with the to a ring nozzle 21 shaped cladding tube 23 , which at the nozzle mouth the relatively wide-sized annular gap 22 forms. Here the enveloping air flows out at a relatively slow speed. Thus, it is not able to decompose wall liquid films into sufficiently small drops, but it prevents in any case a rapid buildup of deposits on the nozzle mouth 8th , This is state of the art and is addressed here only because an important feature of the two-component nozzles becomes obvious. The nozzle lances, including the nozzle and the Hüllluftversorgung should be as lean as possible, because it can be avoided in this way that form on the lance head extended areas with flow separation. Measures for pre-dividing the liquid entering the mixing chamber should therefore be as space-saving as possible.

As already stated, with a view to minimizing the energy expenditure, it is sensible to work towards the fact that already the pre-atomization in the mixing chamber leads to a fine droplet spectrum. 3 shows corresponding explanations. By suitable installations in the liquid supply to the mixing chamber, the liquid is already divided before an intense interaction with atomizing air such that the task of the atomizing air it is much easier. This causes a finer droplet spectrum at the same energy expenditure. Such a pre-division of the liquid jet is already known in principle. However, the concepts practiced lead to an increase in the outer diameter of the nozzles, resulting in significant problems for the design of the lance head, especially when the nozzles are to be surrounded with enveloping air, as in 2 is shown.

As internals come z. B. spin-producing body 24 . 3a and 3b in question, either in the lance tube 2 for hydration or in the bottleneck 10 at the entrance to the mixing chamber 7 can be installed. However, star-shaped inserts could also be advantageous 25 be, 3c through which the liquid is broken down into partial beams, without a swirl being imparted. Another simple possibility, which is not depicted here, is to introduce the liquid into the mixing chamber via a number of individual bores, it being advantageous for the directions of the axes of said bores to be associated with the design of the supply air bores 5 to optimize. The measures proposed here do not increase the nozzle diameter, so that a slender design of the lance head or the Hüllluftdüse 21 is possible.

such activities in the area of the liquid supply line put at nozzles however, according to the prior art, that the liquid not leading to blockages coarser Particles is loaded, or that the liquid is not for deposit formation by precipitations tends on the walls. With those developed by the same inventors Methods for on-line cleaning of nozzles and nozzle lances were the prerequisites created for that also such internals can be used without suitable cleaning techniques a solid transfer of fluid would cause the mixing chamber. On especially big ones free cross sections in the fluid supply to the mixing chamber can therefore in the future be waived.

If a swirl generator 24 into the fluid intake 2 or 10 is incorporated, it should be ensured according to a further development of the invention that the liquid film that forms in the mixing chamber on the wall, no free path between the Zuluftbohrungen is offered. The 4 and 5 show developments of the conical inside of the mixing chamber according to 2 but with different positioning of Zuluftbohrungen on the rows of holes 27 - 30 , 4 represents an unfavorable configuration in which a wall film strand at the given twist strength can flow undisturbed between the Zuluftbohrungen through to the outlet of the mixing chamber. From the thus insufficiently pre-divided liquid strands arise in the outlet part of the nozzle relatively large drops.

By a suitable displacement of the Zuluftbohrungen, 5 , These passages, as it were by slalom rods in the form of supply air jets, can be installed in such a way that the liquid film does not find any loopholes and thus a finer liquid distribution already succeeds in the mixing chamber. In principle, it is desirable that the Zuluftstrahlen the liquid film AS POSSIBLE completely rupture, as a busy with many parallel blades blades plow can tear a wide field area gapless. The supply air holes of the second row 28 Therefore, taking into account the swirl in the film flow and relative to the position of the Zuluftbohrungen in the first row 27 to stand in the gap. The same applies to any existing additional rows of Zuluftbohrungen.

