Ventilated box assembly and non-propulsive turbomachine equipped with an air / oil heat exchanger

Abstract

One aspect of the invention relates to an assembly (100) comprising a ventilated box (110) and a non-propulsive turbomachine (120) accommodated in the ventilated box, wherein: - the turbomachine (120) has an air inlet housing (123) and a transmission casing (125) cooled by an air / oil heat exchanger (130), - the ventilated box (110) has a first air inlet (111) for injecting cooling air (F1) into the ventilated box and a second air inlet (112) for injecting a stream of supply air (F2) into the air inlet housing (123), - the air / oil heat exchanger (130) is accommodated in the cavity of the air inlet housing (123) of the turbomachine, the oil of the air / oil heat exchanger being cooled by the stream of supply air (F2) circulating in the air inlet housing, and the stream of heated air (F5) heated by the air / oil heat exchanger being discharged out of the ventilated box.

Description

DESCRIPTION Ventilated casing assembly and non-propulsive turbomachine equipped with an air / oil heat exchanger TECHNICAL FIELD OF THE INVENTION

[0001] The present invention relates to an assembly of a ventilated box and a non-propulsive turbomachine, housed in an aircraft fuselage or nacelle and equipped with an air / oil heat exchanger mounted in the air inlet casing of the turbomachine so as to avoid the rejection of heated air into the ventilated box.

[0002] The invention has applications in the field of turbomachinery and, in particular, in the field of non-propulsive turbomachinery that does not produce thrust for aircraft propulsion. TECHNOLOGICAL BACKGROUND OF THE INVENTION

[0003] Aircraft typically have one or more propulsion turbomachines, meaning they are designed to propel the aircraft. Some aircraft also have a non-propulsive turbomachine used as an auxiliary power unit (APU) that does not produce thrust for aircraft propulsion. This APU is carried on board the aircraft and is designed to generate electrical, pneumatic, or hydraulic power to supply the aircraft independently of the propulsion turbomachine(s), particularly when the propulsion turbomachine(s) are not in operation.

[0004] An APU, or non-propulsive turbomachine, is used on the ground, for example, to power various onboard systems (electrical voltage, pneumatic and hydraulic pressures, air conditioning, etc.) when the main engines (such as the propulsion turbomachines) are shut down and / or to start these main engines. An APU can also be used in flight, for example, to provide pneumatic or electrical power to equipment.

[0005] APUs are typically mounted onboard and positioned within a small volume of the fuselage, such as the rear fuselage cone or the nacelle of an aircraft. APUs are small gas turbine engines, powered by the same fuel as the Propulsive and oil-lubricated turbomachinery requiring cooling, for example by air.

[0006] An example of an APU according to prior art is schematically represented in Figure 1. Another prior art, disclosed by patent document FR 2 969 123, is shown in Figure 2. In both prior art designs, the APU 120 is housed in a ventilated box 110, itself housed in the nacelle or the rear cone of an aircraft fuselage. The box 110, inside which the APU 120 is mounted, is ventilated by forced airflows circulating within said ventilated box. This airflow circulation is achieved by means of a first opening in the casing, located upstream of the APU 120 and called the first air inlet or cooling air inlet 111, and a second opening in the casing, located upstream of the APU 120 and called the gas generator air inlet 112 or second air inlet.The first air inlet 111 generates a cooling airflow F1 within the ventilated box 110, while the gas generator air inlet 112 generates a supply airflow F2 feeding the thermodynamic cycle of the gas generator 121 through the air inlet housing and its plenum, or cavity, hereinafter referred to as the air inlet housing 123.

[0007] According to these prior art, the APU 120 requires, for optimal operation, oil stored in the transmission 125 and cooled by means of an air / oil heat exchanger 130. In the examples of Figures 1 and 2, the air / oil heat exchanger 130 is mounted upstream of the transmission 125, also called the accessory gearbox, of the APU120. This air / oil heat exchanger 130 is offset from the transmission 125 so as to be located in the cooling airflow F1, opposite the first air inlet 111, in order to be cooled by this cooling airflow F1.

