JP2022176581A - Propulsion unit and fluid machine - Google Patents

Abstract

To provide a propulsion device and a fluid machine with further improved efficiency.SOLUTION: A propulsion device includes: an airframe extending in the axial direction; a first propeller capable of rotating around an axis; a second propeller provided on downstream side of the first propeller capable of rotating around an axis; an electric motor for rotating and driving one of the first propeller and the second propeller; and a heat engine for rotating and driving the other one of the first propeller and the second propeller.SELECTED DRAWING: Figure 1

Description

The present disclosure relates to propulsion devices and fluid machinery.

2. Description of the Related Art As a propulsion device mounted on a machine that travels in water, for example, one described in Patent Document 1 below is known. A device according to Patent Document 1 below includes a generator driven by a gas turbine, an electric motor driven by the power generated by the generator, and an electric power storage device for storing the generated power.

The gas turbine is always operated in the high power range to drive the generator. The generated power is supplied to the electric motor and the power storage device. The gas turbine is supposed to shut down when the power storage device reaches the required maximum charge. Also, only one propeller is rotationally driven by the electric motor.

JP 2013-35297 A

However, in the configuration according to Patent Document 1, energy loss occurs when the power of the gas turbine is converted into electric power by the generator. In addition, since the driving force of the propeller must be provided only by the electric motor, the size of the electric motor is increased. As a result, the efficiency of the propulsion system may be impaired.

The present disclosure has been made to solve the above problems, and an object thereof is to provide a propulsion device and a fluid machine with further improved efficiency.

In order to solve the above problems, a propulsion device according to the present disclosure includes a body extending in an axial direction, a shroud provided so as to surround the body from the outer peripheral side and forming a flow path between the body and the body, A first propeller provided in the flow path and rotatable about the axis, a second propeller provided downstream of the first propeller in the flow path and rotatable about the axis, and the shroud. an electric motor provided inside to rotationally drive one of the first propeller and the second propeller, and a heat engine provided in the airframe to rotationally drive the other of the first propeller and the second propeller Prepare.

According to the present disclosure, it is possible to provide a propulsion device and a fluid machine with further improved efficiency.

1 is a cross-sectional view showing the configuration of a propulsion device and an underwater vehicle (fluid machine) according to an embodiment of the present disclosure; FIG. 4 is a graph showing an example of efficiency characteristics of a fuel cell system and a combustion engine; 4 is a graph showing efficiency characteristics of an electric motor and a heat engine;

(Construction of Underwater Vehicle)
An underwater vehicle 100 (fluid machine) according to an embodiment of the present disclosure will be described below with reference to FIG. As shown in FIG. 1 , the underwater vehicle 100 includes a vehicle main body 80 (fluid machine main body) and a propulsion device 90 . The cruising vehicle main body 80 is configured by a pressure-resistant container extending along the axis O. As shown in FIG. Various devices, power supply, communication equipment, sensors, etc. required for underwater navigation are accommodated in the main body 80 of the cruising vehicle.

(Configuration of propulsion device)
The propulsion device 90 is integrally attached to the rear portion of the vehicle body 80 . The propulsion device 90 is a device for propelling the underwater vehicle 100 underwater. The propulsion device 90 includes a fuselage 1, a shroud 2, a first propeller 3, a second propeller 4, an electric motor 5, a heat engine 6, a transmission 7, an inverter 8, a battery 9, and a first It has a bearing portion 10 , a second bearing portion 11 , a rotating shaft 71 , and a control portion 200 .

(Aircraft configuration)
The fuselage 1 is provided integrally with the cruising vehicle main body 80 . The fuselage 1 may be part of the cruising vehicle main body 80 . The fuselage 1 extends along an axis O. The fuselage 1 of the present embodiment has a truncated cone shape whose diameter decreases from one side in the direction of the axis O (hereinafter referred to as the "upstream side") toward the other side in the direction of the axis O (hereinafter referred to as the "downstream side"). is making

(Shroud configuration)
The shroud 2 has a tubular shape that covers the airframe 1 from the outside. The shroud 2 has an airfoil cross-sectional shape in a cross-sectional view including the axis O. As shown in FIG. In this embodiment, the shroud 2 gradually decreases in diameter from upstream to downstream. It should be noted that the shape of the shroud 2 can be changed in various ways to correspond to the shape of the main body 80 of the cruising vehicle.

