FR3126021A1 - PASSAGE OF SERVITUDES IN AN AIRCRAFT TURBOMACHINE EXHAUST CASING - Google Patents

Abstract

Turbomachine (10) for an aircraft, this turbomachine having a longitudinal axis (A) and comprising from upstream to downstream at least one compressor (14, 16), an annular combustion chamber (18) and at least one turbine (20, 22), the turbomachine further comprising an annular exhaust casing (128) located downstream of said at least one turbine (20, 22), the exhaust casing (128) comprising two annular shrouds (72, 74) coaxial , respectively internal and external, which define between them a flow path for a gas flow and which are connected to each other by radial arms (28a) extending in this path, the internal annular shroud (72) extending at least in part around a piece of equipment which is connected to services radially crossing said section, characterized in that said services are housed in at least one radial jacket (80) located downstream of one of said arm. Figure for abstract: Figure 7

Description

PASSAGE OF SERVITUDES IN AN AIRCRAFT TURBOMACHINE EXHAUST CASING

Technical field of the invention

The present invention relates to an aircraft turbomachine equipped with an exhaust casing which is mounted around a piece of equipment and which is traversed radially by ancillary devices connected to this piece of equipment.

Technical background

The state of the art includes in particular the document FR-A1-3 104 193.

Conventionally, an aircraft turbine engine comprises, upstream to downstream, in the direction of gas flow, a fan, a low pressure compressor, a high pressure compressor, an annular combustion chamber, a high pressure turbine and a low pressure turbine. The low pressure compressor rotor is driven by the low pressure turbine rotor, and the high pressure compressor rotor is driven by the high pressure turbine rotor.

From an engine performance and fuel consumption point of view, it is advantageous to maximize the rotational speed of the low pressure turbine because this makes it possible to obtain better efficiency from the turbine. However, increasing the rotational speed of the turbine involves increasing the centrifugal forces it undergoes, and therefore greatly complicates its design.

One suggestion for increasing the efficiency of a turbine without increasing its rotational speed is to use a counter-rotating turbine. The low pressure turbine is then replaced by a turbine with two rotors, a first rotor of which is configured to rotate in a first direction of rotation and is connected to a first turbine shaft, and a second rotor is configured to rotate in an opposite direction of rotation. rotation and is connected to a second turbine shaft. The first rotor has turbine wheels sandwiched between turbine wheels of the second rotor.

A low-pressure turbine can have a take-off rotation speed of the order of 4,000 revolutions per minute in a conventional architecture where the turbine directly drives the fan or a take-off rotation speed of the order of 10,000 revolutions per minute in a architecture where the turbine drives the fan via a reducer. Its replacement by a counter-rotating turbine whose rotors turn respectively at take-off speeds of the order of 3,000 and 7,000 revolutions per minute makes it possible to have a relative speed of 10,000 revolutions per minute (3000+7000) while having an absolute speed in a low slice of the aforementioned speed range.

This counter-rotating turbine thus comprises a slow rotor and a fast rotor, the slow rotor driving the fan and the fast rotor meshing with a mechanical reduction gear with an epicyclic gear train of the planetary type, the inlet and the outlet of which are counter-rotating (rotating crown, planet carrier fixed, solar rotating).

The gearbox couples the fast rotor and the slow rotor, thus allowing a transfer of power from the fast rotor to the slow rotor. We take advantage of the higher yields of a fast turbine while transferring a large part of the power of the turbine to the fan without transiting through a reducer but through a shaft.

This architecture is complex due to its mechanical integration: the mechanical reduction gear is located downstream of the turbomachine, radially inside a stator casing called the exhaust casing. This casing comprises two coaxial annular shrouds which between them define a flow path for the flow of gas coming from the counter-rotating turbine and which are connected together by radial arms.

Moreover, the reducer releasing considerable energy (about 100kW) in operation, it must be lubricated continuously in order to maintain an acceptable operating temperature. An oil circuit is therefore implemented in order to supply the reducer with oil, its consumption possibly being high, for example of the order of 6000l/h. The evacuation of the oil is an essential problem. Indeed, it must be recovered and evacuated.

In the current technique, the oil is evacuated by pipes which cross at least two arms of the exhaust housing. These arms of the exhaust casing are tubular and oversized to allow the passage of these pipes. For this, they have a master torque or a thickness in the circumferential direction, which is greater than that of the other arms of the casing, which generates significant losses at the aerodynamic level in the vein.

This problem is also present when electrical equipment, such as an electric generator, is mounted inside a turbomachine exhaust casing, and when this equipment must be connected to services which cross the vein defined by the exhaust housing.

There is therefore a need to find a solution for optimizing the passage of oil pipes, and more generally of utilities, through the vein defined by an exhaust casing of a turbomachine, the turbomachine possibly being a conventional or specific turbomachine (eg counter-rotating turbine).

