Turbine blade with non-axisymmetric forward features

Abstract

A turbine blade (140) having a non-axisymmetric forward-facing feature is provided. The turbine blade (140) can include a platform and an airfoil extending radially outward from the platform (142) and configured to extend into a fluid flowpath (160). The airfoil (150) separates an upstream portion (160a) of the fluid flowpath (160) from a downstream portion (160b) of the fluid flowpath (160). A seal member (172) extends axially from the platform (142) toward a stationary nozzle adjacent the platform (142) and separates the fluid flowpath (160) from a wheel space (182). The platform (142) can have a forward face (170) between the seal member (172) and the airfoil (150), and optionally a forward axial face (194) between the forward face (170) and the airfoil (150). The forward face (170) or the forward axial face (194) can face the upstream portion (160a) of the fluid flowpath (160) and can have a profile that is non-axisymmetric with respect to a central line axis thereof.

Description

TECHNICAL FIELD

[0001] Embodiments of the present disclosure generally relate to rotary machines, and more particularly to forward facing features of turbine blades for controlling fluid flow and temperature in the vicinity of the turbine blades to reduce losses that can be caused by temperature build-up in the space adjacent to or below the turbine blade structure. BACKGROUND

[0002] Turbines employ rows of rotating blades on the wheels or disks of a rotor assembly that alternate with rows of stationary blades on a stator or nozzle assembly. These alternating rows extend axially along the rotor and stator and allow the combustion gases or steam to turn the rotor as the combustion gases or steam flow therethrough.

[0003] Axial and / or radial openings at the interface between the rotating blades and the stationary nozzles can allow hot combustion gases or steam to exit the main flow and radially enter the inter-wheel space between the rows of blades. In gas turbines, cooling air or "bleed air" is typically introduced into the wheel space between the rows of blades. This bleed air serves to cool the components and space within the wheel space and other areas radially inward from the blades, and provides a counterflow of cooling air to further limit the intrusion of hot gases into the wheel space. However, the intrusion of combustion gases or steam into the wheel space between the rows of blades directly and / or indirectly results in reduced turbine efficiency due to the need to bleed such gases or steam. SUMMARY

[0004] Aspects of the present disclosure provide a turbine blade comprising: a platform; a fin extending radially outward from the platform and configured to extend into a fluid flowpath, wherein the fin separates an upstream portion of the fluid flowpath from a downstream portion of the fluid flowpath; a seal member extending axially from the platform toward a stationary nozzle adjacent to the platform, wherein the seal member separates the fluid flowpath from a wheel space; and a forward face on the platform between the seal member and the fin and axially facing the upstream portion of the fluid flowpath, wherein a circumferential profile of a top surface of the forward face is non-axially symmetric with respect to a centerline axis of the forward face.

[0005] Further aspects of the present disclosure provide a turbine blade comprising: a platform; an airfoil extending radially outward from the platform and configured to extend into a fluid flowpath, wherein the airfoil separates an upstream portion of the fluid flowpath from a downstream portion of the fluid flowpath; a seal member extending axially from the platform toward a stationary nozzle adjacent the platform, wherein the seal member separates the fluid flowpath from a wheel space; and a forward face on the platform between the seal member and the airfoil and axially facing the upstream portion of the fluid flowpath; and a forward axial face on the platform and extending from a top surface of the forward face to the airfoil, wherein an axial profile of the forward axial face is non-axially symmetric with respect to a centerline axis of the forward face.

