Patent Publication Number: US-2022227497-A1

Title: Aircraft with hydrogen storage tanks

Description:
CROSS-REFERENCE TO RELATED PATENT APPLICATIONS 
     This application is based upon and claims the benefit of priority from British Patent Application No. GB 2100665.5, fled on Jan. 19, 2021, the entire contents of which are herein incorporated by reference. 
     BACKGROUND 
     Technical Field 
     The embodiment relates to an aircraft having hydrogen storage tanks, especially tanks for storage of gaseous hydrogen to be used as a fuel for aircraft propulsion, for example by use in a fuel cell system and/or a hydrogen-burning gas turbine engine. 
     Description of Related Art 
     Use of hydrogen as a fuel in transport applications, including aeronautical applications, is of interest due to the absence of carbon dioxide generation at the point of use. However, storage of gaseous hydrogen on an aircraft requires a significantly greater fuel storage volume compared to that of a conventional aircraft. For many flight missions, conventional aircraft designs are therefore not appropriate for hydrogen-fuelled aviation. If a conventional aircraft is fitted with hydrogen storage tanks, the usable volume within the aircraft&#39;s interior is substantially reduced if the aircraft is intended to maintain its original range and payload. 
     SUMMARY 
     According to an example, an aircraft comprises a fuselage and first, second and third elongate hydrogen storage tanks mounted to the exterior of the fuselage and extending parallel thereto, the aircraft further comprising an aerodynamic fairing, the aerodynamic fairing and the fuselage enclosing the hydrogen storage tanks. 
     The first, second and third hydrogen storage tanks may be disposed vertically above a horizontal plane containing the wing tips of the aircraft, with the aircraft on the ground or in level flight. 
     The first, second and third hydrogen storage tanks may be cylindrical, the first and second hydrogen tanks having a first diameter and being mounted in contact with the exterior of the fuselage adjacent first and second wings of the aircraft respectively, the aircraft further comprising a fourth cylindrical hydrogen storage tank, the third and fourth cylindrical hydrogen storage tanks having a second diameter less than the first diameter and being mounted to the exterior of the fuselage adjacent the first and second hydrogen storage tanks respectively. 
     Alternatively, the first hydrogen storage tank may be mounted to the exterior of the fuselage at top dead-centre thereof. In this case, the second and third hydrogen storage tanks may each be mounted in contact with the first hydrogen storage tank on a respective lateral side thereof. The first, second and third hydrogen storage tanks may be cylindrical, the second and third hydrogen storage tanks having a common diameter less than the diameter of the first hydrogen storage tank. The aircraft may further comprise fourth and fifth cylindrical elongate hydrogen storage tanks mounted to the fuselage in contact with the second and third hydrogen storage tanks respectively, the fourth and fifth hydrogen storage tanks having a common diameter less than that of the second and third cylindrical hydrogen storage tanks. 
     The first, second and third hydrogen storage tanks may be comprised in a set of like hydrogen storage tanks each mounted to the exterior of the fuselage, the set extending completely azimuthally and contiguously around the fuselage. In this case, the hydrogen storage tanks of the set may each be cylindrical and have a common diameter. Alternatively, each hydrogen storage tank may have cylindrical arcuate inner and outer portions extending between first and second azimuthal positions with respect to the fuselage, and first and second planar portions connecting the cylindrical arcuate portions at the first and second azimuthal positions respectively, with the inner arcuate portion being in contact with the exterior of the fuselage; the tanks are optionally integrated in a single multiple-tank structure. 
     The aircraft may comprise at least one of a hydrogen-fuelled fuel-cell system and a hydrogen-burning gas turbine engine, and a conveying system arranged to convey hydrogen from the hydrogen storage tanks to the hydrogen fuel-cell and/or the hydrogen-burning gas turbine engine. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Embodiments are described below by way of example only and with reference to the accompanying drawings in which: 
         FIG. 1  shows a transverse cross-section of the first example aircraft, 
         FIG. 2  shows a longitudinal cross-sections of the aircraft of  FIG. 1 . 
         FIG. 3  shows a transverse cross-section of the second example aircraft, 
         FIG. 4  shows a transverse cross-section of the third example aircraft, 
         FIG. 5  show longitudinal cross-sections of the aircraft of  FIG. 4 , 
         FIG. 6  shows a transverse cross-section of the fourth example aircraft; and 
         FIG. 7  shows a transverse cross-sections of the fifth example aircraft. 
     
    
    
