Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F03—MACHINES OR ENGINES FOR LIQUIDS; WIND, SPRING, OR WEIGHT MOTORS; PRODUCING MECHANICAL POWER OR A REACTIVE PROPULSIVE THRUST, NOT OTHERWISE PROVIDED FOR
  • F03G—SPRING, WEIGHT, INERTIA OR LIKE MOTORS; MECHANICAL-POWER PRODUCING DEVICES OR MECHANISMS, NOT OTHERWISE PROVIDED FOR OR USING ENERGY SOURCES NOT OTHERWISE PROVIDED FOR
  • F03G7/00—Mechanical-power-producing mechanisms, not otherwise provided for or using energy sources not otherwise provided for
  • F03G7/04—Mechanical-power-producing mechanisms, not otherwise provided for or using energy sources not otherwise provided for using pressure differences or thermal differences occurring in nature
  • F03G7/05—Ocean thermal energy conversion, i.e. OTEC
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
  • F01D—NON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAM TURBINES
  • F01D1/00—Non-positive-displacement machines or engines, e.g. steam turbines
  • F01D1/02—Non-positive-displacement machines or engines, e.g. steam turbines with stationary working-fluid guiding means and bladed or like rotor, e.g. multi-bladed impulse steam turbines
  • F01D1/026—Impact turbines with buckets, i.e. impulse turbines, e.g. Pelton turbines
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
  • F01D—NON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAM TURBINES
  • F01D1/00—Non-positive-displacement machines or engines, e.g. steam turbines
  • F01D1/32—Non-positive-displacement machines or engines, e.g. steam turbines with pressure velocity transformation exclusively in rotor, e.g. the rotor rotating under the influence of jets issuing from the rotor, e.g. Heron turbines
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F05—INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
  • F05D—INDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS
  • F05D2210/00—Working fluids
  • F05D2210/10—Kind or type
  • F05D2210/13—Kind or type mixed, e.g. two-phase fluid
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F05—INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
  • F05D—INDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS
  • F05D2240/00—Components
  • F05D2240/20—Rotors
  • F05D2240/24—Rotors for turbines
  • F05D2240/241—Rotors for turbines of impulse type
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F05—INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
  • F05D—INDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS
  • F05D2240/00—Components
  • F05D2240/20—Rotors
  • F05D2240/24—Rotors for turbines
  • F05D2240/242—Rotors for turbines of reaction type
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
  • Y02E10/00—Energy generation through renewable energy sources
  • Y02E10/30—Energy from the sea, e.g. using wave energy or salinity gradient

Definitions

• Diphasic expansion device capable of maximizing the amount of movement produced by a two-phase flow
• the present invention relates to a device for the two-phase expansion with good efficiency of a high saturation flow rate of a hot liquid with low vapor density at operating temperatures of the device. It is particularly applicable to the conversion of thermal energy into mechanical energy between a hot source and a low temperature difference cold source and more particularly to the thermal energy of the sea (ETM).
• ETM thermal energy of the sea
• the thermal energy of the seas is the difference in temperature between the surface layers and the deep layers of the oceans which reaches nearly 20 ° C in the intertropical zones.
• the energy is recovered by simple hydraulic turbining of the liquid phase.
• the term "mistlift” will hereinafter denote the process by which droplets of hot fluid are raised against gravity by their own vapor under the effect of the vapor pressure difference between the hot bottom portion and the cold top portion. of the device.
• Fog generator proposed inefficient with a significant loss of energy during the initial flash vaporization and a coupling vapor / droplets inefficient during the acceleration phase, associated with significant pressure drops, all of these factors resulting in a loss of energy. overall effectiveness of the device very limited.
• the device according to the invention makes it possible, among other things, to provide an answer to the difficulties related to the devices that have been proposed in the prior art by proposing a solution adapted to an efficient two-phase expansion of a low-temperature fluid in which the dispersed phase consists of drops of very small dimensions (diameter from about ten microns to a few millimeters), then called droplets, microdroplets or microdroplets, and the continuous phase of its own vapor, the fluid having very low vapor density at the temperature considered (eg water at 28 ° C). It makes it possible to obtain a good mechanical coupling between the vapor and the droplets and to accelerate the droplets with a good efficiency by limiting the pressure losses of the flow.
• the device can be integrated in a power conversion device using the mistlift process or in a rotating machine using the two-phase jet reaction.
• the invention proposes a two-phase expansion device capable of maximizing the amount of movement produced by a two-phase flow coming from the expansion of a large saturation flow of a fluid coming from a so-called hot source.
• the two-phase expansion device comprises at least:
• a dispenser for distributing the fluid from the hot source to a plurality of two-phase expansion nozzles
• each nozzle comprising successively at least one convergent, a neck and a tube and the nozzles being arranged to receive each a portion of the flow from the hot source;
• the two-phase expansion device thus makes it possible, in particular at the same time to work with high flow rates because of the use of the multitude of two-phase expansion nozzles while controlling the expansion of the vapor during the relaxation, a source of loss of charge and therefore efficiency.
