Connecting assembly for cooling the turbine of a turbine engine

Abstract

A connecting assembly comprising an air distribution housing, between an air inlet passage and at least one duct connected with the housing by at least one bush mounted on an orifice of a wall of the housing. The wall of the housing and an inner wall of the bush are connected by a fillet having a radius which is maximum over an angular sector.

Claims

1. A turbine engine for an aircraft, comprising: a connecting assembly comprising: a housing for distributing air between an air inlet passage of the housing and a plurality of ducts via a plurality of orifices of a first wall of the housing, a plurality of bushes, each of said plurality of bushes connecting a respective one of the plurality of ducts to a respective one of the plurality of orifices to allow air to circulate in contact with an inner wall of the respective bush and in a first direction from the housing into the respective duct, and a plurality of fillets each configured to connect an inner wall of a respective one of the plurality of bushes to a respective inside portion of said first wall of the housing, and having a radius which varies over at least a part of a perimeter of said inner wall to divert air from a second direction within the housing to the first direction, the first direction being different than the second direction; and an outer casing of a turbine of the turbine engine, about a zone of which is positioned the housing for distributing air, a second wall of which extends to be adjacent to said zone of the outer casing.

2. The turbine engine of claim 1, wherein said each of said plurality of bushes has an outer wall having a plurality of flat lugs positioned angularly, about said axis, at a distance from a zone of the perimeter where the radius of the fillet tends towards a maximum.

3. The turbine engine of claim 1, wherein: the air inlet passage and a respective orifice of each of the plurality of bushes have centers through which respective straight lines pass, and the radius of each fillet is maximum over an angular sector centered on the corresponding straight line, open towards the air inlet passage which air comes from, and ranging from 90 to 135°.

4. The turbine engine of claim 1, wherein each of the plurality of ducts has an inner diameter between 12 and 26 centimeters and the radius of the fillet varies from 0.5 to 7 centimeters.

5. The turbine engine of claim 1, wherein the radius of each of the plurality of fillets tends to a maximum at a place of a zone of the perimeter of said respective inner wall which is oriented towards the air inlet passage.

6. The turbine engine of claim 1, wherein each of the plurality of bushes is mounted on a respective orifice of the housing to be adjacent to said second wall of the housing, and has an outer wall provided, on a periphery, with at least one flat lug which, on at least one of the plurality of bushes, is positioned adjacent to said second wall of the housing, so as to position the plurality of orifices of the respective housing, the plurality of bushes, and the plurality of ducts as close to the outer casing of the turbine as possible.

7. The turbine engine of claim 1, wherein each of the plurality of bushes is mounted on a respective orifice of the housing and has, on a periphery, a plurality of flat lugs positioned angularly, about said axis, at a distance from said zone of the perimeter.

8. A turbine for a turbine engine, the turbine engine comprising: a connecting assembly comprising: a housing for distributing air between an air inlet passage of the housing and a plurality of ducts via a plurality of orifices of a first wall of the housing; a plurality of bushes, each of said plurality of bushes connecting a respective one of the plurality of ducts to a respective one of the plurality of orifices to allow air to circulate in a first direction from the housing into the respective duct; and a plurality of fillets each configured to connect an inner wall of a respective one of the plurality of bushes to a respective inside portion of said first wall of the housing, each of said plurality of fillets having a radius which varies over at least a part of a perimeter of said inner wall to change the direction of air from a second direction within the housing to the first direction, the first direction being different than the second direction; and an outer casing of the turbine, about a zone of which is positioned the housing for distributing air, a second wall of which extends to be adjacent to said zone of the outer casing.

9. The turbine of claim 8, wherein each of said plurality of bushes has an outer wall having a plurality of flat lugs positioned angularly, about said axis, at a distance from a zone of the perimeter where the radius of the respective fillet of the plurality of fillets tends towards a maximum.

10. A turbine engine for an aircraft, comprising: the turbine of claim 8, wherein each of the plurality of bushes is arranged such that air changing from the second direction to the first direction circulates in contact with an inner wall of said bush.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) If need be, the characteristics of the solutions disclosed herein will be better understood, and other details and advantages thereof will appear upon reading the following description given by way of a non restrictive example while referring to the appended drawings wherein:

(2) FIG. 1 is a schematic longitudinal section of a turbine of an aircraft turbine engine equipped with an air distribution housing according to the invention;

(3) FIG. 2 is an external local view in perspective of the elements shown in FIG. 1,

(4) FIG. 3 is a local view in reverse perspective of the air distribution housing;

(5) and FIGS. 4, 5 respectively are a section along the IV-IV line of FIG. 2 and a corresponding front view of the bush mounted there.

