The present invention relates to a nozzle stage of a gas turbine and particularly relates to a first stage nozzle airfoil profile and sidewall flowpath surfaces.
In the development of an advanced gas turbine, many specific requirements must be met for each stage of the hot gas path section of the turbine in order to meet design goals. Particularly, and in addition to other goals, the first stage of the turbine must meet efficiency, heat load, life, throat area and vectoring requirements to meet those goals. Conventional nozzle designs do not allow for the added benefit of advanced three-dimensional aerodynamics that improve the use of the combustion gases to improve blade loading sufficiently to meet that goal.
In accordance with the preferred embodiment of the present invention, there is provided unique nozzle flowpath surfaces, specifically an airfoil suction-side surface, an airfoil pressure side surface, an inner sidewall surface and an outer sidewall surface for the nozzle of a turbine stage, preferably the first stage of a gas turbine. Each nozzle flowpath surface is defined by a unique loci of points to achieve the necessary efficiency whereby improved turbine performance is obtained. The suction-side and pressure-side surfaces join smoothly at the airfoil leading and trailing edges.
In accordance with a preferred embodiment of the present invention, there is provided a turbine nozzle having a pressure side airfoil surface, the pressure side airfoil surface having a nominal profile substantially in accordance with Cartesian coordinate values of X, Y and Z set forth in inches in Table I, wherein the Z values are drop dimensions from a reference point origin on an outside diameter flowpath along a nozzle airfoil stacking axis perpendicular to a centerline axis of rotation of the turbine; and wherein the X and Y values, when connected by smooth continuing arcs, define pressure side airfoil surface profile sections at each distance Z from the origin, the profile sections at the Z distances being joined smoothly with one another to form a pressure side airfoil surface shape.
In accordance with a further embodiment of the present invention, there is provided a turbine nozzle having a suction side airfoil surface, the suction side airfoil surface having a nominal profile substantially in accordance with Cartesian coordinate values of X, Y and Z set forth in inches in Table II, wherein the Z values are drop dimensions from a reference point origin on an outside diameter flowpath along a nozzle airfoil stacking axis perpendicular to a centerline axis of rotation of the turbine; and wherein the X and Y values, when connected by smooth continuing arcs, define suction side airfoil surface profile sections at each distance Z from the origin, the profile sections at the Z distances being joined smoothly with one another to form a suction side airfoil surface shape.
In accordance with a further embodiment of the present invention, there is provided a turbine nozzle having an outer sidewall surface, the outer sidewall surface having a nominal profile substantially in accordance with Cartesian coordinate values of X, Y and Z set forth in inches in Table III, wherein the Z values are drop dimensions from a reference point origin on an outside diameter flowpath along a nozzle airfoil stacking axis perpendicular to a centerline axis of rotation of the turbine; and wherein the X and Y values, when connected by smooth continuing arcs at each distance Z, define an outer sidewall surface shape.
In accordance with a further embodiment of the present invention, there is provided a turbine nozzle having an inner sidewall surface, the inner sidewall surface having a nominal profile substantially in accordance with Cartesian coordinate values of X, Y and Z set forth in inches in Table IV, wherein the Z values are drop dimensions from a reference point origin on an outside diameter flowpath along a nozzle airfoil stacking axis perpendicular to a centerline axis of rotation of the turbine; and wherein the X and Y values, when connected by smooth continuing arcs at each distance Z, define an inner sidewall surface shape.
In accordance with a further embodiment of the present invention, there is provided a turbine comprising a turbine nozzle having a plurality of airfoils having an airfoil shape, each airfoil having pressure and suction side airfoil surfaces defining a nominal airfoil profile substantially in accordance with Cartesian coordinate values of X, Y and Z set forth in Tables I and II, wherein the Z values are drop dimensions from a reference point origin on an outside diameter flowpath along a nozzle airfoil stacking axis perpendicular to a centerline axis of rotation of the turbine, and wherein the X and Y values, when connected by smooth continuing arcs, define airfoil profile sections at each distance Z, the profile sections at the Z distances being joined smoothly with one another to form an airfoil shape.
Referring now to
Referring to
A Cartesian coordinate system of X, Y and Z values are given in Tables I–II below and define the nominal profile of the respective pressure and suction sidewall surfaces of the nozzle airfoil 28. Similar X, Y and Z coordinate values for the respective outer and inner sidewall surfaces 44 and 46 are given in Tables III and IV. The coordinate values for the X, Y and Z coordinates are set forth in inches in Tables I–IV although other units of dimensions may be used. The Z values set forth in the Tables are drop dimensions from a point on the flowpath along the nozzle airfoil stacking axis (a specific axis or line perpendicular to engine rotation centerline). The Cartesian coordinate system has orthogonally-related X, Y and Z axes with the Z axis extending perpendicular to a plane normal to a plane containing the X and Y values. By defining X and Y coordinate values at selected locations in a Z direction normal to the X, Y plane, the profile of the surfaces can be ascertained. By connecting the X and Y values for the airfoil with smooth continuing arcs, each airfoil profile section at each distance Z is fixed. The airfoil surface profiles of the various surface locations between the distances Z are determined by smoothly connecting the adjacent profile sections to one another to form airfoil surfaces. Similarly, the X, Y and Z coordinate values for the inner and outer sidewalls define a series of points which may be connected to one another by smooth continuous arcs which, when filled in with continuous surfaces areas, define the shape or profile of the inner and outer sidewall surfaces in part defining the flowpath. These values represent the nozzle flowpath surface profiles at ambient, non-operating or non-hot conditions and are for the coated finished nozzle flowpath. The sign convention is illustrated in
The Cartesian coordinate values in Tables I–IV are generated and shown to three decimal places for determining the profile of the nozzle flowpath surfaces. There are typical manufacturing tolerances as well as coating thickness tolerances, which must be accounted for with the actual flowpath surfaces. Accordingly, the values for the profiles given in Tables I–IV are for nominal flowpath surfaces. Accordingly, a distance of ±0.105 inches in a direction normal to any surface location along the flowpath profile defines the flowpath surface envelopes for this particular nozzle flowpath design and turbine.
The coordinate values given in Table I below define the preferred nominal profile of the pressure sidewall surface 36 of airfoil 28:
The coordinate values given in Table II below define the preferred nominal profile of the suction sidewall surface 34 of airfoil 28:
The coordinate values given in Table III below define the preferred nominal profile of the outer sidewall flowpath surface 44:
The coordinate values given in Table IV below define the preferred nominal profile of the inner sidewall flowpath surface 46:
It will also be appreciated that the flowpath surfaces disclosed in the above Tables may be scaled up or down geometrically for use in similar turbine designs. Consequently, the coordinate values set forth in Tables I–IV may be scaled upwardly or downwardly such that the flowpath surface contours remain unchanged. A scaled version of the coordinates in Tables I–IV would be represented by X, Y and Z coordinate values multiplied or divided by the same constant or number.
While the invention has been described in connection with what is presently considered to be the most practical and preferred embodiment, it is to be understood that the invention is not to be limited to the disclosed embodiment, but on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.
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