• the two-phase expansion device may have the following characteristics, alone or in combination:
• the neck section of at least one two-phase expansion nozzle is designed to produce a liquid jet
• the neck section of the at least one diphasic expansion nozzle for producing a liquid jet is circular or square in shape
• the neck section of at least one two-phase expansion nozzle is designed to produce a liquid web
• the neck section of the at least one two-phase expansion nozzle for producing a liquid web is in the form of an elongated slot
• At least one of the two-phase expansion nozzles comprises a mixing element downstream of the neck
• the space between the two-phase expansion nozzles at the tube outlet is minimized by means of a suitable nozzle outlet geometry, so that the outlet of the tube of a first two-phase expansion nozzle is in contact with the outlet of the tube a second diphasic expansion nozzle adjacent to the first two-phase expansion nozzle.
• liquid from a so-called cold source at a temperature lower than that of the hot source, and intended to condense the vapor produced is ejected in the form of a spray from the space available between the two-phase expansion nozzles at the outlet of the tube two-phase expansion nozzles with a high velocity component in the direction of the two-phase flow exiting the two-phase expansion nozzles;
• the two-phase expansion device comprises extension elements with a variable section at the outlet of the tube of the two-phase expansion nozzles making it possible to ensure a continuity of the sectional variation of the two-phase flow from the outlet of the tube of the two-phase expansion nozzles to the outlet of the common divergent duct extending the two-phase expansion nozzles;
• the means for maintaining the plurality of two-phase expansion nozzles comprises a plate, the two-phase expansion nozzles being machined in the plate or molded with the plate;
• the means for maintaining the plurality of two-phase expansion nozzles comprises means for welding or for gluing the two-phase expansion nozzles together.
• the invention proposes a "Hero" type turbine comprising at least one two-phase expansion device as presented above, at the end of at least one of its arms.
• the invention provides an action type turbine comprising at least one two-phase expansion device as presented above as an injector.
• the invention proposes an energy conversion device using the mistlift method comprising at least one two-phase expansion device as presented above to produce and accelerate the droplets of hot liquid, the conversion device using the mistlift method comprising means for fluid connection with a hot source and means for fluid connection with a cold source.
• the hot source is, for example, hot water at a first depth below the surface of the ocean and the cold source is cold water at a second depth greater than the first depth below the surface of the ocean.
• FIG. 1 represents, from the prior art, a diagram showing the mistlift device as presented in US Pat. No. 4,441,321;
• FIG. 2 represents, in the prior art, a diagram showing a device for the mistlift process
• FIG. 3 represents, from the prior art, a diagram representing a "Hero" type turbine, each arm carrying a fog accelerator;
• FIG. 4 represents a diagram showing a detailed view of the end of the "Hero" turbine arm shown in FIG. 3;
• FIG. 5 represents, from the prior art, a diagram showing a vertical sectional view of the fog generating part of the devices represented in the preceding figures;
• FIG. 6 represents, in the prior art, a schematic diagram of a diphasic expansion nozzle
• FIG. 7 represents, from the prior art, a schematic diagram of a two-phase expansion nozzle comprising a mixing element as presented in the document FR 2 944 460;
• FIG. 8 represents an embodiment of the two-phase expansion device of the present invention, the whole of the expansion being made in a multitude of two-phase nozzles;
• FIG. 9 represents an embodiment of the two-phase expansion device of the present invention, a part of the expansion being made in a multitude of two-phase nozzles and the other part in a suitable conduit;
• Figures 10a and 10b respectively show a top view and a partial sectional view of an embodiment of the two-phase expansion device of the present invention, the space between nozzles at the nozzle outlet being minimized;
• FIGS. 11a and 11b respectively show a top view and a partial sectional view of an embodiment of the two-phase expansion device of the present invention, extension elements being inserted into the duct extending the nozzles;
• FIGS. 12a and 12b respectively show a top view and a partial sectional view of an embodiment of the two-phase expansion device of the present invention, a liquid sheet being generated at the outlet of the neck of the nozzles;
• FIG. 13 is a cross-sectional view of an exemplary embodiment of a device for converting thermal energy into mechanical energy using a "Hero" type turbine, which is provided with a two-phase expansion device according to FIG. 9;
• Fig. 14 is a longitudinal sectional view of the conversion device of Fig. 13;
• Figure 15 is a top detail view of the end of an arm of the "Hero" type turbine of Figures 13 and 14;
• Figure 16 is a view similar to that of Figure 14, for an alternative embodiment of the conversion device.
• the devices represented and described in the various figures are adapted for ⁇ , namely that the hot fluid designated by hot water is in this case seawater extracted at the surface at a temperature which can vary in general between 22 ° C and 30 ° C and the cold fluid designated cold water seawater extracted depths (usually between 500 and 1500m depth) and at a temperature between 5 ° C and 10 ° C, conditions found, for example, in the oceans of intertropical zones.
• the hot fluid designated by hot water is in this case seawater extracted at the surface at a temperature which can vary in general between 22 ° C and 30 ° C and the cold fluid designated cold water seawater extracted depths (usually between 500 and 1500m depth) and at a temperature between 5 ° C and 10 ° C, conditions found, for example, in the oceans of intertropical zones.