[0006] Further aspects of the present disclosure provide a turbine blade comprising: a platform; an airfoil extending radially outward from the platform, the airfoil configured to extend into a fluid flowpath, wherein the airfoil separates an upstream portion of the fluid flowpath from a downstream portion of the fluid flowpath; a seal member extending axially from the platform toward a stationary nozzle, wherein the seal member separates the fluid flowpath from a wheel space; a forward face on the platform between the seal member and the airfoil and axially facing the upstream portion of the fluid flowpath, wherein a circumferential profile of a top surface of the forward face is non-axially symmetric with respect to a centerline axis of the forward face; and a forward axial face on the platform and extending from the top surface of the forward face to the airfoil, wherein an axial profile of the forward axial face is non-axially symmetric with respect to the centerline axis of the forward face. BRIEF DESCRIPTION OF DRAWINGS

[0007] These and other features of the turbine blade of the present disclosure will be more readily understood from the following detailed description, taken in conjunction with the accompanying drawings, which illustrate various embodiments of the present disclosure, in which:

[0008] Figure 1 A schematic cross-sectional view showing a portion of a conventional turbine blade is shown;

[0009] Figure 2 A perspective view showing a turbine blade according to an embodiment of the present disclosure is shown;

[0010] Figure 3 A graph comparing a turbine blade having an axially symmetric forward feature to a turbine blade having a non-axially symmetric forward feature is shown;

[0011] Figure 4 Perspective views showing a plurality of turbine blades having various non-axially symmetric forward features according to embodiments of the present disclosure are shown;

[0012] Figure 5 A perspective view showing a turbine blade according to a further embodiment of the present disclosure is shown; and

[0013] Figure 6 A schematic block diagram of a portion of a multi-shaft power plant system is shown, in which turbine blades are deployed according to embodiments of the present disclosure.

[0014] It should be noted that the accompanying drawings of this invention are not drawn to scale. The drawings are intended to depict only typical aspects and characteristic structures of turbine blades and should therefore not be considered as limiting the scope of the invention. In the drawings, similar numbers denote similar elements between figures. Detailed Implementation

[0015] Now turn to the attached image. Figure 1 A schematic cross-sectional view of a portion of a gas turbine 10 is shown, the gas turbine including blades 40 disposed between two adjacent nozzles (e.g., a first-stage nozzle 20 (sometimes referred to as "fixed blades") and a second-stage nozzle 22). The blades 40 extend radially outward from an axially extending rotor (not shown), as those skilled in the art will recognize. The blades 40 include a platform 42, and vanes 50 extend radially outward from the platform 42. The platform 42 may have a shank portion 60 extending radially inward relative to the vanes 50.

[0016] The handle portion 60 includes a pair of sealing members 70, 72 (sometimes referred to as "angel wings") extending axially outward toward the first-stage nozzle 20 and a sealing member 74 extending axially outward toward the second-stage nozzle 22. It should be understood that different numbers and arrangements of the sealing members are possible. The number and arrangement of the sealing members described herein are provided for illustrative purposes only.

[0017] As in Figure 1 As can be seen, the nozzle surface 30 and the blocking member 32 extend axially from the first-stage nozzle 20 and are arranged radially outward from the sealing members 70 and 72, respectively. Thus, the nozzle surface 30 overlaps with but does not contact the sealing member 70, and the blocking member 32 overlaps with but does not contact the sealing member 72. A similar arrangement is shown for the blocking member 32 and the sealing member 74 relative to the second-stage nozzle 22. Figure 1 In the arrangement shown, during turbine operation, a certain amount of purge air can be positioned, for example, between the nozzle surface 30, the sealing member 70, and the platform lip 44, thereby both restricting the purge air from escaping into the hot gas flow path 28 and restricting the hot gas from intruding from the hot gas flow path 28 into the wheel space 26.

[0018] although Figure 1 The blade 40 is shown positioned between the first-stage nozzle 20 and the second-stage nozzle 22, such that blade 40 represents a first-stage blade, but this is merely for illustrative and explanatory purposes. The principles and embodiments of the invention described herein can be applied to blades in any stage of a turbine, with the expectation of achieving similar results.

