Ventilating air intake arrangement

An aircraft ventilating air intake arrangement has an air passage channel and an air vent that ventilate a confined cone in an aircraft with fresh air entering the channel upstream and exiting the channel downstream towards the zone to be ventilated. A controllable blocking device enables the cross section of the channel to be varied with an elastically deformable membrane, under the action of fluid control, according to the speed and the altitude of the aircraft.

FIELD OF THE INVENTION

The present invention relates to a ventilating air intake arrangement comprising an air passage channel with an air vent, designed to ventilate at least one confined zone in a vehicle, for example an aircraft.

BACKGROUND OF THE RELATED ART

It is known that such ventilating air intake arrangements are widely used in the aeronautical field for air renewal purposes in a confined zone containing thermally sensitive equipment and/or hazardous ambient media, of the flammable or explosive type, for which it is necessary to ensure continuous ventilation of the zone in order to avoid any risk of the equipment malfunctioning or of a surrounding incident.

Such is particularly the case with the numerous mechanical and/or electrical devices provided in the annular confined space or zone between the engine nacelle and the external fan casing and the compressors of an airplane jet engine. These devices, such as, for example, the fadec (full authority digital engine control), the gearbox, the engine oil tank, the fluid components, and so on, normally fixed all around the external casing and thus located in the confined zone, are ventilated by the external air entering into the arrangement through the air vent to pass through the channel provided in the nacelle and be diffused, on exiting from the channel, in the confined zone. The devices, just like the oil or other vapors emanating from this space, are ventilated by the external fresh air diffused by the air channel, which helps to ensure that they operate correctly.

To satisfy current regulations, which impose an appropriate air renewal rate per unit of time in the confined zone concerned, the air passage channel of the arrangement has a predetermined cross section allowing the circulation of a sufficient quantity of air in the channel to ensure, at its outlet, the renewal of air in the confined zone containing the devices to be ventilated.

However, the devices to be cooled and the vapors to be expelled are not ventilated optimally by the known air intake arrangements.

In practice, in these arrangements, while the outside air entering upstream through the air vent into the channel with predetermined cross section of the arrangement and exiting downstream of the latter is sufficient to correctly ventilate the devices when the aircraft is in the taxiing phase, in a take-off phase or in a waiting phase, and therefore at low speed, on the other hand, when the aircraft is in cruising flight phase at maximum speed and altitude, the quantity of air or the air flow rate exiting from the channel of the arrangement towards the zone to be ventilated is too great. This means that the devices are cooled too much, all the more so since the temperature of the external air is very low at this cruising altitude, which can lead to malfunctions. Measurements have, moreover, shown that, in this flight phase, the air circulating in the confined zone via the channel of the arrangement was renewed twice as much as necessary, such that the fadec, in particular, is cooled excessively, which can be prejudicial to its satisfactory operation.

SUMMARY OF THE INVENTION

The object of the present invention is to remedy these drawbacks, and relates to an air intake arrangement, the design of which makes it possible to ensure optimal ventilation of a confined zone such as that above a jet engine—but which can also be a lighting zone or a central zone of the airplane (belly fairing) or, generally, any zone that is more or less closed and thermally sensitive in a vehicle for which air renewal is required.

To this end, the ventilating air intake arrangement comprising at least one air passage channel with an air vent, designed to ventilate at least one confined zone in an aircraft with fresh air entering upstream, through said air vent, into said channel and exiting downstream of the latter towards said zone to be ventilated, said air intake arrangement comprising controllable blocking means enabling the cross section of said channel to be varied, is noteworthy, according to the invention, in that said controllable blocking means comprise at least one membrane, elastically deformable under the action of a fluid control, such that the cross section of said channel varies according to the speed and the altitude of said aircraft.

Thus, with the invention, the cross section of the channel of the air intake arrangement can be varied by deformable blocking means and the air flow rate entering into the confined zone can be modified, according to the flight phases of the airplane, and therefore, the devices concerned can be optimally ventilated.

For example, when the airplane is in cruising flight (maximum speed and altitude), the cross section of the channel of the arrangement is advantageously reduced by the action of the deformable blocking means to reasonably ventilate the devices and so avoid an excessive cooling of the latter. However, when the airplane is taxiing or in a take-off phase (slow speed), the cross section of the channel is open to the maximum by the removal of said deformable blocking means, so as to have a maximum quantity of air circulate and the devices located in the confined zone appropriately ventilated.

Thus, with the invention, the quantity of air taken by the ventilating air intake arrangement is adapted to each flight phase, which minimizes the adverse effect on the performance levels of the aircraft due to the ventilation.

Furthermore, the simplicity with which the blocking means are implemented will be noted, whereby, with a volume-oriented deformation of the membrane in the channel, the cross section of the latter can be varied.

For example, said membrane is attached to a support with which it defines a variable internal volume and which is added in a fixed way to a lateral wall delimiting said channel.

Preferably, said channel has a rectangular cross section delimited by lateral walls opposing in pairs, one of the major lateral walls of said channel comprising said deformable blocking means which, when said cross section is at its maximum, are eliminated from said channel and, when said cross section is at its minimum, partially block said channel.

