US2019694A - Nozzle for the expansion of hot liquids - Google Patents

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Nov. 5, 1935. V I H. B. REITLINGER 2,019,694

NOZZLE FOR THE EXPANSION OF HOT LIQUIDS Filed March 16, 19:55

[227/222 Zor Patented Nov. 5, 1935 PATENT OFFICE.

NOZZLE FOR THE EXPANSION OF HOT LIQUIDS Henri B. Reitlinger, Paris, France, assignor to Oflce National des Recherches Scicntiflques et Indnstrielles et des Inventions,

Bellevuc,

France, and Camille Husson, Paris, France Application March 16, 1933, Serial No. 661,161 In Belgium March 19, 1932 6 Claims.

the temperature concerned.

t after the expansion and having acquired the The object of my invention is to provide a nozzle capable of so mastering the explosion that naturally occurs, whenever a liquid placed under such conditions of temperature and pressure is allowed to expand into a medium at low pressure, that said liquid, partly converted into vapor highest practically attainable velocity, flows out from the nozzle into the low pressure medium in the form of a stable jet with parallel or substantially parallel stream lines. In other words, the object of my invention is to convert the highest possible percentage of the energy available in the hot liquid under pressure into kinetic energy, which can be utilized for actuating a turbine or any jet apparatus, such as an injector, an ejector, or the like.

For this purpose, the nozzle according to my invention is of a special shape, including a converging inlet portion and a diverging outlet portion, and the profile of the inner surface of said diverging portion close to the point where it is joined to the profile of the converging portion is curved, having its concavity turned toward the inside of the nozzle.

Other features of my invention will be hereinafter more specifically described.

A preferred embodiment of the invention will now be described with reference to the accompanying drawing, given merely by way of example, and which is an axial sectional view of a nozzle for the expansion of hot water under pressure.

The problem with which my invention is concerned is to expand hot water (or another liquid) at a pressure higher than the boiling pressure thereof that corresponds to its actual temperature with a view to obtaining motive power. For this purpose, I cause said water to expand progressively and without shock from its initial to the desired low pressure by allowing it to flow and take up velocity inside at least one nozzle according to the present invention, so as to convert the thermal energy initially available in said water into kinetic energy. It is then possible to utilize the kinetic energy of the fluid issuing from the nozzle for actuating a turbine or for any other purpose.

The nozzle according to the present invention consists of a converging portion, or duct, a directly joined with a diverging portion b of a shape analogous to that of an elongated tulip, the whole being so devised that the expansion of water will take place in two phases, as follows:

A first phase which corresponds to the flow of 5 the liquid through the converging portion, from the medium under high pressure to the throat of the nozzle, and during which water flows with out evaporation, in accordance with the laws of hydrodynamics;

A second phase which corresponds to the flow of the fluid through the diverging portion, from the throat (line A-B) of the nozzle into the medium at low pressure and during which a partial evaporation of water takes place, this evapora- 15 tion necessitating, as soon as it starts, that is to say from the throat of the nozzle, a sudden increase of the section of flow afforded to the fluid.

Concerning more particularly the shape to be :0 given to the diverging portion b, said shape is determined (in accordance with the laws of thermodynamics, since the evolving fluid is a heterogeneous mixture of liquid and vapor the temperature and specific moisture of which vary 25 from point to point) so as to obtain a predetermined law of variation of the velocity along the axis of the nozzle. The cross section of the nozzle is thus calculated point by point, as a function of the temperature, the specific moisture of 80 the mixture, the specific volume thereof, and the velocity, for successive points of the axis of the nozzle.

I consider that it is advantageous to choose, as the law of variations of the velocity along the 5 axis of the nozzle, a law of uniform acceleration. In this case, divergent portion b starts from the throat of the nozzle in the form of a surface substantially at right angles to the axis of the nozzle and its profile may present a point of inflection 40 between the throat and the outlet end of said portion b.