[0008] According to these prior art views, the gas generator air inlet 112 is independent of the first air inlet 111 and allows the introduction into the air inlet housing 123 of a supply airflow F2 feeding the gas generator 121 of the APU. This gas generator air inlet 112 is located directly above the exhaust gas flow G of the non-propulsive turbomachine. The exhaust gases G constitute a flow of hot gases which, upon exiting the nozzle 122, pass through an ejector 124 and create a Venturi effect that forces ventilation into the housing 110, and thus the circulation of different airflows within the housing. Indeed, during operation, the APU combustion gas, or exhaust gas G, generates, through the ejector 124, a vacuum in the ventilated box 110, this vacuum causing, by suction, a circulation of airflows within the box 110 and, in particular, a circulation of the cooling airflow F1 through the air / oil heat exchanger 130.

[0009] However, when the air / oil heat exchanger 130 is ventilated, the cooling airflow F1 is heated by contact with the oil in the exchanger; it becomes a hot airflow F5, called the heated airflow, and this heated airflow F5 circulates in the ventilated housing 110, upstream of the APU. Under the influence of the Venturi effect, the heated airflow F5 passes through and ventilates the entire housing 110, which increases the ambient temperature within the housing and consequently reduces the ventilation effect (by creating a pressure drop). This reduction in the ventilation effect is detrimental to all equipment located in the housing 110 that cannot withstand high temperatures, such as electronic equipment or electrical equipment that is continuously powered.Indeed, under the effect of a high ambient temperature, the lifespan of equipment sensitive to high temperatures tends to degrade and safety mechanisms of this equipment may be triggered, leading to the electrical shutdown of said equipment, or even the electrical shutdown of the turbomachine.

[0010] Solutions have been proposed to limit the increase in ambient temperature within the ventilated chamber. One such solution (not shown in the figures) involves installing piping at the outlet of the air / oil heat exchanger to direct the heated airflow to the ventilated chamber's ejector, thus preventing the heated airflow from being ventilated within the chamber. However, this solution requires piping to run the entire length of the ventilated chamber, resulting in significant bulk within the already limited space and adding mass, while one of the ongoing objectives in aeronautics is to reduce the aircraft's overall mass.

[0011] There is therefore a real need for a solution that addresses the problems caused by the increase in temperature throughout the ventilated enclosure, without cluttering or weighing down the enclosure. SUMMARY OF THE INVENTION

[0012] To address the aforementioned problems of temperature increase within the ventilated housing, the applicant proposes a ventilated housing in which the air / oil heat exchanger is positioned in the APU air intake housing, downstream of the transmission, to be cooled by the cooling airflow circulating in this housing.

[0013] More specifically, and according to a first aspect, the invention relates to an assembly comprising a ventilated casing and a non-propulsive turbomachine housed in said ventilated casing, in which the turbomachine includes a gas generator opening into a gas exhaust nozzle, a gearbox in which circulates oil cooled by an air / oil heat exchanger, an air inlet casing in which a cavity is provided between the gas generator and the gearbox, and the ventilated casing includes a first air inlet positioned upstream of the gearbox to inject a cooling airflow into the ventilated casing, a second air inlet positioned downstream of the gearbox to inject into the air inlet casing a supply airflow providing air to the gas generator,and an ejector positioned around the turbomachine nozzle, providing between it and said nozzle an outlet space through which air circulating around the gas generator is evacuated from said ventilated box,

[0014] This assembly is characterized by the fact that the air / oil heat exchanger is housed in the cavity of the turbomachine's air inlet housing, the oil in the air / oil heat exchanger is cooled by the supply airflow circulating in the air inlet housing and the airflow heated by the air / oil heat exchanger is exhausted out of the ventilated box.

[0015] This assembly of a non-propulsive turbomachine housed in a ventilated casing has the advantage of preventing the airflow heated by the air / oil heat exchanger from traversing the entire length of the ventilated casing; the heated airflow is expelled from the casing without being ventilated within it. With the architecture proposed, only the flow of fresh air passes through the ventilated box under the action of air suction by the Venturi effect.