The shroud 2 is fixed to the fuselage 1 by a plurality of struts 2a. The strut 2a extends radially outward from the fuselage 1 . A plurality of struts 2a are arranged at intervals in the circumferential direction. Moreover, the strut 2a extends obliquely toward the downstream side as it goes radially outward. A radially outer end of the strut 2 a is fixed near the upstream end of the shroud 2 . A space between the shroud 2 and the fuselage 1 is a flow path F through which water flows.

(Configuration of first propeller)
The first propeller 3 has an inner ring 31 and first blades 32 . The inner peripheral ring 31 has an annular shape centered on the axis O. As shown in FIG. The inner peripheral ring 31 is rotatably supported around the axis O by a first bearing portion 10 provided on the outer peripheral surface of the body 1 . The first bearing portion 10 has an upstream thrust bearing 10a, a downstream thrust bearing 10b, and a journal bearing 10c. The upstream thrust bearing 10a faces the inner peripheral ring 31 from the upstream side, thereby bearing the thrust load directed toward the upstream side (the load in the direction of the axis O). The downstream thrust bearing 10b faces the inner peripheral ring 31 from the downstream side, thereby bearing the downstream thrust load. The journal bearing 10c bears a radial load by facing the inner peripheral ring 31 from the radially inner side.

The outer peripheral surface of the inner peripheral ring 31 is tapered by gradually decreasing in diameter toward the downstream side. Therefore, the outer peripheral surface of the fuselage 1 and the outer peripheral surface of the inner peripheral ring 31 are substantially flush with each other. A first blade 32 is provided on the outer peripheral surface of the inner peripheral ring 31 . The first blades 32 extend radially outward from the inner ring 31 and are arranged in plurality at intervals in the circumferential direction. These first blades 32 are rotationally driven about the axis O together with the inner ring 31 to generate propulsive force toward the downstream side.

(Configuration of electric motor)
The electric motor 5 is a device for rotating the first propeller 3 . The electric motor 5 is provided inside the shroud 2 . That is, this electric motor 5 is an outer circumference drive motor. The electric motor 5 is housed in a recess formed in the inner peripheral surface of the shroud 2 . The electric motor 5 has a stator 51 fixed to the shroud 2 side and a rotor 52 fixed to the radial outer end of the first blade 32 . The stator 51 has a plurality of coils and the rotor 52 has permanent magnets. Electric power of the battery 9 is supplied to the stator 51 through the inverter 8 . These battery 9 and inverter 8 are housed inside the body 1 .

(Configuration of second propeller)
The second propeller 4 is provided at the downstream end of the airframe 1 with the axis O as the rotation axis. That is, the second propeller 4 is located downstream of the first propeller 3 . Also, the direction of rotation of the second propeller 4 is opposite to the direction of rotation of the first propeller 3 . That is, the first propeller 3 and the second propeller 4 constitute contra-rotating propellers.

The second propeller 4 has a boss portion 41 and second blades 42 . The boss portion 41 has a disc shape centered on the axis O. As shown in FIG. The second blades 42 extend radially outward from the outer peripheral surface of the boss portion 41 and are arranged in plurality at intervals in the circumferential direction. Since the shroud 2 decreases in diameter toward the downstream side as described above, the radial dimension of the second blade 42 is set smaller than the radial dimension of the first blade 32 .

A rotating shaft 71 is attached to the center of the boss portion 41 (that is, the position of the axis O). The rotating shaft 71 has a rod shape extending along the axis O. As shown in FIG. The rotary shaft 71 is rotatably supported around the axis O by a second bearing portion 11 provided at the downstream end of the body 1 . The second bearing portion 11 is a journal bearing.

(Configuration of heat engine and transmission)
The heat engine 6 is a device for rotating the second propeller 4 . Specifically, a gas turbine is suitably used as the heat engine 6 . Heat engine 6 is driven by fuel supplied from tank 61 . The rotational driving force of the heat engine 6 is first transmitted to the transmission 7 . An upstream end of the rotating shaft 71 is connected to the transmission 7 . The transmission 7 is a device for adjusting the rotation speed of the rotating shaft 71 . It is also possible to employ a configuration in which the rotation shaft 71 is directly rotated only by the heat engine 6 without providing the transmission 7 .

