FR3030741A1 - CANDLE GUIDE ASSEMBLY FOR TEST BENCH - Google Patents

Abstract

The test bench assembly comprises: - a candle guide (11a) comprising a fixed part (15a) removably attached to a fixed plate, and a movable part (21a), a first and a second wall delimiting between them a combustion chamber (3) having an axis X1 along which gases generally circulate, the first wall (23) being traversed by a first orifice (13a) bordered by a first rim (35a), - a candle ( 7a): - which extends, along an axis Z1 substantially perpendicular to said axis X1, through a flange to which the candle is screwed, - and which opens into the combustion chamber, through the first orifice, said part movable (21a) being traversed by the candle and being engaged with the first rim (35a), to follow, through it, the movements of the first wall of the combustion chamber following a combustion.

Description

The present invention relates to a guide-candle assembly for a test bed of a combustion chamber.

There are already test fireplaces with several fuel injection systems. These are primarily partial test benches for combustion chambers. They are intended to test a technology or a combustion chamber configuration. Modifications, tests, iterations can thus be carried out during tests in order to have a large sampling of results and thus a lot of information for a possible development of annular combustion chamber. Indeed, the test benches mentioned above are intended for the design, modification and / or testing of combustion chambers intended to be annular in operational version, on the turbomachine considered, such as a turbojet engine or an airplane turboprop engine. . A problem that has been taken into account here is the realization of a set guide candle (s) for such a test bench that is economical, convenient to use, ergonomic and whose assembly is very well adapted to the constraints tests, in particular to the mechanical stresses associated with the thermal stresses due to the combustions that must occur in the combustion chamber. It is therefore proposed that this set includes: - a candle guide comprising a fixed part comprising a flange to be removably attached to a fixed plate (of the test bench), and a movable part, - a first and a second walls delimiting between them a combustion chamber having an axis X along which gases globally circulate, during a combustion, the first wall being traversed by a first orifice bordered by a first rim on an outer face opposite to the combustion chamber - a spark plug: - which extends, along an axis Z substantially perpendicular to said axis X, through the flange to which the spark plug is screwed, - and which opens into the combustion chamber, through the first orifice, said moving part being traversed by the candle and being detachably engaged at the location of the orifice, with first rim (thus in contact with it), to follow, via this first flange, the movements of the first wall of the combustion chamber following combustion. Thus, a portion of (each) candle guide may, in connection with a combustion, follow the displacements of the combustion chamber X and Y, the X, Y and Z axes being perpendicular to each other conventionally. Typically, the tracking limit will be a few mm, especially 1-3 mm. The aforesaid first and second walls of the combustion chamber being, in the assembly in question, then hotter than said flange (s) and fixed plate, said chamber will, in operation, expand more than the fixed plate which , unlike the flange / flanges is large and therefore materialized here for the most part part of the casing, a priori external, a typical combustion chamber, operational aircraft.

For an ergonomic and practical assembly that is even more efficient and both to guide and to favor the desired movements, it is furthermore proposed that the fixed and movable parts of the candle guide in question be connected by a relative removable fixing ring which internally has a space leaving the mobile part to slide relative to said first fixed part in X and Y directions, which are respectively substantially parallel to the axis X and perpendicular to said X and Z axes. In this way, it will promote a displacement of the guide-candle regardless of the position of the candle.

To further promote differential expansion monitoring, it is recommended that the movable portion of the candle guide considered is releasably engaged by a swivel connection with the first flange of said first orifice through which the candle. Thus, articulated tracking will be possible and the movements of the guide-candle relative to the first wall of the combustion chamber further favored. In addition, the question of possible multiposition tests (typically two) of the considered candle has been taken into account, always in connection with an ergonomic approach. In this context, it is proposed that the first orifice is elongated parallel to the axis X, to allow the spark plug concerned, screwed to said first fixed part to be rotated by 1800 about an axis parallel to the Z axis and to the corresponding movable portion of the spark plug guide being rotated accordingly at the location of said first port of the first wall, thereby making it easy to test two different positions of the candle along the X axis. it may be necessary that the orifice which is traversed by the candle may or may not allow a gaseous fluid, typically air, to pass through. So it is expected that in relation to the orifice where it is engaged, the movable part of the guide-candle may include a bottom shutter which will be disposed across the orifice and which will then be crossed by the candle and preferably, next to this candle, through air passage holes. Thus, if the candle is mounted, a cooling of the latter and / or a bypass air supply of the combustion chamber can be achieved and we can thus approach real operating conditions. Another problem taken into account concerns the ability to test several operating situations in the combustion chamber. It is therefore proposed to be able to position one and the same guide-candle assembly at one or the other of at least two locations on the test stand.

