Abstract:
The invention primarily relates to a turbomachine part ( 10 ) comprising a first upstream casing ( 2 ) and a second downstream casing ( 3 ), assembled to one another using at least one flange ( 6 ) formed by an upstream flange part ( 4 ) of the first upstream casing ( 2 ) and a downstream flange part ( 5 ) of the second downstream casing ( 3 ), the first upstream casing ( 2 ) and the second downstream casing ( 3 ) together at least partially delimiting the contour of an enclosure ( 30 ) in which at least one fluid (C) to be evacuated is contained, characterized in that it comprises a drainage device ( 1 ) comprising at least one drainage orifice ( 7   a,    7   b ) formed on the flange ( 6 ) connecting the first upstream casing ( 2 ) and second downstream casing ( 3 ), in particular on the upstream flange part ( 4 ) of the flange ( 6 ), allowing the discharge of said at least one fluid (C) outside the enclosure ( 30 ).

Description:
TECHNICAL FIELD 
       [0001]    The present invention relates to the field of turbomachines, and more particularly the general field of fluid drainage systems for turbomachines. 
         [0002]    The invention applies to all types of land or aeronautic turbomachines, and in particular aircraft turbomachines such as turbojet engines and turboprops. More preferably, the invention may apply to a double body and dual flow turbojet engine. 
         [0003]    It more specifically relates to a turbomachine part comprising a drainage device and a flange, as well as an associated turbomachine. 
       BACKGROUND OF THE INVENTION 
       [0004]    In the field of turbomachines, and in particular aircraft turbomachines, it may prove necessary to provide means for discharging fluids of different natures, for example such as gas, oil or water, and in particular flammable fluid residues. Such a discharge of these fluids may for example be possible to prevent them from accumulating and disrupting the operation of the turbomachines. For example, some turbomachines require bleed operations that cause fluid losses that must be recovered and treated. Furthermore, such drainage is especially necessary in the case of flammable fluids so as to prevent a fire in the turbomachines. 
         [0005]    Several solutions are already known to allow the discharge by drainage of fluids contained in a turbomachine enclosure. Preferably, the drainage of fluids is thus done at a low point of the turbomachine, in particular a low point of the enclosure. “Low point” refers to the point radially furthest from the axis of the turbomachine. To that end, the existing traditional solutions, to establish a bleed at a low point of a turbomachine enclosure, most often consist of forming drainage means on a casing of the enclosure, in particular by piercing and machining the casing to form one or more discharge orifices. 
         [0006]    As an example,  FIG. 1  diagrammatically and partially shows an example of the formation of drainage means  20   a  and  20   b , at the low point of a line of casings of a high-pressure compressor  21  and a combustion chamber  22  of a turbomachine. In this  FIG. 1 , the high-pressure compressor  21  and the drainage means  20   a  and  20   b  have been very diagrammatically shown using blocks for simplification reasons. 
         [0007]    The combustion chamber  22  comprises an annular flame tube  23 , delimited by an inner shroud  24  and an outer shroud  25  concentric to the latter part, and comprising a chamber bottom  26  in the form of a plate passed through by the injectors  27  supplied by injection conduits  28 . A compressor nozzle  29  provides the compressed air used for operation of the turbomachine by supplying a diffusion chamber  30  in which the flame tube  23  is submerged. Furthermore, as can be seen in this  FIG. 1 , the rear casing  2  of the high-pressure compressor  21  and the chamber casing  3  of the combustion chamber  22  are assembled to one another, by upstream  4  and downstream  5  flange parts, respectively. 
         [0008]    In order to ensure the discharge of any fluid residues located in the enclosure formed by the rear casing  2  of the high-pressure compressor  21  and the chamber casing  3  of the combustion chamber  22 , drainage means  20   a  and/or  20   b  can respectively be provided on the rear casing  2  of the high-pressure compressor  21  and on the chamber casing  3  of the combustion chamber  22 . These drainage means  20   a ,  20   b  must preferably be formed at the low point of the line of casings formed by the rear casing  2  and the chamber casing  3  to facilitate the drainage, in other words, in a lowest region of the line of casings, i.e., also at the point radially furthest from the axis T of the turbomachine. It is thus provided to pierce and machine the rear casing  2  to form the drainage means  20   a , and to pierce and machine the chamber casing  3  to form the drainage means  20   b.    