(Configuration of control unit)
A control unit 200 is a device for controlling the operation of the electric motor 5 and the heat engine 6 . When the underwater vehicle 100 is in the low speed range, the controller 200 drives only the electric motor 5 . That is, in the low speed range, only the first propeller 3 is rotationally driven. On the other hand, when the underwater vehicle 100 is in the high speed range, the control unit 200 drives the heat engine 6 in addition to the electric motor 5 . As a result, the first propeller 3 and the second propeller 4 are driven to rotate.

(Effect)
Next, operations of the underwater vehicle 100 and the propulsion device 90 will be described. When operating the propulsion device 90 , the control unit 200 first drives the electric motor 5 with the electric power of the battery 9 . The first propeller 3 rotates around the axis O by driving the electric motor 5 . As a result, the water in the flow path F is pushed downstream, and the underwater vehicle 100 is provided with a propulsive force. When the speed of the underwater vehicle 100 is less than the predetermined threshold, the propulsive force is obtained only by driving the first propeller 3 by the electric motor 5 in this way.

On the other hand, when the speed of the underwater vehicle 100 becomes equal to or higher than the above threshold, the controller 200 drives the heat engine 6 in addition to the electric motor 5 . As a result, the second propeller 4 also rotates, further increasing the speed of the underwater vehicle 100 . Each time the speed range changes, the underwater vehicle 100 travels underwater by repeating switching and disconnection of the driving source as described above.

As described above, according to the above configuration, the first propeller 3 is rotationally driven by the electric motor 5 and the second propeller 4 is rotationally driven by the heat engine 6 . This makes it possible to change the drive source to be used for each speed range, for example. As a result, it becomes possible to operate the propulsion device 90 more efficiently.

Furthermore, according to the above configuration, the rotating direction of the first propeller 3 on the upstream side and the second propeller 4 on the downstream side are reversed to form counter-rotating propellers. It can be collected by the second propeller 4 . Therefore, the turning loss in the wake of the second propeller 4 can be reduced. Thereby, the propulsion performance of the propulsion device 90 can be further improved.

In addition, according to the above configuration, since the electric motor 5 is an outer peripheral drive motor provided inside the shroud 2 instead of inside the airframe 1, it is normally cooled by the water flowing around the shroud 2. . Thereby, the electric motor 5 can be cooled without providing another cooling device. As a result, the efficiency of the propulsion device 90 can be further improved.

Further, since the two power sources of the electric motor 5 and the heat engine 6 are independent of each other, there is no need to add a generator, reducer, or auxiliary equipment for supplying electric power from the heat engine 6 to the electric motor 5. It is possible to avoid complicating the system and increasing the installation space.

As shown in FIG. 2, when the fuel cell system is used as the drive source, the efficiency characteristics are particularly high in the low speed region where the load is small, and the efficiency characteristics are somewhat high even in the high speed region where the load is large. On the other hand, when a heat engine such as a diesel engine or a spark ignition engine is used as a drive source, efficiency characteristics tend to decrease in a low load range. A similar tendency is shown when a gas turbine is used as the heat engine.
On the other hand, according to the above configuration, the first propeller 3 is driven only by the electric motor 5 in the low speed range where the speed is less than the threshold value. That is, as shown in the graph of FIG. 3, the electric motor 5 has superior efficiency characteristics in the low output range compared to the heat engine 6, so the efficiency of the propulsion device 90 can be improved by the above configuration. . In addition, since it is driven only by the electric motor 5, it is possible to improve quietness in the low speed range.

Furthermore, in a high-speed region where the speed is equal to or higher than the threshold value, by operating the heat engine 6 in addition to the electric motor 5, the output can be further improved. As described above, the gas turbine as the heat engine 6 is inferior to the electric motor 5 in efficiency characteristics in the low speed range. Therefore, as described above, the electric motor 5 is mainly driven in the low speed range, and the heat engine 6 is driven when the high speed range is reached, so that the efficiency characteristics of the electric motor 5 and the heat engine 6 can complement each other. can.