     DETAILED DESCRIPTION 
     Referring to  FIGS. 1 and 2 , a first example aircraft  100  comprises a fuselage  118 , wings  116 A,  116 B, first, second and third elongate generally cylindrical hydrogen storage tanks  112 A.  112 B,  112 C mounted on and extending generally parallel to the fuselage  118  and an aerodynamic fairing  114  which, together with the fuselage  118 , encloses the hydrogen storage tanks  112 A,  1128 ,  112 C and provides a continuous external air-washed surface of the aircraft  100 . With the aircraft on the ground or in level flight, a vertical plane  102  longitudinally bisects both the fuselage  118  and the first hydrogen storage tank  112 A, i.e. the first hydrogen storage tank  112 A is mounted on the fuselage  118  at top dead-centre thereof. A horizontal plane  101  includes the tips of the wings  116 A,  116 B. The first, second and third tanks  112 A,  112 B,  112 C are each mounted on the fuselage  118  vertically above the plane  101 . The fairing  114  extends fore and aft of the hydrogen storage tanks  112 A,  112 B,  112 C as shown in  FIG. 2 . The interior  110  of the fuselage  118  provides a space for passengers and/or cargo in use of the aircraft  100 . The second  112 B and third  112 C tanks have a common diameter smaller than that of the first tank  112 A and are each mounted on the exterior of the fuselage  118  on a respective lateral side of the first tank  112 A. The second  1128  and third  112 C tanks are in contact with the first tank  112 A, but in other examples may be separated in azimuth from the first tank  112 A with respect to the fuselage  118 . 
       FIG. 3  shows a second example aircraft  200  which is similar to the aircraft  100  of  FIGS. 1 and 2 . Parts of the aircraft  200  of  FIG. 3  are labelled with reference numerals differing by  100  from those labelling corresponding parts in  FIGS. 1 and 2 . The aircraft  200  comprises a first elongate generally cylindrical hydrogen storage tank  212 A mounted on and extending generally parallel to fuselage  218  at top dead-centre thereof and first  2128 ,  212 C, second  212 D,  212 E, third  212 F,  212 G and fourth  212 H,  212 I pairs of elongate generally cylindrical hydrogen storage tanks, the pairs having respective diameters which decrease moving azimuthally away from the first tank  212 A with respect to the fuselage  218 , and which are each smaller than the diameter of the first tank  212 A. The first, second, third and fourth pairs of tanks  312 B,  312 C,  312 D,  312 E,  312 F,  312 G,  312 H,  312 I also extend generally parallel to the fuselage  218 . The hydrogen storage tanks  212 A-I are mounted to the fuselage  218  vertically above a horizontal plane  201  containing the tips of wings  216 A,  216 B. Aerodynamic fairing  214  and fuselage  218  enclose the hydrogen storage tanks  212 A- 1  and provide a continuous external air-washed surface of the aircraft  200 . 
       FIGS. 4 and 5  show a third example aircraft  300  having a fuselage  318 , wings  316 A,  316 B and a plurality of like elongate cylindrical hydrogen storage tanks such as  312 A,  3128 ,  312 C each mounted on and extending generally parallel to the fuselage  318  within a fairing  314  such that the tanks are contiguous in azimuth with respect to the fuselage  318  and completely surround the fuselage  318 . Tank  312 A is mounted on the fuselage  318  at top dead-centre such that, with the aircraft  300  on the ground or in level flight, a vertical plane  302  which longitudinally bisects the fuselage  318  also longitudinally bisects the tank  312 A. Horizontal plane  301  contains the tips of wings  316 A,  316 B. A hydrogen storage tank  312 Z is mounted to the fuselage  318  at bottom dead-centre thereof. The interior  310  of the fuselage  318  provides space for passengers and/or cargo. 
       FIG. 6  shows a transverse cross-section of a fourth example aircraft  400 , the aircraft  400  comprising fuselage  418 , wings  416 A,  4168  and plurality elongate hydrogen storage tanks such as  412 A mounted on the exterior of the fuselage  418 , each tank being in contact with two other tanks which are adjacent in azimuth with respect to the fuselage  418 , the tanks extending completely azimuthally around the fuselage  418 . Tanks  4128 ,  412 C are adjacent in azimuth to tank  412 A. With the aircraft on the ground or in level flight, vertical plane  402  longitudinally bisects the fuselage  418 . Tank  412 A comprises inner and outer arcuate cylindrical portions  413 A,  413 B which extend between azimuthal positions  415 A,  415 B, the inner portion  413 A being in contact with the fuselage  418 , and planar portions  417 A,  4178  at the azimuthal positions  415 A,  415 B respectively, each of which connects the inner and outer arcuate portions  413 A,  413 B at a respective azimuthal position  415 A,  415 B. The hydrogen storage tanks are enclosed by a fairing  414  and the fuselage  418 . 
     In a first variant of the aircraft  400  of  FIG. 6 , fewer tanks are provided and each tank is spaced apart in azimuth from two neighbouring tanks. In a second variant, contiguous individual hydrogen storage tanks are integrated in a single, multi-tank structure. 
       FIG. 7  shows a transverse cross-section of a fifth example aircraft  500 , the aircraft  500  comprising a fuselage  518 , wings  516 A,  516 B, a first pair of like elongate cylindrical hydrogen storage tanks  512 A,  5128  having a first diameter, a second pair of like elongate cylindrical hydrogen storage tanks  512 C,  512 D having a second diameter smaller than the first diameter and an aerodynamic fairing  514 . Each of the tanks  512 A,  512 B is mounted to the exterior of the fuselage  518  and is in contact with a respective wing  516 A,  516 B of the aircraft  500 . Tanks  512 C,  512 D are each mounted in contact with the fuselage  518  of the aircraft  500  and in contact with a respective one of the tanks  512 A,  512 B. The fairing  514  encloses the hydrogen storage tanks  512 A,  5128 ,  512 C,  512 D and forms a continuous air-washed surface together with a lower portion of the fuselage  518 , except at the position of the wings  516 A,  516 B. The fairing  518  has portions fore and aft of the hydrogen storage tanks  512 A-D as in the case of the fairing  114  of the aircraft  100  of  FIGS. 1 and 2 . With the aircraft  500  on the ground or in level flight, vertical planes  502  bisects the fuselage  518 ; horizontal plane  501  contains the tips of the wings  516 A,  516 B.