[0016] In the description, the expression "housed / installed in the casing" should be understood as "housed / installed in the cavity defined by the casing".

[0017] In the description, the terms "upstream" and "downstream" are understood according to the direction of air flow in the box from the first air inlet in the box towards the exhaust gas outlet.

[0018] In addition to the characteristics mentioned in the preceding paragraph, the assembly formed by the ventilated housing and the non-propulsive turbomachine according to one aspect of the invention may have one or more of the following complementary characteristics, considered individually or in all technically possible combinations: the ventilated housing is housed in an aircraft nacelle or an aircraft fuselage tail. "Housing" shall be understood to mean a box or enclosure closed by means of several partitions (for example, six partitions) and mounted inside an aircraft fuselage or nacelle. The air / oil heat exchanger is positioned against the gearbox and connected to said gearbox through a skin of the air intake casing. The air / oil heat exchanger is positioned at least partially around a central shaft of the turbomachine's gas generator.The air / oil heat exchanger is located away from the transmission and connected to it via an external oil line system. "Lowered" means that the air / oil heat exchanger is installed at a distance from the transmission and is not attached to or placed against it. The gas generator has an inlet for the airflow heated by the air / oil heat exchanger; this heated airflow is then exhausted through the gas generator and subsequently through the turbomachine nozzle. The ventilated housing and non-propulsive turbomachine assembly includes an internal exhaust duct connecting at least the air inlet housing to... The turbomachine nozzle receives the airflow heated by the air / oil heat exchanger, which is then discharged through the internal exhaust duct and subsequently the nozzle. In this embodiment, the internal exhaust duct has an inlet located in the air intake housing and an outlet located in the nozzle. The internal exhaust duct is a degassing conduit with a first end located in the air intake housing and receiving the heated airflow, a second end located in the gearbox and receiving degassing air from said gearbox, and a third end located in the turbomachine nozzle through which the heated airflow and the degassing air are discharged. In this embodiment, the internal exhaust pipe has a first inlet housed in the air inlet housing, a second inlet housed in the transmission box and an outlet housed in the nozzle.The ventilated housing and non-propulsive turbomachine assembly includes an external exhaust duct connecting the air inlet housing to a dedicated outlet on the ventilated housing. The airflow heated by the air / oil heat exchanger is discharged directly through this dedicated outlet. The ventilated housing and non-propulsive turbomachine assembly also includes a suction device to draw the heated airflow through this dedicated outlet on the ventilated housing.

[0019] A second aspect of the invention relates to an aircraft nacelle, characterized in that it comprises an assembly according to the first aspect.

[0020] A third aspect of the invention relates to an aircraft fuselage tail, characterized in that it comprises an assembly according to the first aspect of the invention. BRIEF DESCRIPTION OF THE FIGURES

[0021] Other advantages and features of the invention will become apparent from the following description, illustrated by the figures in which:

[0022] [Fig. 1], already described, represents a schematic view of a non-propulsive turbomachine assembly housed in a ventilated casing according to the prior art;

[0023] [Fig. 2], already described, represents a schematic view of another non-propulsive turbomachine assembly housed in a ventilated casing according to the prior art;

[0024] [Fig. 3] represents a schematic view of a non-propulsive turbomachine assembly housed in a ventilated casing according to a first embodiment of the invention;

[0025] [Fig. 4] represents a schematic view of a non-propulsive turbomachine assembly housed in a ventilated casing according to a second embodiment of the invention;

[0026] [Fig. 5] represents a schematic view of a non-propulsive turbomachine assembly housed in a ventilated casing according to a third embodiment of the invention;

[0027] [Fig. 6] represents a schematic view of a non-propulsive turbomachine assembly housed in a ventilated casing according to a fourth embodiment of the invention; and

[0028] [Fig. 7] represents a schematic view of a non-propulsive turbomachine assembly housed in a ventilated casing according to a fifth embodiment of the invention.