Said fluid control can comprise a controllable pressurized fluid source linked by a pipe to the deformable blocking means. However, in a particularly advantageous embodiment, in which said fluid control is automatic, the latter applies the total pressure (or shut-off pressure) on said aircraft of the fluid in which it moves. In this case, said fluid control comprises a link pipe, an upstream end of which takes said total pressure and the downstream end of which communicates with said deformable blocking means. This therefore constitutes a direct, independent, automatic and reliable control of the inflating of the membrane.

The upstream end of said link pipe can take said total pressure at the intake end of said air vent leading to the channel, while said downstream end of said pipe passes, in a sealed manner, through a communicating hole provided in said membrane.

The elastic deformation of said membrane can be guided axially, said link pipe serving as a guide for said membrane and being fitted perpendicularly into the center of said membrane. Thus, the deformation of the membrane is symmetrical and uniform.

Preferably, said elastically deformable membrane is circular or quadrangular, rectangular for example.

Moreover, the air intake arrangement can also comprise a protection element located at the air vent and at least partially covering said deformable blocking means.

DETAILED DESCRIPTION OF THE INVENTION

The ventilating air intake arrangement1, according to the invention and delimited by a rectangle A inFIG. 1, is provided in a nacelle2of an airplane engine3, such as a jet engine. As is diagrammatically shown inFIG. 1, the nacelle2usually comprises a front air intake part4for feeding air to the engine, a central part5surrounding the external casing7of the fan8and the compressors of the engine, and a rear part6surrounding the combustion chamber and the turbine, from which emerges the external casing of the nozzle9and its cone.

Various mechanical and/or electrical devices or items of equipment10are added to the external casing7of the fan and the compressors, namely in the confined annular space or zone11between the nacelle2and the external casing7of the engine3.FIG. 2symbolically shows some of the devices10located in this zone11, namely the fadec10A, the gearbox10B and the engine oil tank10C.

The renewal of the air in this confined zone11, to maintain the devices10in an appropriate temperature band and allow them to operate correctly, is ensured by the ventilating air intake arrangement1which is located at the top of the front part4of the nacelle2and comprises, to this end, an air passage channel12formed in the structural wall of the front part4and communicating the outside air with the confined zone11. For this, the channel12has upstream an air vent14and, downstream, a diffuser15linked with said space, opening into the central part5of the nacelle.

To optimize the ventilation, the air passage channel12is slightly inclined relative to the outer surface of the part4of the nacelle and is directed forward towards the longitudinal axis of the engine, to best take and direct the outside fresh air into the channel and then expel it tangentially via a double diffuser15, as shown by the arrows F inFIG. 2, on both sides of the annular confined space11.

The general profile of the channel12of the arrangement1represented inFIG. 3is slightly tapered, that is, after having converged after its tangential air vent14, it diverges somewhat towards the diffuser15and its cross section, delimited by the lateral walls16, is, in this example, rectangular as shown in particular byFIG. 4.

Advantageously, this cross section of the channel12is made adjustable and, to this end, the ventilating air intake arrangement1comprises deformable blocking means17with fluid control18. By varying this section, the quantity or flow of ventilating air towards the confined zone11can be reduced or increased, according to the speed and the altitude of the airplane.

In the exemplary embodiment shown inFIGS. 3 to 5, the deformable blocking means17are defined by an elastically deformable and circular membrane19, mounted on its periphery20on a flat circular edge22of a dished rigid support21forming between them an internal volume23. The dished support21and its membrane19are then fixed, by link elements24such as screws, against the corresponding circular edge16B of a circular opening16C provided for this purpose in the bottom wall16A of the channel, roughly in line with the connection between the top wall16D of the channel and the corresponding rounded edge16E of the air vent14. At this point, the cross section of the channel12with tapered profile is smaller.

The fluid control18of these deformable blocking means17is, in this embodiment, provided by a controllable pressurized fluid source25, symbolized by a rectangle and linked by a pipe or similar26, and in a sealed manner, to a communicating hole27provided in the middle of the dished rigid support21.

InFIGS. 3 to 5, the membrane19is in an inactive, flat position, merged with the bottom wall16A of the channel, such that the cross section of the channel12is at its maximum allowing a maximum air flow rate towards the zone11to be ventilated containing the devices10. Such a configuration of the membrane19is desirable in particular when the speed of the aircraft is low, particularly in the taxiing or take-off phase. The renewal of air in the confined zone is thus assured several times per unit of time.

InFIGS. 6 and 7, under the action of the pressurized source25, the fluid, such as a gas, enters into the internal volume23of the means17via the pipe26and inflates the elastically deformable membrane19. The latter takes a roughly hemispherical form until it touches the top wall16D of the channel with its summit. As can be seen in particular inFIG. 7, in this inflated position, the rectangular cross section of the channel12, designed to allow incoming outside air to pass through the air vent14, is then reduced and, in this case, at its minimum since it is reduced by the semi-circular section of the inflated membrane19compared toFIG. 4. This way, the quantity of air passing through the channel12is limited and at its minimum, which means that a lesser ventilating air flow rate is diffused into the confined zone11and in this way prevents, by the inflation of the membrane, excessive cooling of the equipment concerned10when the aircraft is in cruising flight, that is at high altitude and at high speed.

