Abstract:
The invention relates to an aircraft turbomachine comprising a nacelle and an engine comprising at least one outflowing jet of air, wherein a heat exchanger of the precooler type for supplying air to the aircraft is mounted in the nacelle, said exchanger comprising a primary circuit, the inlet of which is connected to means for taking compressed air from the engine and the outlet of which is connected to means for supplying air to the aircraft, and a secondary circuit supplied with air taken from said air flow.

Description:
TECHNICAL FIELD 
       [0001]    The present invention relates to an aircraft turbine engine, said turbine engine comprising a heat exchanger of the precooler type. 
       PRIOR ART 
       [0002]    The prior art includes US-A1-2008/230651, EP-A2-2 492 199 and US-A1-2003/218096. 
         [0003]    On board an aircraft, it is necessary to have a supply of hot air in order to be able to carry out specific functions, such as air-conditioning the cockpit and the passenger cabin or de-icing specific members of the aircraft. Said hot air comes from the turbine engine of the aircraft and must undergo significant cooling before use. For this purpose, at least one heat exchanger is provided, which is generally referred to as a precooler, in which hot air which is taken off at the engine of a turbine engine is cooled by cooler air which is taken off in the fan duct or secondary duct of said turbine engine. 
         [0004]    Each turbine engine is fixed by a strut to a portion of the aircraft, such as the fuselage thereof. In the current state of the art, the above-mentioned exchanger is mounted in the strut. Said exchanger comprises a first air circuit, the input of which is connected by a line to means for taking off hot air, and the output is connected to means for supplying hot air to the aircraft. The air is taken off at the engine and transported to the first air circuit of the exchanger through a line which passes through the secondary duct to the inside of a structural arm and is then connected to the input of said first air circuit. The exchanger comprises a second air circuit which is supplied with air which is taken off in the fan duct of the turbine engine, said air then being discharged to the outside after exchanging heat with the air from the first air circuit, for the purpose of the cooling thereof. 
         [0005]    The present invention proposes an improvement to this technology. 
       SUMMARY OF THE INVENTION 
       [0006]    The invention proposes an aircraft turbine engine, comprising a nacelle and an engine defining at least one flow duct for an air flow, characterised in that a heat exchanger of the precooler type for supplying air to the aircraft is mounted in the nacelle, said exchanger having a primary circuit, the input of which is connected to means for taking off compressed air from the engine, and the output is connected to means for supplying air to the aircraft, and a secondary circuit which is supplied with air which is taken off in said air flow. 
         [0007]    The invention thus proposes a new location for the heat exchanger or precooler, said exchanger being accommodated in the nacelle and not in the strut for connecting the turbine engine to the aircraft. Some aircraft manufacturers could indeed require said exchanger to be accommodated in the nacelle. This would make it possible in particular to facilitate access to this equipment because detaching the outer cowls from the nacelle can allow this access. In addition, it is conceivable for the exchanger to be supplied directly by the air flow which is taken off in the fan duct without it being necessary to connect said exchanger by means of a specific line to means for taking off air in said duct. The invention thus makes it possible in particular to make the technology from the prior art simpler and lighter. Furthermore, this makes it possible to reduce the number of interfaces to the strut, since it is no longer necessary to take the two cold flow and hot flow pipes as far as the strut. Only the mixed and cooled air pipe is routed as far as said strut. This thus simplifies access to the strut and thus the attachment or detachment of the propulsion system to/from the aircraft. In addition, since the strut is a fire-free region (i.e. a region which is not protected in the event of a fire), the temperature of the air and skin of the pipe must not exceed a specific value. The fact that the interfaced pipe contains air cooled by the precooler makes it possible to limit or even eliminate the use of thermal blankets (for the skin temperature) or a double-skin pipe (to contain any leaks). 
         [0008]    The exchanger is preferably fixed to an outer annular housing of the engine. 
         [0009]    The outer annular housing is preferably designed to define the inside of said flow duct for the air flow, which comes for example from a fan of the turbine engine. 
