Turbomachine blade with tip flare

Certain embodiments of the present disclosure include a system having a turbomachine including a plurality of turbomachine blades coupled to a rotor, wherein each turbomachine blade has a blade base portion and a flared blade tip portion flared relative to the blade base portion. Additionally, a trailing edge of each turbomachine blade extends along a common plane.

BACKGROUND OF THE INVENTION

The subject matter disclosed herein relates to turbomachines and, more particularly, to a turbomachine blade geometry for improving performance and durability.

Turbine systems include gas turbines, steam turbines, and hydro turbines. In general, a turbine is configured to use turbine blades to extract energy from a fluid flow, such as gas, steam, or water. For instance, the turbine blades may extend radially outwards from a supporting rotor disk, and the turbine blades may force rotation of the rotor disk as the fluid flow passes across the turbine blades. Unfortunately, existing design of turbine blades may provide limited aerodynamic performance. Additionally, improved turbine blade design may be economically impractical. For example, improved turbine blade design may not be mechanically feasible due to durability limitations. As a result, turbine performance may be limited by the design of the turbine blades.

BRIEF DESCRIPTION OF THE INVENTION

In a first embodiment, a system includes a turbomachine including a plurality of turbomachine blades coupled to a rotor, wherein each turbomachine blade has a blade base portion and a flared blade tip portion flared relative to the blade base portion. Additionally, a trailing edge of each turbomachine blade extends along a common plane.

In a second embodiment, a system includes a turbomachine airfoil having a base portion and a flared tip portion that is flared relative to the base portion. Furthermore, a trailing edge of the turbomachine airfoil extends entirely along a common plane.

In a third embodiment, a system includes a turbine blade including a blade base portion and a flared blade tip portion. The flared blade tip portion extends from the blade base portion and is flared relative to the blade base portion, and a trailing edge of the turbine blade extends entirely along a common plane.

DETAILED DESCRIPTION OF THE INVENTION

As discussed further below, certain embodiments of the present disclosure provide a turbomachine that includes turbomachine blades (e.g., airfoils) configured for enhanced aerodynamic performance and improved durability and/or longevity. For example, the turbomachine may be a turbine, such as a gas turbine or a steam turbine, having turbine blades. In other embodiments, the turbomachine may be a compressor or other turbomachine. In one embodiment, a turbine blade may include a flared blade tip portion. Specifically, the flared blade tip portion may be extended, flared, or “leaned” in a lateral direction, such as a circumferential direction and/or axial direction, relative to a blade base portion. For example, the flared blade tip portion may be flared in a direction of rotation generally around the circumference of the rotor to which the turbine blade is attached. As will be appreciated, the flared geometry of the flared blade tip portion may provide improved aerodynamic performance of the turbine blade. For example, the flared geometry of the flared blade tip portion may help reduce leakage past the turbine blade. More specifically, leakage between the turbine blade and surrounding stationary components (e.g., shrouds, housings, etc.) may be reduced. In this manner, pressure mixing and vortex flow generation may be reduced. Additionally, the entire trailing edge of the turbine blade may extend along a common plane. Specifically, as discussed in detail below, the entire trailing edge of the turbine blade may lie within a common plane defined by a spanwise average blade exit angle. In other words, the common plane may be generally tangent to a mean camber line of the turbine blade at the trailing edge. In this manner, the durability of the turbine blade and the flared blade portion may be improved.

Turning now to the drawings,FIG. 1illustrates a block diagram of an embodiment of a gas turbine system10having turbine blades22with flared blade tip portions. Additionally, the entire trailing edge of each turbine blade22lies within a common plane. The system10includes a compressor12, combustors14having fuel nozzles16, and a turbine18. The fuel nozzles16route a liquid fuel and/or gas fuel, such as natural gas or syngas, into the combustors14. The combustors14ignite and combust a fuel-air mixture, and then pass hot pressurized combustion gases20(e.g., exhaust) into the turbine18. Turbine blades22are coupled to a rotor24, which is also coupled to several other components throughout the turbine system10, as illustrated. As the combustion gases20pass through the turbine blades22in the turbine18, the turbine18is driven into rotation, which causes the rotor24to rotate along a rotational axis25. Eventually, the combustion gases20exit the turbine18via an exhaust outlet26.

