Patent Application
20100032020
The present invention relates to an injection apparatus making it possible to vary the direction and/or the aperture of a fluid jet, for example a jet of air or of oxygen, of nitrogen, of gaseous fuel or else of liquid or solid fuel with a gas, said fluid jet resulting from an interaction between a primary fluid jet and at least one secondary fluid jet. The invention relates notably to such an injection gun.
The invention also relates to the use of said injection apparatus to vary the direction and/or the aperture of a fluid jet, for example in contact with a surface and notably above a load. It also concerns a method of injection in which the user varies the direction and/or the aperture of at least one fluid jet.
It is known practice from EP-A-0545357 to change the direction of an atomized jet by means of a control gas flow: (1) by bringing the material to be atomized across an atomization passageway having a portion of constant cross section and a flared downstream portion, (2) by atomizing the material by means of an annular jet of atomization gas, (3) by placing in contact the jet of atomization gas and a flow of control gas so as to create a pressure differential through the jet of atomization gas and (4) by using this pressure differential to vary the direction of the atomized jet.
However, this method, which is limited to atomized jets, allows only a fairly slight change in the direction of the jet.
The object of the invention is to allow a great variation in the direction and/or the aperture of a fluid jet without having to interrupt the operation of the injector. A further object of the invention is to allow such a variation with an optimized robust apparatus.
The invention proposes to control a primary fluid jet (also called a main jet) by interaction with at least one other fluid jet (called a secondary or actuator jet), the interaction between the jets occurring inside the passageway delivering the primary jet (a pipe with a constant section or a variable section, etc.) before said primary jet emerges from said passageway, optionally close to the location where the primary jet emerges from said passageway (hereinafter called the “main outlet aperture”).
Therefore the invention relates to an apparatus for the injection of a fluid jet resulting from an interaction between a primary jet and at least one secondary jet, said apparatus making it possible to vary the direction and/or the aperture of said resultant jet.
The injection apparatus comprises a passageway for bringing the primary jet to the main outlet aperture. It also comprises at least one secondary pipe for the injection of a secondary jet, this secondary pipe leading into the passageway of the primary jet via a secondary aperture situated upstream of the main aperture. The arrangement between the passageway bringing the primary jet and the secondary pipe defines the point of interaction between the primary jet and the secondary jet coming out of this secondary pipe (hereinafter called the corresponding secondary jet).
The apparatus comprises at least one secondary pipe positioned relative to the passageway so that, at the point of interaction between the corresponding secondary jet and the primary jet, the angle θ between the axis of the corresponding secondary jet and the plane perpendicular to the axis of the primary jet is greater than or equal to 0° and less than 90°, preferably from 0° to 80° and yet more preferably from 0° to 45°.
Also according to the invention, the secondary aperture(s) that are situated upstream of the main outlet aperture are spaced from said main aperture by a distance L that is less than or equal to ten times the square root of the section s of the main aperture. The distance L is preferably less than or equal to 5 times this square root and yet more preferably less than or equal to 3 times this square root.
The at least one secondary jet interacts with the primary jet so as to generate a resultant jet.
From the “Proceedings of FEDSM'02 Joint US ASME-European Fluid Engineering Division Summer Meeting of Jul. 14-18, 2002” and from the article “Experimental and numerical investigations of jet active control for combustion applications” by V. Faivre and Th. Poinsot, Journal of Turbulence, Volume 5, No. 1, March 2004, p. 25, it is known practice to use a specific configuration of four secondary jets around a main jet to stabilize a flame thanks to the interaction between the secondary jets and the primary jet. A wider angle of dispersion is reported.
According to the invention, the apparatus is furnished with means for controlling the force of the at least one secondary jet.
The invention therefore makes it possible to vary the direction and/or the aperture of the resultant jet by changing the force of at least one secondary jet with said means.
Preferably, the means for controlling the force of the at least one secondary jet are means making it possible to control the ratio between the force of the secondary jet and the force of the primary jet.
