SYSTEM FOR HEAT MANAGEMENT OF AN EXTERNAL POWER-GENERATING GONDOLA FOR AN ELECTRICALLY POWERED AIRSHIP, GONDOLA AND AIRSHIP WITH THIS SYSTEM

Description

FIELD OF INVENTION

[0001] The field of the invention is that of rigid-structure, electrically propelled airships designed for the transport of heavy loads, and more particularly that of the cooling and ventilation of electrical power generation systems and associated auxiliary equipment carried on board these airships. STATE OF THE ART

[0002] Heavy-lift airships, thanks to their electronic flight control systems and distributed hybrid or all-electric propulsion, are unique in that they can achieve long hovers for cargo exchange. This presents a specific challenge. On older airships, the engines were directly connected to the propellers for propulsion, requiring a constant flow of "fresh" air to dissipate heat through forced-duct heat exchangers or by natural convection. Document WO03037715A1 describes a cooling system for an aircraft auxiliary power unit (APU). The system is designed for an APU comprising at least one gas turbine compressor and one oil cooler, both housed separately in a single unit.The system comprises the auxiliary power unit housed in the aircraft fuselage, an engine exhaust port defined in the rear of the fuselage and communicating with the gas turbine, at least one first air intake channel communicating with a second opening defined in said fuselage and with said compressor section, and the oil cooler is located in a second channel communicating with an opening other than the engine exhaust port of said fuselage and with the engine exhaust port. The outside cooling air and engine exhaust expelled through said engine exhaust port carry the cooling air through said second channel to said oil cooler, thereby cooling the engine oil.

[0003] On electrically propelled airships, the turbines, and in the future fuel cells, serve only to produce the primary mechanical power that enables the electric generator to produce the electricity needed to power onboard equipment (propulsion, lifting, flight control system). Therefore, the turbine is not connected to a propeller. Despite the fact that it "draws in" air to fuel its thermodynamic cycle and thus create a flow of fresh air, this type of architecture is strongly discouraged for two main reasons: Aviation regulations advise against introducing heat exchangers containing flammable fluids into the turbomachine's air intake ducts. In the event of a leak, such as from an impact of ingested debris, the leak could be ingested by the turbomachine and cause an internal fire, which could be catastrophic for its integrity. Turbines are highly sensitive to pressure losses in their air intakes and exhausts. Therefore, introducing a heat exchanger into the turbomachine's air intake duct would be extremely detrimental to the efficiency and overall performance of the primary power generation chain.

[0004] To address this issue, it is necessary to introduce new solutions and architectures that allow for the dissipation of heat generated by the systems to the external environment. Furthermore, since it is necessary to confine complete turbogenerator systems within fire-resistant enclosures to reduce the risk of fire spreading throughout the nacelle housing these turbogenerators, it is essential to address the cooling problem of the entire turbogenerator system holistically, going beyond the conventional approaches used to date. DESCRIPTION OF THE INVENTION

[0005] This objective is achieved with an airship according to claim 1. Dependent claims 2-7 propose optional features according to the claimed invention.

[0006] This particular arrangement of the ventilation air evacuation means around the combustion gas evacuation duct, like a second skin, has the effect of providing a Venturi effect which helps to energize the ventilation air and accelerate the outgoing flow of a mixture of combustion gas and ventilation air.

[0007] When the thermal management system is implemented with at least one turbogenerator equipped with a plenum chamber designed to homogenize the air around a suction grille equipping the supply air inlet duct, the containment enclosure can then advantageously include a front hood located upstream of the plenum chamber and a rear hood located downstream of the plenum chamber.

[0008] The containment enclosure may include a first fireproof wall separating the front cover from the plenum chamber and a second fireproof wall separating the rear cover from the plenum chamber.

[0009] The ventilation means may include a first air injection duct in the front hood and at least a second air injection duct in the rear hood.

[0010] The means of ventilating air may include an exhaust duct having a height considerably greater than that of the combustion gas exhaust duct and a diameter considerably greater than that of said combustion gas exhaust duct.

[0011] The ventilation means can preferably be arranged to provide forced ventilation of the fire containment enclosure.

