Variable levitation device including anti-stratification diffuser - Patent Application 20070122997

Abstract

To provide a variable-liftability device comprising an anti-stratification diffuser.SOLUTION: A variable-liftability device (1) includes: a pressurized hermetically sealed chamber (4) accepting a gas of density lower than the density of the air; and a mixer (6) arranged at least partially inside the hermetically sealed chamber (4) and configured to introduce air into the hermetically sealed chamber (4).SELECTED DRAWING: Figure 1a

Description

[Technical Field]

[0001] The present invention relates to the field of variably buoyant devices that employ lighter-than-air gases to ascend through the atmosphere. More particularly, the present invention relates to variably buoyant devices that include a single reservoir for storing lighter-than-air gases such as helium, neon, methane, ethane, and hydrogen under pressure. [Background technology]

[0002] A variably levitated device can be understood as a stratospherically maneuverable platform having a pressurized flexible envelope, known as a "blimp."

[0003] Conventionally, variably buoyant devices are provided with several completely airtightly sealed balloons containing a gas lighter than air. It is these balloons filled with a gas lighter than air that make the variably buoyant device rise. These balloons are contained within a flexible structure that forms the envelope of the variably buoyant device. The remaining volume of the envelope is occupied by air. Air is evacuated to rise and injected to descend. The multiple air balloons ensure longitudinal static stability at any air filling level.

[0004] This model is particularly useful for variably levitated vehicles operating in the troposphere, where the air density is high. However, for variably levitated vehicles operating in the stratosphere, i.e., for variably levitated vehicles with cruising altitudes above the tropopause, the density of the air is significantly lower than that of the troposphere. Therefore, the mass of the variably levitated vehicle in the stratosphere must be reduced to allow the variably levitated vehicle to ascend to similar altitudes.

[0005] Currently, many structures (envelopes and balloons) tend to significantly increase the mass of the variably buoyant device.

[0006] The use of a single hermetically sealed reservoir makes it possible to avoid the use of several balloons, significantly reducing the packaging mass.

[0007] According to the prior art discussed above, the lighter-than-air gas is contained in a balloon and is therefore not in direct contact with the air injected into the envelope of the variably buoyant device.

[0008] Solutions requiring direct air injection into a single reservoir are not practical. The resulting heterogeneous mixture of lighter-than-air gas and air can lead to pitch instability of the variably levitated device, i.e., excessive angular difference between the horizontal plane and the longitudinal axis of the stratospheric variably levitated device. This instability can increase with further tilting of the stratospheric variably levitated device until the stratospheric variably levitated device assumes a vertical orientation. This is because lighter-than-air gas has a lower density than air, so it naturally positions itself at the top of the reservoir, leaving air at the bottom of the stratospheric variably levitated device's reservoir. In other words, in the case of a single balloon, injecting air causes the air to move toward the bottom of the reservoir, resulting in this pitch instability. If the air is injected around the balloon and not properly mixed, the same phenomenon occurs. As previously mentioned, air, being denser than the lighter-than-air gas, moves toward the bottom of the envelope. Pitch angle instability occurs due to the non-uniformity of the stratospheric variably levitable device's alignment along its longitudinal axis.

[0009] Therefore, to ensure that such stratospheric variably buoyant devices can be controlled during phases of varying buoyancy, such as the descent phase, it is necessary to obtain a homogeneous mixture within a single possible reservoir. Summary of the Invention [Problem to be solved by the invention]

[0010] The present invention seeks to overcome the above-mentioned problems by proposing a variably levitable device including a mixer capable of ensuring a uniform mixture of air and a lighter-than-air gas in a single pressurized, airtight, enclosed chamber. [Means for solving the problem]

[0011] For this reason, the present invention provides a variably levitable device, - a pressurized, airtight, enclosed chamber that receives a gas of a density less than that of air; a mixer disposed at least partially within the airtight sealed chamber and configured to introduce air into the airtight sealed chamber; The present invention relates to a variably levitable device comprising:

[0012] According to one aspect of the invention, a mixer includes a sleeve having at least one perforation therein and at least one injector for injecting air into the sleeve.

[0013] According to one aspect of the invention, the sleeve is obtained from a porous woven fabric.