         [0010]    Advantageously, the outer annular housing is surrounded by nacelle walls and/or cowls which define an annular space around said outer annular housing, and the heat exchanger is mounted in said annular space. 
         [0011]    Said housing can comprise at least one recess for accommodating the exchanger, which is formed for example by a local deformation of the housing. This facilitates the integration of the exchanger in the nacelle. The exchanger can be fixed to a removable panel of the housing. Said panel can be designed to define said recess. It is thus conceivable, for example during a maintenance operation, to remove the exchanger by detaching the panel from the housing. 
         [0012]    The exchanger can be embedded in part in the housing and comprise a portion which protrudes from the inner surface of the housing. This protruding portion can define an input or intake for supplying air to the exchanger. 
         [0013]    Advantageously, the exchanger comprises a heat exchange block which defines said primary and secondary circuits, a scoop for taking off air in said air flow and supplying the secondary circuit, and an exhaust nozzle for discharging the air leaving the secondary circuit. The exchange block, the scoop and the exhaust nozzle can be fixed directly to one another so as to form an integral assembly. Said assembly can comprise air input and output manifolds which are connected to take-off and supply means of the primary circuit, respectively. The exchanger can further comprise a valve between the scoop and the exchange block or the exhaust nozzle, such as a valve having a flap/flaps. 
         [0014]    The input of the scoop can open radially towards the inside and/or axially upstream, and the output thereof can open axially downstream and/or radially towards the outside. The input of the exhaust nozzle can open radially towards the inside and/or axially upstream, and the output thereof can open axially downstream and/or radially towards the outside. Said housing can comprise, on a portion which is upstream of said recess, an opening which communicates with an input of said scoop. 
         [0015]    Advantageously, the dimensions of said opening are dependent on those of the scoop. This makes it possible to reduce the dimensions of the opening so as to admit into the opening an air flow rate which is equal to or very slightly greater than the flow rate of air with which the exchanger is to be supplied via the scoop. The dimensions of the opening can thus be provided to be small enough relative to the dimensions of the housing that they do not significantly affect the rigidity of the housing, even if said housing is made of composite. 
         [0016]    Preferably, the scoop protrudes at least in part into said duct so as to take off air (in the secondary duct) through the input thereof, and the exhaust nozzle comprises an output which opens out in the region of a cowl of the nacelle. The position of the scoop protruding into the duct allows the scoop to have an opening into the duct with a portion of the opening which intercepts the incident air flow. 
         [0017]    The present invention also relates to a heat exchanger of the precooler type for a turbine engine such as described above, characterised in that it comprises a heat exchange block having primary and secondary circuits, air input and output manifolds of the primary circuit, a scoop which is designed to take off air in an air flow of the turbine engine and to supply the secondary circuit, an exhaust nozzle which is designed to discharge the air from the secondary circuit, and in that the block, the scoop, the exhaust nozzle and the manifolds are fixed to one another and to a panel of the housing so as to form an integral assembly. 
         [0018]    The exchanger and the exchange block thereof are for example of the brick type. 
     
    
     
       DESCRIPTION OF THE DRAWINGS 
         [0019]    The invention will be better understood, and other details, features and advantages of the invention will become apparent upon reading the following description, given by way of non-limiting example with reference to the accompanying drawings, in which: 
           [0020]      FIG. 1  is a schematic perspective view of an aircraft turbine engine according to the invention, 
           [0021]      FIG. 2  is a schematic perspective view of a heat exchanger of the precooler type which is installed according to the invention, 
           [0022]      FIG. 3  is a schematic view in axial section of the exchanger from  FIG. 2 , 
           [0023]      FIG. 4  is a schematic perspective front view of a housing supporting an exchanger, which is embedded in part in said housing, 
           [0024]      FIG. 5  is another schematic partial view in perspective of the housing and of the exchanger from  FIG. 4 , 
           [0025]      FIG. 6  is a schematic view in axial section of the exchanger from  FIGS. 4 and 5 , 
           [0026]      FIGS. 7 and 8  are schematic perspective views of a housing comprising two removable and interchangeable panels, one of which supports an exchanger according to the invention. 