[0029] In the figures, identical elements are identified by identical references. For the sake of readability, the size scales between represented elements are not respected. DETAILED DESCRIPTION

[0030] Examples of the realization of a non-propulsive turbomachine assembly housed in a ventilated box, allowing to limit the increase of the ambient temperature within the ventilated box, are described in detail below, with reference to the attached drawings.

[0031] The assembly according to the invention comprises a non-propulsive turbomachine 120, or APU, housed in a ventilated casing 110, itself mounted, for example, in a nacelle or in the tail, or rear cone, of an aircraft fuselage (referenced 200 in Figure 3), the wall delimiting the housing 110 being formed at least in part by a wall of the aircraft fuselage. The ventilated housing, more simply called the housing, is designed to be ventilated by fresh air from outside the housing and circulating inside it in order to cool the APU and all other equipment related to this APU. For this purpose, the housing has at least one first opening 111 and a second opening 112 forming air inlets allowing the introduction of fresh airflow, also called cooling airflow, into the housing. The housing 110 also has at least one outlet allowing the exhaust of hot gases G from the APU.As the hot gases G escape through the nozzle 122 and the ejector 124, they create a Venturi effect that generates suction within the housing 110 and, consequently, circulates airflow through said housing, thus ensuring the cooling of the APU and its equipment. In this assembly according to the invention, the air / oil heat exchanger 130 is installed in the APU air intake housing 123, between the transmission 125 and the APU gas generator 121. The air / oil heat exchanger 130 is thus cooled by the flow of fresh air circulating in the air intake housing 123, downstream of the transmission 125; the airflow F5 heated by this air / oil heat exchanger 130 is then expelled from the housing 110 without passing through the entire housing.Positioning the air / oil heat exchanger 130 within the air intake housing 123 of the APU 120 leaves the first fresh air inlet 111, located upstream of the transmission 125, unobstructed. This ensures that the cooling airflow F1 remains cool as it circulates through the upstream portion of the housing, until it reaches the APU 120 components it is designed to cool. As explained in detail in the various embodiments that follow, those skilled in the art will understand that the airflow F1 reaching the APU components to be cooled is fresh air (and not air heated by the air / oil heat exchanger as in the prior art), thus improving the cooling of the APU 120 components.

[0032] Figure 3 shows a first embodiment of the ventilated housing and APU assembly according to the invention. As described above, the APU 120 to be cooled comprises, from upstream to downstream, a gearbox 125, an air inlet housing 123, a gas generator 121, and a nozzle 122, all of which is installed in the The housing 110 has a first opening 111, or first fresh air inlet, through which a cooling airflow F1, or first fresh airflow, enters the housing 110, upstream of the APU and, in particular, the transmission 125. The housing 110 has a second opening 112, through which a supply airflow F2 enters the APU air inlet housing 123, downstream of the transmission 125. This supply airflow F2 is a fresh airflow intended to circulate within the gas generator 121 and supply the gas generator's thermodynamic cycle. The second opening 112 is therefore positioned downstream of the transmission 125 and upstream of the gas generator 121.

[0033] In the embodiment shown in Figure 3, the air / oil heat exchanger 130 is mounted in the air intake housing 123, against the transmission 125 (which contains the APU oil reservoir), so as to be positioned as close as possible to the HC / HF oil circuit of the transmission 125. This configuration of the air / oil heat exchanger 130 against the transmission 125 ensures a direct flow of oil between the transmission and the air / oil heat exchanger. Indeed, the flow of both the hot oil (HC) and the cooled oil (HF) is achieved simply through the skin 123a of the air intake housing 123, which minimizes both the length of the oil transport channels and the volume of oil required.

[0034] In this embodiment, where the air / oil heat exchanger is positioned against the transmission, said air / oil heat exchanger can be mounted integrally with the air intake housing 123 or integrally with the transmission housing 125. Its location within the air intake housing 123 is chosen to minimize disturbances to the supply airflow F2 (in particular its distortion) at the inlet of the gas generator 121. For this purpose, the air / oil heat exchanger can be placed against the skin of the air intake housing 123, against the transmission housing 125, as described above. Alternatively, the air / oil heat exchanger 130 can be positioned around or partially around the passage of the central shaft of the gas generator 121. Whichever alternative is chosen, the shape of the air / oil heat exchanger is adapted to fit the casing, i.e. the skin, of the air intake housing 123.

