FUEL GAUGING SENSING DEVICES

Abstract

A fuel gauging sensing device for a fuel tank for aircrafts includes an optical fiber harness along the internal surface of the tank, a master optical controller connected to a first terminal of the optical fiber harness, a slave optical controller connected to a second terminal of the optical fiber harness, wherein the optical fiber harness includes Fiber Bragg Grating (FBG) sensors spaced in the optical fiber harness between 1 mm and 25 mm to provide temperature gradients inside the tank and wherein the master and slave optical controllers are configured to obtain the fuel gauging of the tank based on the output from the FBG sensors.

Claims

1. A fuel gauging sensing device for a fuel tank for aircrafts, the device comprising: an optical fiber harness established along an internal surface of the tank; a master optical controller connected to a first terminal of the optical fiber harness; and a slave optical controller connected to a second terminal of the optical fiber harness; wherein the optical fiber harness comprises a plurality of Fiber Bragg Grating (FBG) sensors; wherein the FBG sensors are spaced in the optical fiber harness between 1 mm and 25 mm and configured to provide temperature gradients inside the tank; and wherein the master and slave optical controllers are configured to obtain the fuel gauging of the tank based on an output from the FBG sensors.

2. The fuel gauging sensing device according to claim 1, wherein the optical fiber harness comprises a plurality of intrinsic fiber sensors configured to measure a refractive index of a medium surrounding the sensors inside the tank, wherein the intrinsic fiber sensors are spaced in the optical fiber harness between 1 mm and 25 mm, and wherein the master and slave optical controllers are configured to obtain the fuel gauging of the tank based on output of the plurality of intrinsic fiber sensors and the plurality of FBG sensors.

3. The fuel gauging sensing device according to claim 2, wherein the optical fiber harness comprises one or more Fabry Perot sensors configured to obtain absolute pressure, and/or temperature and/or refractive index values at specific points inside the tank, wherein the master and slave optical controllers are configured to obtain the fuel gauging of the tank based on output of the one or more Fabry Perot sensors, the plurality of intrinsic fiber sensors and the plurality of FBG sensors.

4. The fuel gauging sensing device according to claim 1, wherein the optical fiber harness comprises single or multiple flexible optical fiber cables.

5. The fuel gauging sensing device according to claim 1, wherein the optical fiber harness comprises a helical form and is established from a first end of the internal surface of the tank to an opposite end of the internal surface of the tank.

6. The fuel gauging sensing device according to claim 5, comprising a helical track configured to allocate the optical fiber harness, the helical track having an adjustable helical pitch and length.

7. The fuel gauging sensing device according to claim 5, wherein the helical track comprises a flat plate configured to attach the fiber harness to the helical track.

8. The fuel gauging sensing device according to claim 5, wherein the helical track comprises a plate with holes configured to attach the fiber harness to the helical track.

9. The fuel gauging sensing device according to claim 5, wherein the helical track comprises a set of brackets configured to attach the fiber harness to the helical track.

10. A cryogen tank comprising the fuel gauging sensing device according to claim 1.

11. The cryogen tank according to claim 10, comprising a frame and a first and second wall interface ports, wherein the frame is configured to allocate the helical track, wherein the first interface port is configured to permit an operator to access the master optical controller, and wherein the second interface port is configured to permit an operator to access the slave optical controller.

12. A liquid hydrogen tank comprising the fuel gauging sensing device according to claim 1.

13. The liquid hydrogen tank according to claim 12, comprising a frame and a first and second wall interface ports, wherein the frame is configured to allocate the helical track, wherein the first interface port is configured to permit an operator to access the master optical controller, and wherein the second interface port is configured to permit an operator to access the slave optical controller.

14. A kerosene tank comprising the fuel gauging sensing device according to claim 1.

15. The kerosene tank according to claim 14, comprising a frame and a first and second wall interface ports, wherein the frame is configured to allocate the helical track, wherein the first interface port is configured to permit an operator to access the master optical controller, and wherein the second interface port is configured to permit an operator to access the slave optical controller.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0022] For a better understanding the above explanation and for the sole purpose of providing an example, some non-limiting drawings are included that schematically depict a practical embodiment.

[0023] FIG. 1 shows the optical fiber harness and the helical track as part of the fuel gauging sensing device according to the disclosure herein.

[0024] FIG. 2 shows the optical fiber harness and the helical track according to the disclosure herein and a section of the fuel tank for aircrafts.

[0025] FIGS. 3 through 5 show the installation of the optical fiber harness and the helical track according to the disclosure herein into the fuel tank for aircrafts.