The invention therefore makes it possible to produce a large variation in the direction and/or aperture of a jet without making use of mechanical means, potential sources of malfunction, in particular in hostile environments, such as high-temperature fire chambers.
The control means notably allow an active or dynamic control of the force of at least one secondary jet, that is to say they make it possible to vary the force or forces without interrupting the injection of the main jet. The apparatus according to the invention therefore allows a dynamic variation in the direction and/or the aperture of the resultant jet.
Preferably, the number of secondary jets interacting with the primary jet to obtain the desired effect on the resultant jet will be minimized so as to limit the complexity and the cost of manufacture of the apparatus but also the complexity and the cost of the system for supplying and regulating the flow rates of the fluids if the secondary jets are controlled in an independent manner. For example, a mono-directional effect may be obtained with a single secondary jet.
Amongst the terms used in the present description, some are worthy of being more precisely defined in the context of the invention in order to better delimit their significance:
The various features of the embodiments of the apparatus according to the invention and its use will appear more clearly from the following detailed description, reference being made to the figures which represent, in a schematic manner, exemplary embodiments given as being nonlimiting and more particularly:
In the following text, the same reference numbers are used, on the one hand, to designate the primary jet and the passageway in which it flows and, on the other hand, to designate the secondary jet or actuator and the corresponding secondary pipe in which this secondary jet flows.
The primary jet to be controlled is brought via the passageway 10 and comes to interact with the secondary jet originating from the secondary pipe 21 so as to create a resultant jet 1 with a direction and/or aperture that are different from the jet coming out of the main outlet aperture 11 in the absence of a secondary jet.
The apparatus comprises a passageway 10 which makes it possible to bring the primary jet to a main outlet aperture 11.
At least one secondary pipe 21 for the injection of a secondary jet leads to the passageway 10 via a secondary aperture 31. This secondary pipe 21 is positioned relative to the passageway 10 so that, at the point of interaction between the corresponding secondary jet and the primary jet, the angle θ between the axis of the secondary jet 21 and the plane perpendicular to the axis of the primary jet 10 is greater than or equal to 0° and less than 90°. (θ=0° in
The distance L makes it possible to influence the impact of the secondary jets on the primary jet with identical respective forces. For example, to maximize the directional effect, the user will attempt to minimize this distance.
As a general rule, L is less than or equal to 20 cm, more preferably less than or equal to 10 cm.
The apparatus comprises means for controlling the force of the secondary jets. These means may usefully be chosen amongst the devices for mass flow-rate control, for pressure loss control, for passageway section control, but also the devices for temperature control, control of the chemical composition of the fluid or for control of pressure.
These means are preferably means making it possible to control the ratio between the force of the secondary jet and the force of the primary jet.
The control means make it possible to activate and deactivate one or more secondary jets (flow or absence of flow of the secondary jet concerned) in order to vary dynamically the direction and/or the aperture of the resultant jet.
The control means preferably make it possible also dynamically to increase and reduce the force (non zero) of one or more secondary jets or to increase and reduce the ratio between the force of a secondary jet and the force of the primary jet.
The apparatus may comprise a block of material 5, such as a block of refractory material, in which at least a portion of the passageway 10 is situated, the main outlet aperture 11 being situated on one of the faces or surfaces of the block: the front face 6.
In
The interaction between the primary jet and the secondary jet takes place at a distance L from the front face 6 of the block from which the passageway 10 of the primary jet emerges, this distance L being able to vary as indicated above.
According to one embodiment making it possible to vary the direction of the resultant fluid jet illustrated in
Such an arrangement between the passageway and the secondary pipe makes it possible to change the angle between the axis of the resultant fluid jet (downstream of the corresponding secondary aperture) and the axis of the primary jet upstream of this secondary aperture by changing the force of at least one corresponding secondary jet.