       
    
    
     DETAILED DESCRIPTION 
       [0027]    Reference is made firstly to  FIG. 1 , which shows a turbine engine  10  according to the invention for an aircraft, said turbine engine in this case being of the bypass type. The turbine engine  10  comprises an engine  12  having an outer housing  14  which defines an annular flow duct for a secondary flow. A primary flow flows inside the engine  12 . In this case, the nacelle of the turbine engine is not shown for the sake of clarity. 
         [0028]    The engine typically comprises, from upstream to downstream, in the direction of flow of the primary flow, at least one compression module, a combustion chamber, at least one turbine module and an exhaust nozzle for ejecting combustion gases. 
         [0029]    The turbine engine  10  is fixed to a portion of the aircraft, such as the fuselage thereof, by means of a strut  18 , of which only the structural elements are shown in  FIG. 1 . 
         [0030]    As explained above, hot air which is taken off at the engine is cooled by means of a heat exchanger of the precooler type and supplied to the aircraft to carry out specific functions, such as air-conditioning the cockpit and the passenger cabin or de-icing specific members of the aircraft. 
         [0031]    In the prior art as shown in  FIG. 1 , said exchanger is mounted in the strut  18  and fixed to one of the structural elements of the strut  18 . 
         [0032]    By contrast, according to the invention and as shown in particular in  FIG. 2 , the exchanger  20  is mounted in the nacelle, i.e. in a space which is formed between the nacelle and the housing  14 , and is preferably fixed to the housing  14 , as shown in  FIG. 1 . 
         [0033]    An exchanger  20  according to the invention can be seen more clearly in  FIGS. 2 and 3 . Said exchanger  20  comprises two circuits, which are primary and secondary, respectively. The primary circuit, which is also referred to as the hot circuit, has an input which is connected by at least one line  22  to means for taking off hot air at the engine  12  (for example in the compression module), the output of said primary circuit being connected by at least one other line  24  to means for supplying hot air to the aircraft. 
         [0034]    The secondary circuit, which is also referred to as the cold circuit, has an input which is connected to means for taking off air from the secondary flow of the turbine engine, the output of said circuit being connected to means for discharging air to the outside of the turbine engine. 
         [0035]    In the example shown in particular in  FIG. 2 , the exchanger  20  comprises essentially six elements: a scoop  26  forming said means for taking off air from the secondary flow, a valve  28  for regulating the flow rate of air circulating in the secondary circuit, a heat exchange block  30  comprising for example bricks which define said primary and secondary circuits, an exhaust nozzle  32  which forms the means for discharging air from the secondary circuit, and air input  34  and output  36  manifolds, respectively, of the primary circuit. 
         [0036]    In this case, the scoop  26  is fixed directly to the outer housing  14  by bolting. It comprises an input  38 , which is shown in  FIG. 3 , or intake which is surrounded by a peripheral collar  40  which is applied and fixed to the outer surface of the outer housing  14 . In the example shown, said input  38  of the scoop  26  communicates with an opening in the housing  14  and opens predominantly radially towards the inside in the flow duct  42  of the secondary flow ( FIG. 3 ). It will be noted that in the region of the input  38  thereof, the scoop  26  has an opening into the duct with a small portion of the opening which intercepts the incident air flow, the direction of the incident air being shown in  FIG. 3  by the straight line drawn below the reference numeral  42 . The output  44  of the scoop  26  is oriented substantially axially downstream. 
         [0037]    The valve  28  is mounted directly downstream of the scoop  26 . The valve is for example a valve  28  having shutters  29 , the valve comprising for example two shutters which are rotatably movable about axes which are transverse to the flow of the secondary flow in the scoop from a position for blocking the flow cross section of the valve to a position for unblocking said flow cross section. 
         [0038]    The heat exchange block  30  can be of the type used in the prior art for this application. 
