Aeroengine and process of operating an aeroengine

Abstract

An aeroengine 100 comprising a cowling 101 with at least two zones 1, 2 enclosed by the cowling 101, wherein a first zone 1 and at least one second zone 2 are separated by a wall 3, the cowling 101 ci

Description

FIELD The disclosure relates to an aeroengine and a process of operating an aeroengine. BACKGROUND In known aeroengines, e.g., in turbo gas turbines, a cowling separates internals of the aeroengine from the environment and thereby covers and protects the internals. Typically, the cowling is surrounding the fan at the inlet of a turbo aeroengine. Within the cowling, there are usually internal zones separated by fireproof walls. The separation between the different regions is, in particular, due to fire hazard within the cowling. In one instance, there is one zone next to the engine casing (also called undercowling compartment) and there is a further zone (also called cowl compartment) around the bypass duct of the engine. One purpose of the different zones is to mitigate the effects of a fire and / or a leakage within the cowling which might occur during the operation of the aeroengine. For this purpose, the zones can, in particular, be ventilated by air separately. All this is regulated by the respective safety boards, requiring certain fireproof time threshold for the structures involved. In the prior art, leakage handling systems, though in a different context, are described in United States patents US 6585191 B2 and US 9976484 B2 and United States patent application US 2018 / 0149086 A1. More efficient designs are needed for an efficient and secure handling of leakages and / or fire hazards. Summary of the disclosure In a first aspect there is provided an aeroengine comprises a cowling with at least two zones enclosed by the cowling, wherein a first zone and a second zone are separated by a wall. The cowling encloses circumferentially a core engine, which is surrounded by a bypass duct comprising radially outer fairing and a radially inner fairing. The at least one second zone is configured to receive fluid leakages from at least one supply line for fluids, in particular entering the at least one second zone through at least one fluid passage in a section of the radially outer fairing of the bypass duct. This section of the radially outer fairing of the bypass duct could be termed service tray. And the at least one second zone comprises at least one duct connecting the at least one second zone to the environment. The at least one second zone provides a compartment but a defined fluid exit feature, such as the at least one duct. This arrangement offers a multilayer fire protection, with a flexible and economic “tray” design, which is not totally fireproof as it accepts fluid leakages, but still a “fire barrier”, as it is of high temperature material. Furthermore, if, e.g., an air supply line would leak, the at least one second zone, which is forming a pressure drop system between the undercowling compartment and the atmosphere, is protecting the cowling from over pressurization. The at least one second zone also works as a manifold collecting leakages which are hot, since the air comes from the undercowling compartment where the air is pressurized and in contact with the engine casings, therefore protecting the cowl compartment of overheating, e.g., relevant for instance for electronic components like the FADEC (or electronic engine controller). The at least one second zone allows that fire proofness requirement may be removed from the interfacing plate between the first zone and the at least one second zone, therefore establishing its function as a "separating feature”, which is not 100% "airtight”, but still serves as fire barrier in case of an in-service engine fire originated within the undercowling compartment. This allows more component design and development flexibility, as a comprehensive validation of fireproof requirement for the at least one second zone is not required. In some embodiments the at least one supply line for fluids carries air, oil, fire extinguishing fluid or fuel. Any leakage of those fluids might be harmful to the cowling. Furthermore, the at least one second zone can enclose and / or can be traversed with at least one supply line, in particular, a supply line for air, oil, fuel or electricity. The supply lines can, e.g., extend between the cowling and the core engine. In some embodiments the at least one second zone comprises at least one fluid passage (or also a fluid labyrinth) from the bypass duct and / or the undercowling compartment defining a