[0026] FIG. 6 shows the fuel gauging sensing device inside the fuel tank for aircrafts, the proposed fuel gauging sensing device comprises the optical fiber harness and the helical track and a plurality of sensors.

[0027] FIG. 7 shows a front view of the tank including the proposed fuel gauging sensing device according to the disclosure herein.

[0028] FIG. 8 shows the master and slave controllers as part of the fuel gauging sensing device according to the disclosure herein.

[0029] FIG. 9 shows three different fiber fixation concepts of the fuel gauging sensing device according to the disclosure herein.

DETAILED DESCRIPTION

[0030] FIG. 1 shows the optical fiber harness as part of the fuel gauging sensing device. The optical fiber harness comprises a helical form and is established from a first end of the internal surface of the tank to an opposite end of the internal surface of the tank (not shown in this figure). The optical fiber cable routing geometry of the optical fiber harness follows a continuous helical form around the inside surface of the tank from one end to the other.

[0031] The helical routing and multiple sensor locations along the complete tank length and around the complete circumference of the tank ensures that the required level measurement accuracy is maintained at all conceivable aircraft pitch and roll attitudes. As shown in the figure, multiple optical fiber cables can be routed in a single track thus providing functional redundancy or increased accuracy.

[0032] FIG. 1 also shows the helical track as part of the fuel gauging sensing device (shown in FIGS. 6 and 7) according to the disclosure herein. Single or multiple flexible optical fiber cables are slid into the helical track which can be rigid and which is attached to the inside surface of the tank. The helical track can be configured to allocate the optical fiber harness. The helical track comprises an adjustable helical pitch and length, providing a simple design that is easily adaptable to different tank lengths/diameters and accuracy requirements by extending or reducing the coil pitch and length of the helical track. Furthermore, the helical track may be mounted on a ‘sub-frame’ to enable ease of installation, particularly on long tanks. Several fixation concepts to attach the optical fiber harness to the helical track are shown in FIG. 9.

[0033] FIG. 2 shows the optical fiber harness and the helical track according to the disclosure herein and a section of the fuel tank for aircrafts. Open “C” section track profile enables optical cable to be in direct contact with the fuel, as e.g., LH2 or kerosene in order to obtain the gauging measurements.

[0034] FIGS. 3 through 5 shows the installation of the optical fiber harness and the helical track as part of the fuel gauging device according to the disclosure herein into the fuel tank for aircrafts. The tank comprises two wall interface ports located in the bezels of the tank to permit installation of the fuel gauging device comprising the optical fiber harness and the helical track. Heat transfer is reduced by having two wall interfaces ports. Furthermore, the installation of the fuel gauging device simplifies tank manufacturing and assembly by pre-assembling the optical fiber harness into the helical track outside the tank and then installing the modular assembly into the tank in one single operation.

[0035] As shown in the figures, one end of the rigid track is located immediately adjacent to a first tank wall port (most likely in the end ‘bezel’ of the tank) through which the optical fiber harness passes or is connected).

[0036] In the event of failure in-service, a default optical fiber cable of the optical fiber harness can be removed (pulled) through the assess tank wall port or and a new optical fiber cable can be installed (pushed) through the same port.

[0037] The proposed fuel gauging sensing device improves operability during the life of the aircraft by enabling the replacement of the optical fiber cables of the optical fiber harness from outside of the tank through the two wall interface ports, preferably located in the bezels of the tank to assure segregation and work in master-slave logic, enabled by the optical fiber harness sliding in the helical track, because access for manual operations inside of the tank will not be possible in service due to all-welded construction of the fuel tank.

[0038] FIG. 6 shows the fuel gauging sensing device inside the fuel tank for aircrafts, the fuel gauging sensing device comprises the optical fiber harness and the helical track and a plurality of sensors. The disclosure herein uses existing Fiber Bragg Grating (FBG) and additionally Fabry Perot Sensing technology for level/gauging sensing which enables multiple measurement points along the length of the optical fiber harness. In particular:

[0039] In a first embodiment, the fuel gauging sensing device comprises a plurality of Fiber Bragg Grating, FBG, sensors with a minimum spacing between 1 mm and 25 mm and configured to provide temperature gradients inside the tank, and wherein the master and slave optical controllers are configured to obtain the fuel gauging of the tank based on the output from the plurality of Fiber Bragg Grating, FBG, sensors. Helical pitch can be adjusted to give more intermediate readings if needed depending on tank proportions. The distance of the spacing between sensors will be depending on the size of the tank and can be targeted to achieve a 1% minimum level of measurement accuracy.