More specifically, it is proposed that this set comprises: a second orifice bordered by a second rim on the outer face opposite the combustion chamber and which passes through the first wall, the second orifices provided with their flanges being identical to the first orifices; , as well as a plug adapted to completely close one or the other of the first and second orifices, which can then then indifferently receive the first movable part of the guide-candle and the candle to be tested, or the cap.

To remain in the search for economic solutions, practical use, ergonomic and mounting very well suited to the constraints of testing, it is furthermore recommended that the aforementioned plug comprises a first portion identical to the moving part of the guide-candle, and a second part: - communicating internally with the first part, - sealingly and removably attached to the first part, - and comprising a solid wall flange, to be fixed to said fixed plate and prohibiting communication between the inside of the first and second parties and outside.

If it is provided, the bottom of the shutter of the movable portion of the candle guide will however be uniformly full, to completely close the orifice at which it will be placed. Still for the same purposes as mentioned above, and in particular to facilitate mounting at the location of the orifice concerned, the ring and one end of the movable part fixed with said ring may comprise, one a tongue, the other a slot where the tongue will be engaged to prevent free rotation between the fixed and movable parts of the guide-candle. In addition to the foregoing, the invention also relates to a combustion chamber test bench comprising a plurality of said candle guides, spark plugs and orifices each bordered by a said flange, the flanges of the fixed parts of the spark plug guides being fixed in such a way removable with the fixed plate and several fuel injectors being arranged to inject fuel into the combustion chamber, generally parallel to each other and parallel to the axis X of said combustion chamber.

In this context, and in connection with the aforementioned problem related to the ability to test several operating situations in the combustion chamber, it is provided, favorably: - that each first orifice will be arranged so that the Z axis of the candle which the crossbar substantially intersects the overall direction of fuel injection into the combustion chamber by one of the injectors, and - each second orifice will be arranged so that the Z axis of the candle passing through it passes between two successive global directions injecting fuel into the combustion chamber by two successive injectors among said injectors.

If one associates with this the capacity of the candle to be rotated of 1800 around the axis Z, it will then be possible to test on the bench four positions of candle, such: two positions in the axis of the injector concerned and two positions between two successive axes of injectors. The invention will be better understood and other details, characteristics and advantages related to the invention may appear on reading the following description given by way of non-limiting example with reference to the accompanying drawings in which: - Figure 1 schematizes a partial combustion chamber test bench where two candles, among several, are schematized naked, without the rest of the assembly means (s) to test them, especially in ignition situation, in accordance with the solutions proposed here FIGS. 2,3 and 6 are detailed views where, as in other figures, the upstream (AM) and the downstream (AV) are identified in relation to the flow of gases from upstream to downstream, - Figures 5,8 are the vertical schematic sections respectively along the lines VV and VIII-VIII, except that the plug of Figure 5 is rotated by 1800 and offset downstream from which is shown in Figure 2 (Z4 / Z3 axes below), the FIG. 4 also showing the same spark plug and candle guide turned 180 ° and offset downstream with respect to what is shown in FIG. 2 (Z2 / Z1 axes below), FIG. FIG. 2, a plug and a spark plug and spark plug assembly, except that this assembly is ready to be mounted, FIG. 7 is a detail of the mounted plug, and FIG. 9 is a diagram of a test stand at Engine floor to which the invention is applicable, Box IV referring to one of Figures 4,5 or 8 for further mounting details. From particularly in Figures 1 to 3, we can see a test bench 1 for a combustion chamber 3 according to what is desired in the context of this project. This test bench 1 comprises several assemblies 5 not shown in FIG. 1 and making it possible to test several candles, such as 7a, 7b for the first two foci 8a, 8b schematized in FIG. 1. The materials used here are metallic. Figure 1, the bench comprises four foci 8a, 8b, 8c, 8d disposed linearly (Y axis) and each provided with a fuel injection system, such 9a for the focus 8a. As already indicated, these homes are primarily partial test benches. They first allow testing a combustion chamber technology or configuration. Structural and / or operating modifications of the spark plugs, injection systems and / or air supply of the combustion chamber (which can here be supplied with total pressure) can be carried out during the test in order to dispose of a large sample of results for the favorable development of an annular combustion chamber in accordance with what is in real situation, on an aircraft turbine engine.

