The present invention relates to a bypass turbine engine provided with a precooler.
It is known that, on board an aircraft, it is necessary to have hot air available to perform certain functions, such as air conditioning in the cockpit and the passenger cabin or for deicing certain parts of the aircraft.
It is also known that this hot air is taken from the turbine engines of the aircraft and has to be cooled significantly before it can be used. To do this, a heat exchanger is provided, this generally being known as a precooler, in which the hot air bled from the central generator of the turbojet engine is cooled by cold air bled from the fan duct, that is to say from the cold stream of the turbine engine. Such a precooler is generally housed in said fan duct, and this generates aerodynamic disturbances in said cold stream of the turbine engine.
What is more, the cold air bled from the cold stream of the turbine engine and used to cool the hot stream bled from the central generator gives rise to a current of heated cold air, which has to be discharged to the outside of the turbine engine, thus increasing the drag of the aircraft.
It is an object of the present invention to remedy the disadvantages of the prior art.
To these ends, according to the invention, the bypass turbine engine for an aircraft comprising:
Thus, by virtue of the present invention it is possible to avoid aerodynamic disturbances in the fan duct attributable to the precooler because the precooler is now housed in the rear part of said inner fairing. In addition, the disadvantages attributable to discharging the heated cold air are avoided because said precooler uses, on the outside, the cold stream leaving the fan duct and which blows said rear part of the inner fairing and, on the inside, said current of cooling air bled from said cold stream by said air intake, passing through said intermediate passage from said air intake as far as said rear orifice and discharged through said rear orifice from the intermediate chamber.
As a preference, said air intake is equipped with a controllable shut-off device. Thus, when the flight conditions are such that the desired temperature of said current of cooled hot air can be obtained using just the cold stream acting on the outside of the precooler, said air intake is closed so that no current of cooling air is bled from said cold stream.
It would be possible to provide a plurality of air intakes distributed at the periphery of the inner fairing. However, as a preference, just one single air intake is used, this being associated with means for setting said current of cooling air in rotation inside said intermediate chamber about said longitudinal axis.
As a preference, in order to obtain satisfactory areas for heat exchange between the hot air flowing through said precooler, the cold flow blowing onto the latter externally and the current of cooling air passing through the intermediate passage, provision is made for said precooler and said intermediate passage to have a shape of annular cross section extending over the entire internal periphery of said rear part of the inner fairing, about said longitudinal axis.
In a preferred embodiment of the present invention, said inner fairing is, at least in its rear part, double walled, that is to say comprises an inner wall and an outer wall which are separated from one another by a space in the form of an annular gap, and said precooler is positioned in said space.
To these ends, said precooler may comprise:
As a preference, between said distribution pipe and said collection pipe (which pipes are positioned at the internal periphery of the rear part of the inner fairing in a way that is optimized for the cooling of the hot air), said precooler comprises a plurality of curved ducts for guiding the hot air, said ducts being transverse to the longitudinal axis of the nacelle and distributed over the length of said annular space.
Such ducts may advantageously be formed by a framework that reinforces the inner fairing, secured to said inner and outer walls thereof.
Advantageously, in order to provide even finer and easier regulation of the temperature of the cooled hot air, a duct is provided, preferably equipped with a controllable valve, mounted in parallel with said precooler and connecting its hot air inlet to its cooled hot air outlet.
The figures of the attached drawing will make it easy to understand how the invention may be embodied. In these figures identical references denote elements that are similar.
The bypass turbine engine shown by each of
Positioned inside the hollow nacelle 1 are:
The inner fairing 10 and the fairing 4, external to it, between them form a fan duct 13 of annular cross section surrounding the central generator 6 and through which the cold stream 9 flows.
Formed between the inner fairing 10 and the central generator 6 are, at the front, an annular air intake slot 14, and, at the rear, an annular air discharge slot 15. Thus, the intermediate chamber 12 can be swept by a ventilation current f bled from the cold stream 9 at the front slot 14 and discharged at the boundary between said hot stream 7 and said cold stream 9 at the rear slot 15, this ventilation current f being used to regulate the temperature of the central generator 6.
Furthermore, in the usual way, the nacelle 1 is supported by a wing 17 of the aircraft (this wing is depicted in part) via a suspension pylon 18.
In the known turbine engine illustrated in
Thus, in this known layout, some of the cold stream is bled off by the precooler 19 to cool the current of hot air 20 and to generate the cooled hot air current 23 and this also results in said precooler forming a current of heated cold air (not depicted) corresponding to said bled-off portion of the cold stream. This current of heated cold air is discharged to the outside, in any known way not depicted in
It will be readily understood therefore that the presence of the precooler 19 in the fan duct 13 and the discharging of the heated cold air are detrimental to the performance of the known engine illustrated in
In the nacelle 1.1, according to the present invention and depicted in
However, in this nacelle 1.1, the precooler 19 has been replaced by a precooler 30 positioned inside the intermediate chamber 12 in thermal contact with the rear part 10R of the fairing 10. The precooler 30 has a shape of annular cross section about the axis L-L and extends over the entire periphery of this rear part 10R. In addition, the precooler 30 forms an intermediate passage 26, of annular cross section, about the axis L-L between itself and the central generator 6, said intermediate passage 26 opening to the rear via said annular air discharge slot 15.
Further, in the nacelle 1.1 of
Thus, on the outside, the precooler 30 is cooled by the cold stream 9 leaving the fan duct 13 and sweeping over the rear part 10R of the inner fairing 10 whereas, on the inside, when the air intake 27 is open, it is additionally cooled by said current of cooling air 29 passing through the intermediate passage 26 and exiting via the slot 15.
The precooler 30 has an inlet 31 connected to the duct 21 supplying the hot air current 20 and an outlet 32 connected to the duct 24 carrying the cooled hot air 23.
The exemplary embodiment of the precooler 30 which is illustrated by
As can be seen in
Furthermore, said precooler 30 comprises (see
As illustrated in
Number | Date | Country | Kind |
---|---|---|---|
0600473 | Jan 2006 | FR | national |
Filing Document | Filing Date | Country | Kind | 371c Date |
---|---|---|---|---|
PCT/FR2007/000091 | 1/18/2007 | WO | 00 | 7/7/2008 |