A further embodiment according to the invention shows 6 , Here is a small partial flow of the atomizing air 15 , z. B. 50% of the volume of liquid to be sprayed, even before entering the mixing chamber via a small bypass line 31 fed into the liquid. The aim of this measure is to penetrate the liquid fine bubbles with gas. By the pressure reduction at the entrance to the mixing chamber, the trapped gas bubbles expand and thus burst the liquid. By this Vorzerteilung the Liquid is significantly reduced by the injected air into the mixing chamber dicing work. Depending on the physical properties of the liquid to be atomized, it may be advantageous to vary the partial air flow introduced into the liquid before entering the mixing chamber between 20% and 200% of the volume of the liquid to be sprayed.

Of course, it may also be useful or even necessary in these nozzle concepts to surround the two-substance jet with enveloping air. Because it is of crucial importance that it also comes from the side of the flue gases, which are to be cleaned or cooled with the help of the nozzles, not for deposit formation in the sensitive for a high atomization quality mouth region of the nozzle. The temperature of the fluid emerging from the two-fluid nozzle is generally far below that of the flue gas or of the gas which is to be cleaned or cooled. In the case of falling below the sulfuric acid dew point on the nozzle outer wall, it would have to come in dust-laden gases over time to build up deposits on the outside of the nozzle and at the nozzle mouth. 4 also shows a version with Hüllluft, where it can be very advantageous to heat the Hülluft to avoid falling below the sulfuric acid dew point on the outside of the Hüllluftrohres, and thus to prevent a disturbing deposit formation and corrosion. Another very important advantage of a configuration with enveloping air is that the shock-resistant Hüllluftdüsen represent an efficient protection for especially in the sharp-edged mouth area shock-sensitive two-fluid nozzles.

1

to atomized liquid

2

lance tube for the Supply of the liquid to the two-fluid nozzle

3

Two-component nozzle

4

lance tube for the Supply of the compressed gas to the two-fluid nozzle

5

Through bores the compressed gas to the mixing chamber ("core air")

