Fluidic actuation for improved diffuser performance

The A diffuser augmented with fluidic actuation, the diffuser comprising:

• a longitudinal axis;
• a diffuser inlet having a width W;
• a diverging section having a diffuser wall;
• an opening in the diffuser wall adjacent the diffuser inlet;
• a curved passageway adjacent the opening, wherein the curved passageway is curved convexly relative to the longitudinal axis, the curved passageway for introducing a secondary jet into the opening and along the diffuser wall for maintaining the secondary jet along the wall using the Coanda effect;
• a plurality of openings distributed about a circumference of the diffuser wall;
• and
• an annular manifold mounted around a circumference of an outer casing of the diffuser, the annular manifold collecting fluid from an outside source and distributing the fluid to the openings.

A diffuser augmented with fluidic actuation, the diffuser comprising:

• a longitudinal axis;
• a diffuser inlet having a width W;
• a diverging section having a diffuser wall;
• an opening in the diffuser wall adjacent the diffuser inlet;
• a curved passageway adjacent the opening wherein the curved passageway is curved convexly relative to the longitudinal axis, the curved passageway for introducing a secondary jet into the opening and along the diffuser wall for maintaining the secondary jet along the wall using the Coanda effect;
• and
• an airway directing air from an upstream turbine into the curved passageway.

A gas turbine having a diffuser augmented with fluidic actuation, the gas turbine and diffuser comprising:

• a diffuser inlet through which passes a main flow of air in a main flow direction;
• a diverging section having a diffuser wall;
• a centerbody placed within the diverging section;
• at least one opening in the diffuser wall adjacent the diffuser inlet;
• at least one opening in a wall of the centerbody in a vicinity of the diffuser inlet;
• and
• an independent booster unit providing a secondary flow of fluid through the at least one opening in the diffuser wall, wherein the independent booster unit feeds air into an annular manifold surrounding the diffuser inlet, wherein the annular manifold distributes the air from the independent booster unit into the at least one opening.

A gas turbine having a diffuser augmented with fluidic actuation, the gas turbine and diffuser comprising:

• a diffuser inlet through which passes a main flow of air in a main flow direction;
• a diverging section having a diffuser wall;
• a centerbody placed within the diverging section;
• at least one opening in the diffuser wall adjacent the diffuser inlet;
• at least one opening in a wall of the centerbody in a vicinity of the diffuser inlet;
• and
• a curved passageway adjoining each opening in the diffuser wall, wherein the curved passageway is curved convexly relative to the main flow direction.

A gas turbine having a diffuser augmented with fluidic actuation, the diffuser comprising:

• a diffuser inlet placed adjacent the turbine;
• a diverging section having a diffuser wall;
• a plurality of openings in the diffuser wall;
• an exit port in the turbine, the exit port separate from a main turbine exit;
• a plurality of airways extending from the exit port to the opening, wherein air is extracted from the turbine and introduced into the diverging;
• and,
• a plurality of ports in the turbine and an annular manifold collecting air from the ports via the airways for distributing to the openings.

A gas turbine having a diffuser augmented with fluidic actuation, the diffuser comprising:

• a diffuser inlet placed adjacent the turbine;
• a diverging section having a diffuser wall;
• an opening in the diffuser wall;
• an exit port in the turbine, the exit port separate from a main turbine exit;
• an airway extending from the exit port to the opening, wherein air is extracted from the turbine and introduced into the diverging section;
• a plurality of airways extending from the turbine, and a plurality of openings in the diffuser wall;
• and
• an annular manifold surrounding the diffuser inlet and the openings, the manifold collecting air from the airways and distributing the air to the openings.

A steam turbine comprising:

• a final turbine stage;
• an axial flow diffuser receiving a main flow from the final turbine stage;
• a diverging wall in the axial flow diffuser, the diverging wall extending from a diffuser inlet to a diffuser exit;
• a centerbody in the axial flow diffuser,
• an opening in the diverging wall and an opening in the centerbody for fluidically actuating the main flow, wherein the openings are located downstream from the diffuser inlet and upstream from a point where boundary layer separation would occur along the walls in a diffuser without the openings;
• and
• a suction source positioned adjacent the diffuser for sucking steam from the axial flow diffuser.