If, in the absence of an actuator jet, the jet originating from the main outlet aperture 311 flows perpendicularly to the plane of
Preferably, the apparatus comprises at least two secondary pipes that are positioned relative to the passageway 310 so that, on the one hand, the two corresponding secondary apertures are situated on one and the same cross section of the passageway 310 and that, on the other hand, at these two secondary apertures, the axes of the corresponding secondary jets are secant or quasi-secant with the axis of the primary jet. In this case, the two corresponding secondary apertures may, usefully, be situated on either side of the axis of the primary jet (on the right and on the left for the apertures 331 and 333; below and above for the apertures 332 and 334), the two secondary apertures and the axis of the primary jet preferably being situated in one and the same plane (horizontal for the apertures 331 and 333; vertical for the apertures 332 and 334).
According to another useful configuration, at the two corresponding secondary apertures, the plane defined by the axis of the primary jet and one of the two corresponding secondary apertures is perpendicular to the plane defined by the axis of the primary jet and the other of the two corresponding apertures. For example, the horizontal plane defined by the axis of the passageway 310 and the secondary aperture 331 is perpendicular to the vertical plane defined by this axis and the secondary aperture 332.
It is also possible to combine these two forms of execution. In this case, as illustrated in
This arrangement makes it possible to vary the angle between the axis of the resultant fluid jet and the axis of the primary jet on the first and on the second plane (for example on the horizontal plane and on the vertical plane) and as required to one or other of the two secondary apertures situated in each plane (for example, to the left and to the right on the horizontal plane, and upward and downward on the vertical plane) and, as explained above, to any intermediate direction.
At the four corresponding secondary apertures 331 to 334, the axes of the four corresponding secondary jets are preferably in one and the same plane perpendicular to the axis of the primary jet 310.
The invention also makes it possible to produce an interaction between the primary jet and one or more secondary jets so as to generate, maintain or strengthen a rotation of the resultant fluid jet about its axis. Such an interaction makes it possible to vary the aperture of the resultant jet.
As illustrated in
The apparatus may usefully comprise two secondary pipes 421 and 422 positioned relative to the passageway 410 of the primary jet so that, at the two corresponding secondary apertures 431, 432, the axes of the two corresponding secondary jets 421 and 422 are not coplanar with the axis of the primary jet 410, the two secondary jets being oriented in one and the same direction of rotation about the axis of the primary jet. The two secondary jets therefore contribute to the force of rotation conferred on the primary jet.
The two secondary apertures are advantageously situated on one and the same cross section of the passageway 410—in one and the same plane perpendicular to the axis of the primary jet. They may be situated on either side of the axis of the primary jet (apertures 421 and 423 or 422 and 424). They may also be situated so that the plane defined by the axis of the primary jet and one of the two secondary apertures 421 is perpendicular to the plane defined by the axis of the primary jet and the other of the two secondary apertures 422.
According to one form of execution, the apparatus comprises at least four secondary pipes 421 to 424 which are positioned relative to the passageway 410 of the primary jet so that, at the corresponding secondary apertures 431 to 434, the axes of the corresponding secondary jets are not in substance coplanar with the axis of the primary jet. Two of the corresponding secondary apertures 431 and 433 are in substance coplanar with the axis of the primary jet 410 on a first plane and situated on either side of the axis of the primary jet. The other two corresponding secondary apertures 432 and 434 are in substance coplanar with the axis of the primary jet 410 on a second plane and also situated on either side of the primary axis, the four corresponding secondary jets being oriented in one and the same direction of rotation about the axis of the primary jet. The first and the second plane may notably be perpendicular relative to one another. It is also preferable that the four corresponding secondary apertures are on one and the same cross section of the passageway 410.
