Abstract:
Disclosed is a ventilating air intake arrangement of an aircraft. The arrangement includes at least one air duct connected to an air intake orifice. At least one confined zone connects with the air duct and the air intake orifice, and the confined zone is configured in a manner in which outside air enters through the air intake orifice. A controllable mobile element modifies the flow of air entering the confined zone by varying a cross section of the air duct. A control unit is used to control the controllable mobile element, with the control unit being arranged so as to control the controllable mobile element to vary the cross section of the at least one air duct as a function of speed and altitude of the aircraft.

Description:
FIELD OF THE INVENTION 
     The present invention relates to a ventilating air intake arrangement comprising an air duct with an air intake orifice, designed to ventilate at least one confined zone in an aircraft. 
     BACKGROUND OF THE INVENTION 
     It is known that such ventilating air intake arrangements are widely used in the aeronautical field for the purposes of replacing the air in a confined zone containing heat-sensitive equipment and/or hazardous ambient locations, of the inflammable or detonating type, for which it is necessary to provide continuous ventilation of the zone in order to prevent any risk of malfunction of the equipment or of nearby incident. 
     Such is the case in particular with many mechanical and/or electrical devices provided in the annular confined space or zone between the nacelle and the outer casing of the fan and the compressors of an aircraft turbojet. These devices, such as, for example, the fadec (full authority digital engine control), the gearbox, the engine oil tank, the fluidic components, etc., usually attached all around the outer casing and thus situated in the confined zone, are ventilated by outside air entering the arrangement via the air intake orifice to pass through the duct made in the nacelle and to diffuse, at the exit of the duct, in the confined zone. These devices, like the oil or other vapors emanating from this space, are ventilated by cool outside air diffused by the air duct, which helps to ensure that they operate correctly. 
     To satisfy the applicable regulation, which requires an appropriate rate of air replacement per unit of time of the confined zone in question, the air duct of the arrangement has a predetermined cross section allowing a sufficient quantity of air to circulate in the duct to ensure, at its exit, the replacement of air of the confined zone containing the devices to be ventilated. 
     However, the cooling devices and the vapors to be expelled are not ventilated optimally by the known air intake arrangements. 
     Specifically, in these arrangements, if the outside air entering upstream via the air intake orifice into the duct with a predetermined cross section of the arrangement and exiting downstream of the latter is sufficient to properly ventilate the devices when the aircraft is in the taxiing phase, in the take-off phase or in the holding phase, hence at low speed, on the other hand, when the aircraft is in the flight cruising phase at a maximum speed and altitude, the quantity of air or the flow of air exiting the duct of the arrangement toward the zone to be ventilated is too great. For this reason, the devices are overcooled because the temperature of the outside air is extremely low at this cruising altitude, which may lead to malfunctions. Furthermore, measures have made it possible to establish that, in this flight phase, the air circulating in the confined zone via the duct of the arrangement was replaced twice more than necessary, such that the fadec, in particular, is overcooled, which may impair its proper operation. 
     The object of the present invention is to remedy these disadvantages, and relates to an air intake arrangement whose design makes it possible to provide an optimal ventilation of a confined zone such as the one hereinabove of a turbojet, but which may also be a lights zone or a belly fairing zone or, in a general manner, any zone more or less enclosed and heat sensitive of a vehicle for which air replacement is desired. 
     SUMMARY OF THE INVENTION 
     Accordingly, the ventilating air intake arrangement comprising at least one air duct with an air intake orifice, designed to ventilate at least one confined zone in an aircraft with outside air entering upstream, through said air intake orifice, into said duct and exiting downstream of the latter toward said zone to be ventilated, said air intake arrangement comprising controllable mobile element closing means, associated with said duct, and means of controlling said controllable mobile element making it possible to vary the cross section of said duct, is notable in that said control means comprise a variable volume reservoir:
         that is connected to said controllable mobile element, and   that receives the total pressure exerted by the air on said aircraft,
 
so that the cross section of said duct varies according to the speed and altitude of said aircraft.