[0019] Figure 2 A perspective view of a portion of a turbine blade 140 having a non-axisymmetric forward-featured structure according to an embodiment of the present disclosure is shown. The turbine blade 140 is... Figure 2 The turbine blade 140 is depicted as being located between the first-stage nozzle 20 and the second-stage nozzle 22, but it can be located at any conceivable location of the turbine where rotation is required. The turbine blade 140 may include a platform 142 and a vane 150 extending radially outward (i.e., at least partially along the radial axis R) from the platform 142. It can be seen that the vane 150 includes a leading edge 152 (e.g., closer to the first-stage nozzle 20) and a trailing edge 154 (e.g., closer to the second-stage nozzle 22). The vane 150 may extend into a fluid flow path 160, which may include an upstream portion 160a upstream of the vane 150 and a downstream portion 160b downstream of the vane 150.

[0020] Platform 142 may include a forward face 170, which is closer to the leading edge 152 than the trailing edge 154. In this case, the leading edge 152 of the vane 150 may face the forward face 170 axially (i.e., along the axial axis Z). The forward face 170 may extend radially from the sealing member 172 to a top surface 174 and may face the upstream portion 160a of the fluid flow path 160. The top surface 174 of the forward face 170 (similar to...) Figure 1 The platform lip 44) separates the forward surface 170 from the top surface 176 of the platform 142. In this case, the wing 150 may be mounted on the top surface 176 of the platform 142 and / or may extend radially outward from the top surface of the platform.

[0021] The sealing member 172 may be formed from the platform 142, for example, by machining from a larger precursor structure, and / or produced by any known or later-developed method. For example, other different features of the sealing member 172 and / or platform 142 may be formed by casting and / or additive manufacturing. Regardless of how it is formed, the sealing member 172 may extend axially toward the first-stage nozzle 20 (i.e., along the radial axis Z). The sealing member 172 may also separate the platform space 178 within the upstream portion 160a from other spaces radially below the sealing member 172 (i.e., in the negative direction along the radial axis R). Such spaces may include, for example, a buffer space 180 radially located between the upstream portion 160a and the wheel space 182. An additional sealing member 184 may radially separate the buffer space 180 from the wheel space 182.

[0022] Platform 142 may include a forward feature structure shaped to be non-axisymmetric about the centerline axis of a corresponding portion of platform 142. One such forward feature structure may include, for example, a top surface 174 of a forward face 170. The forward face 170 may have a centerline axis J extending axially outward from platform 142 (e.g., toward the first-stage nozzle 22). Turbine blades 140 may differ from conventional blade structures, for example, by having at least one forward feature structure that is non-axisymmetric with respect to the centerline axis J. The term "non-axisymmetric" means that the position of any portion of platform 142 is asymmetrical about the centerline axis J. According to one example, such a forward feature structure may include a circumferential profile of the top surface 174. The term "circumferential profile" may refer to the path along which the top surface 174 extends at least partially relative to the circumferential axis C.

[0023] An axisymmetric circumferential profile may include, for example, a linear or arcuate path that is symmetrical about or centered relative to the centerline axis J. Such profiles may include, for example, arcuate, segmented linear profiles and / or other profiles symmetrical about the centerline axis J along the circumferential axis C. In embodiments of this disclosure, the top surface 174 is not axisymmetric about the centerline axis J. For example, in Figure 2 In the example, the top surface 174 includes a nodule N that is closer to one circumferential end of the platform 142 than to the other circumferential end. As used herein, the term "nodule" may refer to at least one protrusion, recess, ramp, bump, groove, and / or other similar feature structure, which may be an arcuate and / or non-arc-shaped difference from the contour of another surface region. Regardless of shape, the nodule N may be closer to the pressure-side surface PS of the vane 150 than to the suction-side surface SS (as shown in the figure), and vice versa.

[0024] It should be understood that the top surface 174 may include multiple nodules, for example, several nodules closer to the suction-side surface SS than the pressure-side surface PS of the vane 150. Any number or arrangement of nodules is permissible, provided that such nodules and / or other non-linear and / or arcuate portions of the top surface 174 are asymmetrical about the centerline axis J. In another example, each nodule N and / or other non-arcuate or non-linear portion of the top surface 174 may have its own non-axisymmetric profile relative to the centerline axis J. Figure 2 As shown, nodal N has a non-axisymmetric profile and asymmetric position within the top surface 174 to illustrate both possibilities.