The invention proposes a turbomachine for an aircraft, this turbomachine having a longitudinal axis and comprising from upstream to downstream at least one compressor, an annular combustion chamber and at least one turbine, the turbomachine further comprising an annular exhaust casing located downstream of said at least one turbine, the exhaust casing comprising two coaxial annular shrouds, respectively internal and external, which define between them a flow path for a flow of gas and which are connected to one another the other by radial arms extending in this vein, the internal annular shroud extending at least partly around equipment which is connected to easements radially crossing said vein, characterized in that said easements are housed in at least least one radial sleeve located downstream of one of said arms.

The easements therefore no longer pass through the arms but through dedicated shirts located downstream of the arms. This makes it possible not to oversize the arms to allow the passage of the easements and therefore reduces the impact of the passage of the easements on the flow of gases in the vein.

The turbomachine according to the invention may comprise one or more of the characteristics below, taken separately from each other or in combination with each other:

• said easements are oil pipelines;
• wherein said equipment is a mechanical reducer or electrical equipment such as an electric generator;
• said shirt extends in the extension of said arm and is formed in one piece with this arm;
• said shirt extends in the extension of said arm and is attached and fixed to this arm;
• said sleeve is located at an axial distance from said arm;
• said sleeve extends between an inner ring and an outer ring which are respectively configured to be fixed to the inner and outer shells;
• said shirt is located at 6 o'clock with reference to the dial of a clock; And

- the turbomachine comprises a counter-rotating turbine located just upstream of said exhaust casing; And

- The turbomachine is of the dual-flow type, respectively primary and secondary;

- Said at least one radial jacket is located downstream of said primary flow.

Brief description of figures

The invention will be better understood and other details, characteristics and advantages of the invention will appear more clearly on reading the following description given by way of non-limiting example and with reference to the appended drawings in which:

there is a very schematic view in axial section of a counter-rotating turbine turbomachine,

there is another very schematic view of a counter-rotating turbine turbomachine,

there is a schematic perspective view of an exhaust casing according to the prior art;

there is a schematic view in axial section of the exhaust casing of the ;

there is a schematic cross-sectional view of an arm of the exhaust housing of the ;

there is a schematic perspective view of an exhaust casing according to a first embodiment of the invention;

there is a schematic view in axial section of the exhaust casing of the ;

there is a schematic perspective view of an exhaust casing according to a second embodiment of the invention;

there is a schematic view in axial section of the exhaust casing of the ;

there is a schematic perspective view of an exhaust casing according to a third embodiment of the invention;

there is a schematic view in axial section of the exhaust casing of the ;

there is a partial schematic perspective view of an exhaust casing, without a jacket to view easements; And

there is a partial schematic view in perspective of a jacket of an exhaust casing and of the services which are housed in this jacket.

Claims (10)

Turbomachine (10) for an aircraft, this turbomachine having a longitudinal axis (A) and comprising from upstream to downstream at least one compressor (14, 16), an annular combustion chamber (18) and at least one turbine (20, 22), the turbomachine further comprising an annular exhaust casing (128) located downstream of said at least one turbine (20, 22), the exhaust casing (128) comprising two annular shrouds (72, 74) coaxial , respectively internal and external, which define between them a flow path for a gas flow and which are connected to one another by radial arms (28a) extending in this path, the internal annular shroud (72) extending at least in part around an item of equipment which is connected to services radially crossing said section, characterized in that said services are housed in at least one radial jacket (80) located downstream of one of said arm. A turbomachine (10) according to claim 1, wherein said utilities are oil lines (70). A turbomachine (10) according to claim 1 or 2, wherein said equipment is a mechanical reduction gear (42) or electrical equipment such as an electric generator. Turbomachine (10) according to one of Claims 1 to 3, in which the said sleeve (80) extends in the extension of the said arm (28a) and is formed in one piece with this arm. Turbomachine (10) according to one of Claims 1 to 3, in which the said sleeve (80) extends in the extension of the said arm (28a) and is attached to and fixed on this arm. Turbomachine according to one of Claims 1 to 3, in which the said sleeve (80) is located at an axial distance from the said arm (28a). A turbomachine (10) according to claim 5 or 6, wherein said sleeve (80) extends between an inner ring (82) and an outer ring (84) which are respectively configured to be attached to the inner and outer shrouds (72, 74). Turbomachine (10) according to one of the preceding claims, in which the said sleeve (80) is located at 6 o'clock with reference to the dial of a clock. Turbomachine (10) according to one of the preceding claims, in which it comprises a counter-rotating turbine (22) located just upstream of said exhaust casing (128). Turbomachine (10) according to one of the preceding claims, in which it is of the double flow type, respectively primary and secondary, and in which the said at least one radial sleeve (80) is located downstream of the said primary flow.