[0035] In the embodiment shown in Figure 3, the box 110 has a third opening 113, or third fresh air inlet, through which a A third fresh air stream F3 enters the housing 110, and specifically the air intake housing 123 of the APU. This third fresh air stream F3 cools the air / oil heat exchanger 130. To achieve this, the third opening 113 is positioned opposite the air / oil heat exchanger 130 so that the third fresh air stream F3 is directed towards said heat exchanger.

[0036] In one variant (not shown in Figure 3), the box 110 has a single second opening 112 (i.e. no third opening), this second opening 112 having relatively large dimensions allowing the introduction of a double flow of fresh air F2-F3 inside the air inlet housing 123 of the APU, the air flow F2 ensuring the supply of air to the gas generator 121 and the air flow F3 ensuring the cooling of the air / oil heat exchanger 130.

[0037] In the embodiment of Figure 3, as in its variant, once the fresh air flow F3 has passed through the air / oil heat exchanger 130, it transforms into a heated air flow F5, or hot air flow. Since the air inlet housing 123 is closed at its end 123b, the hot air flow F5 is then directed towards the gas generator 121 to contribute to its air supply before exiting the APU via the nozzle 122 and the ejector 124. Furthermore, the initial fresh air flow F1 is heated as it travels along the APU 120 and transforms into a hot air flow F4. This hot air flow F4 is evacuated from the box 110 by the ejector 124, the two hot air flows F4 and F5 therefore both evacuate downstream of the APU by the ejector 124.

[0038] Figure 4 shows a second embodiment of the ventilated housing and APU assembly according to the invention. The APU 120 and the ventilated housing 110 are identical to those described previously for the embodiment of Figure 3, only the location of the air / oil heat exchanger 130 and its connection to the transmission 125 differ from those of Figure 3. For the description of the APU 120 and the ventilated housing 110, reference may therefore be made to the description of the embodiment of Figure 3 above. Only the air / oil heat exchanger 130 will be described in connection with Figure 4.

[0039] In this embodiment of Figure 4, the air / oil heat exchanger 130, mounted in the air intake housing 123, is offset from the transmission. 125 to which it is connected by an external oil conduit system 131-132. In particular, the air / oil heat exchanger 130 is installed between the transmission 125 and the upper partition 110a of the housing 110, for example along the skin 123a of the air inlet housing 123. The air / oil heat exchanger 130 is then connected to the oil circuit of the transmission 125 by an external oil line system 131, 132 which includes, for example: an oil inlet line 131 through which the hot oil HC from the transmission 125 flows and is sent to the exchanger 130, and an oil outlet line 132 through which the cooled oil HF from the air / oil heat exchanger 130 flows and is sent to the transmission 125.

[0040] In this embodiment of Figure 4, the air / oil heat exchanger 130 has the advantage of being located close to the inlet of the third fresh air stream F3 (whether it be a third opening 113 or a large second opening 112, as described for Figure 3); the third fresh air stream F3 therefore reaches the air / oil heat exchanger 130 quickly with very little heat loss. This embodiment also allows for optimization of the shape of the air / oil heat exchanger 130 (because the constraints related to the surrounding space are less pronounced) in order to minimize airflow distortion and the impact on the performance of the gas generator. Once the third fresh air flow F3 has passed through the air / oil heat exchanger 130 and cooled the hot oil HC of said exchanger, it becomes a heated air flow F5 which is discharged via the gas generator 121 and then the ejector 124.As with the embodiment in Figure 3, the first fresh air flow F1, which has warmed up while traveling along the APU 120 and has turned into a hot air flow F4, is evacuated from the box 110 by the ejector 124.