       

     Thus, thanks to the invention, it is possible to vary automatically the cross section of the duct of the air intake arrangement by the controllable mobile element closing means and modify, according to the flight phases of the aircraft, the flow of air entering the confined zone and, therefore, better ventilate the devices concerned. 
     For example, during aircraft cruising flight (maximum speed and altitude), the cross section of the duct of the arrangement is advantageously reduced by the actuation of the controllable mobile element of the closing means to ventilate the devices reasonably and thus prevent overcooling of the latter. On the other hand, when the aircraft is taxiing or in the take-off phase (low speed), the cross section of the duct is opened to the maximum by the retraction of the mobile element of said closing means, to thus cause a maximum quantity of air to circulate in the duct and properly ventilate the devices situated in the confined zone. 
     Thus, thanks to the invention, the quantity of air taken in by the ventilating air intake arrangement is adapted to each flight phase, which minimizes the performance penalty of the aircraft due to ventilation. 
     Said variable volume reservoir may be a cylinder/piston assembly, a bladder, a bellows, etc. that receives the total pressure exerted by the air on said aircraft and that is connected to said controllable mobile element. This total pressure is taken in on the aircraft via a pressure intake orifice and, advantageously, this pressure intake orifice is placed in the vicinity of said air intake orifice. 
     Preferably, at least one of the positions of the mobile element of said closing means, defining said minimum cross section and said maximum cross section, is defined by a stop. 
     Said controllable mobile element closing means may be situated at the entrance of said duct, at said air intake orifice, or at the exit of said duct, in a diffuser extending the latter and directing the air toward the zone to be ventilated. 
     Said mobile element of the closing means may be in several forms. For example, it may consist of an elastic plate, deformed against its own elasticity by said control means. 
     As a variant, said mobile element closing means may comprise at least one pivoting flap with a controllable rotation shaft contained in its plane and perpendicular to said air duct, so that said flap may pivot between two limit positions for which said cross sections of said duct are respectively minimal and maximal. 
     When said means are provided at the entrance of said duct, said air intake orifice may have a rectangular cross section delimited by opposite, two by two, side walls and said flap is then arranged at the rear edge of said orifice relative to the flow of air entering the latter, its rotation shaft being parallel to said rear edge. 
     Thus, when said flap is in a position extending said rear edge of the orifice while partially closing it, the cross section of the duct is minimal, allowing a minimum flow of ventilating air toward the annular space, and when it is in a position protruding outward relative to the orifice, the cross section of the duct is then maximal, allowing a maximum flow of ventilating air toward said space. 
     Advantageously, around said air intake orifice, a rectangular frame is fitted whose rear side overlaps the longitudinal rear edge of the pivoting flap and serves as a stop for the latter when it occupies one or other of its two limit positions. In addition, said frame which borders said orifice may support the rotary shaft of said pivoting flap. Thus, the frame and the flap form a one-piece assembly that may be fitted around said orifice. 
     In another embodiment, said mobile element closing means comprise at least one rotary throttle valve with a controllable rotation shaft perpendicular to said air duct and passing in its centre, so that, when said throttle valve is in a position parallel to said duct, the cross section of the latter is maximal and, when said throttle valve is in a position perpendicular to said duct, partially closing it, its cross section is minimal. 
     In this case, said throttle valve is arranged at said air diffuser of the duct and its controllable rotary shaft is supported at its ends by opposite side walls of said diffuser. 
     Preferably, stops are also provided there in said diffuser to mark the two respectively parallel and perpendicular limit positions of said throttle valve relative to said duct. 
     The figures of the appended drawing will clearly explain how the invention can be achieved. In these figures, identical reference numbers indicate similar elements. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  represents schematically and partially in section the nacelle of a turbojet furnished with a ventilating air intake arrangement sketched in the frame A, according to the invention. 
         FIG. 2  is a front view, partially in section along the line II-II of  FIG. 1 , of said nacelle of the turbojet, showing the various devices to be ventilated. 
         FIGS. 3 and 4  illustrate two variants of the arrangement according to the present invention, with different control means. 