In the illustrated embodiment, the compressor12includes compressor blades28. The blades28within the compressor12are coupled to the rotor24, and rotate as the rotor24is driven into rotation by the turbine18, as discussed above. As the blades28rotate within the compressor12, the blades28compress air from an air intake into pressurized air30, which may be routed to the combustors14, the fuel nozzles16, and other portions of the gas turbine system10. The fuel nozzles14may then mix the pressurized air and fuel to produce a suitable fuel-air mixture, which combusts in the combustors14to generate the combustion gases20to drive the turbine18. Further, the rotor24may be coupled to a load31, which may be powered via rotation of the rotor24. By way of example, the load31may be any suitable device that may generate power via the rotational output of the turbine system10, such as a power generation plant or an external mechanical load. For instance, the load31may include an electrical generator, a propeller of an airplane, and so forth. In the following discussion, reference may be made to various directions, such as an axial direction or axis32, a radial direction or axis34, and a circumferential direction or axis36of the turbine18.

FIG. 2is a perspective view of the turbine blade22, illustrating a flared blade tip portion50and a blade base portion52. For example, the blade base portion52may be an unflared blade tip portion of the turbine blade22. In the illustrated embodiment, the turbine blade22also includes a blade tip surface54, a blade root surface56, a leading edge58, and a trailing edge60. As will be appreciated, the blade root surface56of the turbine blade22is coupled to the rotor24of the turbine18. As shown, the flared blade tip portion50extends radially34between the blade base portion52and the blade tip surface54of the turbine blade22. Similarly, the blade base portion52extends radially34between the flared blade tip portion50and the blade root surface56of the turbine blade22. As shown, the flared blade tip potion50flares, or “leans”, in a lateral direction relative to the blade base portion50. For example, the flared blade tip portion50may flare at least partially in the axial direction32and/or the circumferential36direction. In other words, the flared blade tip portion50may flare in a direction from the trailing edge60toward the leading edge58, such that the flared blade tip portion50extends beyond the blade base portion52in that direction, as indicated by arrow64. As a result, the turbine blade22may experience improved aerodynamic performance. For example, the turbine blade22may experience reduced flow leakage between the turbine blade22and surrounding stationary components (e.g., shrouds, housings, etc). In this manner, pressure mixing and vortex flow generation may be reduced.

As will be appreciated, the amount of flaring of the turbine blade22may vary. That is, a height66of the flared blade tip portion50relative to a total height68of the turbine blade22may vary. For example, the height66of the flared blade tip portion50may be approximately 1 to 90, 2 to 80, 3 to 70, 4 to 60, 5 to 50, 6 to 40, 7 to 30, 8 to 20 or 9 to 10 percent of the total height68of the turbine blade22. In other embodiments, the height66of the flared blade tip portion50may be 5 to 50, 10 to 40, or 15 to 25 percent of the total height68of the turbine blade22.

As mentioned above, the entire trailing edge60of the turbine blade22is within a common plane70. The common plane70is defined by a mean camber line72of the turbine blade22at the trailing edge60at each point (e.g., points73) along the trailing edge60. More specifically, the common plane70is tangent to the mean camber line72at the trailing edge60. As will be appreciated, the mean camber line72at the trailing edge60may be defined by a spanwise average74of the turbine blade22at the trailing edge60. Because the entire trailing edge60of the turbine blade22lies within the common plane70, the entire trailing edge60is generally aligned in the radial34direction. In this manner, the mechanical design of the turbine blade22with the flared blade portion50may have improved durability and/or longevity.