[0014] According to one aspect of the invention, the variably buoyant device extends along a first longitudinal axis and the sleeve has the form of a tube extending generally along the first longitudinal axis of the variably buoyant device.

[0015] According to one aspect of the invention, the sleeve extends along a second axis that intersects with the first longitudinal axis of the variably buoyant device.

[0016] According to one aspect of the invention, at least one injector is positioned along the sleeve of the mixer along a first longitudinal axis of the variably buoyant device.

[0017] According to one aspect of the invention, at least one injector is positioned at one end of the sleeve of the mixer.

[0018] According to one aspect of the invention, a cross section of the mixer sleeve taken generally perpendicular to the longitudinal first axis is defined by a characteristic dimension greater than 15 centimeters.

[0019] According to one aspect of the invention, a cross section of the mixer sleeve taken generally perpendicular to the longitudinal first axis is defined by a characteristic dimension of less than 250 centimeters.

[0020] The invention will be better understood and further advantages will become apparent on reading the detailed description of one embodiment thereof, given by way of example and illustrated by the accompanying drawings, in which: FIG. [Brief explanation of the drawings]

[0021] [Figure 1a] 1 shows a schematic side view, in cross section, of a variably levitable device according to the present invention; [Figure 1b] 1 shows a schematic front view, in cross section, of a variably levitable device according to the invention; [Figure 2a] 1 shows a schematic diagram of a mixer of a variably levitable device according to a first embodiment; [Figure 2b] 1 shows a variant of the first embodiment of the mixer of the variably levitable device; [Figure 3a] 1 shows a schematic diagram of a mixer of a variably levitable device according to a second embodiment. [Figure 3b] 1 shows a second embodiment variant of the mixer of the variably levitable device; [Figure 4] 10 shows a schematic diagram of a mixer of a variably levitable device according to a third embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0022] For purposes of clarity, the same elements are given the same reference numbers in the various figures.

[0023] FIG. 1a shows a schematic side view, in cross section, of the variably buoyant device 1. The cross-sectional view of FIG. 1a is a vertical cross-section including the longitudinal axis A1 of the variably buoyant device 1. FIG. 1b shows a schematic front view, in cross section, of the variably buoyant device 1. The cross-sectional view of FIG. 1b is a vertical cross-section perpendicular to the longitudinal axis A1 of the variably buoyant device 1. The variably buoyant device 1 includes a pressurized, airtight, sealed chamber 4 intended to receive a gas having a density lower than that of air. This airtight, sealed chamber 4 may correspond to the envelope of the variably buoyant device 1 from an external perspective. The airtight, sealed chamber 4 is thus in contact with the external periphery 3 along its outer surface 41 and with the gas having a density lower than that of air along its inner surface 42. The airtight, sealed chamber 4 provides a seal between the external periphery 3 and the gas contained in the airtight, sealed chamber 4. However, the present invention also applies to an additional balloon containing a lighter-than-air gas providing a seal. In that case, the additional balloon serves as an airtight sealing chamber 4 .

[0024] The variably levitable device 1 also includes a mixer 6 that is partially disposed inside the airtight sealed chamber 4 and that is capable of introducing air into the airtight sealed chamber 4 and mixing this air with a gas having a density lower than that of the air inside the airtight sealed chamber 4. In particular, the mixer 6 includes a sleeve 61 that is disposed inside the airtight sealed chamber 4, and an injector 62 that is connected on one side to the sleeve 61 and on the other side to the outer periphery 3. In this way, the injector 62 is capable of injecting air from the outer periphery 3 into the sleeve 61.

[0025] The mixer 6 is positioned in the upper part 43 of the inner surface 42 of the airtight sealed chamber 4. More specifically, the sleeve 61 of the mixer 6 is positioned in the upper part 43 of the airtight sealed chamber 4, and the injector 62 penetrates the upper part 43 of the airtight sealed chamber 4 to allow communication with the air in the external surroundings 3. More generally, the invention applies to the injector 62 connected to the sleeve 61, however positioned on the sleeve 61.

[0026] In this way, the injector 62 makes it possible to inject air from the external surroundings 3 into the sleeve 61. The air therefore passes uniformly through the sleeve 61 and diffuses into the airtight sealed chamber 4.

