FR3025184A1 - VENTILATION APPARATUS FOR AIRCRAFT - Google Patents

Abstract

The present invention relates to a ventilation apparatus for an aircraft, comprising: a fan (30) comprising a rotating electrical machine and at least one wheel (34) for moving an air flow, the rotating machine being able to make rotating the wheel about an axis (41), the wheel including a hub (70) connected to a radially extending set of blades (72); and an electronic power device comprising a reversible inverter connected to the rotating machine. A camber of the blades (72) of the wheel (34) is less than 8%. The wheel deflects the air only by aerodynamic detachment and not by the arching of the blades. Depending on its rotation speed, such a ventilation device compresses or relaxes the air and can therefore be used reversibly.

Description

The present invention relates to a ventilation apparatus for an aircraft, of the type comprising: a fan comprising a rotating electrical machine and at least one wheel for moving an air flow, the rotating machine being suitable rotating the wheel about an axis, the wheel including a hub connected to a set of radially extending blades; and an electronic power device, adapted to be connected to a power supply network and comprising a reversible inverter, connected to the rotating machine.

Fans are known for cooling, when the aircraft is on the ground, a heat exchanger located at a dynamic air inlet. The heat exchanger is generally a condenser of a refrigerating cycle of the aircraft, which is in particular an airplane. Fans are particularly useful when the aircraft is on the ground. In this case, the natural convection is not sufficient to cool the heat exchanger satisfactorily. On the other hand, when the airplane is in flight, the heat exchanger is cooled by a flow of air generated by the displacement of the aircraft. The fans become useless and increase the weight of the plane.

In order to upgrade the fans during the flight, it is known, particularly from document FR2956379, to connect them to a reversible inverter. Such an inverter is able to convert electrical energy supplied by the fan driven by the air flow, and then to inject this electrical energy into the power supply network of the aircraft. In case of electrical need in the aircraft in flight, the fan is able to play a role of turbine to provide a surplus of electrical energy. In the state of the art, this type of ventilation device is designed to optimize the efficiency "fan" when the aircraft is on the ground. In particular, the fan blades are arched so as to deflect the flow of air and compress the air. An example of a fan used in this type of device is the Technofan® AS2010 fan (D174mm). Another example of device with arched blades is described in particular in document WO2012 / 134833. However, this type of fan used in "turbine" mode leads to very limited yields, especially less than 30%. The present invention aims to increase the efficiency "turbine" of the fan while maintaining a "fan" efficiency sufficient to use the reversible ventilation device.

For this purpose, the subject of the invention is a ventilation apparatus of the aforementioned type, in which a camber of the blades of the wheel is less than 8%. The wheel of such a ventilation device deflects the air only by aerodynamic detachment and not by the arching of the blades. Such a ventilation apparatus is able to compress or relax the air according to its speed of rotation, all other conditions being equal. According to particular embodiments, the ventilation apparatus comprises one or more of the following characteristics, taken in isolation or in any technically possible combination: the camber of the blades of the wheel is less than 3%; at a fastening end of a blade on the hub, a pitch angle of the blade is between 25 ° and 85 ° and preferably between 45 ° and 75 °; a twisting angle of the blade is between 5 ° and 35 °; The apparatus comprises at least one rectifier connected to an outer surface of the rotating machine, said rectifier being formed of a set of fins extending radially about the axis of rotation of the wheel; the fins are flat and arranged in planes containing the axis of rotation of the wheel; The fins are arched with respect to planes containing the axis of rotation of the wheel and provided with means for reversing a camber orientation. The invention also relates to an aircraft comprising an air duct, said duct being provided with an inlet and an outlet connected to the outside of the aircraft, said duct comprising successively a heat exchanger and a device as described above. The subject of the invention is also a method of operating such an aircraft, the method being defined as follows: in a first mode known as "fan mode", the aircraft being on the ground, the electronic power device supplies energy to the rotary machine for rotating the fan wheel at a first rotational speed; in a second mode called "turbine mode", the aircraft being in flight and a flow of air flowing through the duct, said air flow drives the fan wheel at a second speed of rotation, the rotating machine thus generating electric current transferred to the electronic device. Preferably, the second rotational speed is lower than the first rotational speed.