defined entry for leaked fluids to the at least one second zone. The second zone can be, in particular, connected with a non-structural strut between the radially inner fairing and the radially outer fairing. The supply lines can pass through that non-structural strut. The leakage of a fluid would be within that non-structural strut so that it would be part of the fluid passage. As an additional protection against over pressurization, the at least one second zone can comprise at least one blow-out device, such as a burst disk, a blowout door, in particular a spring loaded door. For monitoring the conditions, some embodiments comprise at least one sensor device for measuring the pressure pz and / or the temperature Tz) in the at least one second zone, wherein the at least one sensor device is configured to supply data to an electrical engine control system. In some embodiments the aeroengine is configured that during operation the pressure pz in the at least one second zone is higher than the pressure pi in the first zone. As the pressure in the first zone is generally at ambient conditions, the overpressure in the at least one second zone relative to the ambient conditions allows an outward flow of leaked fluids in the at least one second zone. In some embodiments the aeroengine is configured such that during operation the pressure Pbpd in the bypass duct is higher than the pressure in the at least one second zone, so that leaked fluid is drawn towards the at least one second zone. In some embodiments a control device controls the pressure pz and / or the temperature T2 in the at least one second zone, by, e.g., controlling a pressure relief valve. It is also possible that the wall separating the first zone and the at least one second zone, the wall of the at least one second zone to the bypass duct and / or the wall of the duct comprise a multilayered structure and / or thermal protection means. This means that the wall can be thermally designed, by means of insulation or double wall / multilayer design, to reach no more than autoignition temperature of a mixture of fuel / air. As the cowl compartment may contain flammable fluid carrying components or temperature sensitive component, the wall separating the zones should not reach more than 200°C to avoid becoming a nominal ignition source or heat dissipator for the first zone. Then, the design of the wall separating the zones comprises a multi-layered structure or is thermally insulated towards the first zone. Depending upon the temperature drop of the leakages between the opening (fluid gap) at the interfacing plate and the exhaust to the environment, thermal insulation might be required for the at least one second zone duct(s). In some embodiments the at least one second zone comprises high temperature material, so it provides a fire barrier protection Therefore, the aeroengine might not be completely fireproof since it allows leakages, but it still provides a level of fire protection from a fire originated in the undercowling compartment. In a second aspect there is provided a process of operating an aeroengine comprising a cowling with at least two zones enclosed by the cowling, wherein a first zone and an at least one second zone are separated by a wall; the cowling circumferentially enclosing a core engine, surrounded by a bypass duct with a radially outer fairing and a radially inner fairing; the process comprising the steps of: the at least one second zone receiving fluid leakages from at least one supply line for fluids entering the at least one second zone through at least one fluid passage in a section of the radially outer fairing of bypass duct; and directing the fluid leakage material from the at least one second zone through at least one duct to the environment. In some embodiments the pressure in the at least one second zone is higher than the pressure in the first zone. In some embodiments the pressure in the bypass duct is higher than the pressure in the at least one second zone. The skilled person will appreciate that except where mutually exclusive, a feature or parameter described in relation to any one of the above aspects may be applied to any other aspect. Furthermore, except where mutually exclusive, any feature or parameter described herein may be applied to any aspect and / or combined with any other feature or parameter described herein. BRIEF DESCRIPTION OF THE DRAWINGS Some exemplary embodiments are depicted in connection with the Figures, wherein: FIG. 1 shows a schematic sectional view of a first embodiment of an aeroengine that has a non-air-sealed zone for collecting