         [0009]    Nevertheless, the solutions of the prior art are not fully satisfactory and have several drawbacks. In fact, the formation of the drainage means on the casings of the turbomachine may have a substantial negative impact on the performance of the turbomachine. In particular, it may prove difficult to truly form drainage zones at the low point of the line of casings, which prevents obtaining optimal drainage of the fluids. Furthermore, being positioned on the casings of the turbomachine causes many constraints in producing the drainage means, and in particular in terms of mass increase, decreased lifetime of the parts, and machining difficulties to form the drainage orifices. 
       BRIEF DESCRIPTION OF THE INVENTION 
       [0010]    There is therefore a need to propose an alternative solution for a fluid drainage device for a turbomachine that is easier to implement and more reliable, while providing effective fluid drainage. 
         [0011]    The invention aims to at least partially resolve the aforementioned needs and drawbacks relative to the embodiments of the prior art. 
         [0012]    According to one aspect, the invention thus relates to a turbomachine part comprising a first upstream casing and a second downstream casing, assembled to one another using at least one flange formed by an upstream flange part of the first upstream casing and a downstream flange part of the second downstream casing, the first upstream casing and the second downstream casing together at least partially delimiting the contour of the enclosure in which at least one fluid to be evacuated is contained, characterized in that it comprises a drainage device comprising at least one drainage orifice formed on the flange connecting the first upstream casing and second downstream casing, in particular on the upstream flange part of the flange, allowing the discharge of said at least one fluid outside the enclosure. 
         [0013]    Owing to the invention, it may be possible to minimize the changes made to the turbomachine to place the drainage means for fluids to be discharged. Advantageously, the invention procures mass savings relative to the solutions previously described, and does not impose the constraints related to the machining of casings of the turbomachine to form drainage orifices, as according to the solutions of the prior art. The invention further allows an advantageous use of flanges connecting the turbomachine casings to achieve effective drainage of the fluids to be discharged, those flanges being particularly situated at the low point of the turbomachine. In this way, the invention makes it possible to ensure the discharge of the fluid residues without having a significant impact on the overall performance of the turbomachine. 
         [0014]    The turbomachine part according to the invention may further comprise one or more of the following characteristics, considered alone or according to any technically possible combination(s). 
         [0015]    The drainage orifice(s) of the drainage device are advantageously through orifices, so as to allow the circulation of the fluid(s) to be discharged. 
         [0016]    Furthermore, preferably, the turbomachine part according to the invention may be a stator turbomachine part. Also preferably, the turbomachine part according to the invention may be a turbomachine compressor part, in particular a high-pressure compressor part. In particular, the turbomachine part according to the invention may be a turbomachine high-pressure compressor stator part. 
         [0017]    The flange connecting the first upstream casing and the second downstream casing, at which the drainage device is formed, may constitute a low point of the line of casings formed by the first upstream casing and second downstream casing. As previously indicated, “low point” means that the flange may constitute the point of the line of casings formed by the first upstream casing and the second downstream casing that is radially furthest from the axis of the turbomachine. 
         [0018]    The drainage device may comprise at least one first drainage orifice, to allow the passage of said at least one fluid within the drainage device from the enclosure, and a second drainage device, to allow the discharge of said at least one fluid. The first and second drainage orifices may be formed, in particular by machining, on a flange part of the flange, in particular the upstream flange part, between two consecutive fastening orifices for screws of the flange. 
         [0019]    The first and second drainage orifices may be radially superimposed relative to one another. 
         [0020]    The first drainage orifice can be formed through the flange part in an oblique direction relative to an axial direction, in other words, relative to the axis of rotation of the turbomachine. In particular, the first drainage orifice may comprise an end emerging on the outer surface of one of the casings, in particular the first upstream casing. 
         [0021]    However, the second drainage orifice may be formed through the flange part in an axial direction, in other words, along the axis of rotation of the turbomachine. 
         [0022]    The first and second drainage orifices may have a substantially cylindrical shape, the first drainage orifice in particular having a diameter smaller than that of the second drainage orifice. 
         [0023]    The direction in which the first drainage orifice extends can form an angle with a radial direction comprised between 45 and 75°, preferably between 55 and 65°. In this way, it may be possible to avoid making the flange more fragile, in particular the upstream flange part, in particular near the curve radii. 