According to a particular embodiment, in the first mode "fan", the fins of the rectifier are oriented at a first orientation angle 3025184 3 opposite the pitch angle of the blades of the wheel; and in the second "turbine" mode, the vanes are oriented at a second wedging angle in the same direction as the wedge angle of the blades of the wheel. The invention will be better understood on reading the description which follows, given solely by way of example and with reference to the drawings, in which: FIG. 1 is a diagrammatic longitudinal sectional view of a duct; aircraft air, equipped with a ventilation apparatus according to one embodiment of the invention; Figure 2 is a longitudinal sectional view of a ventilation apparatus according to a first embodiment of the invention; Figure 3 is a detailed perspective view of the ventilation apparatus of Figure 2; Figure 4 is a sectional view of a detail of the ventilation apparatus of Figure 2; Figure 5 is a sectional view of a detail of the prior art ventilation apparatus; Figures 6 and 7 are diagrams explaining the operation of the ventilation apparatus of Figure 4; Figures 8 and 9 are detailed side views of a ventilation apparatus 20 according to a second embodiment of the invention; and Fig. 10 is a schematic diagram of the electronic structure of a ventilation apparatus according to one embodiment of the invention. FIG. 1 represents an air duct 6 of an aircraft, successively comprising a heat exchanger 8 and a ventilation apparatus 10 according to the invention.

The air duct 6 extends in a longitudinal direction X from the front to the rear of the aircraft. It comprises successively from front to rear a dynamic air inlet 12, a first cylindrical portion 16, the heat exchanger 8, a second frustoconical portion 18, the ventilation apparatus 10 and an outlet 20 of air. The first cylindrical portion 16 and the second frustoconical portion 18 extend longitudinally. A large truncated cone base of the second portion 18 is located near the exchanger 8. A small truncated cone base is located near the ventilation apparatus. The air duct 6 further comprises a first inlet 22 of fan air. Optionally, the duct 6 comprises a second inlet 24 of fan air.

The first inlet 22 is stitched in the cylindrical portion 16, upstream of the heat exchanger 8 and the ventilation apparatus 10. The second inlet 24 is stuck in the frustoconical portion 18, downstream of the Heat exchanger 8 and upstream of the ventilation apparatus 10. The dynamic air inlet 12, the air outlet 20 and the air intake inlets 22, 24 all open onto the outside of the aircraft.

The first fan air inlet 22 has a first valve 26. The second fan air inlet 24 has a second valve 28. FIG. 2 is a detailed view of the fan apparatus 10 of FIG. first embodiment. The apparatus 10 includes a fan 30 and an electronic power device 32 for its power supply. The fan 30, located inside the air duct 6, comprises a wheel 34 and a rotating electric machine 36. The rotating machine 36 is connected to the device 32. The machine 36 is preferably a synchronous machine, similar to machines known from the state of the art and in particular described in the document FR2956379. The machine 36 comprises a rotor 40 and a stator 42. The rotor 40 is generally cylindrical in shape, disposed along an axis 41 parallel to the longitudinal direction X. The stator 42 extends around the rotor 40. housing 44. The housing 44 has a base 46 and a cylindrical side wall 48. The base 46 is extended axially towards the wheel 34 by the wall 48, which forms the outer surface of the rotating machine 36.

A rectifier 50 is connected to the outer surface of the rotating machine 36. The rectifier 50 is thus located downstream of the wheel 34. The rectifier 50 is formed of a set of fins 52 disposed on the cylindrical side wall 48. The fins 52 extend radially about the axis 41. In the embodiment of FIG. 2, the fins 52 are fixed on the wall 48. In the embodiment of FIG. 2, the fins 52 are flat. and arranged in planes containing the axis 41. The housing 44 houses an active portion 60 of the stator 42. The active portion 60 is fixed on an inner surface of the cylindrical side wall 48. The active part 60 comprises armatures formed of ferromagnetic materials and coils wrapped around these frames. The active part 60 extends around an air gap 62.

The rotor 40, which extends longitudinally in the center of the gap 62, carries on its outer surface magnetic elements 63, such as magnetized bars. The rotor 40 is rotatably mounted relative to the stator 42 by means of rotary means 64, 65 fixed to the casing 44. These rotary means 64, 65 are for example ball bearings. The wheel 34 is secured to the rotor 40, for example by screwing.