[0041] Figure 5 shows a third embodiment of the ventilated housing and APU assembly according to the invention. The APU 120 and the ventilated housing 110 are identical to those described previously for the embodiment of Figure 3, including the location of the air / oil heat exchanger 130 and its connection to the transmission 125. In this third embodiment, only the method of exhausting the heated airflow F5 differs from that of the first embodiment. For the description of the APU 120, the ventilated box 110 and the location of the air / oil heat exchanger 130, one can therefore refer to that of the embodiment of figure 3 described previously.

[0042] In the embodiment of Figure 5, the air / oil heat exchanger 130 is mounted in the air intake housing 123, against the transmission 125, so as to be positioned as close as possible to the HC / HF oil circuit of the transmission 125. As explained for the first embodiment, this configuration of the air / oil heat exchanger 130 against the transmission 125 ensures a direct flow of oil between the transmission and the air / oil heat exchanger, through the skin 123a of the air intake housing 123. The third fresh air flow F3, which enters the air intake housing 123 through a third opening 113 or a large second opening 112 (see description of the first embodiment), ensures the cooling of the hot oil HC in the air / oil heat exchanger 130.

[0043] In this embodiment of Figure 5, the airbox and APU assembly includes an external exhaust duct 140 that connects the air intake housing 123 to a specific outlet 145 of the airbox 110. This external exhaust duct 140 extends from a first end 141 located in the air intake housing 123 near the air / oil heat exchanger to a second end 142 located outside the airbox 110, in the fuselage or nacelle 200, passing through the skin at end 123b of the air intake housing 123. This external exhaust duct 140 allows the heated airflow F5 to be discharged through an air outlet 145 in a lower bulkhead 110b of the airbox 110, which is dedicated to the air / oil heat exchanger 130. Indeed, when the third flow Fresh air F3 cooled the hot oil HC of the air / oil heat exchanger 130, it turns into a heated airflow F5 which must be evacuated out of the box 110.Evacuating it via the external exhaust pipe 140 and the specific air outlet 145 reduces the path of this heated airflow F5 within the box 110 to limit the air circulation in the box to the fresh airflow F1 intended to cool the APU and its equipment and to avoid reinjecting this heated airflow F5 into the gas generator 121.

[0044] In this embodiment of Figure 5, the assembly of the housing and APU 100 may further include a specific suction device 148, housed in the fuselage or nacelle of the aircraft, near the specific outlet 145 and having the purpose of aspirating the heated airflow F5 in order to ensure its flow out of the box 110. This aspirating device 148 can be, for example, an ejector, a fan, or any other aerodynamic device generating an air aspiration and dedicated to the external exhaust duct 140.

[0045] Figure 6 shows a fourth embodiment of the ventilated housing and APU assembly according to the invention. The APU 120 and the ventilated housing 110 are identical to those described previously for the embodiment of Figure 3, including the location of the air / oil heat exchanger 130 and its connection to the transmission 125. In this fourth embodiment, only the method of exhausting the heated airflow F5 differs from that of the first embodiment. For the description of the APU 120, the ventilated housing 110, and the location of the air / oil heat exchanger 130, reference may therefore be made to the description of the embodiment of Figure 3 shown previously.

[0046] In the embodiment of Figure 6, the air / oil heat exchanger 130 is mounted in the air intake housing 123, against the transmission 125, so as to be positioned as close as possible to the HC / HF oil circuit of the transmission 125. As explained for the first embodiment, this configuration of the air / oil heat exchanger 130 against the transmission 125 ensures a direct flow of oil between the transmission and the air / oil heat exchanger, through the skin 123a of the air intake housing 123. The third fresh air flow F3, which enters the air intake housing 123 through a third opening 113 or a large second opening 112 (see description of the first embodiment), ensures the cooling of the hot oil HC in the air / oil heat exchanger 130.