To confer a rotary force on the primary jet and therefore to change the aperture of the resultant jet, the user will ensure preferably that at the secondary aperture where the primary jet and the corresponding secondary jet interact, on the one hand, the axis of the secondary jet belongs to the plane perpendicular in this location to the axis of the primary jet, and, on the other hand, the angle between the axis of the secondary jet and the tangent to the secondary aperture (or more exactly to the imaginary surface of the passageway of the primary jet at the secondary aperture) in this plane is between 0 and 90°, preferably between 0 and 45°.
a and b show an exemplary embodiment with secondary jets for the control of the aperture of a resultant jet. The primary jet (which flows from left to right in the passageway 410 in
It is also possible to combine in a single apparatus the embodiment making it possible to vary the direction of the resultant jet according to any one of the application methods described above with any one of the embodiments described above making it possible to generate, maintain or strengthen a rotation of the resultant jet and therefore to vary its aperture.
To obtain both a directional and rotational effect, the user will therefore combine the teaching of the above paragraphs. To obtain a dynamic variation of the directional and rotational effects, the user may for example provide several injection systems of secondary jets. By providing separate secondary pipes with means for regulating the force of the secondary jet, such as supply valves, it is therefore possible to change, in a continuous or discontinuous manner, the shape and the direction of the resultant jet simply by actuating said regulation means (valves).
To allow the secondary jet to act as effectively as possible on the primary jet, the actuator jet must be injected substantially perpendicularly to the direction of the main jet.
For an optimized operation, the apparatus according to the invention may comprise at least one secondary pipe 21 positioned relative to the passageway 10 of the primary jet so that, at the corresponding secondary aperture 31, this pipe has a thickness e and a height l, such that l≧0.5 H e and preferably: 0.5 H e≦l≦5.0 H e (see
For example, in order in practice to achieve a secondary jet such that, at the point of interaction between this secondary jet and the primary jet, the angle θ between the axis of the secondary jet and the plane perpendicular to the axis of the primary jet is 0°, it would be preferable that, before the corresponding secondary aperture, the secondary pipe has a direction substantially perpendicular to the axis of the primary jet for a length l which will preferably be between 0.5 and 5 times the thickness e (the dimension in the direction of flow of the main fluid) of said duct (e is the diameter of the duct when the latter is cylindrical). Naturally, it is also possible for this length l to be greater than 5e, but this does not have any additional effect of significant impact of the secondary jet on the primary jet.
The passageway of the primary jet may consist, in totality or for at least a portion, in a primary pipe for the injection of the primary jet. This primary pipe leads to a primary aperture 309 (see
When, as illustrated in
c represents a variant embodiment similar to
e represents the bottom (inside) of this tip 342 whose inner face 349 comprises a cavity 347 in which the secondary jet originating from the secondary pipe 324 will be distributed and then encounter substantially perpendicularly the primary jet originating from the primary pipe 308 by means of the slot 348 above the main outlet aperture 346. The resultant jet 344 (
It should be noted that the possibility of using a tip to confer the desired orientation on one or more secondary jets before their respective points of interaction with the primary jet is not limited to the secondary jets oriented so as to vary the direction of the resultant jet, but also applies to the secondary jets described above making it possible to vary aperture of the resultant jet.
For the optimal operation of the apparatus according to the invention, the passageway of the primary jet will have, at the at least one secondary aperture, an unobstructed, or at least in substance unobstructed, fluid passageway in the extension of the at least one corresponding secondary pipe, in order to allow an effective interaction between the at least one corresponding secondary jet and the primary jet. Typically, the cross section of the passageway of the primary jet will define an unobstructed or at least in substance unobstructed fluid passageway at the at least one secondary aperture.
The invention also relates to the use of the apparatus in order to vary the direction and/or the aperture of a fluid jet, for example of a fluid jet comprising oxygen and/or argon and/or carbon dioxide and/or hydrogen. Another possibility is the use of the apparatus in order to vary the direction and/or the aperture of a fluid jet comprising a fuel and/or an oxidant injected into a combustion zone.
The resultant jet of which the user thereby varies the direction and/or the aperture may be a supercritical fluid jet.
The jet is typically a gaseous jet; however, the gaseous jet may comprise an atomized liquid and/or solid particles, such as ground solids.