[0027] The sleeve 61 of the mixer 6 advantageously takes the form of a tube and extends substantially along a longitudinal axis A1, defined as the axis passing horizontally through the variably levitable device 1. The sleeve 61 may therefore take any tubular shape, for example but not limited to that of a tube with a rectangular cross section or a tube with a circular cross section. Advantageously, the sleeve 61 is flexible and necessarily takes the shape of a cylindrical tube. According to the invention, the sleeve 61 may take any other shape that occupies a part of the volume of the hermetically sealed chamber 4.

[0028] The sleeve 61 can be made of a hard material, for example polyvinyl chloride or another hard plastic material. Advantageously, the sleeve 61 is made of a soft material, such as a fabric. This therefore reduces the mass of the sleeve 61.

[0029] Furthermore, the sleeve 61 may be defined by a sleeve cross section S1, which is the cross section of the tube. This cross section may be square in the case of a sleeve 61 made as a square cross section tube, or may be circular in the case of a cylindrical sleeve 61. The sleeve cross section S1 is defined by a characteristic dimension D1. For a square sleeve cross section S1, the characteristic dimension D1 may be a precise cross-sectional area, and for a circular sleeve cross section S1, the characteristic dimension D1 may be a diameter. Advantageously, the characteristic dimension D1 is the diameter of the circular sleeve cross section S1. The characteristic dimension D1 is a length that depends on the dimensions of the variably levitable device 1. Nevertheless, the characteristic dimension D1 may be defined as a length between 15 centimeters and 250 centimeters. Ideally, the characteristic dimension D1 is a length of 100 centimeters.

[0030] Furthermore, as shown by Figures 2a and 2b, which show the sleeve 61 with an injector 62 in the case of Figure 2a and with two injectors in the case of Figure 2b, the sleeve 61 is entirely perforated with a plurality of perforations 63. This is one application example. The invention also covers the case where the sleeve 61 is partially perforated, i.e. perforated with at least one perforation 63, and advantageously perforated with a plurality of perforations 63.

[0031] The perforations 63 in the sleeve 61 allow direct exchange of the air injected by the injector 62 with a gas having a density lower than that of air. Therefore, convective exchange can occur between the air in the external surroundings 3 injected by the injector 62 and the gas having a density lower than that of air. In particular, the air injected into the sleeve 61 using the injector 62 creates an overpressure inside the sleeve 61. Therefore, the excess air contained in the sleeve 61 is removed through the perforations 63. Because the density of the injected air is greater than the density of a gas having a density lower than that of air, the injected air naturally moves toward the lower portion 44 of the airtight sealed chamber 4, thereby creating convective cells that promote mixing within the airtight sealed chamber 4.

[0032] Advantageously, the fabric from which the sleeve 61 is made is porous. In particular, pores are defined as all voids contained in a solid material. Currently, voids in a solid material can be understood as perforations. A porous fabric is therefore a fabric provided with a plurality of perforations 63. Thus, by way of example, the sleeve 61 is obtained from a porous fabric so as to maximize the passage of the air injected by the injector 62 from the sleeve 61 toward the airtight sealed chamber 4. The plurality of perforations 63, either as perforations themselves or as holes in the sleeve, allow an increase in the contact area between the injected air and the gas present in the airtight sealed chamber 4. In particular, the mixing zone can be likened to an isosceles triangle with the air injection zone as its main vertex. The contact surface is therefore made up of the sides of the triangle thus formed. This increased surface area of ​​the mixing zone between the two gases contributes to a better mixing of the air with the gas in the airtight sealed chamber 4.

[0033] The mixer 6 may include a single injector 62 positioned along a sleeve 61 according to a first embodiment shown in FIG. 2a.

[0034] Additionally, the mixer 6 may include two injectors 62 positioned along the sleeve 61, as shown in Figure 2b. The present invention is also applicable to instances in which the mixer 6 includes three or more injectors 62.

[0035] Preferentially, according to a second embodiment as shown in FIG. 3a, the injector 62 is positioned at one end of the sleeve 61 of the mixer 6 along the longitudinal axis A1.