         [0039]    The exhaust nozzle  32  is mounted directly in the output of the secondary circuit of the block  30 , the input  46  thereof opening predominantly axially upstream and the output  48  thereof being oriented substantially radially towards the outside. As can be seen in  FIG. 2 , the peripheral edge of the exhaust nozzle  32 , which defines the output  48 , can be equipped with a sealing joint  50  which is intended to bear radially against the inner surface of a removable outer cowl (not shown) of the nacelle. 
         [0040]    The above-mentioned six elements of the exchanger  20  in this case form an integral assembly. In the example shown in  FIG. 4 , the block  30  has a parallelepiped shape and comprises two opposing sides (upstream and downstream) which are connected to the exhaust nozzle  32  and the valve  28 , respectively, and two other opposing sides which are respectively connected to the manifolds  34 ,  36 , respectively, which are shown in  FIG. 2 . The size of the block  30  between the manifolds  34 ,  36  defines the hot run-length of the primary circuit, and the size of the block  30  between the valve  28  and the exhaust nozzle  32  defines the cold run-length of the secondary circuit. 
         [0041]    In order to allow the integration of the exchanger  20 , the housing  14  can comprise a localised recess  49  for receiving the exchanger. As a result, in  FIG. 3 , it can be seen that the flow cross section of the duct  42  is reduced in the region of the exchanger  20  due to this recess. 
         [0042]      FIGS. 4 to 6  show an alternative embodiment of the invention in which the exchanger  120  is embedded in part in the outer housing  114 , the reference numeral  117  in  FIG. 6  denoting the outer wall of the outer housing  114  which generally comprises removable cowls. 
         [0043]    The exchanger  120  comprises the same elements as the exchanger  20  described above, that is to say a scoop  126 , a valve  128 , a heat exchange block  130 , an exhaust nozzle  132  and two manifolds  134 ,  136 . 
         [0044]    In the example shown, portions of the scoop  126  and the block  130  of the exchanger  120  are embedded in the housing  114  and protrude radially inside the housing  114 . Said protruding portions are thus located in the flow duct  142  for the secondary flow of the turbine engine. The input  138  of the scoop  126  opens predominantly axially upstream. Since the incident air flow is directed towards the rear, perpendicularly to the plane in  FIG. 4 , it can be seen that the scoop has an opening onto the duct with a portion of the opening which intercepts the incident air flow. This portion of the opening is produced through the input  138  of the scoop. In this case, the output of the exhaust nozzle  132  is equipped with an exhaust grating  151 . 
         [0045]      FIGS. 7 and 8  show another alternative embodiment of the invention, in which the above-mentioned recess in the outer housing  214  is defined by a removable panel  252  which is applied and fixed to the housing in order to block an opening thereof. The panel  252  is substantially egg-shaped, the peripheral edge thereof being fixed in a sealing manner to the peripheral edge of the opening in the outer housing  214  except in the region of the upstream end portion thereof. Indeed, the peripheral edge  254  of the upstream end portion of the panel  252  is radially offset towards the inside in relation to the corresponding peripheral edge  256  of the opening, and defines, together with said edge, the input  238  of the scoop of the exchanger  220 . Said exchanger is fixed directly to the panel  252 . 
         [0046]    The outer housing  214  comprises another opening, which is identical to the above-mentioned opening, and is closed by another panel  258  which is removable and interchangeable with the panel  252 , i.e. each panel can be used to block one or the other of the openings in the housing  214 . This facilitates the integration of the exchanger in two different positions on the housing  214 . In this case, the panel  258  does not define a recess. 
         [0047]    In the example shown in  FIG. 8 , the openings which are closed by the panels  252 ,  258  are located on either side of an orifice  260  in the housing  214  for mounting the 12 oc arm (which stands for 12 o&#39;clock arm, using the analogy of a clock face) of the turbine engine. The exchanger  220  can thus be positioned on either side of said arm, which allows the exchanger to be mounted on the side of the fuselage of the aircraft for each of the lateral turbine engines of an aircraft. 
         [0048]    The operation of the heat exchanger  20 ,  120 ,  220  according to the invention is the same as that from the prior art for supplying air to an aircraft. The housing  14 ,  114 ,  214  can be made of a metal or composite.