• the devices described could of course operate in a different context than ⁇ with hot and cold fluids different from seawater (for example with geothermal energy and hot water coming from the basement and cold water coming from of a river, or with industrial heat recovery) or at temperatures substantially different from those indicated above with the condition of adaptations to the device obvious to a specialist.
• the present application includes these other uses and / or other fluids.
• the following table gives examples of recoverable heat temperature levels, i.e. the temperature of the hot fluid, in various industrial applications in which the device of the present invention could be used.
• FIG. 1 represents the mistlift process described in US 4,441,321
• the hot water 45 taken near the surface 49 of the ocean is ejected with an upward vertical speed by a fog generator 41 to produce a multitude of micro droplets 43 in a chamber 46 in which a high vacuum is maintained.
• the steam is then relaxed in a vertical divergence where it communicates part of its energy to the water droplets by raising them against gravity in an acceleration zone 40.
• This cold water spray makes it possible to gradually condense the steam in the upper part of the enclosure 46.
• the set consisting of cold water spray, hot water droplets and the remaining vapor converges at the top of the chamber 46 to form a liquid jet.
• the liquid part is released into the ocean.
• a vacuum pump 47 makes it possible to evacuate the non-condensables out of the enclosure 46.
• the energy of the device is recovered by means of a hydraulic turbine 42 inserted into the hot water supply channel.
• this device has the disadvantage of requiring very large steam passage sections associated with very large heights. Indeed, given the very low density of the steam and its initial speed necessarily limited, the pressure upstream of the fog generator is reduced by the pressure drop due to the hydraulic turbine. For example, such a 4 MW device for ⁇ would be 20m in diameter for nearly 100m high.
• the fog generator and acceleration zone assembly is one of the key elements of the device, since it involves transforming the thermal energy contained in the water into kinetic energy for the vapor (by relaxation), itself communicated. in large part to the droplets by the steam.
• the device according to the invention constitutes a new concept of the fog generator and accelerator zone assembly and in particular makes it possible to improve its efficiency.
• the droplets will have to travel a long distance in the enclosure 46 with a very high probability of collision between the droplets themselves or with the walls. Indeed, although initially homogeneous, the dimensions and speeds of the droplets become increasingly heterogeneous as collisions and coalescing phenomena, resulting in different droplet speeds. Each collision constitutes a loss of energy for the device. A significant loss will be made through these collisions. The largest droplets will be little or no steam and may fall back into the chamber. The convergence of the droplets to form a single jet can not be done without a significant loss of energy.
• the contact surface between cold water spray and steam must be very important requiring a fine atomization of the cold water spray to obtain the heat exchange necessary for a total condensation of steam by cold water.
• the collisions of the droplets composing the cold water spray and the hot water droplets, then transforming into a single liquid jet consumes a lot of energy (successive collisions).
• FIG. 2 represents, from the prior art, a variant of the mistlift process in which the transmission of the kinetic energy of the hot water droplets 51 is done by incorporation into a liquid sheet 52 flowing on a wall 55, making it possible to reduce the height of the device above an acceleration zone 50 and to improve the transition from dispersed droplets 51 to a single-phase liquid jet 52 'that can be turbined by a turbine 53.
• FIG. 3 represents, from the prior art, a "Hero" turbine with four arms 1 mounted in rotation in a chamber, specific to a fluid having a very low vapor density at the relaxation temperatures considered.
• Each arm 1 can supply hot water at its end a fog generator assembly 6 and acceleration zone, the latter being for example in the form of nozzle 7.
• the proposed provisions for the Fog generator 6 and the throttle nozzle 7 are the same as those proposed by Stuart L Ridgway for the mistlift process.
• FIG. 4 represents, from the prior art, a detailed view of the end of the arm 1 of the "Hero" turbine of FIG. 3.
• the hot water under pressure feeds a receiver 5 and then passes through the generator of Fog 6.
• the two-phase fluid is then accelerated in the nozzle 7.
• the outgoing jet 8 propels the generator assembly 6 and nozzle 7 by reaction, causing the rotation of the arms 1 in the enclosure.
• FIG. 4 represents the end of one of the arms 1, comprising the receiver 5, followed by the generator 6 and the nozzle 7, oriented so that the jet at the outlet of the nozzle 7 is substantially perpendicular to the axis of rotation of the bars 1.
• FIG. 4 represents, from the prior art, a partial partial section view of the mist generator 6 proposed in the mistlift or "Hero" turbine concepts described above.
• the fog generator 6 proposed in the prior art must make it possible to cope with the specific constraints of ⁇ namely considerable amounts of hot water and extremely low vapor densities.
• a 10 MW ETM plant must treat a hot water flow of about 20m 3 / s.
• Each cubic meter of hot water will produce approximately 240 billion droplets 27 of 200 microns in diameter and 930 m 3 generate steam at the end of relaxation.
• the mist generator 6 consists of a plate 20 pierced with a multitude (several million) of injection holes 21 of convergent shape in which the water is accelerated under the effect of pressure.
• the holes of 100 microns in diameter are spaced by 2 mm or 250,000 holes per m 2 , a 10MW plant requiring a plate area of 350 m 2 .