Each set 5 comprises one or more candle guides, such as 11a, at least one candle, such 7a or 7b Figure 1 and one or more orifices, such as 13a, 131b. Figure 1, to avoid overloading the figure, each candle is shown alone, especially without its guide-candle. The objective being therefore a test of candle (s), there is, within a set 5 to guide candle, such as that mounted with the fireplace 8a and as shown in Figures 2-6 including: - a guide-candle, 11a which comprises: - a fixed part 15a provided with a flange 17a to be removably attached to a fixed plate 19 (see Figures 1.6), and a movable part 21a, - a first and a second wall , respectively 23 and 25 (Figure 1) delimiting between them the combustion chamber 3, the first wall 23 being traversed by the orifice 13a, said first orifice, - and the candle 7a screwed at 26 (Figure 4) to the fixed part 15a then provided with a tapping. Each candle, such as 7a, will extend along an axis Z (here Z1) substantially perpendicular to said axis X, through the flange to which this candle can be screwed, and lead into the combustion chamber 3 through the first corresponding orifice, here 13a. Thus, the spark plug 7a screwed along the axis Z1 (FIG. 4) and the portion 15a fixed coaxially, for example also screwed, to the plate 19 are fixed with respect to this plate, which double externally the wall 23 traversed by the spark plugs and which corresponds, in a real combustion chamber environment of a turbojet or propellant, to the annular housing, here external. The combustion chamber 3 has an axis X along which gases circulate globally, during a subsequent combustion: fuel injection via all or part of the fires 8a-8d, a suitable supply of combustion air, less around these foci (arrows 27a, 27b figures 1,4,5, the direction 27a being also the direction, substantially along the axis X1, fuel injection by the injector 90a)) - and flashing candles. In test, the combustion chamber 3 will be hotter than the fixed plate 19. Thus, in operation it will therefore expand more than the plate.

Also there is provided a capacity for movement on each guide-candle, such as 11a, between their so-called respectively fixed and mobile parts. Figure 4, we see that this arrangement will favorably include a ring, such 29a attached to a tip 31a of the fixed part 15a. The ring 29a internally has a space 33a leaving the movable portion 21a sliding relative to the fixed portion 15a along directions X1 and Y1 respectively substantially parallel to the X axis (or X1 which is parallel thereto) and perpendicular to said X and Z axes (or X1 and Z1 which are parallel to them). Thus, the guide candle can move independently of the position of the candle that passes through. Favorably, the movable portion 21a of the candle guide concerned may slide vis-à-vis the fixed part following the movements of the combustion chamber 3 substantially X and Y within the limit of about 2 mm.

For the mounting of each candle and the accompaniment of the movements of the movable part, such 21a, of the corresponding spark plug guide, it has been planned to taper the orifice, such as 13a, to allow the spark in the combustion chamber , a rim said first edge, here 35a. For sealing, as well as an optimized safety and guidance, each orifice 13a, 13b ... will preferably be entirely surrounded by such a flange which will stand on an outer face, opposite to the combustion chamber, of the wall concerned, here 23, but it could be the wall 25. Passed by the candle, the movable portion 21a of the guide-candle is, at the location of the orifice 13a concerned and removably and quite narrow, engaged with the first flange 35a, to follow, through this flange, the hot movements of the wall of the combustion chamber.

To best adapt to the differential expansion between the walls here 19 and 23, it has been preferred that the movable portion 21a of the guide plug is detachably engaged by a swivel connection 37 with the interior of the rim 35a of the orifice through which the candle passes.

