DEVICE FOR DE-ICING AN AIRCRAFT TURBOJET ENGINE NACELLE AIR INTAKE LIP

Abstract

The present disclosure provides a device for de-icing an air intake lip of an aircraft turbojet engine nacelle. The de-icing device includes a de-icing circuit in which a heat transfer fluid, working in a two-phase form, circulates. The de-icing circuit includes at least one device for circulating the heat transfer fluid in the de-icing circuit, a system for heating the heat transfer fluid and configured to change the phase of the fluid to a vapor phase, and an inlet conduit that opens into the lip through a rear wall and injects the vapor phase fluid into the lip. The fluid changes phase when it condenses on the front wall of the lip to de-ice the lip.

Claims

1. A de-icing device for an air inlet lip of an aircraft turbojet engine nacelle, the lip forming a volume delimited by a front wall to be de-iced, forming a leading edge, and a rear partition, the de-icing device including a de-icing circuit that circulates a heat transfer fluid that operates in two-phase form, the de-icing circuit comprising: a reservoir containing the heat transfer fluid; a circulation device operable to circulate the heat transfer fluid in the de-icing circuit, the circulation device including at least one circulation pump; a heating system operable to heat the heat transfer fluid into a vapor phase; an inlet duct configured to inject the vapor-phase heat transfer fluid into the lip through the rear partition of the lip, wherein the vapor-phase heat transfer fluid is at a temperature close to its condensation point when injected into the lip and the vapor-phase heat transfer fluid changing in phase by condensing on the front wall of the lip to de-ice the lip; and an outlet duct configured to evacuate the heat transfer fluid out of the lip through the rear partition of the lip.

2. The de-icing device according to claim 1, wherein the circulation device includes a turbine that is supplied with vapor-phase heat transfer fluid via an intake duct and the turbine drives the at least one circulation pump in motion.

3. The de-icing device according to claim 1, wherein the circulation device includes a motor that drives the at least one circulation pump in motion.

4. The de-icing device according to claim 1 further comprising a regulation system, the regulation system comprising: a central control unit; and a temperature sensor that measures a temperature of the heat transfer fluid at an outlet of the heating system and communicates with the central control unit.

5. The de-icing device according to claim 4, wherein the regulation system includes a pressure relief valve operable to reduce pressure in the de-icing circuit and in the lip.

6. The de-icing device according to claim 4, wherein the regulation system includes a manometer for controlling pressure in the lip and communicating with the central control unit.

7. The de-icing device according to claim 4, wherein the regulation system includes a plurality of regulating valves adapted to regulate pressure of the heat transfer fluid in the de-icing circuit and regulate pressure of the heat transfer fluid injected into the lip.

8. The de-icing device according to claim 1, wherein the heating system includes an electric heater operable to heat the heat transfer fluid.

9. The de-icing device according to claim 1, wherein the heating system includes a heat exchanger supplied with oil heated by a turbojet engine, the heat exchanger adapted to transfer thermal energy from said oil to the heat transfer fluid.

10. The de-icing device according to claim 1, wherein the reservoir is formed by a sump arranged in a lower part of the lip such that the heat transfer fluid flows under gravity into said reservoir, wherein the outlet duct draws liquid-phase heat transfer fluid into the reservoir for evacuating the heat transfer fluid contained in the lip.

11. The de-icing device according to claim 1 further comprising a fan configured to circumferentially circulate the vapor-phase heat transfer fluid in the lip.

12. A nacelle for an aircraft turbojet engine comprising a de-icing device according to claim 1.

Description

DRAWINGS

[0042] In order that the disclosure may be well understood, there will now be described various forms thereof, given by way of example, reference being made to the accompanying drawings, in which:

[0043] FIG. 1 is a schematic perspective view illustrating a nacelle equipped with a simplified de-icing device, according to a first form of the present disclosure;

[0044] FIG. 2 is a schematic perspective view illustrating a de-icing device equipped with a regulation system, according to a second form of the present disclosure;

[0045] FIG. 3 is a schematic perspective view illustrating a de-icing device equipped with an oil to heat transfer fluid heat exchanger, according to a third form of the present disclosure;

[0046] FIG. 4 is a schematic perspective view illustrating a de-icing device equipped with a steam turbine, according to a fourth form of the present disclosure;

[0047] FIG. 5 is a schematic perspective detail view illustrating condensation of heat transfer fluid on an inner front wall of an air inlet lip; and

[0048] FIG. 6 is a schematic perspective detail view of a nacelle in accordance with the present disclosure, whose air inlet lip is equipped with a fan.

