Gas turbine with stator shroud in the cavity beneath the chamber
View Patent ↗A turbomachine including a high pressure compressor with a downstream cone, a diffuser extending downstream by an inner casing disposed radially outside the downstream compressor cone, a combustion chamber disposed radially outside the inner diffuser casing, and a high pressure turbine whose rotor is connected to the downstream cone of the compressor by a connection drum, the inner diffuser casing and the downstream compressor cone defining between them an under-chamber cavity that is situated downstream from a discharge labyrinth in which cooling air flows downstream, wherein the engine also includes a stator shroud that is installed under the inner diffuser casing downstream from the discharge labyrinth.
1. A turbomachine having an axis comprising, from upstream to downstream, a high pressure compressor whose rotor presents a downstream cone, a diffuser extending downstream beside the axis by an inner casing disposed radially outside said downstream compressor cone, a combustion chamber disposed radially outside said inner diffuser casing, and a high pressure turbine whose rotor is connected to the downstream compressor cone by a connection drum, the inner diffuser casing and the downstream compressor cone defining between them an annular cavity that is situated downstream from a discharge labyrinth and in which cooling air flows downstream, wherein a stator shroud is installed radially internally from the inner diffuser casing downstream from the discharge labyrinth to define with said diffuser casing a closed thermally insulating chamber.
2. The turbomachine according to claim 1 , wherein said stator shroud is shaped so that the cross section of the annular cavity defined by the stator shroud and the downstream cone is substantially constant from upstream to downstream.
3. The turbomachine according to claim 1 , wherein a temperature of the air in the closed thermally insulating chamber is between a temperature of an air flowing through the diffuser and a temperature of an air flowing through the annular cavity.
4. The turbomachine according to claim 3 , wherein the temperature of the air in the closed thermally insulating chamber is substantially equal to half the sum of the temperature of the air flowing through the diffuser and the temperature of the air flowing through the annular cavity.
5. The turbomachine according to claim 1 , wherein, for a given air flow rate through the annular cavity, a temperature of an air flowing into an enclosure located downstream from the annular cavity is reduced by as much as 26° C.
6. The turbomachine according to claim 1 , wherein, if an air flow rate through the annular cavity is reduced such that a temperature of an air flowing into an enclosure located downstream from the annular cavity is the same as in a chamber without the closed thermally insulating chamber, a reduction in specific fuel consumption of the turbomachine is estimated to be about 0.1%.
7. A turbomachine, comprising:
a high pressure compressor including a compressor cone;
a diffuser including an inner diffuser casing forming with an Outside jacket a main flow passage, the inner diffuser casing being disposed radially outside the compressor cone;
a combustion chamber disposed radially outside the inner diffuser casing, the combustion chamber receiving an air flow flowing through the main flow passage;
a high pressure turbine having a rotor connected to the compressor cone via a connection drum, the inner diffuser casing and the compressor cone defining therebetween an annular cavity;
a discharge labyrinth disposed under the diffuser between the inner diffuser casing and the compressor cone; and
a stator shroud disposed radially internally from the inner diffuser casing downstream from the discharge labyrinth, the stator shroud defining with the diffuser inner casing a closed chamber and with the compressor cone a leakage air flow passage for air flowing through the discharge labyrinth.
8. The turbomachine according to claim 7 , wherein a cross section of the leakage air flow passage is substantially constant along an axial direction of the turbomachine.
9. The turbomachine according to claim 7 , wherein a temperature of the air in the closed chamber is between a temperature of an air flowing through the main flow passage and a temperature of an air flowing through the leakage air flow passage.
10. The turbomachine according to claim 9 , wherein the temperature of the air in the closed chamber is substantially equal to half the sum of the temperature of the air flowing through the main flow passage and the temperature of the air flowing through the leakage air flow passage.
11. The turbomachine according to claim 7 , wherein, for a given air flow rate through the leakage air flow passage, a temperature of an air flowing into an enclosure located downstream from the leakage air flow passage is reduced by as much as 26° C.
12. The turbomachine according to claim 7 , wherein, if an air flow rate through the leakage air flow passage is reduced such that a temperature of an air flowing into an enclosure located downstream from the leakage air flow passage is the same as in a chamber without the stator shroud, a reduction in a specific fuel consumption of the turbomachine is estimated to be about 0.1%.