[0036] 3b, two injectors 62 may be positioned along the longitudinal axis A1 at each end of the sleeve 61 of the mixer 6. The mixer 6 may include more than two injectors 62, so long as the mass added by the multiple injectors 62 does not adversely affect the buoyancy and overall weight of the variably buoyant device 1.

[0037] Finally, a third embodiment can be envisaged, as shown in Figure 4. The sleeve 61 of the mixer 6, extending along the longitudinal axis A1, can include a secondary portion 611 of the sleeve 61. The secondary portion 611 of the sleeve 61 adopts the tubular shape of the sleeve 61 and extends along a second axis A2 that intersects with the longitudinal axis A1 of the variably levitable device 1. In one preferred embodiment, the second axis A2 is perpendicular to the longitudinal axis A1. The secondary portion 611 of the sleeve 61, like the sleeve 61, includes at least one, preferably multiple, perforations 63.

[0038] Furthermore, the secondary portion 611 of the sleeve 61 is defined by a secondary cross section S2. The secondary cross section S2 is preferably identical to the sleeve cross section S1. However, the secondary cross section S2 of the secondary portion 611 of the sleeve 61 can be different from the sleeve cross section S1.

[0039] 4 allows for an increased potential surface area for exchange of the air injected through the perforations 63 in the sleeve 61 and secondary part 611 with gases having a density lower than that of air, thus improving the homogenization of the mixture.

[0040] The present invention is based on the injection of a so-called heavy gas onto a so-called light gas contained in an airtight sealed chamber 4. This injection (i.e. the injection of air into the airtight sealed chamber 4) is advantageously carried out over a large surface area along the sleeve 61 of the mixer 6 so as to obtain an optimal mixture between the two gases. This creates convection cells which can improve the mixing of the gases and the heat transfer with the external surroundings 3. The present invention therefore benefits from the injection of air into the sleeve 61 and the mixing of the gases in the airtight sealed chamber 4 in order to provide good controllability of the variably levitable device 1 when descending. [Explanation of symbols]

[0041] 1 Variable levitation device 3. External perimeter 4. Airtight sealed chamber 6 Mixer 41 Exterior 42 Inner 43 Upper 44 Lower 61 Sleeve 62 injector 63 Perforation 611 Secondary part A1 First longitudinal axis A2 Second axis D1 characteristic dimension S1 Sleeve cross section S2 Secondary section

Claims

1. In a variably levitable device (1), a pressurized, airtight, enclosed chamber (4) that receives a gas of a density lower than that of air in contact with the external surroundings (3); a mixer (6) arranged at least partially inside the hermetically sealed chamber (4) and configured to introduce air into the hermetically sealed chamber (4) and mix the introduced air with a gas having a density lower than that of air inside the hermetically sealed chamber (4), the mixer (6) comprising a sleeve (61) provided with at least one perforation (63) and at least one injector (62) connected to the outer periphery (3) for injecting air into the sleeve (61). A variably levitable device (1) comprising:

2. 2. The variably levitable device (1) according to claim 1, wherein said sleeve (61) is obtained from a porous fabric.

3. 3. A variably buoyant device (1) as described in claim 1 or 2, wherein the sleeve (61) has the form of a tube extending substantially along the first longitudinal axis (A1) of the variably buoyant device (1).

4. The variably buoyant device (1) of claim 3, wherein the sleeve (61) extends along a second axis (A2) that intersects with the first longitudinal axis (A1) of the variably buoyant device (1).

5. The variably buoyant device (1) according to any one of claims 1 to 4, wherein the at least one injector (62) is positioned along the sleeve (61) of the mixer (6) along a first longitudinal axis (A1) of the variably buoyant device (1).

6. 6. The variably buoyant device (1) according to claim 5, wherein said at least one injector (62) is positioned at one end of said sleeve (61) of said mixer (6).

7. A variably levitable device (1) as described in any one of claims 3 to 6, wherein a cross section (S1) of the sleeve of the mixer (6) that is approximately perpendicular to a first longitudinal axis (A1) is defined by a characteristic dimension (D1) greater than 15 centimeters.

8. A variably levitable device (1) as described in any one of claims 3 to 7, wherein a cross section (S1) of the sleeve of the mixer that is approximately perpendicular to a first longitudinal axis (A1) is defined by a characteristic dimension (D1) that is less than 250 centimeters.

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