[0047] In this embodiment of Figure 6, the casing and APU assembly includes an internal exhaust duct 150 which connects the air inlet housing 123 to a dedicated air outlet 155, internal to the APU. This internal exhaust duct 150 extends from a first end 151 located in the air inlet housing 123 near the air / oil heat exchanger 130 to a second end 152 located in the nozzle 122 of the APU. The internal exhaust duct 150 passes through the side skin 123c of the air inlet housing 123 and runs alongside the gas generator 121 to the nozzle 122, into which it opens via a dedicated air outlet 155. This internal exhaust duct 150 allows the heated airflow F5 from the APU nozzle 122 to be exhausted. Indeed, when the third fresh airflow F3 cools the hot oil HC from the air / oil heat exchanger 130, transforming it into a heated airflow F5 that must be exhausted from the housing 110. Exhausting it via the internal exhaust duct 150 and the nozzle 122 allows this heated airflow F5 to be channeled along a hot zone inside the housing 110 (namely the gas generator) so that it does not mix with the fresh airflow F1 intended to cool the APU and its components. The heated airflow F5 is then exhausted along with the exhaust gases G from the gas generator 121 through the nozzle 122 and then the ejector 124.

[0048] Figure 7 shows a fifth embodiment of the ventilated housing and APU assembly according to the invention. The APU 120 and the ventilated housing 110 are identical to those described previously for the embodiment of Figure 3, including the location of the air / oil heat exchanger 130 and its connection to the transmission 125. In this fifth embodiment, only the method of exhausting the heated airflow F5 differs from that of the first embodiment. For the description of the APU 120, the ventilated housing 110, and the location of the air / oil heat exchanger 130, reference may therefore be made to the description of the embodiment of Figure 3 shown previously.

[0049] In the embodiment shown in Figure 7, the air / oil heat exchanger 130 is mounted in the air intake housing 123, against the transmission 125, so as to be positioned as close as possible to the HC / HF oil circuit of the transmission 125. As explained for the first embodiment, this configuration of the air / oil heat exchanger 130 against the transmission 125 ensures a direct flow of oil between the transmission and the air / oil heat exchanger, through the skin 123a of the air intake housing 123. The third fresh air flow F3, which enters the air intake housing 123 through a third opening 113 or a large second opening 112 (see description of the first embodiment), ensures the cooling of the hot oil HC in the air / oil heat exchanger 130.

[0050] In this embodiment of Figure 7, the housing and APU assembly includes an internal degassing duct 160 connecting the transmission 125 and the air intake housing 123 to a dedicated air outlet 165, internal to the APU. This internal degassing duct 160 has a first end 161 opening into the air intake housing 123 at the outlet of the air / oil heat exchanger 130, a second end 162 opening into the transmission 125, and a third end 163 opening into nozzle 122 of the APU. The first end 161 of the internal degassing duct 160 receives the heated airflow F5 exiting the air / oil heat exchanger 130 and directs it into the internal degassing duct 160 extending between the transmission housing 125 and the nozzle 122. This internal degassing duct 160 is a pre-existing exhaust duct in the housing 110, whose role is to degas the air from the transmission housing, namely the hot air pressurizing the bearings of the gas generator 121. The second end 162 of the internal degassing duct 160 therefore receives the hot air exiting the transmission housing 125. In this fifth embodiment, the internal degassing duct 160 not only allows the degassing of the air from the transmission housing but also the exhaust of the heated airflow F5 by the APU nozzle 122.Using the internal degassing duct 160 to vent the heated airflow F5 from the nozzle 122 increases the fluid volume in the ejector 124, thereby enhancing airflow within the housing 110 and consequently at the outlet of the air / oil heat exchanger. It also allows for a very small increase in both mass and size compared to the existing mass and dimensions of the APU 120.

[0051] In all the embodiments described above, all known types of air / oil heat exchangers can be used, such as plate heat exchangers, tubular heat exchangers, finned heat exchangers, etc.

[0052] Overall, all the embodiments described above make it possible to reduce the ambient temperature within the ventilated enclosure 110 without adding any additional mass to said ventilated enclosure, for the first embodiment, or a small mass for the other embodiments. The mass added by the ducts or pipes, when present, is less than that required in the proposed prior art solution, since the length of these ducts or pipes is significantly reduced. The same applies to the space required by the solutions of the embodiments proposed in the invention, which is much less than in the prior art solution.