[0012] This airship can be of the rigid-structure type, dedicated to the transport of heavy loads and vertical transfer ( hovering ) of these charges. BRIEF DESCRIPTION OF THE FIGURES

[0013] There figure 1 This represents a side view of an example of an airship equipped with two electric power generation nacelles. figure 2 is a perspective view of the interior of an electrical power generation nacelle according to the invention. figure 3 illustrates four functional principles of ventilation and cooling that can be implemented. figure 4 is a perspective view of an example of an implementation of a thermal management system according to the invention, as applied in an electrical power generation nacelle according to the invention. figure 5 is a schematic cross-sectional view of a thermal management system according to the invention. figure 6 illustrates a schematic perspective view of the thermal management system of the Figure 5 . DETAILED DESCRIPTION

[0014] With reference to the figure 1 , a rigid-structure airship D comprises a set of propulsion units P powered by electrical energy from electrical power generation systems integrated into two external fin-shaped nacelles 1 (only one of which is shown on the figure 1 ).

[0015] A fin-shaped gondola 1 includes, with reference to the figure 2 , a mechanical structure 30,32 made from a lattice of composite material beams and covered with a hull or fairing skin 10. The upper part 31 of the mechanical structure is connected to a frame 4 of the main body of the airship via a mechanical interface 3 and three cables 7,70,71.

[0016] The nacelle 1 incorporates two turbogenerator sets 84.1,84.2 mounted suspended from the upper part 31 of the mechanical structure of the nacelle 1, a storage battery system 85, and a floor 5.

[0017] This floor 5 includes an access route 50 from inside the airship D into the gondola 1, and a part of the floor 52 surrounding the two turbogenerators 84.1,84.2. Hollowed parts 51 are provided in the floor 5 to allow the turbogenerators to be removed by means of winches provided on the upper part 31 of the mechanical structure.

[0018] We will now describe, with reference to the figure 3 , four functional principles of ventilation and cooling that can be implemented within a thermal management system.

[0019] According to a first functional principle (A) corresponding to a forced exchange by upstream overpressure prior to the heat or thermal exchange, the thermal management system 100A located within the nacelle 1 comprises an air flow / pressure generation system 60 receiving fresh air from an air inlet duct 82 and delivering pressurized air to the inlet of a thermal exhaust system 101A designed to extract thermal energy from a thermal emitter system 84, in this case a turbogenerator or a fuel cell. The thermal exhaust system 101A emits hot air which is exhausted from the nacelle 1 via an outlet duct 88.

[0020] According to a second functional principle (B) corresponding to a forced exchange by depression downstream of the heat exchange, the thermal management system 100B arranged within the nacelle 1 comprises a thermal exhaust system 101B coupled to a thermal emitter system 84 and receiving fresh air from outside via an air inlet duct 82. The hot air produced by the thermal exhaust system 101B is injected into the inlet of an air flow / depression generation system 61 which delivers hot exhaust air to the outside of the nacelle 1 via an outlet duct 88.According to a third functional principle (C) corresponding to natural convection heat exchange by generating flow upstream of the heat exchange chamber, the thermal management system 100C comprises an air flow / pressure generation system 60 injecting pressurized fresh air into a heat exchange chamber 62 encompassing a thermal emitter system 84 such as a turbogenerator or a fuel cell. The thermal energy emitted by this thermal emitter system 84 is removed from the heat exchange chamber 62 in the air ejected from this chamber to the outside of the nacelle 1 via an air duct 88.

[0021] According to a fourth functional principle (D) corresponding to a natural convection exchange by downstream flow generation to the heat or thermal exchange enclosure, the thermal management system 100D comprises a heat exchange enclosure 62 containing a thermal emitter system 84, such as a turbogenerator or a fuel cell, and receiving fresh air inlet via an air inlet duct 82 and injecting hot air from the heat exchange into an air flow / pressure generation system 61 delivering hot air via an outlet duct 88 to the outside.

[0022] We will now describe, with reference to figures 4 à 6 , an example of the realization of a thermal management system according to the invention, corresponding to the third functional principle (C) previously described implemented in a nacelle integrating two turbogenerators and a high voltage generator 20 NPES.

[0023] The nacelle 1 comprises two turbogenerators 84.1,84.2 connected in input to a fuel supply line 24 and out output to an energy conversion system 85, a storage battery system 92 and a high voltage power supply line 90 extending within the airship D to power the electric propulsion groups.

