Patent Grant
7467920
The present invention relates to airfoil shapes for a gas turbine and particularly relates to nozzle and bucket airfoil shapes for the first and second stages of the gas turbine.
There are many considerations in the design and construction of nozzle and bucket airfoils for turbines, including optimized aerodynamic efficiency, aerodynamic and mechanical blade loading and the interaction between various stages of a gas turbine. For example, and with respect to turbine nozzles, the airfoil shape of the nozzles provides guided turning of the hot gases for interactions along the hot gas path among the various stages of the turbine with substantial effect on the overall efficiency of the turbine. Accordingly, there is a need for airfoil shapes for each of the first and second stage nozzles and buckets for optimizing the efficiency of the gas turbine.
In a preferred embodiment of the invention, there is provided a turbine nozzle including an airfoil having an airfoil shape, the airfoil having a nominal profile substantially in accordance with Cartesian coordinate values of X, Y and R set forth in millimeters in Table I wherein R is a distance along a radius from an axis of rotation of the turbine and X and Y are distances which, when connected by smooth continuing arcs, define airfoil profile sections in planes normal to the radius and at each distance R, the profile sections at the R distances being joined smoothly with one another to form the airfoil shape.
In a further preferred embodiment of the present invention, there is provided a turbine bucket including an airfoil having an airfoil shape, the airfoil having a nominal profile substantially in accordance with Cartesian coordinate values of X, Y and R set forth in millimeters in Table II wherein R is a distance along a radius from an axis of rotation of the turbine and X and Y are distances which, when connected by smooth continuing arcs, define airfoil profile sections in planes normal to the radius and at each distance R, the profile sections at the R distances being joined smoothly with one another to form the airfoil shape.
In another embodiment of the present invention, there is provided a turbine nozzle including an airfoil having an airfoil shape, the airfoil having a nominal profile substantially in accordance with Cartesian coordinate values of X, Y and R set forth in millimeters in Table III wherein R is a distance along a radius from an axis of rotation of the turbine and X and Y are distances which, when connected by smooth continuous arcs, define airfoil profile sections in planes normal to the radius and at each distance R, the profile sections in planes normal to the radius and at the R distances being joined smoothly with one another to form the airfoil shape.
In another preferred embodiment of the present invention, there is provided a turbine bucket including an airfoil having an airfoil shape, the airfoil having a nominal profile substantially in accordance with Cartesian coordinate values of X, Y and R set forth in millimeters in Table IV wherein R is a distance along a radius from an axis of rotation of the turbine and X and Y are distances which, when connected by smooth continuous arcs, define airfoil profile sections in planes normal to the radius and at each distance R, the profile sections at the R distances being joined smoothly with one another to form the airfoil shape.
In a still further preferred embodiment of the present invention, there is provided a first stage of a turbine having a plurality of nozzles in a circumferential array thereof about a turbine axis and a plurality of buckets in a circumferential array thereof about the axis downstream of the nozzles, each nozzle including an airfoil having an airfoil shape, the airfoil having a nominal profile substantially in accordance with Cartesian coordinate values of X, Y and R set forth in millimeters in Table I wherein R is a distance along a radius from the axis of rotation of the turbine and X and Y are distances which, when connected by smooth continuing arcs, define airfoil profile sections in planes normal to the radius and at each distance R, the profile sections at the R distances being joined smoothly with one another to form the airfoil shape, each bucket including a bucket airfoil having an airfoil shape, the bucket airfoil having a nominal airfoil profile substantially in accordance with Cartesian coordinate values of X, Y and R set forth in millimeters Table II wherein R is a distance along a radius from the axis of rotation of the turbine and X and Y are distances which, when connected by smooth continuing arcs, define bucket airfoil profile sections in planes normal to the radius and at each distance R, the profile sections at the R distances of Table II being joined smoothly with one another to form the bucket airfoil shape.