Further, according to the above configuration, the electric motor 5 is driven using power supplied from the battery 9 independent of the heat engine 6 . As a result, it is possible to avoid a decrease in efficiency in a low-speed range where the load of the heat engine is small when adopting a configuration in which electric power generated by the heat engine 6 is supplied to the electric motor 5, and it is possible to eliminate the loss that occurs during power conversion. . Therefore, the efficiency of the propulsion device 90 can be further improved.

The embodiments of the present disclosure have been described above. Various changes and modifications can be made to the above configuration without departing from the gist of the present disclosure. For example, in the embodiment, the first propeller 3 is driven by the electric motor 5 and the second propeller 4 is driven by the heat engine 6 . However, the configuration is not limited to this, and the first propeller 3 may be driven by the heat engine 6 and the second propeller 4 may be driven by the electric motor 5 .

Furthermore, in the above-described embodiment, an example in which the cross-sectional shape of the shroud 2 is wing-shaped has been described, but the cross-sectional shape may not necessarily be wing-shaped. The cross-sectional shape of the shroud 2 is preferably streamlined, but may be other shapes such as a rectangular shape. Even in this case, the diameter of the shroud 2 is reduced toward the downstream side, thereby defining and forming a flow path in which the cross-sectional area of the flow path becomes smaller toward the downstream side.

Further, in the above embodiment, an example in which the propulsion device 90 according to the present disclosure is applied to the underwater vehicle 100 has been described. However, it is not limited to this, and the propulsion device 90 may be applied to, for example, a ship or the like that navigates on water. Also, the configuration of the propulsion device 90 may be applied to other fluid machinery used underwater, such as a pump. Moreover, the present invention may be applied not only to a fluid machine that pumps water but also to a fluid machine that pumps other liquids such as oil.

<Appendix>
The propulsion device 90 and the underwater vehicle 100 (fluid machine) described in each embodiment are understood as follows, for example.

(1) The propulsion device 90 according to the first aspect includes the airframe 1 extending in the direction of the axis O, the first propeller 3 rotatable around the axis O, and the first propeller 3 provided downstream of the A second propeller 4 rotatable around the axis O, an electric motor 5 for rotationally driving one of the first propeller 3 and the second propeller 4, and the other of the first propeller 3 and the second propeller 4. a heat engine 6 driven in rotation.

According to the above configuration, one of the first propeller 3 and the second propeller 4 is rotationally driven by the electric motor 5 and the other of the first propeller 3 and the second propeller 4 is rotationally driven by the heat engine 6 . This makes it possible to change the drive source to be used for each speed range, for example. As a result, it becomes possible to operate the propulsion device 90 more efficiently.

(2) The propulsion device 90 according to the second aspect includes a shroud 2 that is provided so as to surround the fuselage 1 from the outer peripheral side and forms a flow path F between the fuselage and the shroud 2 that is provided in the flow path F. the first propeller 3 provided in the flow path F, the second propeller 4 provided downstream of the first propeller 3 in the flow path F, the electric motor 5 provided in the shroud 2, and the fuselage 1 provided and the heat engine 6 which is

According to the above configuration, the electric motor 5 is a peripheral drive motor provided inside the shroud 2 rather than inside the airframe 1, so that it is normally cooled by the water flowing around the shroud 2. Thereby, the electric motor 5 can be cooled without providing another cooling device. As a result, the efficiency of the propulsion device 90 can be further improved.

(3) In the propulsion device 90 according to the third aspect, the rotation directions of the first propeller 3 and the second propeller 4 are opposite.

According to the above configuration, the first propeller 3 on the upstream side and the second propeller 4 on the downstream side are contra-rotating propellers in which the directions of rotation are reversed. It can be collected by the propeller 4. Therefore, the turning loss in the wake of the second propeller 4 can be reduced.

(4) In the propulsion device 90 according to the fourth aspect, the electric motor 5 includes a stator 51 fixed to the shroud 2, and the first propeller 3 and the second propeller radially inside the stator 51. 4, with a rotor 52 fixed to the outer periphery of one of the rotors.