The wheel 34 has a hub 70 of revolution. The hub 70 carries a set of blades 72 connected to said hub by their end 74 of attachment. A free end 75 of the blades 72 substantially follows a profile of an inner surface 76 of the air duct 6 at the wheel 34. The blades 72 of the wheel 34 will be described in greater detail hereinafter. According to an alternative embodiment, the apparatus 10 comprises a plurality of wheel 34 / rectifier 50 couples, said couples being called stages. For example, several stages are located on the same motor shaft output, or the stages are distributed on each side of the motor along the axis 41, with two shaft outputs. According to another variant, the stages are distributed over several different motors, having different speeds of rotation. Optionally, the stage closest to the air outlet does not have a rectifier. Optionally, the ventilation apparatus 10 also comprises a distributor 80. The distributor 80 is placed in the duct 6 upstream of the wheel 34, that is to say between the wheel 34 and the second frustoconical portion 18. The dispenser 80 has blades 82 extending radially about the axis 41. Each blade 82 has a fixed end 84 connected to the inner surface 76 of the air duct 6. Each blade 82 also has a free end 86 close to the axis 41. Each blade 82 is pivotable about an axis 87, perpendicular to the axis 41 and connecting the fixed end 84 to the free end 86 A motor (not shown) controls the rotation of each blade 82 about its axis 87. The blades 82 include means (not shown) for locking in a precise angular orientation about their axis 87. FIG. in perspective of the fan 30 of Figure 2. The wheel 34 of the fan is intended to rotate about the axis 41 in a direction represented by an arrow 88 in Figure 3. The blades 72 have two surfaces 90, 92 opposite, of which a lower surface 90 and an upper surface 92. The underside is oriented so as to precede the extrados during rotation. Figure 4 is a sectional view of a blade 72, in a section of constant radius at the end 74 of attachment. Figure 5 is a sectional view of a blade 102 of a fan according to the state of the art, in a section of constant radius at the attachment end. The different elements of the blades 72, 102 are hereinafter referred to by the same reference numerals. The intrados 90 and the extrados 92 meet at a leading edge 94 and a trailing edge 96. The leading edge 94 and the trailing edge 96 extend radially with respect to the axis 41. A line 98 of rope connects the leading edge 94 and the trailing edge 96.

In known manner, the camber of the blades 72, 102 is defined by the ratio f / c (FIG. 5), between the maximum deflection f of a line 100 equidistant from the intrados 90 and from the extrados 92, and the rope c represents a length of the line 98 between the leading edge 94 and the trailing edge 96. Over the entire length between the attachment end 74 and the free end 75, the camber f / c of the blade 72 is preferably less than 8% and more preferably less than or equal to 3%. A pitch angle of the blade 72 is defined by an angle α formed by the rope line 98 and the axis 41, a projection of which is shown in FIG. 4. The axis 41 corresponds to the flow direction of the flow. in the duct 6. At the end 74 of attachment, the pitch angle α of the blade 72 is preferably between 25 ° and 85 ° and more preferably between 45 ° and 75 ° . In a known manner, the blade 72 is twisted in order to vary the wedging angle between the attachment end 74 and the free end 75. A twisting angle of the blade 72 is preferably between 5 ° and 35 °. The village angle is defined as the angle between the rope of the profile of the end 74 of attachment and the cord of the profile of the end 75 free.

FIGS. 6 and 7 are section views of the blade 72 in the same section as FIG. 4. The speed vectors are represented, respectively in "fan" mode (FIG. 6) and in "turbine" mode (FIG. 7). . At the leading edge 94, the driving speed U of the wheel 34 is perpendicular to the axis 41. The speed V of the air flow is parallel to the axis 41. This results in the relative speed W of the air flow relative to the leading edge 94. At the trailing edge 96, the velocity U is the same as at the leading edge 94, but the airflow is deflected. The velocity V 'of the air flow at the trailing edge 96 has an axial component Va, parallel to the axis 41, and a tangential component Vt, perpendicular to the axis 41. This results in the relative speed W' of the flow of air relative to the trailing edge 96. In general, the profile of the blade 72 is defined so that the aerodynamic power is zero for a certain flow Qv of air in the duct 6 and a certain speed of rotation of the wheel 34. The aerodynamic power is defined by P = px Qv x U x Vt, where p is the density of the air and velocities are measured at the trailing edge 96. The flow Qv of air is proportional to the speed V of the air flow at the edge 94 of attack. For each condition of pressure, temperature and air flow in front of the apparatus 10, there is a certain value No of the speed N of rotation of the wheel 34, ie a certain value U0 for driving the wheel, for the flow of air is not deflected by the rotation of the wheel 34. Thus we get V '= Va = V, so Vt = 0 at the edge 96 leak.