[0040] In a second embodiment, the optical fiber harness further comprises a plurality of intrinsic fiber sensors configured to measure the refractive index of the medium surrounding the sensor inside the tank. The refractive index for gas hydrogen and for liquid hydrogen can be different so this fact would allow to obtain the gauging of the fuel inside the tank. The sensors can have a minimum spacing between 1 mm and 25 mm in order to be able to detect the interface between liquid hydrogen and gas hydrogen. The distance of the spacing between sensors can depend on the size of the tank and it is targeted to achieve a 1% minimum level of measurement accuracy. The master and slave optical controllers are configured to obtain the fuel gauging of the tank based on the output of the plurality of Fiber Bragg Grating, FBG, sensors and the intrinsic fiber sensors. The sensors can be fixed to the track and connected through the flexible optical fiber harness.

[0041] In a third embodiment (which is shown in FIG. 6), the fuel gauging sensing device further comprises one or more Fabry Perot sensors configured to provide absolute pressure, and/or temperature and/or refractive index values at specific points inside the tank, wherein the master and slave optical controllers are configured to obtain the fuel gauging of the tank based on the output of the one or more Fabry Perot sensors, the output of the plurality of Fiber Bragg Grating, FBG, sensors, and the intrinsic fiber sensors. The sensors can be fixed to the helical track and connected through the flexible optical fiber harness.

[0042] FIG. 7 shows a front view of the tank including the fuel gauging sensing device according to the disclosure herein. The fuel gauging sensing device permits a simple design that is easily adaptable to different tank lengths/diameters and accuracy requirements by altering the number of FBG, sensors, Fabry Perot sensors and the intrinsic fiber sensors on the fibers. Helical pitch can be adjusted to give more intermediate readings if needed depending on tank proportions.

[0043] Hence, the present application permits fuel gauging covered by fiber optic with FBG's sensors installed in the helical track can provide temperature gradients in the interface liquid-to-gas combined with absolute pressure/temperature optical sensors based on Fabry Perot technology and intrinsic fiber sensors that permit independent level sensing based on absolute pressure/temperature and refractive index optical sensing.

[0044] FIG. 8 shows the master and slave controllers as part of the fuel gauging sensing device according to the disclosure herein. Two wall ports can be used in order to route the optical cables in a master-slave configuration with the master and slave controllers.

[0045] FIG. 9 shows three different fiber fixation concepts performed in the fuel gauging sensing device according to the disclosure herein. The helical track is configured to allocate the optical fiber harness. The attachment or fixation of the optical fiber harness within the helical track of the fuel gauging sensing device can be carried out by performing different fixation concepts.

[0046] A first fixation concept is show in FIG. 9, wherein the optical fiber harness comprising a single optical fiber can be attached to a flat plate.

[0047] A second fixation concept is shown in FIG. 9, wherein the optical fiber harness fiber can be attached to a plate with holes.

[0048] A third fixation concept shown in FIG. 9, wherein the optical fiber harness fiber is attached to a set of brackets. It is show in FIG. 9, that the optical fiber harness can be hanging from those brackets.

[0049] The fuel gauging sensing device according to the disclosure herein can be used in a cryogen tank, in a liquid hydrogen tank and/or a kerosene tank.

[0050] The subject matter disclosed herein can be implemented in or with software in combination with hardware and/or firmware. For example, the subject matter described herein can be implemented in or with software executed by a processor or processing unit. In one example implementation, the subject matter described herein can be implemented using a computer readable medium having stored thereon computer executable instructions that when executed by a processor of a computer control the computer to perform steps. Example computer readable mediums suitable for implementing the subject matter described herein include non-transitory devices, such as disk memory devices, chip memory devices, programmable logic devices, and application specific integrated circuits. In addition, a computer readable medium that implements the subject matter described herein can be located on a single device or computing platform or can be distributed across multiple devices or computing platforms.

[0051] While at least one example embodiment of the invention(s) is disclosed herein, it should be understood that modifications, substitutions and alternatives may be apparent to one of ordinary skill in the art and can be made without departing from the scope of this disclosure. This disclosure is intended to cover any adaptations or variations of the example embodiment(s). In addition, in this disclosure, the terms “comprise” or “comprising” do not exclude other elements or steps, the terms “a”, “an” or “one” do not exclude a plural number, and the term “or” means either or both. Furthermore, characteristics or steps which have been described may also be used in combination with other characteristics or steps and in any order unless the disclosure or context suggests otherwise. This disclosure hereby incorporates by reference the complete disclosure of any patent or application from which it claims benefit or priority.