DETAILED DESCRIPTION

(6) FIG. 1 shows a low pressure turbine 1 of a turbine engine 10 comprising several turbine stages stepping along the axis X of the turbine engine.

(7) Each stage includes a distributor 2 having stationary vanes 3 and supported by an outer casing 4 of the turbine, and a rotor wheel 5 mounted downstream from distributor 2, and having rotating blades 6.

(8) The distributors 2 each comprise respectively internal and external walls of revolution 8 which are radially connected together by the vanes 3.

(9) The blades 6 rotate about the axis X, in a substantially truncated enclosure formed by ring sectors 7 circumferentially supported end to end by the outer casing 4 of the turbine.

(10) The rotor blades 6 are integral with a turbine shaft, and each comprises respectively external 9 and internal flanges.

(11) The internal and external walls of revolution and the external and internal flanges together define an annular jet 11 of gas flowing into the turbine.

(12) In order to control the clearance between the ends of the external flange 9 of the rotating blades 6 of the turbine, and the—stationary—outer casing 4, air is thus injected onto the outer casing, so as to control the expansion thereof according to the turbine operating conditions.

(13) Relatively cold air is supplied to the outer casing 4 through a plurality of ducts 13, which are connected to an air distribution housing 15.

(14) Beforehand, air reaches the housing 15 through a feed tube 17. The housing 15 distributes the air to the ducts 13, like a plenum chamber.

(15) The ducts 13 are perforated tubes (a few orifices 130 are illustrated in FIG. 2).

(16) Each duct 13 is connected with the housing 15 at the side walls of the housing, one 151 of which can be seen in FIGS. 1, 2, with the opposite one 153 being visible in FIG. 3.

(17) The air provided by the feed tube 17 goes into the housing 15 through an air inlet passage 155 provided in one (so-called first) wall among the side walls thereof.

(18) In the disclosed and illustrated solution, bushes 19 make it possible to connect the ducts 13 and the housing 15, through orifices 21 provided in the side walls 151 or 153 of the housing.

(19) Each bush 19 is fitted into the matching orifice 21 of the housing 15, as shown in FIG. 4.

(20) And one end of the corresponding duct 13 is mounted in the bush 19, for instance fitted into same, as shown. Brazing may be used to provide tightness.

(21) Each bush has a through passage 190 with an internal wall 191 in contact with which air can circulate, after reaching the concerned orifice 21.

(22) In FIGS. 2, 4, the arrow 23 shows the general direction of the air circulation from the air inlet passage 155 to the bush 19 concerned by FIG. 4. In such FIG. 4, the arrow 25 shows, after the curvature, the arrival of air at the matching orifice 21 and then in the bush.

(23) Transversality between the housing 15 elongation axis X1 and the axis of the bushes (refer to the axis X2 for the bush in FIGS. 4, 5) induced that, for the quality of the air circulation at the bush 19 inlet, the first wall (here 151) of the housing is connected with the internal wall 191 of the bush by a fillet 27 having a radius R which varies over at least a part of the perimeter of the internal wall 191. Such fillet is tangent. In FIG. 4, the position, at the place concerned, of the centre of the generant arc of circle, located outside the bush 19, has been marked with an O.

(24) Such fillet 27 will then provide, parallel to the axis X2, a greater flaring depth over a sector 273 of the perimeter 275 than anywhere else on such perimeter (see the depths H1, H2, H3 in FIG. 4).

(25) Such flaring depth is defined, parallel to the axis X2, by the radius R set between the two walls 151 and 191, perpendicular to each other, to be connected together. The radius R of the fillet 27 may vary as follows, on the perimeter of the orifice 21, between the smallest and the largest radius:

(26) TABLE-US-00001 inner Ø (D) of the duct 13(cm) Radius R (cm) 12 to 13. 0.5 to 3. 15 to 16. 0.5 to 4. 19 to 20. 0.5 to 5. 25 to 26. 0.5 to 7.

(27) Each duct 13 will then advantageously have an inner diameter D between 12 and 26 cm and the radius R of the fillet 27 will vary accordingly from 0.5 to 7 cm.