For identical conditions of pressure, temperature and air flow in front of the apparatus 10, FIG. 6 shows, in fan mode, N> No and U> U 0. The vectors U and Vt have the same orientation therefore P> 0; energy is supplied to the air flow; in FIG. 7, in turbine mode, N <No and U <Uo. The vectors U and Vt have opposite orientations therefore P <0; energy is removed from the airflow. The deflection of the air by the wheel 34 is obtained solely by aerodynamic detachment on the extrados 92 in fan mode and on the intrados 90 in turbine mode, and not by the physical camber of the blades 72. FIGS. 8 and 9 show side views of a fan 130 according to a second embodiment of the invention. The fan 130 is able to replace the fan 30 in the ventilation device 10 shown in FIG.

Several elements of the fan 130 are identical to those of the fan 30 and will hereinafter be referred to as the same reference numerals. In particular, the fan 130 comprises a wheel 34 and a rotating machine 36 identical to those of the fan 30. A rectifier 150 is connected to the outer surface of the rotating machine 36. The rectifier 150 is formed of a set of fins 152 extending radially about the axis 41 of the fan 130. Each fin 152 has an attachment end 154 connected to the outer surface of the rotating machine 36 or the inner surface 76 of the air duct 6. Preferably, each fin 152 has a camber, defined in a manner similar to the camber of the blades 72. More preferably, the camber of the fins 152 is between 3% and 9% (3/0). reversing an orientation of its arch, so as to adapt to the fan mode or to the turbine mode For example, each fin 152 comprises an outer skin made of flexible material and movable inner frames 30 controlled by a motor (no 8 represents a first orientation of the camber of the fins 152 of the rectifier 150. This orientation is adapted to the fan mode In this first orientation, a wedging angle of the fins 152 is in the opposite direction of the wedging angle. The pitch angle of fins 152 is preferably between -10 ° and -25 °, more preferably the angle α 'is about -12 °.

FIG. 9 shows a second orientation of the fins 152 of the straightener 150. In this second orientation, the stall angle of the fins 152 is in the same direction as the pitch angle of the blades 72 of the wheel 34. The angle Preferably, the angle α "is about 12 °.

FIG. 10 is a diagram of the electronic power device 32 of FIG. 2. The device 32 includes an input stage 202, an inverter 204, a controller 206 and a position sensor 208 of the rotor 40 with respect to the stator 42. , such as a Hall effect sensor. Via the device 32, the ventilation apparatus 10 is connected to a HVDC high-voltage power supply network 210. This network 210 is that of the aircraft and is for example under a voltage of 540 volts. The network 210 comprises a general switch 211 able to switch between a closed position and an open position. In the closed position, the apparatus 10 is connected to the network 201. In the open position, the apparatus 10 is disconnected from the network 210.

The device 32 is connected to the network 210 via the input stage 202. The input stage 202 comprises a reversible low-pass filter 212 and two terminals A and B connected to the network 210. The filter 212, between the terminals A and B, comprises a coil 214 connected in series at a point C with a capacitor 216. The power supply output of the inverter 204 consists of points B and C. The inverter 204 is reversible. . It comprises three switching branches corresponding to the three phases of the motor. These three branches are connected in parallel between the entry points C and B. Each branch comprises two switches 218, 219 connected in series and between which is formed a point R, S, T of three-phase supply of the rotary machine 36. . Each switch comprises a transistor 220 and a diode 221 mounted in antiparallel. The transistor 220 is able to switch between an open position and a closed position. In the closed position, the transistor 220 of each switch 218, 219 is able to pass a current respectively from the terminal C to the one R of the terminals R, S, T, 30 or one of the terminals R, S , T to the terminal B. In the open position, the transistor 220 does not let any current flow. The transistor 220 is for example an insulated gate bipolar transistor (IGBT). The diode 221 of each switch 218, 219 is adapted to pass a current respectively from the terminal B to the one R of the terminals R, S, T, or from one R of the terminals R, S, T to the C. When the transistors 220 are all open, the diodes 221 form a bridge rectifier.

