Rotary-wing aircraft

Abstract

This specification provides a rotary-wing aircraft that can suppress the temperature rise of a fuel cell more effectively than conventional aircraft by utilizing the airflow from the rotor. [Solution] The rotorcraft disclosed herein comprises a rotor that generates lift, a hydrogen source, and a flow channel that delivers hydrogen from the hydrogen source to a fuel cell stack. The flow channel passes beneath the rotor. The rotorcraft disclosed herein cools the hydrogen before it enters the fuel cell stack with the airflow generated by the rotor. By supplying cool hydrogen to the fuel cell stack, the rotorcraft disclosed herein can suppress the temperature rise of the fuel cell stack.

Description

Technical Field

[0001] The technology disclosed in this specification relates to rotary-wing aircraft. The rotary-wing aircraft in this specification includes so-called drones that fly unmanned, in addition to manned flying bodies such as helicopters and autogyros.

Background Art

[0002] Patent Document 1 discloses a rotary-wing aircraft including a fuel cell and a radiator that cools the fuel cell. The radiator cools the refrigerant by receiving the wind during flight. Further, Patent Document 2 discloses a rotary-wing aircraft in which a heat dissipation plate is disposed at a position where the airflow generated by the rotor hits.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] This specification provides a rotary-wing aircraft that can more effectively suppress the temperature rise of a fuel cell by utilizing the airflow of the rotor than in the prior art.

Means for Solving the Problems

[0005] [[ID=…]] <000…]]

[0006] ​ The flow channel should ideally extend parallel to the rotor axis. This allows for a longer range of airflow from the channel to the rotor and reduces turbulence caused by the channel.

[0007] Rotary-wing aircraft may have multiple rotors. In that case, the airflow conduit should ideally pass under at least two rotors. This structure also allows for a longer range of airflow conduit that receives airflow from the rotors.

[0008] Details of the technology disclosed herein and further improvements are described in the following "Modes for Carrying Out the Invention". [Brief explanation of the drawing]

[0009] [Figure 1] This is a plan view of the rotary-wing aircraft of the first embodiment. [Figure 2] This is a side view of a rotary-wing aircraft. [Figure 3] This is a front view of a rotary-wing aircraft. [Figure 4] This is a front view of the rotary-wing aircraft of the second embodiment. [Modes for carrying out the invention]

[0010] (First Embodiment) The first embodiment of the rotor-wing aircraft 10 will be described with reference to Figure 1-3. Figures 1-3 are the top view, side view, and front view of the rotor-wing aircraft, respectively. The X and Y axes of the coordinate system in the figures represent the front-rear and rear directions and the lateral direction of the rotor-wing aircraft 10, respectively. The +Z direction represents the vertically upward direction.

[0011] The rotary-wing aircraft 10 is a so-called drone that flies by remote control. The rotary-wing aircraft 10 consists of a main body 11, four rotors 12, a hydrogen source 15, a fuel cell stack 16, and flow path pipes 17. For the sake of explanation, the "fuel cell stack" will be referred to as the "FC stack" below.

[0012] The rotary-wing aircraft 10 flies by generating lift with four rotors 12. The four rotors 12 are each positioned at one of the four corners of the main body 11. The rotors 12 are driven by motors 13. The motors 13 are driven by power generated by the FC stack 16. The main body 11 is equipped with a battery, and any surplus power generated by the FC stack 16 that is not consumed by the motors 13 is stored in the battery. If the power from the FC stack 16 is insufficient to drive the motors 13, power from the battery is used. The main body 11 is equipped with a device that converts the power generated by the FC stack 16 (and the battery power) into power suitable for driving the motors 13, but the illustration and explanation of this device are omitted.

[0013] A hydrogen source 15 is positioned on top of the main body 11. The hydrogen source 15 stores sodium borohydride (SBH) and water. The hydrogen source 15 generates hydrogen by mixing water with SBH. Both SBH and water are stored in the hydrogen source 15 at atmospheric pressure. In fuel cell vehicles and the like, high-pressure hydrogen tanks are generally used as the hydrogen source, but high-pressure hydrogen tanks are heavy in order to withstand high pressure. The hydrogen source 15 of the rotary-wing aircraft 10 can store SBH and water at atmospheric pressure, so its dry weight (weight excluding SBH and water) is lighter than that of a high-pressure hydrogen tank, making it suitable for the rotary-wing aircraft 10 that flies on electricity.