         FIG. 5  is an enlarged longitudinal section of another embodiment with pivoting flap of said arrangement of  FIG. 1 , in a position allowing a minimum intake of ventilating air toward said space to be ventilated. 
         FIG. 6  is a top view, along the arrow F of  FIG. 5 , of said arrangement. 
         FIG. 7  is a cross section passing through the flap of said arrangement, along the line VII-VII of  FIG. 5 . 
         FIG. 8  is a section of the arrangement similar to  FIG. 5  in a position allowing a maximum intake of ventilating air. 
         FIG. 9  is a longitudinal section of yet another embodiment with a horizontal throttle valve of said arrangement, in a position allowing a minimum intake of ventilating air. 
         FIGS. 10 and 11  are respectively an end view along the arrow G and a view in section along the line XI-XI of said arrangement of  FIG. 9 . 
         FIG. 12  is a side view of the diffuser along the arrow H of  FIG. 11 . 
         FIG. 13  is a section of the arrangement similar to  FIG. 9 , in a position allowing a maximum intake of ventilating air. 
         FIG. 14  is an end view of said arrangement along the arrow J of  FIG. 13 . 
         FIG. 15  is a longitudinal section of a variant embodiment with vertical throttle valve of said arrangement, in a position allowing a maximum intake of ventilating air. 
         FIGS. 16 and 17  are respectively an end view along the arrow K and a top view along the arrow L of said arrangement of  FIG. 15 . 
         FIG. 18  is a section of the arrangement similar to  FIG. 15 , in a position allowing a minimum intake of ventilating air. 
         FIG. 19  is an end view of said arrangement along the arrow M of  FIG. 18 . 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The ventilating air intake arrangement  1 , according to the invention and delimited by a rectangle A in  FIG. 1 , is provided in a nacelle  2  of an aircraft engine  3 , such as a turbojet. As shown schematically in  FIG. 1 , the nacelle  2  comprises, as usual, a front air intake portion  4  to deliver air to the engine, an intermediate portion  5  surrounding the outer casing  7  of the fan  8 , the engine compressors and the combustion chamber and the turbine, from which emerges the outer casing of the nozzle  9  and its cone. 
     Various mechanical and/or electric items of equipment or devices  10  are fitted to the outer casing  7  of the fan and of the compressors, that is to say in the annular space or zone  11  confined between the nacelle  2  and the outer casing  7  of the engine  3 .  FIG. 2  represents symbolically certain of the devices  10  that are in this zone  11 , that is to say the fadec  10 A, the gearbox  10 B and the engine oil reservoir  10 C. 
     The replacement of the air in this confined zone  11  to keep the devices  10  in an appropriate temperature range and allow them to operate correctly is provided by the ventilating air intake arrangement  1  that is situated at the top of the front portion  4  of the nacelle  2  and comprises, for this purpose, an air duct  12  made in the structural wall of the front portion  4  of the nacelle and connecting the outside air with the confined zone  11 . For this, the duct  12  has an air intake orifice  14  upstream and, downstream, a diffuser  15  (see also  FIGS. 5 ,  8 ,  9 ,  13  and  15 ) connected with said space opening into the central portion  5  of the nacelle. 
     To optimize the ventilation, the air duct  12  is slightly inclined relative to the outer surface  4 A of the portion  4  of the nacelle and is directed downstream toward the longitudinal axis of the engine, to take in and to best conduct the cool outside air into the duct and then discharge it tangentially via the double-outlet diffuser  15 , as shown by the arrows f in  FIG. 2 , of both sides of the annular confined space  11 . 
     In the examples shown, the general profile of the duct  12  of the arrangement  1  is slightly progressive, that is to say that after having converged following its tangential air intake orifice  14 , it diverges slightly toward the diffuser  15  and its cross section, delimited by side walls  16 , is rectangular. 
     According to the present invention, this cross section of the duct  12  is rendered adjustable thanks to controllable mobile element closing means  17 . In this manner, it is possible therefore to decrease or increase the quantity or the flow of ventilating air circulating in the duct  12  toward the confined zone  11 , as a function of the speed and altitude of the aircraft, as is illustrated schematically in  FIGS. 3 and 4 . 