         [0024]    The first and second drainage orifices may further be formed through the flange part substantially midway on the distance between the two consecutive fastening orifices for the screws of the flange. In this way, it may be possible to avoid overloading the stresses on one of the two fastening orifices. It is thus possible to obtain an equivalent distribution of the stresses on each of the two consecutive fastening orifices. 
         [0025]    Furthermore, advantageously, the second drainage orifice and the two consecutive fastening orifices of the screws of the flange may be made on a same radius of the flange, i.e., they may be situated at identical distances relative to the outer periphery of the flange. In this way, it may be possible to facilitate the production of the flange, in particular the flange part comprising the drainage orifice, and in particular to facilitate the machining operations. 
         [0026]    The drainage device may comprise a basin formed, in particular by machining, on the flange part of the flange, in particular the upstream flange part, between two consecutive orifices for fastening screws of the flange, the first and second drainage orifices being formed through the basin. 
         [0027]    The basin is advantageously not a through basin. The basin may have any type of shape, and in particular a substantially oblong shape in radial section. 
         [0028]    The first drainage orifice may comprise a first through end on the outer surface of the flange part and a second through end on the basin. 
         [0029]    Likewise, the second drainage orifice may comprise a first through end on the basin and a second through end on the surface of the flange part opposite the basin. 
         [0030]    Preferably, the axial depth of the basin, i.e., the thickness of the basin measured in an axial direction, is comprised between ⅛ and ⅓ of the axial thickness (i.e., measured in an axial direction) of the flange part on which the basin is formed. 
         [0031]    In fact, if the axial depth of the basin is less than ⅛ of the axial thickness of the flange part, there is a risk of not providing the necessary flow rate for the discharge of fluid(s). Likewise, if the axial depth of the basin exceeds ⅓ of the axial thickness of the flange part, there is a risk of making the flange part more fragile. 
         [0032]    Furthermore, the radial height of the basin, i.e., the length of the basin measured in a radial direction, in other words perpendicular to the axis of rotation of the turbomachine, may be comprised between ½ and ¾ of the radial height of the flange part measured on the surface provided with the basin from the inner surface of the flange part. The radial height of the flange part may particularly be determined as a function of the position of the second drainage orifice, in particular in order to facilitate the machining of the flange part. 
         [0033]    The drainage device may comprise a drainage connector, a first end of which is fastened on the flange connecting the first upstream casing and the second downstream casing, in particular on the upstream flange part of the flange, in particular through screws of the flange, so as to ensure fluid communication between the drainage connector and said at least one drainage orifice of the drainage device, and a second end of which is designed to be connected to a drainage channel to discharge said at least one fluid, with which the drainage connector is in fluid communication. 
         [0034]    The drainage connector may for example have a generally bent shape. 
         [0035]    At its first end, the drainage connector may comprise two mounting orifices through which two successive screws of the flange can be inserted, between which said at least one drainage orifice of the drainage device is formed, so as to allow the fastening of the drainage connector on the flange, and in particular on the upstream flange part. 
         [0036]    The drainage connector may comprise a valve, in particular a flap gate, controlled so as to allow or prohibit the passage of said at least one fluid through the drainage device so that it may be discharged outside the enclosure. 
         [0037]    The valve may for example be controlled electrically and/or mechanically and/or by a pressurized fluid to allow its operation. 
         [0038]    The valve member may in particular be situated across from the second drainage orifice of the drainage device. 
         [0039]    The valve may be open when the pressure difference between the pressure in the enclosure and the pressure outside the enclosure, i.e., the pressure difference between the outer and inner zones of the line of casings formed by the first upstream casing and second downstream casing, is below a predetermined pressure threshold. 
         [0040]    The valve thus makes it possible to control the circulation of the drained fluid(s) in the drainage device. This allows precise control of the discharge moment of the drained fluids, so that they are not for example discharged upon ignition of the turbomachine. 
         [0041]    Furthermore, the diameter of the first drainage orifice, preferably with a substantially cylindrical shape, may for example be comprised, non-limitingly, between 1 and 3 mm. 
         [0042]    Likewise, the diameter of the second drainage orifice, preferably substantially cylindrical, may for example be comprised, non-limitingly, between 1 and 5 mm, more preferably still between 2 and 4 mm. The diameter of the second drainage orifice may for example be determined to ensure potential good integration with the valve of the drainage connector. 