[0025] The presence of other portions of the junction N and / or top surface 174 that are not axisymmetric about the centerline axis J provides a circumferential profile that facilitates efficient use of purge air PA in the space adjacent to turbine blade 140 and avoids the intake of hot gas from fluid flow path 160. This property of turbine blade 140 provides, for example, a reduced gas temperature at the leading face 170 and top surface 174 of platform 142. The reduced gas temperature, in turn, reduces the total purge flow rate into the space adjacent to turbine blade 140 and thus improves the efficiency of the turbine system. By being positioned on the leading face 170, the non-axisymmetric portion of top surface 174 can provide preferred heat concentration in turbine blade 140 without significantly interfering with the flow of the working fluid in fluid flow path 160.

[0026] The non-axisymmetric feature structure of turbine blade 140 may be limited to one of its feature structures, such as the forward face 170. According to one example, platform 142 may include a front face 190, which is axially opposite to the forward face 170 and faces the downstream portion 160b of fluid flow path 160. The front face 190 itself may include a top surface 192 (shown in dashed lines) different from the top surface 174 of the forward face 170. The top surface 192 of the front face 190 may be axisymmetric about the centerline axis K of the front face 190. Therefore, the top surface 192 may not contain any nodules N, such as those shown exemplarily in the top surface 174.

[0027] In another example, top surface 192 may include one or more nodes N, but such nodes may differ from those in top surface 174 by being arranged symmetrically about the centerline axis K. Thus, regardless of how top surface 192 is shaped, it may have a profile that is geometrically different from top surface 174 of forward face 170 by being symmetrical about its centerline axis K.

[0028] Figure 3 Forward feature structures (e.g., platform lip 44) are provided for conventional turbine blades. Figure 1 The part of the turbine blade 140 ( Figure 2 Forward feature structure (e.g., top surface 174) Figure 2 The graphs are used to compare the parts of the blade 140. The axis “C” indicates the circumferential position of the top surface 174 (or platform lip 44) from one side of the blade 140 to the other, while the axis “S” indicates the height of the top surface 174 in the radial direction R relative to the top surface 176 of the platform 142. Figure 3 The interval “N” in the example represents the span of a node “N” in the specific implementation. Figure 3 The curve shown and marked "non-axisymmetric" can be represented as follows: Figure 2A portion of the top surface 174 is depicted. In conventional turbine blades, the top surface of the leading face (i.e., the platform lip 44) can be substantially linear and therefore symmetric about the centerline axis J (e.g., Figure 2 As shown). In this case, as Figure 3 As shown in the diagram, the top surface of a conventional turbine blade can be fixed at approximately zero percent height relative to the average height of the platform 142 relative to its lowest point on the radial axis R. Such a graph is labeled "axisymmetric".

[0029] However, in an embodiment of the turbine blade 140 of the present invention, the knot N will cause the top surface 174 to have a valley along the axis S (i.e., in the radial direction R) that is about 10 percent smaller than the median height of the platform 142. The knot N can also cause the top surface 174 to have peaks at different circumferential locations that are about 5 percent smaller than the median height of the platform 142 in the radial direction R. In this case, the peaks of the top surface 174 are located closer to the blade 150 than the valleys of the top surface 174. According to... Figure 3 The exemplary graph depicted shows that the peaks and valleys of the top surface 174 can be circumferentially away from the leading edge 152 of the blade 150. Figure 2 The position of ) is indicated by the mark "LE" in the example graph.

[0030] In another example, the peaks and valleys of the top surface 174 may be in opposite positions, or at other locations along the circumferential axis C. It should also be understood that further embodiments may include multiple peaks and multiple valleys (e.g., formed by corresponding nodules N within the top surface 174). In any case, Figure 3 All of these indicate that the top surface 174 can be non-axisymmetric with respect to the central axis J.