• a jet 22 of liquid is formed at the outlet of each hole 21 of the plate 20, the diameter of the jet being substantially equal to the outlet diameter of the hole 21.
• this jet is suddenly depressurized at a lower pressure. at its vaporization pressure.
• the initial creation of the steam is perpendicular to the jet following the arrows 23, so as to fill the available volume between the holes 21 with the steam.
• this steam-creation phase does not provide any useful work on the droplets driving them in a direction perpendicular to that of the desired jet.
• the experiments carried out show rather a slowing in the direction of the jet of the initial speed of the droplets in this phase, the sudden creation of vapor causing a great turbulence in this zone. This energy is lost for the device. It is therefore necessary to limit this creation of initial vapor to a portion of the thermal energy available in the droplets.
• the steam 27 is then driven along the arrow 24 under the effect of the pressure difference between the hot injection zone and a zone kept cold by means of water from the cold source, in an acceleration zone 25.
• a divergent nozzle 26 corresponding to the nozzle 7 of Figure 4, common holes 21 of the plate 20 where the steam relaxes and converts the remaining enthalpy kinetic energy.
• this common nozzle 26 the droplets continue to cool and produce steam.
• the kinetic energy of the vapor is partly transmitted to the droplets under the effect of the friction forces between vapor and droplets which are accelerated.
• the jet path section changes abruptly, from the exit of the injection hole 21 to the acceleration zone (25) where the expansion of the vapor 27 is perpendicular to the jet velocity (the section passes abruptly from the section of the hole to a section 500 times larger). Not only does this vapor expansion 27 not transmit kinetic energy to the droplets in the desired direction, but it splits the jet into a multitude of droplets entrained perpendicularly to the jet. The velocity of these droplets and steam after this steam-creation phase is no longer in the direction of flow and there has been a loss of much of the initial kinetic energy of the jet.
• the acceleration that can be imparted to the droplets by the steam is proportional to the drag divided by the mass of the droplet.
• the mass of the droplet is itself proportional to the cube of the diameter. So in the end, the possible acceleration of the droplet is inversely proportional to the diameter of the droplet. For a diameter of 500 microns and a sliding speed of 20m / s, the possible acceleration is only 18 m / s 2 acceleration requiring a distance of at least 46 m. Droplets of 100 microns would allow acceleration and a distance respectively of 80m / s 2 and 10m while droplets of 10 microns respectively 890m / s 2 and 0.9m.
• the pressure drops of the two-phase vapor / droplet flow in the acceleration part are very large, compared to the available pressure difference. It is therefore essential to reduce the length of the acceleration zone as much as possible.
• the solution is to reduce the size of the droplets. Except the droplets quickly tend towards a large equilibrium diameter (500 microns) and the initial diameter is itself fixed by the diameter of the jet which is difficult to reduce below 100 microns taking into account the risks of plugging holes 21 injection (with a fluid such as seawater and bio-fouling) and given the pressure losses caused by the injection holes themselves.
• the fog generator device consisting of a plate 20 pierced with a multitude of holes 21 associated with an acceleration zone 25 as proposed in the prior art has serious constraints which will drastically limit the yields of the engine. device.
• FIG. 6 represents, from the prior art, an expansion nozzle for two-phase fluid.
• a nozzle comprises, successively in the direction of flow of the fluid, a convergent 10, a neck 1 1 and a tube 12.
• the fluid in the liquid state is first accelerated in the convergent 10 to the neck 1 1
• steam is produced by flash vaporization of the liquid.
• This steam is guided in the tube 12 which can be divergent from half-angle (a) from the section of the neck 1 1 and the flash vaporization controlled by the geometric parameters of the divergent 12.
• a controlled flash vaporization is obtained, with a vapor velocity represented by arrows 13 having a major component in the direction of flow.
• This type of nozzle is used in the ejectors and it has also been proposed, in the prior art, to use it in rotating machines of the "Hero" turbine type, each arm 1 carrying a nozzle at the end.
• This mixing element 14 represented on a nozzle in FIG. 7, can be for example a fixed or mobile propeller. This mixing element 14 allows effective mixing of the liquid and vapor phases downstream of the neck 1 1 and thus improve the mechanical coupling liquid / vapor.
• any increase in flow passes through an increase in the neck section 1 1 of the nozzle and therefore the diameter of the jet at the immediate exit of the neck 1 1. It is clear that the increase in the diameter of the jet will decrease the efficiency of the steam production during the flash, the exchange surfaces as a function of the water mass being reduced, the heat exchange inside the jet more difficult, and will also decrease the effectiveness of the formation of microdroplets during the breaking of the jet. Any increase in the liquid flow also involves increasing the flow of steam produced. Outside, in the case of ⁇ , very low density steam requires very large passage sections. The section of the nozzle at the outlet of the tube 13 must therefore be very important.
• the poor efficiency of the formation of microdroplets from the jet will limit the friction between vapor and droplets and cause the need for a very large acceleration length (for example a length of 46 m for drops of 500 microns in diameter while the length is 0.9m for drops of 10 microns in diameter) It should also be noted that it would take 80 nozzles of this type to treat a flow rate of 20m 3 / s hot water corresponding to a power ETM of 10 MW.
