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In accordance with one embodiment of the instant invention, there is provided an airfoil compressor shape for a vane of a gas turbine that enhances the performance of the gas turbine. The airfoil shape hereof also improves the interaction between various stages of the compressor and affords improved aerodynamic efficiency, while simultaneously reducing stage airfoil thermal and mechanical stresses.

The vane airfoil profile, as embodied by the invention, is defined by a unique loci of points to achieve the necessary efficiency and loading requirements whereby improved compressor performance is obtained.

The positive X, Y and Z directions are axial toward the exhaust end of the turbine, tangential in the direction of engine rotation and radially outwardly toward the static case, respectively.

The X, Y, and Z coordinates are given in distance dimensions, e. Each defined airfoil section in the X, Y plane is joined smoothly with adjacent airfoil sections in the Z direction to form the complete airfoil shape.

It will be appreciated that an airfoil heats up during use, as known by a person of ordinary skill in the art. The airfoil profile will thus change as a result of mechanical loading and temperature. Accordingly, the cold or room temperature profile, for manufacturing purposes, is given by X, Y and Z coordinates. A distance of plus or minus about 0.

The airfoil shape is robust to this variation, without impairment of the mechanical and aerodynamic functions of the vane. The airfoil, as embodied by the invention, can be scaled up or scaled down geometrically for introduction into similar turbine designs.

Consequently, the X, Y and Z coordinates of the nominal airfoil profile may be a function of a constant. Referring now to FIG. Each stage includes a plurality of circumferentially spaced stator blades, as well as rotor blades 14 mounted on the compressor rotor The first stage compressor stator blades 12 are circumferentially spaced one from the other, having airfoils 18 of a particular airfoil shape or profile specified below.

Referring to FIG. Referring now to FIGS. The coordinate values are set forth in inches in Table I below. The Cartesian coordinate system includes orthogonally related X, Y and Z axes with the Z axis extending along a radius from the centerline of the compressor rotor, i.

The Z distance commences at zero in the X, Y plane at the radially outermost aerodynamic section. This Z distance, i. The X axis lies parallel to the compressor rotor centerline, i. By defining X and Y coordinate values at selected locations in a Z direction normal to the X, Y plane, the profile of airfoil 20 can be ascertained.

By connecting the X and Y values with smooth continuing arcs, each profile section at each distance Z is fixed. The surface profiles at the various surface locations between the distances Z are connected smoothly to one another to form the airfoil. The tabular values given in Table I below are in inches and represent airfoil profiles at ambient, non-operating or non-hot conditions and are for an uncoated airfoil.

The sign convention assigns a positive value Z in a radially inward direction and positive and negative values for the X and Y coordinate values as typically used in Cartesian coordinate systems. To define the airfoil shape of the vane airfoil, a unique set or loci of points in space are provided. This unique set or loci of points meet the stage requirements so the stage can be manufactured.

This unique loci of points also meets the desired requirements for stage efficiency and reduced thermal and mechanical stresses. The loci of points are arrived at by iteration between aerodynamic and mechanical loadings enabling the compressor to run in an efficient, safe and smooth manner. The loci, as embodied by the invention, defines the vane airfoil profile and can comprise a set of points relative to the axis of rotation of the engine.

For example, a set of points can be provided to define a vane airfoil profile. At pressures below the triple-point pressure of kPa, carbon dioxide exists as a solid or gas. Freezing point is the temperature at which freezing starts for fruits and vegetables, and the average freezing temperature for other foods. Klein and F. The new formulation is based on the correlations of Saul and Wagner J. Data, 16, , with modifica- tions to adjust to the International Temperature Scale of The modifications are described by Wagner and Pruss J.

Data, 22, , Gallagher, and George S. The routine used in calculations is the Ra, which is based on the fundamental equation of state developed by R. Tillner-Roth and H.

Chem, Ref. Data, Vol. Note: The reference point used for the chart is different than that used in the Ra tables. Therefore, problems should be solved using all property data either from the tables or from the chart, but not from both. Used with permission of Dr. Edward E. Obert, University of Wisconsin. Standard Atmosphere Supplements, U.