[0031] Figure 4 A plurality of turbine blades 140 are depicted alongside a conventional turbine blade 40 to further illustrate the differences between embodiments of the present disclosure and the differences between the turbine blade 140 according to embodiments of the present disclosure and the conventional turbine blade 40. It should be understood that Figure 4 The depictions in the text are for comparison only, and various configurations of turbine blade 140 may not be deployed together in a single machine and / or may not be deployed together with conventional turbine blade 40.

[0032] Figure 4Four distinct turbine blades 140 are depicted, each having a corresponding forward face 170 with a top surface 174 of a significantly different shape. As shown, each top surface 174 may have a corresponding nodule N, which makes each top surface 174 of the turbine blade 140 non-axisymmetric with respect to the corresponding centerline axis J of the forward face 170. In contrast, the turbine blade 40 has no nodule N and more significantly has an axisymmetric profile on its forward face. Therefore, it should be understood that the top surface 174 of the forward face 170 can be formed using any conceivable shape, profile, etc., such that it has a non-axisymmetric profile along the circumferential axis C with respect to the corresponding centerline axis J of the forward face 170. It should also be understood that, as Figure 4 As shown, the position where the wing 150 intersects with the top surface 176 can vary based on the shape, number, and / or position of the nodal N within the top surface 174.

[0033] Figure 5 Further examples of turbine blades 140 with various additional feature structures are depicted. Unless otherwise specified herein, turbine blades 140 may include several feature structures that are the same as or similar to those discussed in other embodiments (e.g., such as...). Figure 2 , Figure 4 The turbine blade 140 depicted in the figure. Figure 5 The various features of the turbine blade 140 shown may be implemented together with those features in other embodiments, or separately from those features in other embodiments. In some embodiments, the platform 142 may include a forward axial surface 194 extending from the top surface 176 to at least a portion of the forward surface 170. In some cases, the forward axial surface 194 may extend from the vane 150 to the sealing member 172. Additionally, the forward axial surface 194 may be directed toward the upstream portion 160a of the fluid flow path 160.

[0034] Regardless of its presentation, the forward axial surface 194 can take the form of an additional surface and / or raised area axially positioned between a portion of the vane 150 (e.g., leading edge 152) and the sealing member 172. The forward axial surface 194 can have any conceivable axial profile that is non-axisymmetric with respect to the centerline axis J of the forward surface 170. Due to the variations in the structure of the forward surface 170, the axis J is shown facing towards... Figure 2 Different directions within. In Figure 5In this configuration, the forward axial surface 194 extends substantially axially along a portion of the forward surface 170, but is circumferentially curved along the forward surface 170 and a portion of the top surface 174 closer to the vane 150 toward the suction-side surface SS of the vane 150. In this configuration, the axial profile of the forward axial surface 194 is asymmetrical about the centerline axis J of the forward surface 170, and is therefore non-axisymmetric as described herein. Furthermore, one axial end of the forward axial surface 194 may contact a portion of the pressure-side surface SS at a location axially offset from the leading edge 152 (e.g., between the leading and trailing edges 154).

[0035] Another embodiment of the forward axial face 194 may extend across the top surface 176 by any conceivable axial profile that is non-axisymmetric about the centerline axis J, and such axial profile may include linear and / or non-linear axial paths. Regardless of the shape and position of the forward axial face 194, the forward face 170 may optionally be characterized by a top surface 174 having a circumferential profile that is also non-axisymmetric about the centerline axis J. In such cases, the position of one or more nodules N in the top surface 174 may coincide with the position of the forward axial face 194 on the platform 142. It should also be understood that the forward axial face 194 may alternatively be positioned on the platform 142, wherein the top surface 174 is not characterized by a non-axisymmetric circumferential profile. However, similar to other embodiments described herein, the turbine blade 140 may include a front face 190 having a top surface 192, wherein the circumferential profile of the top surface 192 is axisymmetric about the centerline axis K of the front face 190.