[0049] The drawings described herein are for illustration purposes only and are not intended to limit the scope of the present disclosure in any way.

DETAILED DESCRIPTION

[0050] The following description is merely exemplary in nature and is not intended to limit the present disclosure, application, or uses. It should be understood that throughout the drawings, corresponding reference numerals indicate like or corresponding parts and features.

[0051] In the description and the claims, the terms front and rear will be used without limitation with reference to the front part and to the rear part respectively of FIGS. 1 to 6.

[0052] In addition, to clarify the description and the claims, the terminology longitudinal, vertical and transverse will be used without limitation with reference to the trihedron L, V, T indicated in the figures, whose axis L is parallel to the axis of the nacelle.

[0053] As used herein, the terms upstream and downstream should be understood in relation to the circulation of the heat transfer fluid inside the de-icing circuit.

[0054] Also, for the different variants, the same references may be used for elements that are identical or that provide the same function, for the sake of simplification of the description.

[0055] FIG. 1 shows a de-icing device 10 for an air inlet lip 12 of an aircraft turbojet engine nacelle 14.

[0056] As can be seen in FIG. 5, the lip 12 forms a ring-shaped volume of a D-shaped 90 longitudinal section which is delimited by a front wall 16 to be de-iced, forming a leading edge, and a rear partition 18 which separates the volume delimited by the lip 12 and the segment of the nacelle which is connected to the lip 12.

[0057] As can be seen in FIGS. 1 to 6, the de-icing device 10 includes a de-icing circuit 20 in which circulates a heat transfer fluid 22 which operates in two-phase form, that is to say the heat transfer fluid 22 adopts two different phases, namely a liquid phase and a vapor phase.

[0058] The circuit 20 generally forms a closed loop which comprises the lip 12 and which allows circulating the heat transfer fluid 22 through the lip 12.

[0059] To this end, the circuit 20 comprises a reservoir 24 of heat transfer fluid 22, which is formed by a sump arranged in a lower part of the lip 12, so that the heat transfer fluid 22 flows under gravity toward the reservoir 24.

[0060] In addition, the de-icing circuit 20 includes a circulation device 26 for the heat transfer fluid 22, a heating system 28 for the heat transfer fluid 22, an inlet duct 30 for the heat transfer fluid 22 which opens into the lip 12, through the rear partition 18, to inject the vapor-phase heat transfer fluid 22 inside the lip 12, and an outlet duct 34 for the heat transfer fluid 22 which opens into the lip 12, through the rear partition 18, to evacuate the heat transfer fluid 22 outside the lip 12.

[0061] According to one variant not shown, the inlet duct 30 is connected to a plurality of inlet ports for injecting the heat transfer fluid in a distributed manner inside the lip 12.

[0062] According to a first form of the present disclosure shown in FIG. 1, the circulation device 26 for the heat transfer fluid 22 includes a circulation pump 36 which is supplied with heat transfer fluid 22 by the outlet duct 34 and which is driven by an electric motor 38.

[0063] According to whether the inlet duct 30 is immersed or not in the heat transfer fluid 22 contained in the reservoir 24, the circulation pump 36 is of the liquid or two-phase type with a gas to liquid separation capacity.

[0064] Still according to the first form, the heating system 28 includes an electric heater 40 which is designed to heat the heat transfer fluid.

[0065] In one variant, the electric heater 40 includes an electrical resistance which is mounted in a balloon in which the heat transfer fluid 22 circulates to bring the heat transfer fluid 22 from a liquid phase to a vapor phase.

[0066] As seen in FIG. 1, the electric heater 40 is connected to an outlet of the circulation pump 36 by a duct 41 to be supplied with liquid-phase calorific fluid 22, and an outlet of the electric heater 40 is connected to the lip 12 by the inlet duct 30 provided for this purpose.

[0067] In addition, the de-icing device 10 according to the first form is equipped with a regulation system that includes a central control unit 42, and a temperature sensor 44 which measures the temperature of the heat transfer fluid 22 at the outlet of the heating system 28, such as the outlet of the electric heater 40.

[0068] The temperature sensor 44 communicates with the central control unit 42 which regulates the temperature of the heat transfer fluid 22 by controlling the heater 40.

[0069] Similarly, the motor 38 of the circulation pump 36 is controlled by the central control unit 42 to regulate the suction pressure of the circulation pump 36 in the lip 12.

[0070] In addition, the regulation system includes a pressure relief valve 46 that allows reducing the pressure in the lip 12 in the event of excess pressure.