     In these figures, said controllable mobile element of the closing means  17  is formed by an elastic plate  6  placed in the orifice  14  over its whole width and attached to the outer surface  4 A of the front portion  4  of the nacelle. In addition, said closing means  17  shown by  FIGS. 3 and 4  comprise control means  17 A or  17 B, respectively, capable of acting automatically on said elastic plate  6  against its own elasticity. The control means  17 A of  FIG. 3  is a pneumatic cylinder, while the control means  17 B in  FIG. 4  is a bladder or bellows. The chamber of said pneumatic cylinder  17 A and the bellows  17 B are in communication, by means of a conduit  20 , with a pressure intake orifice  14 A provided on the periphery  14 B of the orifice  14  and taking in the total pressure (or pitot pressure) of the air on the nacelle  2  of the aircraft engine  3 . Naturally, in order not to disrupt the air flow inside the duct  12 , the conduit  20  may pass on the outside of the latter. 
     When this total pressure is low, the cylinder  17 A and the bellows  17 B are in a retracted position and the elastic plate  6  occupies a position  6 . 1 , butting against the cylinder  17 A or the bellows  17 B, extending the walls of the air intake orifice  14  and/or of the duct  12 . Therefore this duct  12  then has a maximum cross section allowing a maximum air flow toward the zone  11 . 
     On the other hand, when the total pressure increases, the cylinder  17 A and the bellows  17 B dilate and push the elastic plate  6  which then protrudes into the air intake orifice  14  and/or the duct  12 . Thus, depending on the value of said total pressure, the plate  6  may take a plurality of protruding positions  6 . 2  partially closing the duct  12  in consequence. When the total pressure reaches its maximum value, corresponding to the maximum speed and the maximum altitude of the aircraft, the plate  6  closes the duct  12 , so that the latter has a minimum cross section allowing a minimum air flow toward the zone  11 . 
     In the embodiment shown in  FIGS. 5 to 8 , the controllable mobile element of the closing means  17  of the arrangement  1  is defined by a pivoting flap  18  situated at the rectangular air intake orifice  14  of the duct  12  and fixedly attached to a rotation shaft  19  that can, by means of the control means  17 A or  17 B, rotate the flap  18  between two distinct limit positions for which the cross section of said duct  12  at the orifice  14  is minimal ( FIG. 5 ) or maximal ( FIG. 8 ). 
     In particular, the flap  18  is arranged, relative to the direction of flow of the outside air in the duct (arrow f,  FIG. 3 ), ahead of the rear edge  16 A of the rectangular orifice  14 , forming the connection between the outer surface  4 A of the portion  4  of the nacelle and the corresponding wall  16 B (top on  FIG. 5 ) of the duct. The rotation shaft  19  of the flap is parallel to the rear edge  16 A and, in this example, consists of two identical end-pieces  21  housed at the respective ends of an axial passageway  22  provided in the longitudinal edge  23  of the flap, turned in parallel toward the rear edge  16 A of the air intake orifice  14 . 
     As shown in particular in  FIGS. 6 and 7 , the length of the flap  18  corresponds substantially to the width of the rectangular orifice  14  and its width is naturally less than the length of said orifice for a partial closure of the latter. The end-pieces  21  are engaged respectively via holes  16 F in the opposite side walls  16 C and  16 D of the duct and thus support said flap. To provide the rotational connection of the two end-pieces  21  with the flap  18 , two pins or dowels  24  radially traverse the end-pieces and the flap. And to provide the pivoting of the flap  18  between its two limit positions, and any other intermediate position, a lever  25  is provided outside the air duct  12  and is fixedly attached in rotation to one of the end-pieces  21 . This lever  25  is connected, via a connection  26 , to the control means  17 A or  17 B. 