Of course, the air flow rate diffused in the zone11can be modulated between the two minimum and maximum values by acting for this purpose on the inflation of the membrane19of the blocking means, the effect of which is to modify the cross section of said channel12.

The embodiment variant of the blocking means17of the arrangement1illustrated inFIGS. 8 to 10differs in that the rigid support21and the elastically deformable membrane19are rectangular. Thus, the support21takes the form of a rectangular dish30with flat bottom31, while the membrane is mounted on the corresponding flat peripheral edge22of the support, defining with the latter the variable internal volume23. The assembly comprising support21and membrane19is fixed by screws24to the bottom wall16A of the channel, the cross section of which is still rectangular, and in a same place as previously. A communicating hole27provided in the flat bottom31of the support21allows the internal volume23to communicate with the pressurized fluid source25via the pipe26.

The operation of the deformable blocking means17for the purposes of varying the passage section of the channel12via the rectangular membrane19is, of course. similar to the previous embodiment ofFIGS. 3 to 7. A position shown by chain-dotted lines of the inflated membrane19is represented inFIGS. 8 and 9.

In a preferred embodiment variant of the arrangement1shown inFIGS. 11 and 12, the blocking means17are similar to those described previously and comprise a rectangular support21(or dish30) with flat bottom31and an elastically deformable membrane19, the assembly comprising support21and membrane19being disposed in the same way in the rectangular section channel12. However, the fluid control18, to act on the membrane, applies the total pressure on the airplane of the fluid in which it moves and comprises, in place of a pressurized fluid source25, a link pipe32, similar to a Pitot tube, an upstream end33of which is in direct contact with the outside air and the downstream end34of which opens into the internal volume23of the support-membrane assembly.

More particularly, the pipe32crosses the channel through the walls16A and16D, and its upstream end33is located in a hollow space16F in the top rounded edge16E of the channel, partly delimiting the air vent14and constituting a front edge of the arrangement1. Advantageously, at least one total pressure vent16H is provided in the wall of the top edge16E to allow the upstream end33of the pipe to communicate with the outside environment (air), and the downstream end34of the pipe passes in a sealed manner through a hole35provided in the membrane19and opening into the internal volume23.

Thus, it will be understood that the inflation of the elastically deformable membrane19is automatic according to the total pressure at the pressure vents16H, via the pipe32and the internal volume23of the blocking means17. There is thus obtained an automatic and independent adjustment of the cross section of the channel. For example, when the aircraft is at minimum speed (taking off or taxiing), the total pressure in the pipe32is low such that the membrane19is little or not at all inflated, and the air passage cross section in the channel12of the arrangement1is then at or near its maximum, allowing an appropriate ventilation of the devices10in the confined zone11.

However, when the aircraft is in cruising flight approaching maximum speed, the total pressure in the pipe32via the vents16H and then in the internal volume23is high and generates the inflation of the membrane19in the channel12and, simultaneously, a reduction in the passage cross section of the latter. Thus, the air flow rate diffused in the confined zone11is less, preventing an excessive cooling of the devices10while ensuring acceptable ventilation.

The ventilating air intake arrangement1represented inFIG. 13comprises an element36protecting the elastically deformable membrane19of the blocking means17. This element36is defined simply by a thin flexible plate37which extends from the rounded bottom edge16G of the air vent14and over the width of the channel, to the middle, at least, of the membrane. The upstream end38of the flexible plate is then hinged on the rounded bottom edge16G by screws40, while its downstream end39is free and rests elastically on the membrane. Thus, the plate37protects the membrane19from the external medium entering into the channel, optimizes the flow of the air entering into the channel12and, under its natural elastic action, returns the membrane to the deflated position when the pressure from the pipe ceases.

InFIGS. 11 to 13, the pipe32is shown crossing the channel12. Of course, it is, if necessary, possible to have said channel circumvented by the pipe32, if it is desirable for the latter not to disrupt the passage of cooling air in said channel12.

In the embodiment variant of said arrangement1represented inFIGS. 14 and 15, however, the fact that the link pipe32passes through said channel12is exploited to use as a guide for the elastically deformable membrane19when the latter passes from a deflated state to an inflated state and vice versa.

For this, the link pipe32is perpendicular to the membrane19and its downstream end34is connected to the center of the membrane to open into the internal volume23via a hole35provided in the latter. An intermediate bearing41joins the downstream end34of the pipe to the membrane19. As for the upstream end33of the pipe, it is incorporated in the corresponding wall of the rounded top edge16E delimiting the channel. Thus, during its expansion and retraction phases, the elastic membrane19retains a roughly symmetrical and uniform shape.

The variation of the cross section of the channel12for air renewal in the confined zone11according to the speed and the altitude of the airplane is, of course, similar to the embodiment described in light ofFIGS. 11 and 12.