         [0043]    According to another of its aspects, the invention also relates to a turbomachine compressor, in particular a high-pressure compressor, characterized in that it comprises a turbomachine part as previously defined. 
         [0044]    According to another of its aspects, the invention also relates to a turbomachine, characterized in that it comprises a turbomachine part as previously defined or a compressor as previously defined. 
         [0045]    The turbomachine may comprise, from upstream to downstream, a compressor, in particular a high-pressure compressor, and a combustion chamber. The first upstream casing and second downstream casing may respectively constitute a rear casing of the compressor and a chamber casing of the combustion chamber forming a line of casings at least partially delimiting the contour of an enclosure of the combustion chamber, in particular a diffusion chamber, containing at least one fluid to be discharged, in particular fuel. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWING 
         [0046]    The invention may be better understood upon reading the following detailed description of one non-limiting example embodiment thereof, as well as examining the partial and diagrammatic figures of the appended drawing, in which: 
           [0047]      FIG. 1  shows an axial sectional view of an example of the formation of fluid drainage means according to the prior art, on a line of casings of a high-pressure compressor and a combustion chamber of a turbomachine, 
           [0048]      FIG. 2  shows a partial perspective view of an example turbomachine part according to the invention comprising a drainage device formed on a flange comprising casing flange parts of a high-pressure compressor and a combustion chamber of a turbomachine, 
           [0049]      FIG. 3  shows a partial axial sectional perspective view of a detail of an embodiment of the drainage device on the upstream flange part of the flange of  FIG. 2 , 
           [0050]      FIG. 4  shows, partially in radial section, the upstream flange part of the flange of  FIG. 2  at the drainage device, and 
           [0051]      FIG. 5  shows, partially in axial section, the upstream flange part of the flange of  FIG. 2  at the drainage device. 
       
    
    
       [0052]    In all of these figures, identical references may designate identical or similar elements. 
         [0053]    Furthermore, the different parts shown in the figures are not necessarily shown using a uniform scale, to make the figures more legible. 
       DETAILED DESCRIPTION OF THE INVENTION 
       [0054]    Throughout the description, it is noted that the terms “upstream” and “downstream” should be considered relative to a main normal flow direction F of the gases (from upstream to downstream) for a turbomachine. Furthermore, the axis of the turbomachine refers to the radial axis of symmetry of the turbomachine. The axial direction of the turbomachine corresponds to the direction of the axis T of the turbomachine. A radial direction of the turbomachine is a direction perpendicular to the axis T of the turbomachine. Furthermore, unless otherwise specified, the adjectives and adverbs “axial”, “radial”, “axially” and “radially” are used in reference to the aforementioned axial and radial directions. Furthermore, unless otherwise specified, the terms “inner” and “outer” are used in reference to a radial direction, such that the inner part of an element is closer to the axis T of the turbomachine than the outer part of the same element. 
         [0055]      FIG. 1  has already been described above with regard to the part relative to the prior state of the art. 
         [0056]    In reference to  FIGS. 2 to 5 , we will now describe one example embodiment of a turbomachine part  10  according to the invention, comprising a drainage device  1  formed at flange  6 . 
         [0057]    More specifically,  FIG. 2  shows, in a partial perspective view, the turbomachine part  10  comprising the flange  6  provided with the drainage device  1 . 
         [0058]      FIGS. 3 ,  4  and  5  show, in axial sectional perspective view, radial sectional view and axial sectional view, respectively, the upstream flange part  4  of the flange  6  of  FIG. 2  at the drainage device  1 . 
         [0059]    In the example embodiment of the turbomachine part  10  described below, it is considered that the latter is a stator part of a high-pressure compressor  21 , this turbomachine part  10  thus comprising a first upstream casing  2  and a second downstream casing  3  together forming a line of casings of the high-pressure compressor  21  and a combustion chamber  22 , similarly to what has been previously described in reference to  FIG. 1 . In particular, the first upstream casing  2  constitutes a rear casing  2  of the high-pressure compressor  21 , and the second downstream casing  3  constitutes a chamber casing  3  of the combustion chamber  22 . In this way, the elements of the turbomachine part  10  already described above in reference to  FIG. 1  are not covered again below. Of course, this choice is in no way limiting, and the turbomachine part  10  could be different from a part situated at a high-pressure compressor  21  and a combustion chamber  22 . 