     In the position illustrated in  FIG. 5 , it can be seen that the flap  18 , which extends the rear edge  16 A, is contained in the plane of the air intake orifice  14  and thus partially closes the latter. In this way, the air passage cross section of the duct, at this point, delimited by the free longitudinal edge  27  of the flap and by the bottom wall  16 E and side walls  16 C and  16 D of the duct, is reduced and in this case is minimal. 
     Such a configuration of the flap  18  reducing the cross section of the duct  12  then allows a minimum air flow toward the zone  11  to be ventilated containing the devices  10  and is particularly recommended when the aircraft is in cruising flight, that is to say at high altitude and high speed, preventing the devices  10  from being overcooled. 
     Note, furthermore, in  FIGS. 5 to 7 , that, all around the air intake orifice  14  a rectangular frame  28  is fitted by screws  29 , thus delimiting said orifice. The outer rear side  30  of the frame, attached to the rear edge  16 A, partly overlaps the longitudinal edge  23  of the flap  18  and defines, as shown in  FIG. 5 , a stop  31  marking the limit position occupied by the flap and thus preventing it from pivoting further toward the left in  FIG. 5  and reducing by too much the cross section of the air duct  12 . 
     The frame  28  which borders the orifice  14  may furthermore support, via its lateral sides parallel to the walls  16 C,  16 D, the rotary shaft  19  of the pivoting flap  18  and constitute, with the latter, a one-piece assembly fitted by screwing to the portion  4  of the nacelle. 
     As shown in  FIG. 8 , under the action of the control means  17 A or  17 B and via the connection  26 , the lever  25  has pivoted angularly in the clockwise direction (angle AG), moving in its rotation the flap  18  by means of the end-pieces  21  and the pins  24 . The flap  18  then protrudes outward relative to the air intake orifice  14  and further opens the latter, so that the cross section of the duct  12  increases and is at maximum in this other limit position of the flap, allowing a maximum air flow toward the zone  11  to be ventilated containing the devices. Again, this limit position of the flap is marked by the contact of a notch  32  provided on the outer face of the edge  23  of the flap  18 , with the rear side  30  of the frame  28 , defining the stop  31 . Such a configuration of the flap  18  is particularly desirable when the speed of the aircraft is low, particularly during the taxiing, take-off or holding phases. The air in the confined zone is thus replaced several times per unit of time. 
     Naturally, thanks to the control means  17 A or  17 B, the air flow diffused into the zone  11  can be modulated between the two maximum and minimum values according to the value of the total pressure taken in by the orifice  14 A. 
     In the embodiment shown in  FIGS. 9 to 12 , the controllable mobile element closing means  17  of the arrangement  1  are defined by a rotary throttle valve  35  whose rotation shaft  36  is not only perpendicular to said duct  12  but also horizontal relative to the latter and passes in its centre. 
     More particularly, the rotary throttle valve  35  is mounted in the diffuser  15  of the duct  12 , that is to say at its exit and, as shown in  FIGS. 9 and 10 , the diffuser is attached to the rear of the portion  4  of the nacelle  2  by fastening members  37  such as screws, and its diverging double exit  15 A represented in  FIG. 11  diffuses the cool air toward the annular space  11 , of both sides of the latter. 
     Structurally, the rotary shaft  36  of the throttle valve traverses a central passageway  38  provided in the body of the throttle valve and is supported at its ends by the opposite side walls  1513 ,  15 C of the diffuser, via matching holes  15 H, made in the latter, as shown in  FIG. 11 . In a manner similar to the previous embodiment, pins or dowels  24  provide the rotational connection of the shaft  36  with the throttle valve  35 . 
     Furthermore it can be seen in  FIGS. 9 to 11  that the diffuser  15  comprises, on the inside, intermediate separating partitions  15 D through which the body of the throttle valve  35  passes axially. In addition to the fact that they make it possible to stiffen the diffuser and best channel the cool air toward the annular space  11 , the partitions  15 D define stops  15 E,  15 F for the two limit positions that may be occupied by the throttle valve  35 . 