6

outer annulus or annular chamber of the two-fluid nozzle

7

mixing chamber the two-fluid nozzle

8th

Nozzle mouth or nozzle orifice

9

Binary mixture from compressed gas and liquid droplets

10

Through bore the liquid (Bottleneck) towards the mixing chamber

11

divergent Nozzle outlet part

12

fluid retention

13

detached big drop / edge drop

14

bottleneck at the outlet of the mixing chamber

15

compressed gas

16

drops containing Gas in the mixing chamber

17

liquid film

18

beam core

19

axis the two-fluid nozzle

20

sheath air

21

Ring nozzle of the cladding tube

22

annular gap for the sheath air

23

Hüllluftrohr

24

swirl generator

25

star-shaped insert

26

Liquid strands, the on the wall of the mixing chamber between

neighboring Supply air holes pass through

27

Row 1 of the supply air holes 5

28

Row 2 of the supply air holes 5

29

Series 3 of the supply air holes 5

30

Row 4 of the supply air holes 5

31

small Bypass line for the compressed gas

bibliography

• 1 Wurz, D.E .: Flow behavior of thin water Film under the effect of a co-current air flow of moderate to high subsonic velocities; effect of the film on the air flow; Proceedings of the Third International Conference on Rain Erosion and Associated Phenomena, England, Elvetham Hall, vol. 2, pp. 727-750, 11-13 August (1970) Published by A.A. Fyall and R.B. King, Royal Aircraft Establishment, England
• 2 Wurz, D.E .: Experimental Investigation of the Flow Behavior thinner Water films and their reaction to a rectified air flow of moderate to high subsonic velocity, Dissertation, Karlsruhe (1971)
• 3 Wurz, D.E .: Flow behavior of thin water films under the effect of a co-current air flow of moderate supersonic velocities; Proceedings of the Fourth International Conference on Rain Erosion and Associated Phenomena, Germany, Meersburg, Vol. 1, pp. 295-318, 08-10 May (1974), Edited by A.A. Fyall and R.B. King, Royal Aircraft Establishment, England
• 4 Wurz, D.E .: Experimental investigation into the flow behavior of thin water films; Effect on a co-current air flow of moderate to high supersonic velocities. Pressure distribution at the surface of a rigid wavy reference structure. XII Biennial Fluid Dynamics Symposium "Advanced Problems and Methods in Fluid Dynamics ", Bialowieza, Poland, 1975, Archives of Mechanics, 28, 5-6, pp. 969-987, Warsaw (1976)
• 5 Wurz, D.E .: liquid film flow under Action of a supersonic air flow; Habilitation Thesis, Karlsruhe (1977)
• 6 Wurz, D.E .: Subsonic and supersonic gas liquid film flow; Paper No. 78-1130, AIAA-11-th Fluid and Plasma Dynamics Conference, Seattle, Washington (USA), 10-12 July (1978)
• 7 Reske, R., D.E. Root: Droplet impingement on walls and wavy water films Colloquium EUROMECH 162; Stability and Evaporation of Thin liquid films in two-phase flow; Palace of Jablonna, Poland, 20-23 Sept. (1982)
• 8 Sill, K.H., D.E. Wurz: Experimental and theoretical investigation of shear driven evaporating liquid films; Colloquium EUROMECH 162; Stability and Evaporation of Thin Liquid Films in Two-Phase Flow; Palace of Jablonna, Poland, 20-23 Sept. (1982)
• 9 Wurz, D.E .: The subsonic-supersonic controversy of the shear-driven liquid film flow Colloquium EUROMECH 162; Stability and evaporation of Thin Liquid Films in Two-Phase Flow; Palace of Jablonna, Poland, 20-23 Sept. (1982).

Claims (10)

Two-fluid nozzle for spraying liquids with the aid of a compressed gas with a mixing chamber, in which the liquid and the compressed gas are introduced, a converging in the flow direction section at the outlet of the mixing chamber and a divergent in the flow direction nozzle outlet part, characterized in that in the divergent outlet part to the Nozzle outlet, the nozzle mouth, supersonic speed occurs.

Two-substance nozzle according to claim 1, characterized in that the ratio of the diameter D _{n, m of} the cross-sectional areas perpendicular to the flow direction at the nozzle mouth and at the constriction 14 at the outlet from the mixing chamber D _{n, mc, e} is dimensioned according to the following relationship: two-fluid nozzle according to claim 2, characterized in that the difference of Diameter of the nozzle mouth and the bottleneck at the mixing chamber outlet by a factor of maximum 5 is measured, measured at the diameter difference, according to claim 2 for pure gas flow was calculated. two-fluid nozzle according to one of the claims 1-3, characterized in that the decomposition of the liquid in the mixing chamber by measures is favored in the liquid supply. two-fluid nozzle according to one of the claim 4, characterized in that said activities in the installation of spiral roses, star-shaped displacement elements or from perforated surfaces into the supply line of the liquid exist to the mixing chamber. two-fluid nozzle according to claim 4, characterized in that a small subset the atomizing gas corresponding to about 20-200% of the volume of the liquid to be sprayed already in the liquid supply line is introduced to the mixing chamber. two-fluid nozzle according to claim 4, characterized in that devices are present are that lead to a fine bubble division of the amount of partial gas, the already in the liquid supply line is injected to the mixing chamber. two-fluid nozzle according to one of the claims 1-7, characterized in that the bores, over which the atomizing gas is blown into the mixing chamber, arranged in such a gap are that a liquid film There is no undisturbed passage on the wall of the mixing chamber. two-fluid nozzle according to the claims 5 and 7, characterized in that in the liquid supply line a swirl generator is installed and that the holes through which the atomizing gas is introduced into the mixing chamber, approximately on a coaxial Generating line lie. two-fluid nozzle according to one of the claims 1-9, characterized in that the degree of slimming of the divergent Nozzle exit part in the range between 1 and 4.