• each arm 1 carries a single nozzle of the type shown in Figures 6 and 7 at the end is not possible for power of a few MW, considering the flows to be treated.
• FIG. 8 represents, in one embodiment, a schematic diagram of the two-phase expansion device according to the invention, able to maximize the amount of movement produced by a two-phase flow.
• This is a sectional representation, on which a support 61, in the form of plate has been shown, only partially.
• a plurality of nozzles 60 each having at least one convergent 65, a collar 66 and a tube 67, preferably diverging in the flow direction of the fluid, are arranged adjacent to the support, next to one another, so that the total flow of hot water to be treated is distributed in each of the nozzles 60.
• the adjacent nozzles 60 are machined in a plate 61 which may be metallic or of any material resistant to corrosion and having characteristics sufficient mechanical Examples are steel, titanium or plastics or composites. The whole could, among the multiple possible embodiments, be obtained by molding or any other method.
• the nozzles 60 could also be produced separately individually and collected by a suitable support, or directly attached to each other by welding or gluing, for example.
• the hot water represented by the arrow 62 enters a receiver 63 whose role is to distribute the water to the multitude of nozzles 60 by minimizing the pressure drops of the flow at the inlet of the nozzles 60.
• turbulence can be inserted into the receiver 63.
• Sealing means are placed between the nozzles 60, so that a fraction of the flow of the fluid passes through each nozzle 60, without fluid flow between the nozzles 60.
• the flow represented by the arrows 64 passing through each nozzle 60 is controlled by the number of nozzles 60 of the device. This number can be chosen so as to be in a flow range favorable to the operation of each nozzle 60 and also so as to reduce the necessary length of the divergent tube 67 of each nozzle 60.
• an increase in the flow rate through the nozzle causes, among other things, an increase in the length of the diverging portion.
• this can be adjusted by adapting the number of nozzles 60 available on the support.
• the section of the neck 66 is designed so that, under the conditions of pressure and temperature of use of the device, a jet or a layer of liquid is obtained at the outlet of the neck 66, in the divergent tube 67, where a the diphasic expansion, generating a mist of droplets in their vapor.
• a mixing element similar to that described with reference to FIG. 7, can be integrated into the diverging tube 67 of part or all of the two-phase expansion nozzles 60.
• the totality of the available expansion is carried out in each of the nozzles 60.
• the two-phase fluid at the outlet of the nozzles 60 thus consists of liquid droplets 68 accelerated and dispersed in the vapor.
• the expansion and acceleration of the droplets being terminated at the outlet of the nozzles 60, this fluid will then be guided to the downstream devices for recovering the kinetic energy of the droplets and vapor condensation in the case of the mistlift and vapor condensation process. and recovery of the liquid in the case of the method using the principle of the turbine "Hero".
• the arrows referenced 69 indicates the direction of movement of the droplets and the vapor.
• each of the nozzles 60 is only partial, so that the fluid out of the nozzles 60 can be further expanded.
• a pipe 70 whose section varies appropriately and forming a divergent common to the plurality of two-phase expansion nozzles 60 extends the set of nozzles 60 in the direction of flow of the fluid.
• the common diverging conduit 70 makes it possible to terminate the expansion of the two-phase fluid and to terminate the acceleration phase of the droplets in an acceleration zone 71.
• This arrangement makes it possible both to produce the first expansion part in the nozzles 60 in favorable efficiency conditions with regard to this initial expansion and fractionation of the jet in micro droplets and with good guidance of the two-phase fluid and to achieve the end of the expansion with a minimum pressure drop by minimizing the wall surfaces.
• FIGS. 10a and 10b respectively show, in top view and in partial section, an almost square outlet section 60 for nozzles 60 making it possible to minimize the space between the nozzles 60.
• the passage section of the steam therefore varies little in the immediate output of the nozzles avoiding a sudden relaxation source of loss of load.
• extension elements 73 with variable section at the outlet of nozzles 60 to ensure continuity of the section variation.
• a possible arrangement of this type of element is shown in plan view and in partial sectional view respectively in FIGS. 11a and 11b.
• the extension elements fill the space between and at the outputs of the tube 67 diverging from the nozzles 60. Their section then varies gradually.
• FIGS. 11a and 11b show an embodiment in which the section of the extension elements 73 progressively decreases, allowing an expansion of the vapor on the zone referenced 74.
• the cold water The condensing of the steam produced can be ejected under spray form from these extension elements by means of suitable supply lines and injectors. This arrangement makes it possible to condense the vapor as close as possible to the end of the droplet acceleration zone 71 and thus to reduce the pressure drops and also to introduce the cold water spray 75 into the two-phase flow with a strong component the initial velocity in the same direction as the two-phase flow to obtain only one flow.
• the cold water spray can be positioned on the space available between the nozzle outlets 60, with a large component of the initial velocity in the same meaning that the two-phase flow to get only one flow.