[0071] To this end, the pressure relief valve 46 is mounted on a wall of the lip 12, for example on the rear partition 18, to evacuate the vapor-phase calorific fluid 22 toward the outside of the lip 12.

[0072] Also, the regulation system includes a manometer 48 for controlling the pressure in the lip 12 which communicates with the central control unit 42, this characteristic enabling the central control unit 42 to regulate the pressure within the lip 12 by acting on the circulation pump 36 and on the heating system 28 of the heat transfer fluid 22.

[0073] The operation of the de-icing device 10 according to the first form is described below.

[0074] The heat transfer fluid 22 is drawn into the reservoir 24 by the circulation pump 36 through the outlet duct 34.

[0075] The circulation pump 36 makes the heat transfer fluid 22 circulate to the inlet of the electric heater 40 which raises the temperature of the heat transfer fluid 22 to a temperature allowing the fluid 22 to adopt a vapor phase.

[0076] The heat transfer fluid 22, still in the vapor phase, is injected into the lip 12 via the inlet duct 30, and the heat transfer fluid 22 condenses on the cold front wall 16 of the lip 12 to transmit its calories to the front wall 16, in order to de-ice the lip 12, as seen in FIG. 5.

[0077] Under gravity, the condensed liquid-phase heat transfer fluid 22 flows on the front wall 16 of the lip 12, to the reservoir 24 located at bottom of the lip 12.

[0078] According to this first form, the regulation of the pressure in the lip 12 is driven by the regulation of the motor speed 38 of the circulation pump 36 and by the regulation of the temperature of the electric heater 40.

[0079] Indeed, the more the suction generated by the circulation pump 36 is strong, the more the pressure in the lip 12 decreases, and the more the heater 40 temperature is high, the more the pressure and the de-icing temperature of the heat transfer fluid 22 increase.

[0080] FIG. 2 shows the de-icing device 10 according to a second form which differs from the de-icing device 10 according to the first form in that it includes a plurality of regulating valves.

[0081] According to the second form, the de-icing device 10 includes a first valve 50 for regulating the discharge of the pump circulation 36 toward the heating system 28, which is tapped onto the outlet duct 34, upstream of the pump 36, and a second valve 52 for regulating the discharge of the circulation pump 36 toward the heating system 28, which is tapped onto the duct 41 downstream of the circulation pump 36.

[0082] Thus, the first discharge regulating valve 50 and the second discharge regulating valve 52 allow regulating the pressure within the electric heater 40.

[0083] Complementarily, the de-icing device 10 includes a valve 54 for regulating the injection of the heat transfer fluid 22 into the lip 12, which is tapped onto the inlet duct 30, in order to regulate the injection pressure of the heat transfer fluid 22 injected into the lip 12.

[0084] To this end, the two discharge regulating valves 50, 52 and the injection regulating valve 54 are controlled by the central control unit 42.

[0085] FIG. 3 shows the de-icing device 10 according to a third form which differs from the de-icing device 10 according to the second form in that the heating system 28 includes a heat exchanger 56 which is associated with the electric heater 40.

[0086] According to the third form, the heat exchanger 56 is supplied with oil heated by the motor (not shown) arranged in the nacelle 14, and which is adapted to transfer thermal energy from the oil to the heat transfer fluid 22.

[0087] According to one aspect, the heat exchanger 56 is arranged directly upstream of the electric heater 40.

[0088] In addition, a first oil supply duct 58 connects an inlet of the heat exchanger 56 to an oil supply source and a second discharge duct 60 connects an outlet of the exchanger 56, for allowing the flow of the oil through the heat exchanger 56.

[0089] In addition, a valve 62 controlled by the central control unit 42 regulates the motor oil flow rate which passes through the heat exchanger 56.

[0090] It should be noted that the temperature of the motor oil, according to one variant, is at least equal to the vaporization temperature of the heat transfer fluid 22, so that the heat exchanger 56 allows bringing the heat transfer fluid from a liquid phase to a vapor phase.

[0091] FIG. 4 shows the de-icing device 10 according to a fourth form which differs from the de-icing device 10 according to the third form in that the circulation device 26 includes a turbine 64 which is supplied with vapor-phase heat transfer fluid 22 by an intake duct 66 connected to the electric heater 40, and which drives the circulation pump 36 in motion.

[0092] Thus, before being injected into the lip 12, the vapor-phase heat transfer fluid 22 passes through the turbine 64, which operates as a steam engine.

[0093] As seen in FIG. 4, a regulating valve 67 is interposed between the electric heater 40 and the turbine 64, this valve being controlled by the central control unit 42.