[0036] Although the embodiment of turbine blade 140 is described as being positioned between the first-stage nozzle 20 and the second-stage nozzle 22, it should be understood that turbine blade 140 may be placed between nozzles of other stages and / or adapted to other parts of the turbine. Therefore, turbine blade 140 is operable to be deployed within fluid flow path 160 to reduce the gas temperature at or near the forward face 170 and / or the forward axial face 194.

[0037] The turbine blade 140 differs from conventional rotating blade structures, for example, by including a non-axisymmetric geometry of a forward face 170 (specifically, a top surface 174) and / or a forward axial face 194 on the forward axial surface of the platform 142. The forward face 170 and / or the forward axial face 194, with their non-axisymmetric features, can be adjacent to purge air cooling spaces (e.g., platform space 178 and / or buffer space 180) at the top surface of the forward face 170, thereby creating a more significant temperature difference (e.g., at least approximately 200°F) between the portion of the platform 142 adjacent to the blade 150 and the portion of the platform 142 adjacent to the sealing member 172. Such a temperature difference can provide an improvement in operating efficiency compared to conventional rotating blade structures, for example, providing an efficiency improvement of at least approximately 0.20% in turbine stages using the platform 142. Furthermore, such a temperature difference can reduce the amount of purge air required to cool certain heat-sensitive areas of the platform 142.

[0038] It should be understood that, in various embodiments, many dimensions, shapes, profiles, etc., of the top surface 174 and / or the forward axial surface 194 of the blade structure 140 may vary, and may include configurations not specifically shown or described herein. Various other blade parameters (e.g., wall apex location, blade spacing, width, aspect ratio between the lengths and / or areas of various surfaces, etc.) are also feasible and may further influence the shape and dimensions of the top surface 174 and / or the forward axial surface 194 of the forward surface 170. Any example values ​​of such parameters given herein are merely illustrative of several embodiments among the many possible implementations according to this disclosure.

[0039] Go to Figure 6 A schematic diagram of a portion of a multi-shaft combined cycle power plant 900 is shown, in which turbine blades 140 can be deployed. The combined cycle power plant 900 may include, for example, a gas turbine 980 operatively connected to a generator 970. The generator 970 and the gas turbine 980 may be mechanically coupled via a shaft 915 that transfers energy from the drive shaft (not shown) of the gas turbine 980 to the generator 970. Figure 6 The diagram also shows a heat exchanger 986 operatively connected to a gas turbine 980 and a steam turbine 992. The heat exchanger 986 is fluidly connected to both the gas turbine 980 and the steam turbine 992 via conventional conduits (numbers omitted). The gas turbine 980 and / or the steam turbine 992 may include components as described in the references. Figure 2 , Figure 4 and Figure 5 One or more turbine blades 140 are shown and described in and / or in other embodiments described herein. The heat exchanger 986 may be a conventional heat recovery steam generator (HRSG), such as those used in conventional combined cycle power systems.

[0040] As is known in the field of power generation, heat exchanger 986 can use a combination of hot exhaust gas from gas turbine 980 and a water supply to generate steam for supply to steam turbine 992. Steam turbine 992 may optionally be coupled to a second generator system 970 (via a second shaft 915). It should be understood that generator 970 and shaft 915 can have any size or type known in the art and can vary depending on their application or the system to which they are connected. The common designation of the generator and shaft is for clarity and does not necessarily indicate that these generators or shafts are identical. In another embodiment, single-shaft combined cycle power plant 990 may include a single generator 970 (not shown) coupled to both gas turbine 980 and steam turbine 992 via a single shaft 915 (not shown). Steam turbine 992 and / or gas turbine 980 may include references to... Figure 2 , Figure 5 and Figure 5 One or more turbine blades 140 shown and described in and / or other embodiments described herein.