The invention also relates to an injection method in which the apparatus according to the invention is used to inject a fluid jet resulting from an interaction between a primary jet and at least one secondary jet and in which the user varies dynamically the direction and/or the aperture of the resultant jet by varying the force of at least one secondary jet or else by varying the ratio between the force of at least one secondary jet and the force of the primary jet.
Therefore the invention relates to a method for controlling dynamically or actively the performance of a fluid injection system with the aid of one or more secondary jets (also called actuator jets), impacting the primary jet in order to change the flow of the primary jet and to produce a resultant jet whose direction and/or aperture may be modified according to the characteristics (notably direction and quantity of movement) of the primary and/or secondary jets. This method may be used to regulate in a closed loop or in an open loop the performance of a combustion system or more generally of industrial methods using injections of fluid jets (liquid, gaseous or solid dispersion).
The sensors 214, 216 and 217 measure respectively the magnitudes characterizing the combustion products, the operating conditions of the combustion or of the fire chamber and the operation of the apparatus or of the gun. These measurements are transmitted with the aid of the lines 218, 219 and 220 to the controller 215. The latter, depending on instructions given for these characteristic magnitudes, determines the operating parameters of the secondary jets so as to maintain the characteristic magnitudes at their set point values and, with the aid of the line 221, transmits these parameters to the members for controlling the apparatus/the gun.
The apparatus according to the invention advantageously comprises means for controlling the forces of the secondary jet(s), preferably means for controlling the ratio of the pulses of the primary jet and of the secondary jet(s).
This ratio is a function of the ratio of the section of the passageway of the primary jet and of the sections of the secondary pipes, of the ratio of the flow rates in the secondary pipes to the flow rate of the resultant jet and of the ratio of the densities of the fluids of the primary jet and of the secondary jet(s). (In the paragraphs below, when consideration is given to the variation of one of these ratios, the other two are considered constant.)
The more the value of the ratio of the section of the primary jet and of the section of a secondary pipe at the corresponding secondary aperture increases, the greater (at constant respective flow rates) the impact that the corresponding secondary jet has on the primary jet. The user will preferably choose a ratio of sections of between 5 and 50, more preferably between 15 and 30.
The ratio of the flow rate of all the secondary jets to the total flow rate of the resultant jet will typically vary between 0 (no secondary jets) and 0.5 and preferably between 0 and 0.3; more preferably between 0 and 0.15; in the knowledge that the greater this ratio of flow rates, the greater the deviation and/or the aperture of the resultant jet will be.
The ratio of the density of each fluid forming the secondary jets to the density of the fluid of the primary jet makes it possible to control the impact of the secondary jets. The smaller the value of this ratio, the greater will be the effect of the secondary jet on the primary jet, at constant flow rate. For practical reasons, the user will often use the same fluid in the secondary jets and in the primary jet (the ratio equal to unity). To increase (at a constant mass flow rate) the effects of the secondary jets, the user will use a fluid with a smaller density than that of the fluid in the primary jet. The nature of the fluid in the secondary jets will be chosen according to the intended application. It is possible to use for example, to control the deviation of an air jet, a mixture of air and helium (of lesser density) or to increase the driving of the combustion products in a flame whose fuel is propane, control the main jet of fuel and/or oxidant with a secondary jet of water vapor. In general, the ratio of the densities of the densest fluid to the least dense fluid may vary between 1 and 20, preferably between 1 and 10, more preferably between 1 and 5.
The geometry of the section of the passageway of the primary jet and/or of the secondary pipes may have various shapes and notably circular, square, rectangular, triangular, oblong, multilobe, etc. shapes.
The geometry of these injection sections influences the development of the instabilities of the resultant jet. For example, a jet coming out of an injector of triangular shape will be more unstable than that originating from an injector of circular shape, this instability promoting the mixture of the resultant jet with the surrounding medium. Similarly, an injector of oblong shape will promote, in a near field of the injector, the symmetrical development of the jet unlike an injector of circular or square shape.