• the liquid jet leaving the neck 66 of each nozzle 60 and then disintegrating in the form of droplets may be of any section, usually circular. The shape of its section is generated by the shape of the section of the neck of the nozzle.
• the liquid leaving the neck 66 is in jet form, that is to say with all the dimensions of the flow in a plane perpendicular to the flow of the same order of magnitude.
• the section of the neck 66, in a plane perpendicular to the flow of the liquid is for example circular or square: the jet then has a circular or square section and all the dimensions of the flow in a plane perpendicular to the flow of the same order of magnitude.
• FIGS. 12a and 12b show respectively in top view and in partial section another embodiment in which the shape of the section of the neck 66 of the nozzles 60 is arranged so as to produce and eject a liquid layer instead of a jet.
• liquid means a thickness of the liquid flow much smaller than its width.
• the neck section 66 may be, for example, rectangular as shown in Figure 12 and the section of the convergent 65 and the tube 67 diverging from the nozzles.
• This arrangement makes it possible to facilitate the production of the nozzle assembly, the neck being an elongate slot 80 and to reduce the number of nozzles 60 for the same flow rate, each nozzle 60 having a large elongation.
• This embodiment also makes it possible to minimize the space between nozzles 60 at the outlet of nozzles 60. It slightly reduces, however, the surfaces in contact between liquid and vapor and the heat exchanges.
• the device thus formed for relaxing a fluid then makes it possible to maximize the amount of movement produced by a two-phase flow.
• the flow rates with which the device can work can be increased without increasing the length of the assembly and on the other hand the losses load due in particular to the expansion of the steam are reduced, the atomization of the liquid flow at the neck outlet is more efficient to obtain smaller droplets and better liquid vapor coupling.
• the potential power provided by the device, when it is integrated for example in a device implementing the mistlift process, is much greater than that obtained with the devices of the state of the art.
• the disintegration (atomization) of the jet or the layer at the outlet of the neck 66 of the nozzles 60 is a very important factor in the effectiveness of the device. Indeed, the smaller the size of the droplets generated, the more the mechanical coupling by friction between the liquid phase and the vapor phase is important, and the whole is effective.
• the device according to the invention makes it possible to create a two-phase flow with good efficiency by maximizing the amount of movement created.
• a preferential application is the Thermal Energy of the Seas.
• FIG. 13 represents a first embodiment seen in section from above of a device for converting mechanical energy of thermal energy, of the "Hero" type. It is completed by Figure 14 which shows the same type of device "Hero" side section view.
• the drawings are purely schematic and serve the purpose of helping to understand the device.
• the conversion device is part of an installation, which may include several conversion devices.
• the installation is in fluid connection on the one hand with a hot source of a so-called hot fluid and on the other hand with a cold source of a so-called cold fluid, the cold fluid being at a temperature lower than that of the hot fluid .
• the hot fluid and the cold fluid are water.
• the conversion device comprises an enclosure 100 and delimiting an internal environment.
• the enclosure 100 has an axis 103 called rotation, fixed relative to the enclosure 100.
• the axis 103 of rotation, when the installation is put in place, is preferably substantially vertical.
• axial designate any direction parallel to the axis 103 of rotation
• transverse designate any direction perpendicular to the axis 103 of rotation
• radial will designate in the following any direction, in a transverse plane, secant with the axis 103 of rotation, and “orthogonal” any direction, in a transverse plane, non-secant with the axis of rotation, with reference to components of a rotational speed about the axis 103 of rotation.
• the enclosure comprises a wall defining the inner medium, and of cross section to the axis 103 of substantially circular or elliptical rotation about the axis 103 of rotation.
• the wall of the enclosure 100 makes it possible to ensure the seal between the outside atmosphere and inside the enclosure 100, where a partial vacuum is maintained, for example of the order of 0.013 bars in the context of ⁇ .
• This enclosure 100 may be made of any material to ensure its resistance and its sealing. This list may include, but is not limited to, concrete, steel, composite materials among the possible materials or a combination of these materials.
• this chamber 100 Given the large dimensions of this chamber 100, it will preferably adopt a shape to best withstand the external pressure, such as partially elliptical shapes, hemispherical, cylindrical, etc.
• the enclosure 100 shown in FIGS. 13 and 14 may comprise flotation means, and thus be floating on the surface of an ocean, or any other body of water, kept totally immersed between two waters by anchors or maintained partially immersed by anchors in order to overcome the constraints of the swell.
• It can also be a structure placed on the ground or placed and maintained on the bottom of a body of water when the height of water is not too important, for example to overcome length of pipe supply of cold water too important.
• the device comprises an inlet pipe 1 12, for bringing and distributing inside the enclosure 100 of hot water.
• the arrow 1 13 represents the arrival of hot water in the inlet pipe 1 12.
• the hot water is pumped to a first depth below the surface of the ocean, in a deep zone where the water is at maximum temperature, usually between 0 and 100m.
• the conversion device comprises a distributor 150, in fluid connection with the hot source. More precisely, according to one embodiment, the dispenser 150 comprises a first so-called central pipe 102, extending along the axis 103 of rotation, and in fluid connection with the inlet pipe 1 12.