A steam turbine comprising

• a final turbine stage;
• an axial flow diffuser receiving a main flow from the final turbine stage;
• a diverging wall in the axial flow diffuser, the diverging wall extending from a diffuser inlet to a diffuser exit;
• a centerbody in the axial flow diffuser;
• an opening in the diverging wall and an opening in the centerbody for fluidically actuating the main flow, wherein the openings are located downstream from the diffuser inlet and upstream from a point where boundary layer separation would occur along the walls in a diffuser without the openings;
• a plurality of openings in the diverging wall, each opening located equidistantly from the diffuser inlet;
• and
• an annular manifold surrounding the plurality of openings in the diverging wall, the annular manifold collecting fluid from an outside source for distributing to the openings.

A steam turbine comprising:

• a final turbine stage;
• an axial flow diffuser receiving a main flow from the final turbine stage;
• a diverging wall in the axial flow diffuser, the diverging wall extending from a diffuser inlet to a diffuser exit;
• a centerbody in the axial flow diffuser;
• and
• an opening in the diverging wall and an opening in the centerbody for fluidically actuating the main flow, wherein the openings are located downstream from the diffuser inlet and upstream from a point where boundary layer separation would occur along the walls in a diffuser without the openings,
• wherein steam is extracted from the diffuser exit and reinjected into the opening in the diverging wall.

A steam turbine comprising:

• a final turbine stage;
• a down-flow exhaust hood;
• a centercone in the down-flow exhaust hood;
• a steam guide passage in the down-flow exhaust hood receiving a main flow of air from the final turbine stage;
• an opening in the steam guide for fluidically actuating the main, flow, wherein the opening is located downstream from the steam guide inlet and upstream from a point where boundary layer separation would occur along a steam guide without the opening;
• and
• an independent booster unit positioned adjacent the exhaust hood for injecting fluid into the down-flow exhaust hood.

A steam turbine comprising:

• a final turbine stage;
• a down-flow exhaust hood;
• a centercone in the down-flow exhaust hood;
• a steam guide passage in the down-flow exhaust hood receiving a main flow of air from the final turbine stage;
• an opening in the steam guide for fluidically actuating the main flow, wherein the opening is located downstream from the steam guide inlet and upstream from a point where boundary layer separation would occur along a steam guide without the opening;
• and
• a suction source positioned adjacent the exhaust hood for sucking steam from the down-flow exhaust hood.

The A steam turbine comprising:

• a final turbine stage;
• a down-flow exhaust hood;
• a centercone in the down-flow exhaust hood;
• a steam guide passage in the down-flow exhaust hood receiving a main flow of air from the final turbine stage;
• an opening in the steam guide for fluidically actuating the main flow, wherein the opening is located downstream from the steam guide inlet and upstream from a point where boundary layer separation would occur along a steam guide without the opening;
• a plurality of openings in the steam guide, each opening located equidistantly from the exhaust hood inlet;
• and
• an annular manifold surrounding the plurality of openings, the annular manifold collecting fluid from an outside source for distributing to the openings.

A method of improving diffuser performance comprising:

• allowing a main flow to pass through the diffuser;
• providing an opening in a diffuser wall;
• selecting a fluid source;
• injecting fluid into the opening for preventing separation of the main flow from the diffuser wall;
• and,
• directing the fluid at an angle relative to the main flow and relative to the diffuser wall, wherein directing the fluid at an angle comprises sending the fluid through a curved passageway having a curvature which is convex relative to the main flow prior to injecting fluid into the opening.

A method of improving diffuser performance comprising:

• allowing a main flow to pass through the diffuser;
• providing an opening in a diffuser wall;
• selecting a fluid source;
• injecting fluid into the opening for preventing separation of the main flow from the diffuser wall, wherein injecting fluid into the opening comprises injecting a pulsating jet of fluid;
• and,
• directing the fluid at an angle relative to the main flow and relative to the diffuser wall.

A method improving diffuser performance comprising:

• allowing a main flow to pass through the diffuser;
• providing an opening in a diffuser wall;
• selecting a fluid source, wherein selecting a fluid source comprises redirecting fluid exiting the diffuser to the opening;
• injecting fluid into the opening for preventing separation of the main flow from the diffuser wall;
• and,
• directing the fluid at an angle relative to the main flow and relative to the diffuser wall.