As for the outline or profile to be given to the converging portion a, it is determined, in accordance with the laws of hydrodynamics, so as to obtain a variation of the velocity along the axis that corresponds to the law that has been chosen. Of course, account should be taken of the thermodynamic phenomena that determine the point at which vaporizing of the liquid is to begin and 50 therefore at which the converging portion 0 stops so as to be angularly joined to the diverging portion b.

For the sake of cleamess I have assumed that the diverging portion of the nozzle is a body 55 of revolution. This is not at all a necessary feature of my invention and said portion of the .-nozzle may be given any desired cross section,

polygonal or other, and the center line may be curved as well as rectilinear.

Because of the special shape of the nozzle according to rm; invention, it is possible to utilize the maximum of the energy available in the expension of hot Water under pressure, whereas, up to now, no satisfactory industrial results had ever been obtained, because use was made of nozzles having a profile substantially continuous (that is to say without an angular point). Such nozzles do not provide a sudden increase of the cross section at the point where a partial evaporation of the liquid begins to take place. Consequently the liquid cannot expand down to the pressure of the low pressure medium, so that when entering into this medium, the liquid explodes therein.

On the contrary, the nozzle according to the present invention makes it possible to bring the fluid gradually and without shock down to the pressure of the final medium and therefore to obtain, at the outlet of the nozzle, a jet having stream lines that are very substantially and even nearly rigorously parallel so that the whole of the energy that can be supplied by such an expansion (within excellent limits of practical efficiency) is accumulated in that expanded fluid.

- It will be readily understood that the nozzle according to the present invention renders it possible to obtain mechanical energy from heated fluids at relatively low temperatures with a fairly good coeflicient of efliciency, a system which could not be obtained with systems making use only of steam.

While I have described what I deem to be a practical and efficient embodiment of the present invention, it should be well understood that I do not wish to be limited thereto as there might be changes made in the arrangement, disposition and form of the parts without departing from the principle of the present invention as comprehended within the scope of the appended claims.

What I claim is:

1. A nozzle for the shockless expansion of a hot liquid at a pressure higher than the boiling pressure thereof that corresponds to the temperature of said liquid, which comprises, a converging inlet part and a diverging outlet part directly joined with each other, the inner end of the profile of said diverging part being curved, with its concavity turned toward the inside of the nozzle, and

starting substantially at right angles to the center line of the nozzle at the point where it is joined to the profile of the converging part.

2. A nozzle for the shockless expansion of a hot liquid at a pressure higher than the boiling 6 pressure thereof that corresponds to the temperature of said liquid, which comprises, a converging inlet part and a diverging outlet part directly joined with each other, the portions of said parts where they are joined to each other be- 10 ing curved, and their respective tangents being substantially at right angles to each other, the inner end of the profile of said diverging part, adjoining the place where the parts are joined. being curved, with its concavity turned toward 15 the inside of the nozzle.

3. A nozzle for the shockless expansion of a hot liquid at a pressure higher than the boiling pressure thereof that corresponds to the temperature of said liquid, which comprises, a con- 20 verging inlet part and a diverging outlet part directly joined to each other, the portions of said parts where they are joined to each other being curved, and their respective tangents being substantially at right angles to each other and the 26 tangent to the diverging part at the place where the parts are joined being substantially at right angles to the center line of the nozzle, the inner end of the profile of said diverging part, adjoining this place of joining, being curved, with its 30 concavity turned toward the inside of the nozzle.

4. A nozzle for the shockless expansion of a hot liquid at a pressure higher than the boiling pressure thereof that corresponds to the temper- 35 ature of said liquid, which comprises, a'curved converging inlet part and a curved diverging outlet part directly joined to each other, the profiles of said parts being joined to each other where they are curved in opposite directions re- 40 spectively, and where the tangent to the profile of the diverging part is substantially at right angles to the center line of the nozzle, the concavity of the portion of said diverging part adjoining the place where the parts are joined be- 45 ing turned toward the inside of the nozzle.

5. A nozzle according to claim 3 in which the inner surface of the nozzle is a surface of revolution.

6. A nozzle according to claim 4 in which the IQ inner surface of the nozzle is a surface of revolution.

HENRI B. REITLINGER

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