According to the above configuration, the electric motor 5 is a peripheral drive motor provided inside the shroud 2 rather than inside the airframe 1, so that it is normally cooled by the water flowing around the shroud 2. Thereby, the electric motor 5 can be cooled without providing another cooling device. As a result, the efficiency of the propulsion device 90 can be further improved.

(5) The propulsion device 90 according to the fifth aspect further includes a control unit 200 that controls the operation of the electric motor 5 and the heat engine 6. If it is less than a predetermined threshold, only the electric motor 5 is operated, and if it is equal to or greater than the threshold, the heat engine 6 is operated.

According to the above configuration, one of the first propeller 3 and the second propeller 4 is driven only by the electric motor 5 in a low speed range where the speed is less than the threshold. Since the electric motor 5 is superior to the heat engine 6 in efficiency characteristics in a low output range, the efficiency of the propulsion device 90 can be improved by the above configuration. In addition, since it is driven only by the electric motor 5, quietness can be improved. Furthermore, in a high-speed region where the speed is equal to or higher than the threshold value, by operating the heat engine 6 in addition to the electric motor 5, the output can be further improved.

(6) In the propulsion device 90 according to the sixth aspect, the electric motor 5 rotates one of the first propeller 3 and the second propeller 4 with electric power supplied from the battery 9 .

According to the above configuration, electric power supplied from the battery 9 independent of the heat engine 6 is used to drive the electric motor 5 . As a result, it is possible to avoid a decrease in efficiency in a low-speed range where the load of the heat engine is small when adopting a configuration in which electric power generated by the heat engine 6 is supplied to the electric motor 5, and it is possible to eliminate the loss that occurs during power conversion. . Therefore, the efficiency of the propulsion device 90 can be further improved.

(7) A fluid machine (underwater vehicle 100) according to a seventh aspect includes a fluid machine main body (vessel main body 80) and a propulsion device 90 according to any one of the above aspects provided in the fluid machine main body. And prepare.

According to the above configuration, the efficiency of the fluid machine can be improved.

100 Underwater Vehicle 90 Propulsion Device 1 Body 2 Shroud 2a Strut 3 First Propeller 4 Second Propeller 5 Electric Motor 6 Heat Engine 7 Transmission 8 Inverter 9 Battery 10 First Bearing 10a Upstream Thrust Bearing 10b Downstream Thrust Bearing 10c Journal bearing 11 Second bearing part 31 Inner peripheral ring 32 First blade 41 Boss part 42 Second blade 51 Stator 52 Rotor 61 Tank 71 Rotating shaft 80 Vehicle main body 200 Control part

Claims (7)

an axially extending fuselage;
a first propeller rotatable about the axis;
a second propeller provided downstream of the first propeller and rotatable about the axis;
an electric motor that rotationally drives one of the first propeller and the second propeller;
a heat engine that rotationally drives the other of the first propeller and the second propeller;
A propulsion device comprising a a shroud that is provided so as to surround the fuselage from the outer peripheral side and forms a flow path between the fuselage and the fuselage;
the first propeller provided in the flow path;
the second propeller provided downstream of the first propeller in the flow path;
the electric motor provided within the shroud;
the heat engine provided in the airframe;
A propulsion system according to claim 1, comprising: 3. A propulsion device according to claim 1 or 2, wherein the directions of rotation of said first propeller and said second propeller are opposite. The electric motor is
4. An outer peripheral drive motor comprising a stator fixed to the shroud and a rotor fixed to the outer peripheral portion of one of the first propeller and the second propeller radially inside the stator. The propulsion device described in . further comprising a control unit that controls operations of the electric motor and the heat engine;
5. The method according to any one of claims 1 to 4, wherein the control unit operates only the electric motor when the speed of the propulsion device is less than a predetermined threshold, and operates the heat engine when the speed is greater than or equal to the threshold. A propulsion device according to any one of the preceding claims. The propulsion device according to any one of claims 1 to 5, wherein the electric motor rotates one of the first propeller and the second propeller by electric power supplied from a battery. a fluid machine body;
A fluid machine comprising: the propulsion device according to any one of claims 1 to 6 provided in the fluid machine main body.

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