[0014] The FC stack 16 is located below the main body 11, and the hydrogen source 15 and the FC stack 16 are connected by a flow channel pipe 17. Hydrogen generated in the hydrogen source 15 is supplied to the FC stack 16 through the flow channel pipe 17. As shown in the front view (Figure 3), for the sake of explanation, the flow channel pipe 17 connecting the hydrogen source 15 and the FC stack 16 will be described by dividing it into the upper part of the flow channel pipe 17a, the middle part of the flow channel pipe 17b, 17c, and the lower part of the flow channel pipe 17d. Also for the sake of explanation, the rotor 12 depicted on the left side of Figure 3 will be represented by the reference numeral 12a, and the rotor 12 depicted on the right side will be represented by the reference numeral 12b.

[0015] The upper part 17a of the flow channel is connected to the hydrogen source 15 and splits into two branches midway. The upper part 17a of the flow channel extends below the left and right rotors 12a and 12b, respectively. The upper end of the middle section 17b of the flow channel is connected to the left end of the upper part 17a of the flow channel, and the upper end of the middle section 17c of the flow channel is connected to the right end of the upper part 17a of the flow channel. The middle section 17b (17c) of the flow channel extends below the rotor 12a (12b) along the axis Ax of the rotor 12a (12b). The lower part 17d of the flow channel is connected to the FC stack 16 and splits into two branches midway. The lower end of the middle section 17b of the flow channel is connected to the left end of the lower part 17d of the flow channel, and the lower end of the middle section 17c of the flow channel is connected to the right end of the lower part 17d of the flow channel. The hydrogen generated in the hydrogen source 15 splits into two at the upper part of the flow channel 17a and flows under the rotors 12a and 12b respectively, along the axis Ax of the rotors 12a and 12b. After that, the hydrogen merges at the lower part of the flow channel 17d and flows to the FC stack 16.

[0016] The rotary-wing aircraft 10 generates lift by pushing air downwards from the rotor 12 during flight. During flight, airflow flows along the axis Ax below the rotor 12. Part of the flow channel 17 (intermediate sections 17b and 17c) extends along the axis Ax, and hydrogen is cooled by the airflow as it flows through the intermediate sections 17b and 17c. The rotary-wing aircraft 10 is equipped with four landing gear 14, and the intermediate sections 17b and 17c of the flow channel extend close to the lower ends of the landing gear 14. Note that the landing gear 14 are not shown in Figure 1. Because the intermediate sections 17b and 17c of the flow channel extend along the axis Ax, the hydrogen is cooled by the airflow over a relatively long distance. By providing the flow channel 17 which extends long along the axis Ax, the hydrogen is effectively cooled. The flow channel 17 is made of a metal with high thermal conductivity (typically copper).

[0017] The FC stack 16 generates electric power by reacting hydrogen with oxygen (air). Heat is also generated when hydrogen and oxygen react. Usually, a fuel cell includes a cooler for cooling the FC stack. However, since the cooler of the fuel cell includes a pump and the like, the weight increases. The rotary wing machine 10 suppresses the temperature rise of the FC stack 16 by cooling hydrogen with the airflow of the rotor 12 and supplying the cooled hydrogen to the FC stack 16. The rotary wing machine 10 does not need to have a complex and heavy cooler. The fact that the flow path pipe 17 extends under the plurality of rotors 12 also contributes to the effective cooling of hydrogen.

[0018] (Second Embodiment) FIG. 4 shows a front view of the rotary wing machine 20 of the second embodiment. The rotary wing machine 20 is different from the rotary wing machine 10 of the first embodiment in that the flow path pipe 27 is different. The structure of the rotary wing machine 20 is the same as that of the rotary wing machine 10 of the first embodiment except for the flow path pipe 27.

[0019] The flow path pipe 27 includes an upper flow path pipe portion 27a, two intermediate flow path pipe portions 27b, 27c, and a lower flow path pipe portion 27d. The upper flow path pipe portion 27a and the lower flow path pipe portion 27d are the same as the upper flow path pipe portion 17a and the lower flow path pipe portion 17d in FIG. 3, respectively. The two intermediate flow path pipe portions 27b, 27c macroscopically extend along the axis Ax of the rotor 12. However, the two intermediate flow path pipe portions 27b, 27c are microscopically bent in a zigzag shape. By being bent in a zigzag shape, the two intermediate flow path pipe portions 27b, 27c have a longer flow path length and can more effectively cool hydrogen.