The controller 206 comprises means for receiving information concerning the position P of the rotor 40, supplied by the sensor 208. The controller 206 also comprises means for receiving an operating setpoint F coming from a control unit 225 of the aircraft. On the basis of said information and instructions, the controller 206 is able to determine control laws 230 and 235, respectively switches 218, 219 and motors of the blades 82 of the distributor 80. In the case where the apparatus 10 comprises a fan 130 according to the second embodiment described above, the controller 206 is also able to determine a law 236 for controlling the vane motors 152 of the rectifier 150.

The control unit 225 comprises means for receiving information S on the situation in flight or on the ground of the aircraft and means for receiving an order E for reinjection of electrical energy into the electrical network 210. of the aircraft. It is suitable for deriving from it the instruction F, as well as the control laws 238, 240, 241, respectively of the main switch 211, the first valve 26 and, optionally, the second valve 28. According to the inputs S, E received by the control unit 225, its outputs 238, 240, 241 and F vary. Table 1 below gives the values of the outputs 238, 240, 241, F according to the inputs S, E: Inputs Outputs S = "on the ground" 238 = closed 240 = open 241 = closed F = motor supply S = " in flight "E = 0 238 = open 240 = closed 241 = closed F = reel S =" in flight "E = 1 238 = closed 240 = closed 241 = open F = energy generator 20 Table 1 Thus, in a first mode of operation of the aircraft, the aircraft is on the ground. The main switch 211 is closed, the first valve 26 is open, the second valve 28 is closed and the ventilation device 10 is in a motor supply mode. In a second mode of operation of the aircraft, the aircraft is in flight and has no specific electrical energy requirements. The main switch 211 is open, the valves 26, 28 are closed and the ventilation apparatus 10 is in a reel mode.

In a third mode of operation of the aircraft, the aircraft is in flight and has a specific need for electrical energy. The main switch 211 is closed, the first valve 26 is closed, the second valve 28 is open and the ventilation device 10 is in a power generating mode.

According to the setpoint F received by the controller 206, its outputs 230, 235, 236 vary. Table 2 below gives the values of the outputs 230, 235, 236 as a function of the setpoint F: Setpoint F "Motor supply" outputs 230 = Pulse width modulation control 235 = first position 236 = first orientation (FIG. 6) "reel" 230 = open 235 = / 236 = / "energy generator" 230 = switching control 235 = second position 236 = second orientation (figure 7) Table 2 10 In motor supply mode, the control law 230 sent to the switches 218, 219 of the inverter 204 is of high-frequency switching type; the inverter 204 is thus able to convert the direct current supplied by the input stage 202 into a three-phase current transmitted to the active part 60 of the stator 42 of the machine 36.

The blades 82 of the distributor 80 are oriented in a first position. The first position is determined experimentally to optimize an air flow generated by the wheel 34, when it is driven by the rotating machine 36. In the case where the apparatus 10 includes a fan 130 according to the second embodiment described above, the fins 152 of the rectifier 150 are configured according to the first camber orientation of FIG. 8. In the energy generator mode, the transistors 220 of the inverter 204 are switched-controlled by the controller 206; the inverter 204 is thus able to convert a three-phase current from the rotating machine 104 to a direct current fed back to the supply network 210. The blades 82 of the distributor 80 are oriented in a second position, determined experimentally to optimize an energy electrical supplied by the rotating machine 36 driven by the wheel 34, itself subjected to a flow of air passing through the duct 6.

In the case where the apparatus 10 comprises a fan 130 according to the second embodiment described above, the fins 152 of the rectifier 150 are configured according to the second camber orientation of FIG. 9. An operation of the apparatus Figure 10 is described below: When the aircraft is on the ground, the ventilation apparatus 10 operates in engine power mode, or fan mode. With the switch 211 closed, the network 210 supplies the apparatus 10 with direct current. The inverter 204 converts the DC current to three-phase power which supplies the rotating machine 36. The rotor 40 rotates at a speed N1 of rotation, controlled by the controller 206. N1 is greater than the speed No defined previously. By way of example, No is of the order of 10,000 to 20,000 rpm. The rotor 40 drives the wheel 34 which rotates in the direction 88 and generates a flow of air, depending on its speed of rotation. In the second embodiment, the first camber orientation fins 152 is intended to optimize the losses on the flow.