FIG. 3is a side view of the turbine22, illustrating the flared blade tip portion50and the blade base portion52(e.g., the unflared blade tip portion), where the entire trailing edge60of the turbine blade22lies within the common plane70. In the illustrated embodiment, the flared blade tip portion50is flared at least partially in the axial32direction and the circumferential36direction. However, in certain embodiments, the flared blade tip portion50may be flared in the circumferential36direction, or the axial32direction, or both the circumferential36and the axial32direction. As will be appreciated, the direction of the flare or “lean” of the flared blade tip portion50may be selected to achieve a desired aerodynamic performance or improvement. Regardless of the direction of the flare or “lean” of the flared blade tip portion50, the entire trailing edge60extends within the common plane70, as described above. As a result, the durability and/or longevity of the turbine blade22with the flared blade tip portion50may be improved.

As mentioned above, the amount of flaring of the turbine blade22may vary. In other words, the height66of the flared blade tip portion50relative to a total height68of the turbine blade22may vary. For example, the height66of the flared blade tip portion50may be greater than or equal to approximately 5, 10, 15, 20, 25, 30, 35, 40, 45, or 50 percent of the total height68of the turbine blade22. Additionally, the amount of flare or “lean” of the flared blade tip portion50in the axial32direction and/or circumferential36direction may vary. Specifically, in the illustrated embodiment, the flared blade tip portion50flares a distance100of a total width102of the turbine blade22between the leading and trailing edges58and60(e.g., measured at the blade base portion52). In certain embodiments, the distance100may be 1 to 50, 2 to 45, 3 to 40, 4 to 35, 5 to 30, 6 to 25, 7 to 20, 8 to 15 or 9 to 10 percent of the total width102of the turbine blade22.

FIG. 4is a schematic of the flared blade tip portion50of the turbine blade22and the blade base portion52(e.g., the unflared blade tip portion) of the turbine blade22, illustrating the trailing edge60of the turbine blade22within the common plane70. Specifically, the flared blade tip portion50is flared relative to the blade base portion52. In the illustrated embodiment, the flared blade tip portion50is flared in the axial32direction and the circumferential36direction. More specifically, as indicated by arrow120, the flared blade tip portion50is flared, or shifted, in the circumferential direction36. Without any additional flare, the flared blade tip portion50would be located in the position indicated by dashed line122. However, as shown, the flared blade tip portion50is further flared, or shifted, in the axial32direction, as indicated by arrow124. More particularly, the flared blade tip portion50is flared in the axial32direction such that the trailing edge60of the flared blade tip portion50is aligned with the trailing edge60of the blade base portion52. Specifically, in the manner described above, the trailing edge60of the flared blade tip portion50and the trailing edge60of the blade base portion52lie within the common plane70defined by the mean camber line72at each point along the trailing edge60. As discussed above, the common plane70is tangent to the mean camber line72, which may be defined by the spanwise average74of the turbine blade22at the trailing edge60. In this manner, the aerodynamic performance of the turbine blade22may be improved while maintaining a feasible mechanical design. More specifically, flow leakage between the turbine blade22and surrounding stationary components (e.g., housings, shrouds, etc.) may be reduced, while the durability and/or longevity of the turbine blade22may be increased.

As discussed above, embodiments of the present disclosure are directed toward a turbine blade22having a flared blade tip portion50and a blade base portion52(e.g., an unflared blade tip portion). Specifically, the flared blade tip portion50may be flared, or “leaned”, in the axial32direction, the circumferential36direction, or both the axial32and the circumferential36directions, wherein the entire trailing edge60of the turbine blade22is aligned in a common plane70. In this manner, the aerodynamic performance of the turbine blade22may be improved. For example, flow leakage between the turbine blade22and surrounding stationary components (e.g., shrouds, housings, etc.) may be reduced, thereby reducing pressure mixing and vortex flow generation. The common plane70is at least partially defined by a mean camber line72of the turbine blade22at each point along the trailing edge60. The mean camber line72may be defined by the spanwise average74of the turbine blade22at the trailing edge60. Due to the alignment of the entire trailing edge60in the common plane70, the mechanical design of the turbine blade22may provide improved durability and/or longevity.