[0020] Points to note regarding the technology described in the embodiments are described. The hydrogen source 15 of the rotary wing machines 10 and 20 in the embodiments was a device that generates hydrogen by mixing water with SBH. The hydrogen source 15 may be a device that generates hydrogen with a compound other than SBH. Alternatively, the hydrogen source 15 may be a tank that stores hydrogen or a hydrogen storage alloy. That is, the hydrogen source 15 may be a device that generates hydrogen or a storage device that stores hydrogen. However, it is desirable that the hydrogen source 15 is a device that supplies hydrogen at room temperature. This is because the rotary wing machine disclosed in this specification cools the hydrogen before it is supplied to the FC stack 16 by the airflow of the rotor.

[0021] In the rotary wing aircraft 10(20) of the embodiment, the flow path pipe 17(27) branches horizontally into two from the hydrogen source 15, bends downward under each of the two rotors 12a and 12b, extends along the axes of the rotors 12a and 12b, and then merges and is connected to the FC stack 16. This structure can increase the ratio of the portion passing under the rotor 12 with respect to the total length of the flow path pipe. That is, this structure of the flow path pipe is lightweight and provides high cooling efficiency.

[0022] The rotary wing aircraft 10(20) of the embodiment includes a plurality of rotors 12, and the flow path pipe 17(27) passes under at least two rotors 12. The rotary wing aircraft disclosed in this specification only needs to pass under at least one rotor. A part of the flow path pipe may extend along the axis of the rotor directly below the rotor.

[0023] Viewed from another perspective, the hydrogen flowing through the flow path pipe can be regarded as a refrigerant for cooling the FC stack. That is, viewed from another perspective, the rotary wing aircraft disclosed in this specification is characterized in that the refrigerant is cooled by the downward airflow generated by the rotor. Based on this perspective, the rotary wing aircraft of the embodiment can be expressed as having the following characteristics. The rotary wing aircraft 10(20) disclosed in this specification includes a rotor 12 that generates lift and a flow path pipe (intermediate portions 17b, 17c, 27b, 27c of the flow path pipe) that extends along the axis Ax of the rotor 12 below the rotor 12. A refrigerant flows through the flow path pipe 17(27), and the refrigerant that has passed through the flow path pipe is sent to a heat generating body (FC stack 16) included in the rotary wing aircraft 10(20). By including a flow path pipe (intermediate portions 17b, 17c, 27b, 27c of the flow path pipe) that extends along the axis Ax below the rotor 12, the rotary wing aircraft 10(20) can effectively cool the refrigerant without significantly increasing the weight. This rotary wing aircraft can use the airflow of the rotor to cool the refrigerant more effectively than before. In this regard, the heat generating body may be other than the FC stack, and the refrigerant may be other than hydrogen (for example, water).

[0024] The rotorcraft 10(20) is equipped with multiple rotors 12, and the flow channels (intermediate sections 17b, 17c, 27b, 27c) are preferably positioned below at least two of the rotors 12. This allows for more effective cooling of the refrigerant.

[0025] Although specific examples of the present invention have been described in detail above, these are merely illustrative and do not limit the scope of the claims. The technologies described in the claims include various modifications and changes to the specific examples illustrated above. The technical elements described in this specification or drawings exhibit technical usefulness individually or in various combinations, and are not limited to the combinations described in the claims at the time of filing. Furthermore, the technologies illustrated in this specification or drawings can achieve multiple objectives simultaneously, and achieving even one of these objectives itself constitutes technical usefulness. [Explanation of symbols]

[0026] 10, 20: Rotary-wing aircraft 11: Main body 12, 12a, 12b: Rotor 13: Motor 14: Landing gear 15: Hydrogen source 16: Fuel cell stack 17, 27: Flow tubes 17a, 27a: Upper part of flow tubes 17b, 17c, 27b, 27c: Middle part of flow tubes 17d, 27d: Lower part of flow tubes

Claims

1. A rotor that generates lift, Hydrogen source, Fuel cell stack and A flow channel pipe for supplying hydrogen from the hydrogen source to the fuel cell stack, It is equipped with, The flow channel passes beneath the rotor. Rotary-wing aircraft.

2. The rotary-wing machine according to claim 1, wherein the flow channel extends parallel to the axis of the rotor.

3. The rotorcraft according to claim 1 or 2, having a plurality of rotors, wherein the flow channel passes beneath at least two of the rotors.

Images