         [0060]    As described in reference to  FIG. 1 , the first upstream casing  2  comprises an upstream flange part  4  and the second downstream casing  3  comprises a downstream flange part  5 , the upstream  4  and downstream  5  flange parts forming the flange  6  as shown in  FIG. 2 . That  FIG. 2  also shows the drainage device  1  making it possible to discharge one or more fluids contained in the enclosure  30  (see  FIG. 1 ) outside the enclosure  30 , so as to ensure the drainage, required in some cases, of the residual fluid(s). Furthermore, the screws  11  of the flange  6  are also shown. 
         [0061]    Advantageously, placing the drainage device  1  directly at the flange  6  can make it possible to form the drainage for the fluid(s) to be discharged from the low point of the line of casings formed by the first upstream casing  2  and second downstream casing  3 , without creating the constraints previously described relative to the solutions of the prior art. 
         [0062]    As can be seen in  FIGS. 3 ,  4  and  5 , the drainage device  1 , formed on the upstream flange part  4  of the flange  6 , comprises a first drainage orifice  7   a , to allow the passage of the fluid C within the drainage device  1  from the enclosure  30 , and a second drainage orifice  7   b , to allow the discharge of fluid C outside the enclosure  30 . In this way, the first  7   a  and second  7   b  drainage orifices are through orifices. 
         [0063]    Furthermore, as can be seen in particular in  FIG. 4 , first  7   a  and second  7   b  drainage orifices are formed on the upstream flange part  4  between two consecutive fastening orifices  12  for the screws  11  of the flange  6 . Furthermore, these first  7   a  and second  7   b  drainage orifices are in particular radially superimposed relative to one another. 
         [0064]    Furthermore, as can be seen in  FIGS. 3 ,  4  and  5 , the drainage device  1  further comprises a basin  8  formed on the upstream flange part  4  between two consecutive fastening orifices  12  of the screws  11  of the flange  6 . The first  7   a  and second  7   b  drainage orifices are formed through that basin  8 . 
         [0065]    The basin  8  is advantageously not a through basin and for example has, in radial section, a substantially oblong shape. 
         [0066]    Furthermore, the drainage device  1  also comprises a drainage connector  9 , shown in  FIG. 2 , a first end  9   a  of which is fastened on the upstream side part  4  by screws  11  of the flange  6 , so as to be able to provide fluid communication between the drainage connector  9  and the second drainage orifice  7   b  of the drainage device  1 , and whereof the second end  9   b  of the drainage connector  9  is connected to a drainage channel  13  that makes it possible to discharge the fluid(s) C to be drained, the second end  9   b  being in fluid communication with the drainage channel  13 . 
         [0067]    The drainage connector  9  can, as shown in  FIG. 2 , have a generally bent shape. Furthermore, the drainage connector  9  comprises, at its first end  9   a , two mounting orifices  14   a  and  14   b  through which two successive screws  11  of the flange  6  are inserted, such that the drainage connector  9  is fastened to the upstream flange part  4 . 
         [0068]    Advantageously, although not shown, the drainage connector  9  also comprises a valve, in particular a flap gate, that is controlled so as to allow or prohibit the passage of the fluid(s) C from the drainage device  1  so that they may be discharged outside the enclosure  30 . 
         [0069]    In particular, the flap gate may be formed at the second drainage orifice  7   b  of the drainage device  1 . 
         [0070]    The opening and closing of the flap gate may be controlled in different ways. In particular, in order to limit the performance losses during normal operation of the turbomachine part  10 , the flap gate may be opened when the pressure difference between the pressure in the enclosure  30  and the pressure outside the enclosure  30 , in other words, the pressure difference between the outer and inner zones at the line of casings formed by the first upstream casing  2  and second upstream casing  3 , is below a predetermined pressure threshold. In this way, the valve may make it possible to precisely control the discharge moment of the drained fluids so that they are not discharged in certain operating scenarios of the turbomachine. 
         [0071]    Furthermore, as can be seen in particular in  FIGS. 3 and 5 , the first drainage orifice  7   a  can be formed through the upstream flange part  4  in an oblique direction relative to an axial direction. In particular, as shown in  FIG. 5 , the direction in which the first drainage orifice  7   a  extends forms an angle α with a radial direction is for example comprised between 45 and 75°, and more preferably between 55 and 65°. This value of the angle a may be chosen so as to avoid making the flange  6  more fragile, and in particular the upstream flange part  4 , in particular near the curve radii. 