[0053] In addition to the advantages mentioned above and those described in the various embodiments, the heated airflow F5 in the air inlet housing 123 of the box 110 of the invention can be used to perform a function aircraft accessory, such as the de-icing or anti-icing function of the air intake in operation.

[0054] Although described through a number of examples, variants and embodiments, the ventilated box and APU assembly according to the invention includes various variants, modifications and improvements which will be obvious to a person skilled in the art.

Claims

DEMANDS

1. Assembly (100) comprising a ventilated casing (110) and a non-propulsive turbomachine (120) housed in said ventilated casing, - the turbomachine (120) comprising a gas generator (121) opening into a gas exhaust nozzle (122), a gearbox (125) through which circulates oil cooled by an air / oil heat exchanger (130), an air intake housing (123) within which a cavity is provided between the gas generator and the gearbox, and - the ventilated housing (110) comprising a first air inlet (111) positioned upstream of the transmission to inject a cooling airflow (F1) into the ventilated housing, a second air inlet (112) positioned downstream of the transmission to inject a supply airflow (F2) into the air inlet housing (123) supplying air to the gas generator (121), and an ejector (124) positioned around the nozzle (122) of the turbomachine, providing between it and said nozzle an outlet space through which air circulating around the gas generator is evacuated from said ventilated housing, characterized in that the air / oil heat exchanger (130) is housed in the cavity of the air inlet housing (123) of the turbomachine, between the gas generator and the transmission, the oil in the air / oil heat exchanger being cooled by the supply airflow (F2) circulating in the air intake housing,and the heated airflow (F5) from the air / oil heat exchanger being exhausted from the ventilated enclosure.

2. Assembly according to claim 1, characterized in that the ventilated box (110) is housed in an aircraft nacelle (200) or an aircraft fuselage tail.

3. Assembly according to claim 1 or 2, characterized in that the air / oil heat exchanger (130) is positioned against the transmission box (125) and connected to said transmission box through a skin (123a) of the air inlet housing.

4. Assembly according to claim 3, characterized in that the air / oil heat exchanger (130) is positioned at least partially around a central shaft of the gas generator (121) of the turbomachine.

5. Assembly according to claim 1 or 2, characterized in that the air / oil heat exchanger (130) is offset from the transmission (125) and connected to said transmission via an external oil conduit system (131, 132).

6. Assembly according to any one of claims 1 to 5, characterized in that the gas generator (121) has an inlet of the heated airflow (F5) by the air / oil heat exchanger, said heated airflow being discharged by the gas generator and then the nozzle of the turbomachine.

7. Assembly according to any one of claims 1 to 5, characterized in that it comprises an internal discharge pipe (150, 160) connecting at least the air inlet housing (123) to the nozzle (122) of the turbomachine, the airflow heated (F5) by the air / oil heat exchanger being discharged through the internal discharge pipe (150, 160) and then the nozzle.

8. Assembly according to claim 7, characterized in that the internal exhaust duct is a degassing duct (160) having a first end (161) housed in the air inlet housing (123) and receiving the heated air stream (F5), a second end (162) housed in the transmission box (125) and receiving degassing air from said transmission box and a third end (163) housed in the nozzle (122) of the turbomachine and through which the heated air stream and the degassing air are discharged.

9. Assembly according to any one of claims 1 to 5, characterized in that it comprises an external exhaust duct (140) connecting the air inlet housing (123) to a specific outlet (145) of the ventilated box, the airflow heated (F5) by the air / oil heat exchanger being discharged directly through the specific outlet.

10. Assembly according to claim 9, characterized in that it comprises a suction device (148) for suctioning the flow of heated air, through the specific outlet (145) of the ventilated box.

11. Aircraft nacelle (200), characterized in that it comprises an assembly according to any one of claims 1 to 10.

12. Aircraft fuselage tail, characterized in that it comprises an assembly according to any one of claims 1 to 10.

Images