fluids; FIG. 1A shows a schematic perspective view of a part of the aeroengine shown in FIG. 1; FIG. 2 shows a detailed view of the non-air-sealed zone of an embodiment of the aeroengine; FIG. 3A shows a first arrangement for an aeroengine attached to the fuselage; FIG. 3B shows a second arrangement for an aeroengine underneath a wing of an aircraft; FIG. 4A shows a sectional view perpendicular to the rotational axis of the aeroengine; FIG. 4B shows a perspective view of the inner part of the aeroengine shown in FIG. 4A. The following table lists the reference numerals used in the drawings with the features to which they refer: Ref Feature FIG. 1 First zone 1 2 4A 2 Second zone 1 2 2A Second zone 1A4A4B 2B Second zone 1A4A 3 Wall 1A2 4B 4 Non-structural strut 1 2 4A 4B 5 First supply line (air) 1 6 Second supply line (fuel) 1 2 4A 7 Third supply line (oil) 1 8 Fourth supply line (electricity) 1 2 9 Blowout device 2 10 Sensor device (pressure, temperature) 2 12 Control device 2 100 Aeroengine 1 2 3A 3B 4A 101 Cowling 1 2 4A 102 Bypass duct 1A2 4A 104 Core engine 1 2 4A 105 Fan 1 106 Undercowling compartment 1 4A 107 Compressor 1 108 Combustion chamber 1 109 Turbine 1 110 Non-structural strut 1 1A2 4A4B 111 Radially inner fairing 1 1A2 4A 112 Pylon 3A 3B 4A 113 Inlet opening of first zone 1 114 Outlet opening of second zone 1 115 Environment control system (ECS) 1 116 Full authority digital engine control (FADEC) 1 117 Gearbox 1 118 Radially outer fairing of bypass duct 1 1A2 4A4B 119 Inlet opening of undercowling compartment 1 120 Outlet opening of undercowling compartment 1 121 Environment control system (ECS) 2 130 Aircraft 3A 3B 131 Fuselage of aircraft 3A 132 Wing of aircraft 3B A Air flow 1 E Environment 1 Pi Pressure in first zone 1 2 p2 Pressure in second zone 1 2 Pe Pressure in the environment 1 2 Pbpd Pressure in bypass duct 1 2 Pucc Pressure in undercowling compartment 1 2 DETAILED DESCRIPTION Aspects and embodiments of the present disclosure will now be discussed with reference to the accompanying figures. Further aspects and embodiments will be apparent to those skilled in the art In FIG. 1, a sectional half view of the front part of an aeroengine 100 is shown, which is, e.g., used in commercial aircraft. It can be used in non-commercial aircraft as well. For reasons of simplicity, the view in FIG. 1 only shows structures located at radial distal parts of the aeroengine, in particular not the complete core engine 104. The aeroengine 100, in this case a fan turbo engine, comprises a fan 105 which is enclosed by the cowling 101. The fan 105 provides generally main thrust of the aeroengine 100. When in use, the direction of the air flow A is indicated by an arrow. A bypass duct 102 of the aeroengine 100 is located radially between the cowling 101 and the core engine 104. A large part of the air flow A is flowing through the bypass duct 102, proving thrust. A compressor 107, a combustion chamber 108 and a turbine 109 are parts of the aeroengine 100, which are here shown only schematically. An undercowling compartment 106 is located between a radially inner fairing 111 of the bypass duct 102 and the core engine 104. The undercowling compartment 106 comprises inlet openings 119 (towards the front of the aeroengine 100) and outlet openings 120 (towards the rear of the aeroengine) for air. The position of those openings 119, 120 is shown schematically in FIG. 1. The air flow through the undercowling compartment 106 ensures that no little flammable material accumulates in the undercowling compartment 106. At the top or the side (see FIG. 3A and 3B) of the aeroengine 100, the cowling 101 is connected to a pylon 112 (dashed line). The pylon 112 can be connected to a fuselage (FIG. 3A) or a wing structure (FIG. 3B), both are not shown in FIG. 1. The embodiments of the aeroengine 100 herein relate to embodiments in which it is attached sideways to the fuselage (as shown in FIG. 3A). It will be clear for the person skilled in the art that other forms of attachments of the aeroengine 100 can be used as well. The cowling 101 comprises a first zone 1 (also termed cowl compartment) which extends axially along the cowling 101. In other embodiments, the first zone 1 only axially extends along a part of the cowling 101. This first zone 1 has inlet openings 113 and outlet openings 114 (both only schematically shown in FIG. 1) for air entering from the environment E and then again leaving towards the environment E. The air flow through the first zone 1 prevents the accumulation of flammable fluids in the first zone 1. Optionally, an ECS (environment control system) 115, a