In another embodiment of the present invention, there is provided a second stage of a turbine having a plurality of nozzles in a circumferential array thereof about a turbine axis and a plurality of buckets in a circumferential array thereof about the axis downstream of the nozzles, each nozzle including an airfoil having an airfoil shape, the bucket airfoil having a nominal profile substantially in accordance with Cartesian coordinate values of X, Y and R set forth in millimeters in Table III wherein R is a distance along a radius from the axis of rotation of the turbine and X and y are distances which, when connected by smooth continuous arcs, define airfoil profile sections in planes normal to the radius and at each distance R, the profile sections at the R distances being joined smoothly with one another to form the airfoil shape, each bucket including a bucket airfoil having an airfoil shape, the bucket airfoil having a nominal profile substantially in accordance with Cartesian coordinate values of X, Y and R set forth in millimeters in Table IV wherein R is a distance along a radius from the axis of rotation of the turbine and X and Y are distances which, when connected by smooth continuous arcs, define airfoil profile sections in planes normal to the radius and at each distance R, the profile sections at the R distances of Table IV being joined smoothly with one another to form the bucket airfoil shape.
Referring now to
A Cartesian coordinate system of X, Y and R values given in millimeters in Tables I-IV define the profile of the airfoils 16, 18, 20 and 22, respectively. The coordinate values for the X, Y and R coordinates are set forth in millimeters in these tables although other units of dimensions may be used. The Cartesian coordinate system has orthogonally related X, Y and R axes. The R axis is a linear distance in millimeters from an axis of rotation of the turbine and along a radius to a plane normal thereto containing the X and Y values which define airfoil profile sections at each distance R from the axis of rotation. The X axis extends in a direction parallel to the turbine rotor centerline, i.e. the axis of rotation, and the Y axis extends in a tangential direction
By defining X and Y coordinate values in planes perpendicular to and at selected distances in an R direction, the profile of each airfoil can be ascertained. By connecting the X and Y values in each plane with smooth continuing arcs, each profile section at each distance R given in the Tables is fixed. The surface profiles at the various surface locations between the profile section planes at distances R are determined by smoothly connecting the adjacent profile sections to one another to form the airfoil shape.
The values set forth in Tables I-IV represent the airfoil profile sections at ambient non-operating or non-hot conditions. The values provided in Tables I-IV are generated and shown to three decimal places for determining the profiles of the airfoils. There are typical manufacturing tolerances as well as coatings which must be accounted for in the actual profile of each airfoil. Accordingly, the values for the profiles given in Tables I-IV are for nominal airfoils. It will therefore be appreciated that ± typical manufacturing tolerances, i.e., ± values, including any coating thicknesses, are additive to or subtractive from the X, Y values given in the tables below. Accordingly, a distance of ±4.064 mm in a direction normal to any surface location along each airfoil surface defines an airfoil profile envelope for the particular airfoil shape.
The coordinate values given in Table I below provide the preferred nominal profile shape excluding fillet regions for the first stage nozzle airfoil 16.
As an example, the profile sections of the first stage nozzle airfoils 16 at each of near root, near pitch and near tip distances R are illustrated in
The coordinate values given in Table II below provide the preferred nominal profile shape excluding the fillet region for the first stage bucket airfoil 18.
As an example, the profile sections of the first stage bucket airfoils 18 at each of the near root, near pitch and near tip distances R are illustrated in
The coordinate values given in Table III below provide the preferred nominal profile shape excluding fillet regions for the second stage nozzle airfoils 20.
As an example, the profile sections of the second stage nozzle airfoils 20 at each of the near root, near pitch and near tip distances R are illustrated in
The coordinate values given in Table IV below provide the preferred nominal profile shape excluding the fillet region for the second stage bucket airfoils 22.
As an example, the profile sections of the second stage bucket airfoils 22 at each of the near root, near pitch and near tip distances R are illustrated in
It will also be appreciated that the airfoils disclosed in the above Tables I-IV may be scaled up or down geometrically for use in other similar turbine designs. Consequently, the coordinate values set forth in Tables I-IV may be scaled upwardly or downwardly such the airfoil shapes remain unchanged. A scaled version of the coordinates values in Tables I-IV would be represented by X, Y and R 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.
This application is a continuation of application Ser. No. 11/090,300, filed Mar. 28, 2005, now abandoned the entire content of which is hereby incorporated by reference in this application.
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| Number | Date | Country | |
|---|---|---|---|
| 20080175707 A1 | Jul 2008 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 11090300 | Mar 2005 | US |
| Child | 11648906 | US |