(28) The largest radius R1 may be set to be constant over an angular sector (reference number 273 in FIGS. 3 and 5) between 90° and 135°, preferably of the order of 120°, within 10°. The most important depth H1 will then be set in this sector.

(29) As a matter of fact, to have the air circulating in the direction 23 (FIGS. 2 and 4) change its path towards the transversal direction 25 with limited risks of separation at the inlet into the corresponding bush, when passing into the orifice 21, the radius of the fillet 27 tends to a maximum R1 at a zone of the perimeter of the internal wall corresponding to the above-mentioned sector 273 and which is oriented towards the air inlet passage 155; refer, for example to the direction 230d in FIGS. 2 and 3 and the fillet at the top of the illustration in FIG. 4 or 5.

(30) As illustrated in FIG. 3, on a housing 15, the bushes 19, and thus the orifices 21 thereof, are typically substantially aligned along a zone of the outer casing 4, at various distances from the passage 155. As illustrated in FIG. 3, it can additionally be considered that the air inlet passage 155 and the orifice 21 of each bush 19 have centres (respectively 155a and 21a to 21d in the Figure) through which respective straight lines (230a to 230d in the Figure) pass which show that the air from the air inlet passage 155 reaches the orifices 21 of the bushes 19 in various directions. The above-mentioned direction 23 is one of these.

(31) For the already mentioned purposes, and taking account of such design of the housing 15 and the internal distribution of air, it has been decided that the radius R of each fillet 27 should be maximum (R1) over an angular sector 273 centred on the corresponding straight line, open towards the air inlet passage 155 where the air comes from, and ranging from 90 to 135°, as illustrated for two bushes in FIG. 3. An angular sector of 120°, within 10°, is still preferred.

(32) The maximum (R1) value of the radius R may be constant all over the sector 273.

(33) To be positioned on, supported by the housing 15 and to be tight, the buses 19 may each have an external peripheral rim 31, at the external wall 29 thereof, toward the axial end where they have a fillet.

(34) At a distance from the sector 273 of the perimeter 275 where the flaring depth is the greatest (H1), thus of the angular zone where the radius R is maximum (R1) and may be constant, the external rim 31 is truncated by one or more flat lugs 33a, 33b, 33c (see FIG. 3) positioned angularly about the axis X2 of the through passage 190.

(35) A second advantage will be to additionally avoid affecting efficiency in the flowing of air, which is affected by the fillet. As a matter of fact, at this sector 273, the radius R1 of the fillet 27 would be truncated (which is inappropriate), if a flat lug were arranged therein.

(36) Two diametrally opposed flat lugs 33a, 33c are provided for the direction, and an angularly intermediate flat lug 33b is provided between the two other ones, for the sense.

(37) As a matter of fact, the flat lug 33b positioned diametrally opposite the angular zone where the radius R is maximum (R1) makes it easier, when positioning a bush relative to its orifice 21, to identify the angular orientation of such bush about the axis X2. The bush is thus well positioned relative to the optimal direction materialized by the corresponding straight line 230a-230d and the radius R1 is so oriented as to face the air intake 23.

(38) As for the two other angularly intermediate flat lugs 33a, 33c between the sector 273 and the flat lug 33b, they can more particularly be used to angularly move the bush, for the positioning thereof, since they are located diametrally opposite one another.

(39) Besides, such flat lugs may enable to use conventional tools (such as pliers) for positioning the bushes.

(40) Eventually, such flat lugs may make it possible to position the ducts 13 radially closer to the outer casing 4.

(41) As a matter of fact, as can be noted when comparing FIGS. 2 and 3, an elongated, transversal (so-called second) wall 157 of the air distribution housing 15 globally extends along the outer casing 4, immediately adjacent to the zone (or part) of such casing which is thus covered, so that the air leaving the passages 130 of the ducts 13 is blown onto the outer casing 4, as close thereto as possible.

(42) The transversal wall 157 of the housing 15 is globally elongated substantially parallel to the axis X.

(43) At least one flat lug, here the flat lug 33b is provided to be angularly located diametrally opposite the sector 273, so that the ducts 13 are as close as possible to the outer casing 4.

(44) FIG. 3 thus shows that, as the bushes 19 are mounted on the orifices 21, they are immediately adjacent to the second transversal wall 157 of the housing 15, with one of the flat lugs (33c in fact) being oriented towards the wall 157 in order to reduce the distance between the wall 157 and the bush considered.