FADEC (Full Authority Digital Engine Control) 116 and / or a gearbox 117 can be located within the first zone 1. A second zone 2 within the cowling 101 is separated by a wall 3 from the first zone 1. As will be shown in connection with FIG. 4A, there can be more than one second zone 2. The wall 3 can, e.g., be made of high-temperature material. The second zone 2 borders radially outwards and axially on the first zone 1, i.e., the first zone 1 surrounds the second zone 2 on several sides. To operate the aeroengine 100, it is necessary that material and / or electrical power / signals can be exchanged between the core engine 104 and the cowling 101 or other parts of the aircraft. This implies that the supply lines 5, 6, 7, 8 must cross the bypass duct 102. Therefore, the second zone 2 is separated from the bypass duct 102 by a non-structural strut 110 (see FIG. 1A). Around the circumference of the bypass duct 102, in a typical embodiment, there may be located one to three such non-structural struts 110. The non-structural strut 4 does not have any structural function, as it serves as an aerodynamic and foreign object protection and passageway for supply lines 5, 6, 7, 8 that need to cross the bypass duct 102. The situation of the non-structural strut 110 within the aeroengine 100 but, in particular without the supply lines 5, 6, 7, 8, is shown in FIG. 1A. In the embodiment shown in FIG. 1, the first supply line 5 is a line for air connecting the ECS 115 with the core engine 104. A second supply line 6 is a fuel line connecting a fuel tank (not shown here) at a distance from the pylon 112 with the combustion chamber 108 in the core engine 104. A third supply line 7 is an oil line connecting the gearbox 117 with the turbine area of the core engine 104. The fourth supply line 8 is transmitting electricity and / or electrical signals between the core engine 104 and the FADEC 116. It is expressly noted that the use of these supply lines 5, 6, 7, 8 is only exemplary. In other embodiments, more or less than those four supply lines can be used. It is also possible that other media are transmitted through those supply lines 5, 6. 7, 8. In this embodiment, at least the second and third supply lines 6, 7 carry flammable material, i.e., fuel or oil. If one of those lines 6, 7 would leak, there is a danger that the oil and / or fuel would be ignited. Therefore, the embodiment shown in FIG. 1 provides features which mitigate that risk. In the embodiment shown, all supply lines 5, 6, 7, 8 coming from the core engine 104 pass into or through the second zone 2. The radial outer fairing 118 comprises at least one fluid passage to the second zone 2, here in the form of the non-structural strut 110. The location and the number of supply lines 5, 6, 7, 8 in this embodiment is only exemplary. In general, the opening (or gaps) might be specifically designed for a particular pressure drop from the undercowling compartment 106 to the second zone 2. If there would be a leak, e.g., in the oil line 7, the second zone 2 is configured to receive that leaked oil. The pressure p2 in the second zone 2 is much lower than, e.g., the pressure Pbpd in the bypass duct 102 or the essentially equal pressure pucc in the undercowling compartment 106. The oil leaking out of the oil line would be transported into the second zone 2 due to the pressure difference. Same would apply to leaks in another supply line 5, 6. Furthermore, the second zone 2 comprises at least one duct 4 connecting the second zone 2 to the environment E as shown in FIG. 1. Because the pressure in the second zone 2 is higher than the pressure Pe in the environment, fluids received in the second zone 2 will be transported out to the environment (i.e., flammable fluids are drained out of the powerplant), reducing the amount of flammable material within the aeroengine 100. In the embodiment shown in FIG. 1, the duct 4 is a tube or channel which ends in an opening in the wall of the cowling 101 towards the downstream end of the aeroengine 100. In other embodiments, the opening of the duct 4 can be located elsewhere depending upon the external pressure distribution, to ensure ability to discharge at any normal flight condition. It is possible that the duct 4 comprises a multilayered structure (e.g., a double wall) and / or some thermal protection means, as e.g., an insulation. As the pressure p2 in the second zone 2 is in operation higher than in the environment E, material, in particular a flammable material, is transported from the second zone 2 via the duct 4 into the environment E. This makes sure that in the second zone 2 none