When the aircraft is in flight, there is no longer any need for forced convection to cool the heat exchanger. The apparatus 10 is most often in reel mode. The air enters the duct 6 through the inlet 12 under the sole effect of the speed of the aircraft relative to the air masses. The air passes naturally through the air duct 6 and exits through the outlet 20, while cooling the heat exchanger 8 and passing through the apparatus 10. The wheel 34 offers only a very low resistance to air flowing in the duct 6 and turns randomly. The aircraft may need extra power during the flight. In this case, the ventilation apparatus 10 provides the necessary electrical energy. If necessary, an order E of reinjection of electrical energy in the network 25 reaches the control unit 225. It then sends a setpoint F to the controller 206 controlling the tilting of the ventilation device 10 mode energy generator, or turbine mode. Under the effect of the air flowing in the duct 6, the wheel 34 rotates in the direction 88, at a speed N2 lower than the speed No defined above. The rotation of the wheel 34 causes the formation of alternating currents in the windings of the rotating machine 36. These alternating currents enter the inverter 204 at the points R, S, T. The transistors 220 modulate the passage of this current to generate a continuous output current, adapted to the voltage level of the network 210. This current is then injected on the network 210 of the aircraft via the terminal A.

A ventilation apparatus 10 as described above achieves an aerodynamic efficiency greater than 60% in fan mode and a yield greater than 50% in turbine mode.

Claims (10)

CLAIMS1.- Aircraft ventilation apparatus (10) comprising: - a fan (30, 130) comprising a rotating electric machine (36) and at least one wheel (34) for moving an air flow, the rotary machine (36) being rotatable about an axis (41), the wheel including a hub (70) connected to a radially extending set of blades (72); and an electronic power device (32) adapted to be connected to a power supply network (210) and comprising a reversible inverter (204) connected to the rotating machine; characterized in that a camber (f / c) of the blades (72) of the wheel (34) is less than 8%. 2. Apparatus according to claim 1, such that the camber (f / c) of the blades of the wheel is less than 3%. 3. Apparatus according to claim 1 or claim 2, such that at one end (74) of attachment of a blade to the hub, a wedge angle (a) of the blade (72) is between 25 ° and 85 ° and preferably between 45 ° and 75 °. 4. Apparatus according to one of the preceding claims, such that a twisting angle of the blade is between 5 ° and 35 °. 5. Apparatus according to one of the preceding claims, comprising at least one rectifier (50, 150) connected to an outer surface of the machine (36) rotating, said rectifier being formed of a set of fins (52, 152 ) extending radially about the axis (41) of rotation of the wheel. 6. Apparatus according to claim 5, such that the fins (52) are flat and arranged in planes containing the axis (41) of rotation of the wheel. 7. Apparatus according to claim 5, such that the fins (152) are arched relative to planes containing the axis (41) of rotation of the wheel, said fins being provided with means for reversing a direction of rotation. the arch. 3025184 14 8. Aircraft comprising an air duct (6), said duct being provided with an inlet (12) and an outlet (20) connected to the outside of the aircraft, said duct comprising successively an exchanger ( 8) of heat and a device (10) for ventilation according to one of the preceding claims. 5 9. A method of operating an aircraft according to claim 8, such that: in a first mode called "fan mode", the aircraft being on the ground, the device (32) electronic power supply energy to the machine ( 36) for rotating the impeller (34) of the blower (30, 130) at a first rotational speed (N1); in a second mode called "turbine mode", the aircraft being in flight and a flow of air flowing through the duct (6), said air flow drives the wheel (34) of the fan (30, 130), a second rotational speed (N2), the rotating machine (36) thereby generating electric power transferred to the electronic device (32). 15 10. The method of claim 9 taken in combination with claim 7, such that: in the first mode "fan", the vanes (152) of the rectifier (150) are oriented at a first angle of registration (a ') opposite to the pitch angle (a) of the blades (72) of the wheel (34); - In the second mode "turbine", the fins (152) are oriented at a second angle of registration (a ") in the same direction as the wedging angle (a-) of the blades (72) of the wheel.