[0094] The temperature of the heat transfer fluid 22 at the inlet of the turbine 64 will have to verify the following equation:

Tinlet=Tsat.(1+)+W/Cp

[0095] with Tinlet for the heat transfer fluid temperature at the inlet of the turbine 64 in degrees Kelvin, Tsat for the vaporization temperature of the heat transfer fluid 22 under the pressure conditions of the lip 12 in degrees Kelvin, for a margin coefficient, W for the power of the circulation pump 36 desired for the injection of the heat transfer fluid 22 into the lip 12 in Watt and Cp for the calorific coefficient at constant pressure of the heat transfer fluid 22.

[0096] This condition makes it possible to maintain a vapor phase at the outlet of the circulation pump 36 while injecting the heat transfer fluid 22 into the lip 12 at a temperature close to the condensation point, or dew point.

[0097] In steady-state, the energy migrates to the condensation areas whose condensation heat-transfer coefficient is in the order of 1200 to 1500 W/K.m.sup.2 (unit in Watts per square meter Kelvin) while the gas-phase heat exchange hardly exceeds 300 W/K.m.sup.2.

[0098] The temperature of the heat transfer fluid 22 is fixed by the dew point chosen in lip 12.

[0099] The rear partition 18 remains at a temperature substantially similar to the temperature of the vapor-phase heat transfer fluid 22 injected into the lip 12.

[0100] The temperature of the lip 12 remains equal to the condensation temperature of the heat transfer fluid 22 if the energy brought to the heat transfer fluid 22 is greater than the external drop vaporization energy, which verifies the following equation:

QDH=fS

[0101] With S, in square meters, for the surface of the lip to be de-iced, f in Joule x meter/second for the flow to maintain on the front wall 16 to be de-iced in order to obtain the evaporation or the melting of frost according to the desired goal, Q in cubic meters/second for the flow rate of heat transfer fluid 22 to be injected and DH in Joule for the enthalpy of condensation which is substantially equal to the latent heat of evaporation of the heat transfer fluid 22 at the pressure prevailing in the lip 12.

[0102] It is thus notable that it is possible to de-ice the lip 12 provided that the flow rate of heat transfer fluid 22 is sufficient considering the latent heat of the heat transfer fluid 22.

[0103] It is therefore desired to use a fluid whose latent heat is the highest possible.

[0104] The de-icing device 10 according to the present disclosure has several advantages.

[0105] Indeed, the de-icing device 10 is self-regulating in temperature within the lip 12 as a function of the pressure in this area.

[0106] It is not necessary to monitor the temperature of the possible overheating areas.

[0107] If an area has no more droplets to be vaporized, its temperature stabilizes between the steam temperature and the condensation temperature of the heat transfer fluid 22.

[0108] The lip 12 and its environment cannot exceed the temperature of the injected vapor-phase heat transfer fluid 22 which is regulated by the heating system 28 and which is driven by the properties of the heat transfer fluid 22.

[0109] Therefore, no temperature sensor is necessary.

[0110] The quality of the condensation flow compensates for the need of temperature which may remain below 110 degrees Celsius or less, with much better efficiency than an air system or a Joule effect electrical system.

[0111] The heat energy of the motor oil is recovered by the phase-change heat exchanger 56 in an effective manner in most cases of aircraft flight.

[0112] In the descent phase, if the oil is not hot enough, the electric heater 40 can be used.

[0113] The electric heater 40 also makes it possible to overheat the heat transfer fluid 22 if the turbine 64 involves power, therefore an intake temperature, too high to be coming from the heat exchanger 56.

[0114] Thus, the present disclosure makes it possible to dispense with a heavy electrical resistance element and complex regulation.

[0115] If only the electrical energy is used to heat the heat transfer fluid 22, the electric heater has a compact volume in the order of one liter.

[0116] Also, the turbine and the pump are the only movable elements of the system with the valves.

[0117] The mass of the de-icing device 10 is substantially less than that of an aeraulic or electrical system, the flow of heat transfer fluid 22 being four times higher than that of air and the associated mass flow rate is four times lower for the same efficiency.

[0118] As shown in FIG. 6, it will be advantageously possible to add a fan 80 in the D-shaped duct 90 in order to make the fluid 22 circulate in the gas phase within this duct and to homogenize the thermal flow at the wall 16.

[0119] The description of the disclosure is merely exemplary in nature and, thus, variations that do not depart from the substance of the disclosure are intended to be within the scope of the disclosure. Such variations are not to be regarded as a departure from the spirit and scope of the disclosure.