For this, the axial hollow shaft 210a of the movable portion 21a ends in a bowl-shaped cross portion 212a whose upright external face 214a is convex to roll against the outer surface here flat flange 35a. Such a swiveling connection will ensure a good seal between the hearth, such 8a, and the bypass volume 39 (Figure 4) through which passes a portion of the air to feed the combustion chamber 3. The bottom, identified 216a Figure 8, of the transverse portion in bowl 212a of the candle guide 11a will be originally full, but will preferably present, in the case where it is associated with a candle, a series of holes 40a (or multi-perforations) and a passage 40b reserved for the sparkling of the candle, crossing it. To promote a cooling of the candle and complete the combustion air bypass of the combustion chamber (volume 39 then 27c power supply Figure 4) these holes 40 will be in correspondence with another series of holes 41 (multi-perforations) passing through a another (second) transverse wall 218a which doubles the first. The two transverse walls 216a, 218a are only perforated in some places and in sealing contact with both the rest of the bowl 212a and in this case the axial hollow shaft 210a of the movable portion 21a which passes through them. To also facilitate candle tests with their stresses, it is expected that the first orifice 13a which therefore receives the candle guide 11a will preferably be elongated parallel to the axis X to allow the candle screwed to said first part. fixed 15a to be, as can be seen by comparing Figures 4 and 8, rotated 180 ° around the axis Z1 and the movable portion 21 to be rotated accordingly and to replace in the recess of the flange 35a, allowing thus to test two different positions of the candle along the axis X. Besides two such positions shifted along the axis X, it can be useful to be able to test situations of candles laterally offset (linearly along the axis Y) between two successive global directions, such as X1, X2, FIGS. 2, 3, injecting the fuel into the combustion chamber 3 by two successive injectors, such as those shown schematically 90a, 90b, belonging to the injection means and each oriented to inje fuel to the combustion chamber generally parallel to each other and the X axis. It is for this purpose that orbits such as 13b are preferably provided, each being favorably bordered by a said rim, called second rim, 35b, in order to engage removably and gas-tight a plug, such 11b, which is somehow the closed double of the guide-candle, as 11a, as schematically Figures 2.5. Favorably, the second orifice 13b provided with their flanges will be identical to the first and will also be located on the outer face opposite the combustion chamber. They are adapted to completely close one or the other of the first and second orifices, which can therefore indifferently receive the first movable portion 21a of the relevant guide-plug containing the candle to be tested, or a first portion 21b of the plug considered (such 11b) identical to the movable part of the guide-plug, except the bottom shutter whose transverse walls 216b, 218b will be full, for sealing (see Figure 7).

As illustrated, it will also be preferable for: each first orifice, such as 13a, to be arranged so that the axis, such as Z1 or Z2 of the spark plug 7a, which crosses it substantially intersects the overall direction then referenced X1 of fuel injection hereby by the injector 90a, and that each second orifice, such as 13b, is arranged so that, if a set 5 with a candle and a candle-guide is mounted therein, its axis (thus that Z3, or that Z4 of the spark plug, in position offset from the axis X2 and rotated by 1800 about the axis Z3), passes between two successive global directions such X1, X2 fuel injection in the combustion chamber 3. Thus, we can to test several axial and transverse positions, such as Z1 / Z2 or Z3 / Z4, of candles, with correspondingly several plug positions of the type of that 11b. Regarding the / each plug, it will preferably include, for the sake of ease of use, ergonomics and economy, in addition to the first part 21b, a second portion 150b communicating internally with the first portion, fixed in a sealed and removable manner in the first part and comprising a flange 170b with a solid wall, to be fixed to said fixed plate 19 and prohibiting a communication between the outside and the inside of the first and second parts 21b, 150b. A ring such as that 29a mentioned above may provide the connection between the first and second parts 21b, 150b, so as to allow sliding or sliding again substantially along the axes X2, Y4, in the situation of FIG. 5. And the first part 21b will be favorably engaged tightly and removably by the swivel connection 37 with the inside of the rim 35b of said second orifice 13b that closes its transverse portions 216b, 218b background; see FIG. 7. At the bushings near the bottoms 216b, 218b, the area shown in FIG. 7 is identical for the solutions with candle and plug guides. It should also be noted that, in order to prevent free rotation between the fixed parts 15a and mobile 21a of the spark plug 11a, the ring 29a and the upper end of the movable part, surrounded, like the tip 31a of the fixed part, by the ring will preferably comprise, one a tongue 45, the other a slot 47 where the tongue will be engaged. It will be the same for the plug solution 11, as shown schematically in Figure 2 where it is further seen that the slot 47 is on the ring 29a and the tab on the upper end of the movable portion 21a. Note also the flat lateral supports 310a cooperating with a corresponding form of the ring to also provide this anti-rotation, around the axis Z1 Figure 2, gain space and limit the size of the through hole. Furthermore, in FIG. 9, there is seen a variant of a schematized ground test bench 50 which makes it possible to test, in a chamber 51, the operation of an aeronautical engine 53 maintained by a frame 55 in the X-orientation, Y, Z indicated and to which the invention applies: in a combustion chamber 3, several sets 5 allow to test several candles as explained above. Box IV, where these elements are located, also refers to one of Figures 4,5 or 8 for more details. In this case, the first wall (23) of the combustion chamber and the fixed plate (19) above should be constituted by what is usually called respectively the outer shell and the outer casing of the chamber.