     For example, in  FIGS. 9 to 11 , the rotary throttle valve is, under the action of the control means  17 A or  17 B, connected by the connection  26  to the external lever  25  fixedly attached to the shaft  36  ( FIG. 11 ) in a position perpendicular to the air duct  12 , so that the cross section of the latter is reduced and minimal, since it is partially closed by the wings  35 A,  35 B of the throttle valve  35 . As for the embodiment shown in  FIGS. 5 to 7 , such a configuration is recommended when the aircraft is in cruising flight, for the reasons previously given. In this limit position, one of the wings  35 A of the throttle valve then presses against one of the sides of a lug  15 G provided coaxially in each intermediate partition  15 D, thus marking said position. This side of each lug then defines the stop  15 E. 
     Dimensionally, as shown in particular in  FIGS. 10 and 11 , the width of the throttle valve is substantially equal to the corresponding horizontal dimension of the rectangular duct, while its height ( FIGS. 9 and 10 ) is less than the other, vertical, dimension of the duct, so as to allow a predetermined minimum air flow over and under the wings of the throttle valve toward the annular space, when it occupies the position illustrated in  FIGS. 10 and 11 , that is perpendicular to the flow f of the air in the duct  12 . 
     In the other of its limit positions illustrated with respect to  FIGS. 11 and 12 , under the action of the control means  17 A or  17 B having rotated the lever  25  90° (angle AG in  FIG. 12 ) and therefore the shaft  36 , the throttle valve  35  is in a horizontal position, parallel to the air duct  12 , so that the cross section of the latter is then maximal. The other wing  352  of the throttle valve, which has rotated 90°, is then pressed against the other side of the lug  15 G provided in each of the intermediate partitions  15 D, this other side defining the stop  15 F. A maximum air flow then passes through the diffuser  15  of the duct to ventilate in this way the sensitive devices  10  and other dangerous vapors that are in the annular space  11 , particularly when the speed of the aircraft is low. 
     In the variant embodiment shown in  FIGS. 15 to 17 , the controllable mobile element closing means  17  of the arrangement  1  are also defined by a rotary throttle valve  35  but its rotation shaft  36 , that is still perpendicular to said duct  12 , is then arranged vertically relative to the latter and passes in its centre. 
     In this case, the height of the throttle valve  35  is substantially equal to the corresponding vertical dimension of the rectangular duct  12 , while its width is less than the horizontal dimension of the duct, so as to allow a predetermined minimum air flow to pass both lateral sides of the wings  35 A,  35 B of the throttle valve toward the annular space, when it occupies the limit position illustrated in  FIGS. 18 and 19 , perpendicular to the duct, and a predetermined maximum air flow when it occupies the other limit position, merging with the duct, illustrated in  FIGS. 15 and 16 . 
     Structurally, this variant embodiment is similar to the preceding embodiment in that the throttle valve  35  is fixedly attached to a rotation shaft  36  supported by the side walls, in this case top and bottom  15 B,  15 C, of the diffuser  15  also attached to the rear of the portion  4  of the nacelle. At one of the ends of the rotary shaft  36 , the lever  25  is arranged rotatably connected to the shaft and able to be rotatably controlled by the moving member  17 A or  17 B via the link  26 . 
     The 90° rotation of the lever (angle AG,  FIG. 17 ) operates that of the throttle valve  35  by means of the shaft  36  via the pins  24 , which throttle valve may adopt either the position parallel to the duct ( FIGS. 15 and 16 ), for which the cross section of the duct is maximal (since the wings  35 A and  35 B are in alignment with said duct) and allows a maximum air flow toward the devices of the annular space  11 , via the diffuser  15  with double outlet  15 A, or the position perpendicular to the duct ( FIGS. 18 and 19 ) for which the cross section of the duct is minimal (since the wings of the throttle valve are perpendicular to said duct closing it partially) and allows a minimum air flow toward the annular space  11 . 
     Naturally, irrespective of the embodiments used, any other intermediate position of the mobile element (flap, throttle valve) of the closing means  17  between the two limit positions is obtained thanks to the control means  17 A and  17 B to best modulate the desired ventilating air flow by varying the cross section of the duct, mainly as a function of the speed and altitude of the aircraft.