[0041] The apparatus and devices disclosed herein are not limited to any particular engine, turbine, jet engine, generator, power generation system, or other system, and can be used with aircraft systems, other power generation systems (e.g., combined cycle, simple cycle) and / or other systems (e.g., nuclear reactors, etc.). Furthermore, the apparatus of this disclosure can be used with other systems not described herein that can benefit from the increased efficiency of the apparatus and devices described herein.

[0042] In various embodiments, components described as "connected" to each other can be joined along one or more interfaces. In some embodiments, these interfaces may include joints between different components, and in others, these interfaces may include firmly and / or integrally formed interconnections. That is, in some cases, components that are "connected" to each other can be formed simultaneously to define a single continuous member. However, in other embodiments, these connected components may be formed as separate members and subsequently joined by known processes (e.g., fastening, ultrasonic welding, bonding).

[0043] As used herein, the singular forms “a,” “an,” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that, when used in the specification, the terms “comprising” and / or “including” specify the presence of the stated features, integers, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof.

[0044] This written description uses examples to disclose the invention, including the best mode, and also enables any person skilled in the art to practice the invention, including making and using any device or system and performing any associated or combined methods. The patentable scope of the invention is defined by the claims and may include other examples that would occur to a person skilled in the art. Such other examples are contemplated within the scope of the claims if they have structural elements that are not different from the literal language of the claims, or if they include equivalent structural elements that are not substantially different from the literal language of the claims.

Claims

1. A turbine blade (140), the turbine blade comprising: Platform (142); A winglet (150) extends radially outward from the platform (142) and is configured to extend into a fluid flow path (160), wherein the winglet (150) separates an upstream portion (160a) of the fluid flow path (160) from a downstream portion (160b) of the fluid flow path (160). A sealing member (172) extends axially from the platform (142) toward a fixed nozzle adjacent to the platform (142), wherein the sealing member (172) separates the fluid flow path (160) from the wheel space (182); and A forward surface (170), located on the platform (142) and between the sealing member (172) and the vane (150), and axially facing the upstream portion (160a) of the fluid flow path (160); and A forward axial surface (194) is located on the platform (142) and extends from the top surface (174) of the forward surface (170) to the winglet (150). The circumferential profile of the top surface (174) of the forward surface (170) is non-axisymmetric with respect to the centerline axis of the forward surface (170); The axial profile of the forward axial surface (194) is non-axisymmetric with respect to the centerline axis of the forward surface (170); and The forward axial surface (194) is formed as a raised area extending axially from a portion of the flap (150) to the sealing member (172).

2. The turbine blade (140) according to claim 1, wherein the forward surface (170) of the platform (142) located between the sealing member (172) and the platform (142) of the blade (150) defines the fluid flow path (160) axially located in the platform (142) space between the platform (142) and the fixed nozzle.

3. The turbine blade (140) according to claim 1 further includes a buffer space (180) defined between the fluid flow path (160) and the wheel space (182), wherein the sealing member (172) radially separates the forward surface (170) of the platform (142) from the wheel space (182) and the buffer space (180).

4. The turbine blade (140) according to claim 1, wherein the top surface (174) of the forward surface (170) includes a radial valley that is positioned further away from the blade (150) than the radial peak of the top surface (174).

5. The turbine blade (140) according to claim 1, wherein the forward surface (170) is adjacent to the purge air cooling space, and the purge air cooling space is adjacent to the turbine blade (140).

6. The turbine blade (140) according to claim 1, wherein the leading edge (152) of the blade (150) faces the forward surface (170) axially.

7. The turbine blade (140) according to claim 1 further includes a front face (190) located on the platform (142), the front face being axially opposite to the forward face (170) and axially facing the downstream portion (160b) of the fluid flow path (160), wherein the circumferential profile of the top surface (174) of the front face (190) is axisymmetric with respect to the centerline axis of the front face (190).

8. A gas turbine (10) comprising turbine blades according to any one of claims 1 to 7.

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