Among the advantages of the above-mentioned characteristics, it will be noted: - a possible compatibility with a small chamber 3, with a short length of walls 23,25 and a distance from the fixed plate 19 (the one to which the / each candle is attached) - the possibility of keeping the maximum number of components between the candle and plug solutions, in order to reduce costs, - the possibility of testing four candle positions very close axially, avoiding leaks and projections on the wall 23 it crosses, - the possibility of favorable relative deflection between this wall 23 and the plate 19. 25

Claims (10)

REVENDICATIONS1. A candle guide assembly for a test stand (1,50), the assembly being characterized in that it comprises at least: - a candle guide (11a) comprising a fixed part (15a) comprising a flange to removably attach to a fixed plate (19), and a movable part (21a), - a first and a second wall (23,25) delimiting between them a combustion chamber (3) having an axis X along which circulate globally gases, during a combustion, the first wall (23) being traversed by a first orifice (13a) bordered by a first flange (35a) on an outer face opposite the combustion chamber, - a candle (7a ): - which extends, along an axis Z substantially perpendicular to said axis X, through the flange (17a) to which the candle is screwed, - and which opens into the combustion chamber, through the first orifice, said movable portion (21a) being traversed by the candle and being detachably engaged at the location of the orifice, ec the first rim (35a), to follow, through said first rim, the movements of the first wall of the combustion chamber following a combustion. 2. The assembly of claim 1, wherein the movable portion (21a) of the candle guide is detachably engaged by a swivel connection (37) with the first flange (35a) of said first orifice through which the candle. 3. An assembly according to claim 1 or 2 wherein the fixed and movable parts of the guide-candle (11a) are connected by a ring (29a) of relative removable attachment and which internally has a space (33a) leaving the movable portion to slide relative to said first fixed portion according todirections X and Y respectively substantially parallel to the axis X and perpendicular to said axes X and Z, the candle guide thus moving independently of the position of the candle (7a). 4. An assembly according to any one of claims 1 to 3, wherein the first hole (13a) is elongated parallel to the axis X to allow the candle screwed to said first fixed portion (15a, 17a) to be rotated from 1800 about an axis parallel to the axis Z and the movable portion (21a) of the guide-candle to be rotated accordingly at the location of said first port of the first wall, thereby to test two different positions of the candle along the X axis. 5. An assembly according to any one of the preceding claims, wherein, opposite the orifice where it is engaged, the movable portion (21a) of the guide-plug comprises a bottom closure (216a, 218a) arranged across the orifice (13a), and which is traversed by the candle (7a) and preferably, next to the candle, through air passage holes. 6. An assembly according to any one of the preceding claims, comprising: - a second orifice (13b) bordered by a second flange (35b) on the outer face opposite the combustion chamber and which passes through the first wall (23), each second orifice provided with its flange being identical to the first one (s), a plug (11b) adapted to completely close one or the other of the first and second orifices, which can therefore indifferently receive the first movable part (21a) of the guide-candle and the candle (7a) to be tested or the plug. 7. The assembly of claim 6, wherein the plug comprises a first portion (21b) identical to the movable portion (21a) of the guide-plug, except the bottom closure (216b, 218b) and a second portion (150b) communicating internally with the first portion, sealingly and removably attached to the first portion and including a solid wall flange (170b), to be attached to said fixed plate (19) and prohibiting communication between the interior of the first and second portions and outside. 8. An assembly according to claim 3 alone or in combination with one of claims 4 to 7, wherein the ring and an upper end of the movable part fixed with said ring (29a) comprise, one a tongue (45), the other a slot (47) where the tongue is engaged to prevent free rotation between the fixed and movable parts of the guide-candle. 9. Combustion chamber test bench (1,50) comprising an assembly according to one of claims 1 to 8, comprising several said guide-candles, candles and orifices (13a, 13b) each bordered by a said rim (35a, 35b), the flanges of the fixed portions of the spark plug guides (11a) being removably attached to the fixed plate (19) and a plurality of fuel injectors (90a, 90b) being arranged to inject fuel into the combustion (3), generally parallel to each other and parallel to the axis X of said combustion chamber. 10. Test bench according to claim 9, wherein: - each first orifice (13a) is arranged so that the Z axis of the spark plug (7a) therethrough substantially intersects the overall direction of fuel injection into the chamber of combustion by one of the injectors, - each second orifice (13b) is arranged so that the Z axis of the candle which passes through it passes between two successive directions (Xi, X2) of injection of the fuel into the combustion chamber by two injectors (90a, 90b) successive among said injectors.