or very little flammable material can accumulate. The details related to the second zone 2 can also be seen in the enlarged view of FIG. 2. This, in particular, shows the separating wall 3 towards the first zone 1 and the duct 4, connecting the second zone 2 with the environment E and the bypass duct 102. The embodiment shown in FIG. 2 is a variation of the embodiment shown in FIG. 1, as it comprises further optional features. But the embodiment shown here only has a supply line for fuel 6 and supply line for electricity 8. This shows that different embodiments can have a different number of supply lines 5, 6, 7, 8. One additional and optional feature is a blowout device 9, such as burst disk. Alternatively, a blowout door, in particular a spring loaded door can be used as blow out device 9. In case, the pressure in the second zone 2 increases beyond a certain critical threshold, the blow out device 9 breaks and releases the material in the second zone 2 into the first zone and eventually, in particular, using another blow out device, towards the environment E. A further optional feature is a sensor device 10 which measures the pressure p2 and / or the temperature T2 in the second zone 2. The measured data is transmitted to the ECS 115 which is in this case located in the first zone 1. If a certain threshold is exceeded, a warning message may be displayed in the cockpit for further pilot action (e.g., reduce engine thrust to idle). Another feature is a control device 12 which, in this embodiment, is located in the first zone 1. The control device 12 can process data from the second zone 2 (and transmit it to the sensor device 10). The control device 12 can derive a control action which then can be executed via the FADEC 116 (not shown in FIG. 2). Again, a warning message for an engine thrust reduction or a message for an on-ground maintenance crew to perform an inspection: gap condition is issued. The message could, e.g., relate to a potential burst pipe inside undercowling compartment 106; followed by an unlatching of the message and allowing a dispatch. In FIG. 3A and 3B different arrangements for an aeroengine 100 relative to an aircraft 130 are shown schematically, i.e., only one side of the aircraft 130 is shown. In FIG. 3A the aeroengine 100 is connected through a pylon 112 with a fuselage 131 of an aircraft 130 so that it is located to the side of fuselage 131. In FIG. 3B, the aeroengine 100 is located underneath a wing 132 of the aircraft 130. A pylon 112 connects the aeroengine 100 to the wing 132. FIG. 4A shows a sectional view through an embodiment of an aeroengine 100. The cowling 101 encloses the units within, such as the radially outer fairing 118 of the bypass duct 102 and the radially inner fairing 111 of the bypass duct 102. The core engine 104 with the undercowling compartment 106 is located within the inner fairing 111. A pylon 112 connects the aeroengine 100 to an aircraft, as, e.g., shown in FIG. 3A. Radially within the inner fairing 111 are two second zones 2A, 2B, one first second zone 2A at top and one second zone 2B at the bottom of the aeroengine 100. The two second zones 2A, 2B are connected to non-structural struts 110 forming connections to the undercowling compartment 106 (not shown in FIG. 4A). As described above, the supply lines 5, 6, 7, 8 run from the undercowling compartment 106 through the non-structural struts 110 to the second zones 2A, 2B. In the embodiment of FIG. 4A, a supply line 6 for fuel is carrying fuel from tank in the fuselage (or wing) to the aeroengine 100. The supply line 6 is passing through the first second zone 2A and a second second zone 2B. In case of a leakage, the second zones 2A, 2B receive fluid leakages from the supply line 6 and through the non-structural strut 110. Furthermore, the zones 2A, 2B comprise each one duct 4 connecting them to the environment E. FIG. 4B shows a detail of the upper part of the embodiment shown in FIG. 4A in a perspective transparent view. Here, the dome-like section 2A is shown above the entry of the non-structural strut 110. The wall 3 is separating the second zone 2A within the wall 3 and the first zone 1 outside the wall 3. It will be understood that the invention is not limited to the embodiments above-described and various modifications and improvements can be made without departing from the concepts described herein. Except where mutually exclusive, any of the features may be employed separately or in combination with any other features and the disclosure extends to and includes all combinations and sub-combinations of one or more features described herein.