• the distributor 150 also comprises a second pipe 104, said arrival, extending transversely to the axis 103 of rotation from the central pipe 102.
• the distributor comprises four delivery lines 104, distributed at 90 ° around the axis 103 of rotation, each fixed rigidly to the central duct 102. The number and distribution of the arrival lines 104 may, however, be otherwise.
• the arrival lines 104 may be rectilinear or curved.
• the hot water enters the inlet pipe 1 12 and arrives at the arrival pipes 104 through the central pipe 102.
• the hot water enters the central duct 102 which is rotatably mounted about the axis 103 of rotation relative to the enclosure 100, and more precisely, with respect to the walls of the enclosure 100.
• a rotating seal 1 14 provides sealing between the inlet pipe 1 12 and the central pipe 102 while allowing their relative rotation.
• Bearings 1 15 equipped with the necessary means, such as bearings, stops, etc. allow to maintain the central pipe 102 substantially parallel to and aligned on the axis 103 of rotation.
• the pipes 102, 104, January 12 may be made of any material to ensure the mechanical strength of the assembly with respect to particular centrifugal forces.
• steel, aluminum and composite materials may be mentioned.
• the conversion device comprises at least one two-phase expansion device 106, according to the invention, rigidly attached to the free end of an inlet pipe 104, which forms an arm, making it possible to generate and accelerate a fog of water droplets in their own vapor, inside the chamber 100.
• the conversion device comprises four inlet pipe 104 distributed around the axis 103 of rotation, a diphasic expansion device 106 according to the invention being rigidly attached to the end of each arm 104.
• the assembly formed by the central duct 102, the inlet ducts 104, the two-phase expansion devices 106, which may optionally comprise a common divergent duct 70, is said to be rotating as it pivots around the axis 103 of rotation by relative to the enclosure 100.
• the rotation of the rotating assembly is represented by the arrow 1 1 1.
• the water under the effect of the rotation of the rotating assembly, acquires pressure, and the rotation of the rotating assembly is maintained by the acceleration of the fog leaving the devices 106 of two-phase expansion which creates by reaction a thrust and drives the rotating assembly.
• the rotation of the rotating assembly can, if necessary, be initiated by an auxiliary device, such as a motor, or a pump putting water under pressure in the inlet pipe 104, and whose power would be reduced at as the speed of rotation of the rotating assembly increases until a determined speed is reached.
• an auxiliary device such as a motor, or a pump putting water under pressure in the inlet pipe 104, and whose power would be reduced at as the speed of rotation of the rotating assembly increases until a determined speed is reached.
• a rolling device may be associated with the rotating assembly.
• the rolling device is for example in the form of a wheel train, to accompany the rotation of the assembly rotating in the chamber 100 about the axis 103 of rotation.
• the rolling device is retractable.
• the pressurized hot water is received at the end of each inlet pipe 104 in the distributor 105 of the two-phase expansion device 106, the shape of which makes it possible to minimize the pressure losses due to the displacement of the water and to eject the water. effect of the water pressure through the two-phase expansion nozzles 60.
• Each common diverging conduit 70 is oriented approximately orthogonally to the axis 103 of rotation on the free end of the pipe 104 corresponding arrival, to generate a fog 8 billion of droplets, the fog 8 of vapor and droplets being animated with an initial speed at the output of the two-phase detent device 106 represented by the arrows 109, whose orthogonal direction is approximately opposite to the orthogonal component of the rotating speed 1 1 1 of the rotating assembly.
• the steam transforms its enthalpy into kinetic energy.
• the pressure and temperature of the steam gradually decrease.
• the friction and viscosity forces are much greater than the weight thereof and allow a significant acceleration of the droplets.
• the vapor thus transmits a large part of its relaxation energy to the droplets.
• the droplets continue to produce steam on their way, allowing the vapor to reach nearly 2.6% of the liquid mass.
• each two-phase expansion device 106 At the outlet of each two-phase expansion device 106, the droplets have thus been accelerated by the steam and have a speed greater than the rotational speed of the rotating assembly.
• More than 80% of the relaxation energy of the vapor can be transferred as kinetic energy to the droplets.
• the fluid velocity at the output of the two-phase expansion device 106 is as close as possible to the peripheral speed due to the rotation in order to minimize the absolute velocity of the fluid. the exit.
• the efficiency of the conversion device can be greater than 75% depending on the conditions.
• the vapor and liquid phases separate, the stream 128 of vapor being sucked by the vacuum at the level of the condensation means 1 16 inside the chamber 100, due to the fact that a vacuum pump 1 19 placed downstream of the condensing means 1 16 with respect to the circulation of the vapor inside the chamber 100.
• the vacuum pump 1 19 also makes it possible to maintain the partial vacuum at room temperature. the interior of the enclosure 100 while evacuating the non-condensable gases and the portion of vapor that would not have condensed (arrow 126).
• the condensing means 1 16 must allow the condensation by direct thermal exchange and / or indirect with cold seawater from the depths, and more precisely to a second depth, greater than the first depth from which is pumped. Hot water.
• the means 1 16 of condensation comprise a set of pipes 1 17 for bringing cold water 127 inside the chamber 100 and a system 1 18 for spraying water cold on the steam allowing its condensation.