With respect to the physical-chemical properties of the fluid used to produce the secondary jets, they may be chosen to control certain properties of the resultant flow. For example, it is possible to modify the reactivity of a mixture of main fuel (for example natural gas) jets, oxidant (for example air) jets, by the use of oxygen (or another oxidant) and/or hydrogen (or another fuel).
According to one embodiment, the apparatus is a gun (for example for injecting an oxidant such as oxygen into a combustion zone) of which the jet has a variable direction and/or aperture. Naturally, such a gun may also be used for injecting fuel, that is liquid and/or gaseous and/or solid, into a combustion zone, for example a powdered coal gun (gas such as air which propels solid powder such as coal).
The present invention therefore also relates to a method for heating in which such a gun is used for injecting a jet of fuel and/or oxidant with a variable aperture and/or direction into a combustion zone.
If the end of the passageway of the primary jet, just before the point of interaction of the primary and secondary jets, is furnished with a nozzle comprising a convergent/divergent (also called a de Laval nozzle in the literature), it is possible, at the exit of the divergent, to obtain (in a manner known per se in the literature) a primary fluid jet and a resultant jet, for example a jet of oxygen, that is supersonic, which will then be able to have a variable direction (optionally of variable aperture but usually losing its supersonic speed, which makes it possible to alternate the subsonic and supersonic speeds in certain methods). The de Laval nozzle may also be placed on the resultant jet in front of the main outlet aperture.
According to a variant of the method, at least two secondary jets are used in order to obtain a variation in the direction of the resultant jet in at least secant planes in order to sweep at least a portion of a surface, such as the surface of a load.
By using a secondary jet of which the axis is not secant or quasi-secant with the axis of the primary jet, the aperture of the resultant jet above the load may be varied, alone or in combination with a sweep.
Preferably, means for controlling the quantity of movement of the primary jet and/or of the at least one secondary jet are provided.
It should be noted that, although in the foregoing the apparatus and the method have been illustrated above by making reference to a form of application with a single primary jet that is made to interact with one or more secondary jets, it is evident that the present invention also covers such an apparatus for the injection of a multitude of jets of which the aperture and/or the direction are variable and notably the case in which this multitude of jets with a variable aperture and/or direction are produced from a multitude of primary jets, each primary jet interacting with one or more secondary jets.
c shows these same main jets in a situation in which the jets are controlled or deviated in the same direction (upward in the figure): the secondary jets 63 and 65 act upwardly respectively on the main jets 61 and 60, which generates resultant jets both of which are directed upward. These three examples make it possible to obtain flames with very different direction and morphology (length, flattening, etc.). The flame 64 will be very wide in the horizontal midplane of the injectors, while the flame 67 will be greatly deviated upward.
According to the invention, at the point of interaction between the secondary jet and the primary jet, the axis of the secondary jet makes, with the plane perpendicular to the axis of the primary jet, an angle that is less than 90°, and preferably equal to 0°. However, as illustrated in
However, the use of the apparatus for very high temperature processes (T for a process>1000° C.) may lead to overheating and damage to the injection tip.
To avoid this type of problem, the user will seek in the design of the injection tip to reduce the front surface of the apparatus subjected to the radiation in the high-temperature enclosure. For this, the user will seek to limit the ratio l/e.
It is also possible to use one of the two solutions illustrated in
Preferably, the ratio R/d will range from 0.3 to 3, while the angle α will be in the range [0°, 60°].