[0024] The thermal management system 100 equipping nacelle 1, which integrates the two turbogenerators 84.1 and 84.2, comprises: two air inlet ducts 81.1,81.2 for cooling the turbines integrated into the turbogenerators 84.1,84.2; two fans 80.1,80.2 for cooling the turbines, arranged downstream of the two air inlet ducts 81.1,81.2; two heat exchangers 116 coupled to the two turbogenerators 84.1,84.4; two air inlet ducts 115.1,115.2 provided for cooling the front cowling enclosures 114.1,114.2 of the turbogenerators 84.1,84.2; two plenum chambers 82.1,82.2 connected to the two air inlet ducts 115.1,115.2 for cooling the front cowlings 114.1,114.2; two ducts 88.1,88.2 for the evacuation of air and combustion gases, of the "eductor" type.

[0025] We will now describe, with reference to figures 5 And 6A practical example of the implementation of a thermal management system 200 according to the invention, implemented for cooling a turbogenerator 84 equipped with a gearbox 120 and enclosed within a fire containment enclosure 62. This containment enclosure 62 has a fuel drain bottom configured, for example, with two slopes 62a, 62b. The thermal management system 200 comprises an engine air intake duct 82 opening into a plenum chamber 182 surrounding a portion of the turbine of the turbogenerator 84 and a pressurized ventilation air inlet duct 115 into the containment enclosure 62. The plenum chamber 182 is designed to homogenize the air around a suction grille fitted to the supply air inlet duct.

[0026] With reference to the figure 6The containment enclosure 62 includes a front cowl 114 covering the upstream stage of the turbine and a rear cowl 117 covering the downstream stage of the turbine and the gearbox 120. The ventilation air inlet duct 115 feeds a first air injection duct 115a in the front cowl 114, and second and third air injection ducts 115b,115c in the rear cowl 117. The front and rear cowls 114,117 are each separated from the plenum chamber 182 by a fireproof wall (or firewall) 8a,8b.

[0027] The thermal management system 200 further includes an air exhaust duct 88 from the containment building 62, which surrounds the flue gas exhaust duct 184 from the turbine. This exhaust duct 88 has a significantly greater height and diameter than the flue gas exhaust duct, so that this geometric configuration contributes to creating a Venturi effect applied to the outgoing ventilation airflow mixed with the flue gas.

[0028] Of course, other embodiments of a thermal management system can be considered without departing from the scope of the present invention, the object of which is defined solely by the claims. In particular, other geometries of the fire containment enclosure can be considered. The configuration of the ventilation air injection circuit can vary, especially with regard to the number of air injection ducts in the fire containment enclosure.

Claims

1. Electrically propelled airship (D) equipped with at least two external nacelles (1) for generating electrical energy, each of the nacelles comprising (i) electrical generation means implementing at least one turbogenerator (84) contained in a fire containment vessel (62) and provided with an air inlet duct (82) for turbine feed air and a flue gas exhaust duct (184), and (ii) a thermal management system (200) comprising ventilation means (115) for injecting external air into the fire containment vessel (62), and means (88) for discharging the ventilation air from the containment vessel (62), said means (88) for discharging the ventilation air surrounding the flue gas exhaust duct (184).

2. Airship according to the preceding claim, each of the nacelles implementing at least one turbogenerator equipped with a plenum chamber provided to homogenize the air around a suction grid equipping the air inlet duct, the containment vessel (62) comprising a front cowl (114) arranged upstream of the plenum chamber (182) and a rear cowl (117) arranged downstream of the plenum chamber (182).

3. Airship according to the preceding claim, wherein the containment vessel (62) includes a first firewall (8a) separating the front cowl (114) from the plenum chamber (182) and a second firewall (8b) separating the rear cowl (117) from the plenum chamber (182).

4. Airship according to either of the two preceding claims, wherein the ventilation means (115) comprise a first duct (115a) for injecting air into the front cowl (114) and at least one second duct (115b,115c) for injecting air into the rear cowl (117).

5. Airship according to any of the preceding claims, wherein the means for discharging ventilation air comprise an exhaust duct having a height much greater than that of the flue gas exhaust duct and a diameter substantially greater than that of said flue gas exhaust duct.

6. Airship according to any of the preceding claims, wherein the ventilation means (115) are arranged to provide forced ventilation of the fire containment vessel.

7. Airship according to any of the preceding claims, of the rigid-structure type, dedicated to transporting heavy loads and to vertically transferring these loads.