• the sputtering system 1 18 may be a combination of different cross current, counter current, etc. systems.
• the condensation means 1 16 may be composed in whole or in part of indirect exchangers between the cold water and the steam allowing, if desired, to manufacture fresh water from the steam by recovering its condensed phase. .
• a recuperator 120 makes it possible to recover together the cold water and the condensed vapor and a pump 121 makes it possible to evacuate them outside the enclosure 1 (arrow 125).
• a recuperator 122 makes it possible to recover the hot water and a pump 123 makes it possible to evacuate it outside the enclosure (arrow 124).
• a generator 131 for transforming the rotational mechanical energy of the rotating assembly into electrical energy. It is a rotary linear alternator 131 directly coupled to the upper part of the central pipe 102 in rotation, for example of the type that is installed on wind turbines. This choice makes it possible to dispense with a very expensive reduction box and seems interesting considering the rotational speeds envisaged.
• This alternator 131 may of course be installed inside the enclosure 100 or outside thereof, provided that the central pipe 102 is extended by a rotating axis.
• a conventional generator / reduction box system can also be considered.
• the hydroelectric group 133 may be inserted into the central duct 102 of hot fluid when it comes under pressure as illustrated in FIG. 16.
• several hydroelectric units may be inserted in each of the supply lines 104, using the pressurization generated by the rotation of the rotating assembly
• FIG. 15 represents a schematic view of the rotating assembly and in particular of its elements 104, 105, 60 and 70.
• the formation of a multitude of micro-jets at the output of the two-phase expansion device 106 makes it possible to create the mist in which the continuous phase is the vapor 108 and the dispersed phase the droplets.
• This multitude of droplets has a contact surface with steam very favorable to heat exchange.
• One solution may be to give a non-zero angle A, so that the liquid droplets are ejected with a component to the periphery sufficient to prevent them from colliding with the receiver 105 of the following two-phase detonator device 106.
• This angle should be minimum to minimize the loss of power.
• An angle of 5 ° to 15 ° may be suitable in some configurations.
• Flow rates are 6.5 m 3 / s for hot and cold water.
• the conversion device has a turning radius of 20m for a rotational speed of 2rd / s (radians per second).
• the peripheral speed due to rotation is 40m / s.
• the pressure of the hot water due to the rotation is 8.4 bars in the receiver 105 of the two-phase expansion devices 106 resulting in an output speed 109 of 54 m / s at the output diphasic expansion devices 106.
• the mechanical power restored is 3500 KW.
• the droplet output speed which represents 98% of the ejected mass, is close to the peripheral speed, which allows the excellent efficiency of the conversion device.
• the conversion device presented equipped with two-phase expansion devices 106 according to the invention, therefore while maintaining high efficiency to limit the rotational speeds and centrifugal forces through excellent mechanical coupling of the liquid phase and vapor.
• the output speeds of the two-phase expansion device 106 remain sufficiently high (approximately 60 m / s) to allow moderate two-phase expansion device dimensions 106.
• the conversion device makes it possible to choose the speed of rotation and the radius of the rotating assembly as well as the dimensions of the droplets produced and the dimensions of the two-phase expansion device 106, and in particular the dimensions of the two-phase expansion nozzles 60 and the length of the leads 70 divergent common to find the best compromise between the following constraints:
• the path length of the droplets in the proposed conversion device is very limited, limiting the numbers of collisions between droplets and with the walls, a source of significant energy losses, in contrast to the conversion devices proposing a vertical rise of the liquid phase requiring courses of nearly 100m.
• a Pelton turbine uses the kinetic energy of a liquid jet produced by one or more injectors to produce mechanical energy.
• the purpose of the injector is to transform the pressure energy of the water into kinetic energy.
• the two-phase expansion device converts the thermal energy of a hot fluid into kinetic energy in the form of accelerated droplets and vapor.
• the use of the two-phase expansion device in place of an injector makes it possible to propel on Pelton turbine buckets a stream of droplets and vapors at high speed.
• the shape and size of the buckets and the characteristic sizes of the Pelton turbine can be adapted accordingly.
• Two-phase expansion devices can be used for the same Pelton turbine wheel.
• the two-phase expansion device proposed according to the invention makes it possible to transform into mechanical energy the thermal energy contained in two low-temperature difference fluids with good efficiency and a simple and inexpensive device.

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• Combustion & Propulsion (AREA)
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• Life Sciences & Earth Sciences (AREA)
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• 2013
  • 2013-07-10 FR FR1301676A patent/FR3008452B1/fr active Active
• 2014
  • 2014-07-09 WO PCT/FR2014/051766 patent/WO2015004389A1/fr active Application Filing
  • 2014-07-09 JP JP2016524876A patent/JP2016524093A/ja active Pending
  • 2014-07-09 US US14/894,419 patent/US20160108899A1/en not_active Abandoned
  • 2014-07-09 EP EP14745209.8A patent/EP3019746A1/de not_active Withdrawn
  • 2014-07-09 CN CN201480033288.0A patent/CN105473851A/zh active Pending

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