Claims

1. An aeroengine (100) comprising a cowling (101) with at least two zones (1, 2) enclosed by the cowling (101), wherein a first zone (1) and at least one second zone (2) are separated by a wall (3);the cowling (101) circumferentially enclosing a core engine (104), surrounded by a bypass duct comprising a radially outer fairing (118) and a radially inner fairing (111);the at least one second zone (2) configured to receive fluid leakages from at least one supply line for fluids (5, 6, 7), in particular entering the at least one second zone (2) through at least one fluid passage in a section of the radially outer fairing of bypass duct (118); andthe at least one second zone (2) comprises at least one duct (4) connecting the at least one second zone (2) to the environment (E).

2. The aeroengine of claim 1, wherein the at least one supply line for fluids (5, 6. 7) carries air, oil, fire extinguishing fluid or fuel.

3. The aeroengine of claim 1 or 2, wherein the at least one second zone (2) encloses and / or is traversed with at least one supply line (5, 6, 7, 8), in particular, a supply line for air, oil, fire extinguishing fluid, fuel or electricity.

4. The aeroengine of any preceding claim, wherein the at least one second zone (2) comprises at least one fluid passage from the bypass duct (102) and / or the undercowling compartment (106), in particular, within a non-structural strut (110) between the radially inner fairing (111) and the radially outer fairing (118).

5. The aeroengine of any preceding claim, wherein the at least one second zone (2) comprises at least one blow-out device (9).

6. The aeroengine of any preceding claim, with at least one sensor device (10) for measuring the pressure (pz) and / or the temperature (Tz)) in the at least one second zone (2), wherein the at least one sensor device (10) is configured to supply data to an electrical engine control system (115).

7. The aeroengine of any preceding claim, configured that during operation the pressure (pz) in the at least one second zone (2) is higher than the pressure (pi) in the first zone (1).

8. The aeroengine of any preceding claim, configured that during operation the pressure (Pbpd) in the bypass duct (102) is higher than the pressure in the at least one second zone (2).

9. The aeroengine of any preceding claim, wherein a control device (12) controls the pressure (P2) and / or the temperature (T2) in the at least one second zone (2).

10. The aeroengine of any preceding claim, wherein the wall (3) separating the first zone (1) and the at least one second zone (2), the wall of the at least one second zone (2) to the bypass duct (102) and / or the wall of the duct (4) comprises a multilayered structure and / or thermal protection means.

11. The aeroengine of any preceding claim, wherein the at least one second zone (2) comprises high temperature resistant material providing a fire barrier protection.

12. A process of operating an aeroengine (100) comprising a cowling (101) with at least two zones (1, 2) enclosed by the cowling (101), wherein a first zone (1) and an at least one second zone (2) are separated by a wall (3); the cowling (101) circumferentially enclosing a core engine (104), surrounded by a bypass duct with a radially outer fairing (118) and a radially inner fairing (111); the process comprising the steps of:the at least one second zone (2) receiving fluid leakages from at least one supply line for fluids (5, 6, 7) entering the at least one second zone through at least one fluid passage in a section of the radially outer fairing of bypass duct (118); anddirecting the fluid leakage material from the at least one second zone (2) through at least one duct (4) to the environment (E).

13. The process of claim 12, wherein the pressure (P2) in the at least one second zone (2) is higher than the pressure (pi) in the first zone (1).

14. The process of claim 12 or 13, wherein the pressure (pbpd) in the bypass duct (102) is higher than the pressure in the at least one second zone (2).13

Images