         [0072]    The second drainage orifice  7   b  may be formed through the upstream flange part  4  in an axial direction, as can be seen in  FIGS. 3 and 5 . 
         [0073]    The first  7   a  and second  7   b  drainage orifices may preferably have a substantially cylindrical shape, the first drainage orifice  7   a  having a diameter d 1  smaller than the diameter d 2  of the second drainage orifice  7   b.    
         [0074]    In particular, as shown in  FIG. 5 , the diameter d 1  of the first drainage orifice  7   a  may for example be substantially equal to m/3, where m represents the distance between the upstream inner bend c 1  of the upstream flange part  4  and the downstream inner bend c 2  of the upstream flange part  4 . This diameter d 1  of the first drainage orifice  7   a  may for example be comprised between 1 and 3 mm. 
         [0075]    Likewise, the diameter d 2  of the second drainage orifice  7   b  may be substantially comprised between 1 and 5 mm, and more preferably between 2 and 4 mm. In any case, the diameter d 2  of the second drainage orifice  7   b  may be determined so as to be able to ensure good integration of the flap gate equipping the drainage connector  9 , that flap gate being able in particular to be a standard manufactured part. 
         [0076]    Furthermore, as shown in  FIG. 4 , the first  7   a  and second  7   b  drainage orifices are preferably formed through the upstream flange  4  substantially halfway over the distance between two consecutive fastening orifices  12  of the screws  11  of the flange  6 . In other words, the distance t between the first  7   a  and second  7   b  drainage orifices and an adjacent fastening orifice  12  is equal to half of the distance T between the two consecutive fastening orifices  12 . In this way, it may be possible to avoid overloading the stresses on a single one of the two fastening orifices  12 . Advantageously, an equivalent distribution is obtained at the stresses on each of the two consecutive fastening orifices  12 . 
         [0077]    Furthermore, as also shown in this  FIG. 4 , the second drainage orifice  7   b  and the two fastening orifices  12  that are situated on either side thereof are advantageously formed on a same radius of the upstream flange part  4 , in other words at a same distance from the inner or outer periphery of the upstream flange part  4 , such that the machining operations of the upstream flange part  4  can be made easier. 
         [0078]    Furthermore, as shown in  FIG. 5 , the axial depth p of the basin  8 , i.e., the depth of the basin  8  measured in an axial direction, is comprised between ⅛ and ⅓ of the axial thickness P of the upstream flange part  4 . In fact, if p is less than P/8, then there is a risk of not providing the necessary flow rate for the discharge of the fluid(s) C. Likewise, if p is greater than P/3, then there is a risk of making the flange  6  more fragile, and more particularly the upstream flange part  4 . 
         [0079]    Furthermore, the radial height h of the basin  8 , i.e., the length of the basin  8  measured in a radial direction, may be comprised between ½ and ¼ of the radial height H of the upstream flange part  4  measured on the surface provided with basin  8  from the inner surface  4   a  of the upstream flange part  4 . This radial height H of the flange part may more particularly be determined as a function of the position of the second drainage orifice  7   b , so as to facilitate the machining of the upstream flange part  4 . 
         [0080]    Advantageously, the piercing and machining of the basin  8  and the first  7   a  and second  7   b  drainage orifices of the drainage device  1  formed on the upstream flange part  4  of the flange  6  may be made in a simpler and optimal manner without increasing the mass and machining constraints related to the solutions of the prior art. 
         [0081]    Furthermore, generally, the dimensioning of the first  7   a  and second  7   b  drainage orifices in the basin  8  formed on the upstream flange part  4  may be determined as a function of the flow rate of the fluid(s) C designed to be discharged through the drainage device  1 , and also as a function of the thermal stresses applied to the upstream flange part  4 . 
         [0082]    Thus, the invention makes it possible to propose an alternative solution to the solutions already known to produce fluid drainage for fluids to be discharged in a turbomachine, the drainage here being done in an optimized manner owing to the use of the flange  6  located on the low point of the line of casings of the high-pressure compressor  21  and the combustion chamber  22 . 
         [0083]    Of course, the invention is not limited to the example embodiment described above. Various changes may be made by one skilled in the art. 
         [0084]    The expression “comprising a” must be understood as being synonymous with “comprising at least one”, unless otherwise specified.