The second solution consists in fitting a refractory piece of the sleeve type directly to the snout of the apparatus (where the main outlet aperture is situated) as illustrated in
In
b also illustrates the changes of angle of aperture of the resultant jet as a function of the ratio of the flow rates of the actuators and of the main jet: the curve C3 corresponds to the configuration CONF3 with actuators impacting the main jet at 90° (that is to say on a plane perpendicular to the axis of the main jet: θ=0°) at a distance 2Hh from the main outlet aperture (similar to CONF2), while the curve C4 corresponds to the configuration CONF4 which is identical to CONF3, except for the angle of incidence a of the actuators which is 45° relative to the axis of the main jet (that is to say the angle θ between the axis of the actuators and the plane perpendicular to the axis of the main jet=90°−α=45°). Note that, when the actuator jets are perpendicular to the main jet (CONF3: θ=0°), all other things being equal, a larger jet aperture is obtained than when the angle of incidence α of the actuator jets is smaller (in this instance 45°) (CONF4: θ=45°).
This curve shows all of the experimental data obtained for the control of the aperture of a jet. The angle of aperture measured is entered as a function of the physical parameter J which is the ratio of the specific forces of the actuator jets and the main jet. This ratio is written as the product of the ratio of the densities (actuator fluid on main fluid) and of the ratio of the square of the speed of the actuator jets and of the square of the speed of the main jet. The main fluid is the same for all the experiments, while different fluids have been used for the actuators. These fluids differ mainly by their density (from the highest density to the lowest: CO2, air, air helium mixture). It is observed that all the experimental points (irrespective of the flow rates and the fluids used) fall into a straight line. This shows that the physical parameter which controls the aperture of the jet is indeed the ratio of the specific forces defined above. The invention also relates to the use of an apparatus/a gun according to the invention to inject a resultant fluid jet the aperture and/or the direction of which are variable, said resultant jet being able for example to include oxygen and/or nitrogen and/or argon and/or carbon dioxide and/or hydrogen. The resultant jet may in particular be a gaseous jet, or else a gaseous jet comprising an atomized liquid and/or solid particles carried along by gas.
The apparatus may notably be used to inject a fluid jet comprising a fuel and/or an oxidant, for example to supply the combustion in a furnace.
The invention is notably useful for injecting a supercritical or supersonic fluid jet.
The invention may also apply to items of food or industrial cryogenics apparatus in which jets of cryogenic liquid (for example liquid nitrogen) are injected, each jet, thanks to the invention and the use of one of more actuator jets, being able to sweep a surface (for example “spray” a whole surface of products to be frozen thanks to a single jet nozzle that can be varied (direction-shape) etc).
The method and the technology of the present invention may be used for the injection, for example, of nitrogen in order to render certain reactors or processes inert. Specifically, a combination of injectors with variable direction or rotational effect (aperture of the jet) makes it possible to more rapidly homogenize the atmosphere of a reactor, for example by increasing its drive in the jets of inert gas, or by promoting the delivery of nitrogen to the sensitive locations thanks to the directional effects.
The invention may also apply to the filling of pressurized gas bottles: the use of composite materials for pressurized storage, for example hydrogen, in lightweight tanks, limits the speed of filling because of the risk of hot spots.
The flow inside the bottle is organized into a jet along the axis of the bottle with an expansion at the entrance of the bottle, then a zone downstream (the bottom of the bottle) where the gases slow down and are compressed (therefore heat up) and two recirculation zones on each side where the hot gases are carried along the walls before being carried into the central jet. The use of an injection with variable aperture, during the filling of the bottle, makes it possible to reverse the latter situation. Specifically, the injection of a jet with very considerable rotational effect makes it possible to generate a flow inside the bottle where the cold gases cooled by the expansion at the entrance of the bottle will travel along the walls of the bottle before being compressed when they reach the bottom of the bottle and to return to the center of the latter along the axis of the latter. The alternating of these two situations during filling makes it possible to limit the temperature of the bottle and to remain in a risk-free temperature range including for high filling speeds.
Another application of the invention is gas quenching: the directional capability of the injectors according to the invention makes it possible to homogenize the temperature in parts that have a complex shape and high heat-resistance.
| Number | Date | Country | Kind |
|---|---|---|---|
| 06 52845 | Jul 2006 | FR | national |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/FR07/51597 | 7/5/2007 | WO | 00 | 10/21/2009 |