Government Printing Office, The low speed spool 30 generally includes an inner shaft 40 that interconnects a fan 42 , a low pressure compressor 44 and a low pressure turbine The inner shaft 40 is connected to the fan 42 through a speed change mechanism, which in exemplary gas turbine engine 20 is illustrated as a geared architecture 48 to drive the fan 42 at a lower speed than the low speed spool The high speed spool 32 includes an outer shaft 50 that interconnects a high pressure compressor 52 and high pressure turbine A combustor 56 is arranged in exemplary gas turbine 20 between the high pressure compressor 52 and the high pressure turbine A mid-turbine frame 58 of the engine static structure 36 is arranged generally between the high pressure turbine 54 and the low pressure turbine The mid-turbine frame 58 further supports bearing systems 38 in the turbine section The inner shaft 40 and the outer shaft 50 are concentric and rotate via bearing systems 38 about the engine central longitudinal axis X which is collinear with their longitudinal axes.

The core airflow is compressed by the low pressure compressor 44 then the high pressure compressor 52 , mixed and burned with fuel in the combustor 56 , then expanded over the high pressure turbine 54 and low pressure turbine The turbines 46 , 54 rotationally drive the respective low speed spool 30 and high speed spool 32 in response to the expansion. It will be appreciated that each of the positions of the fan section 22 , compressor section 24 , combustor section 26 , turbine section 28 , and fan drive gear system 48 may be varied.

For example, gear system 48 may be located aft of combustor section 26 or even aft of turbine section 28 , and fan section 22 may be positioned forward or aft of the location of gear system The engine 20 in one example is a high-bypass geared aircraft engine. In a further example, the engine 20 bypass ratio is greater than about six 6 , with an example embodiment being greater than about ten 10 , the geared architecture 48 is an epicyclic gear train, such as a planetary gear system or other gear system, with a gear reduction ratio of greater than about 2.

In one disclosed embodiment, the engine 20 bypass ratio is greater than about ten , the fan diameter is significantly larger than that of the low pressure compressor 44 , and the low pressure turbine 46 has a pressure ratio that is greater than about five Low pressure turbine 46 pressure ratio is pressure measured prior to inlet of low pressure turbine 46 as related to the pressure at the outlet of the low pressure turbine 46 prior to an exhaust nozzle.

The geared architecture 48 may be an epicycle gear train, such as a planetary gear system or other gear system, with a gear reduction ratio of greater than about 2. It should be understood, however, that the above parameters are only exemplary of one embodiment of a geared architecture engine and that the present disclosure is applicable to other gas turbine engines including direct drive turbofans.

Now with reference to FIGS. The cooling air is delivered to the turbine rotor through a plurality of nozzles. As shown in FIG. Outer endwall is radially spaced apart from inner endwall Airfoils extend radially from inner endwall to outer endwall Each airfoil has a leading edge and a trailing edge Inner and outer endwalls and , respectively, form a gas path annulus therebetween with a radial height B ranging from 0.

For example, radial height B can be approximately 0. Those skilled in the art will readily appreciate that while two airfoils are shown, there can be any number of suitable airfoils circumferentially spaced apart between inner and outer endwalls, and respectively, for example, there can be twenty-four 24 airfoils evenly spaced apart. The distance from centerline axis A to an outer surface of outer endwall ranges from 5. For example, the distance from centerline axis A to an outer surface of outer endwall can be approximately 5.

The distance from centerline axis A to an outer surface of inner endwall ranges from 4. For example, the distance from centerline axis A to an outer surface of inner endwall can be approximately 5.

The ranges described above are all normalized, e. Axial chord Y, for example, can range from 0. Circumferentially segmented portions are joined to form respective continuous inner and outer endwall rings. It is contemplated that inner and outer endwalls and , respectively, can each be formed as a single continuous endwall ring. With reference now to FIG.

The mean gage distance is the mean of all of the gage distances C between airfoils over a given range Q, best seen in FIG. The mean gage distance between airfoils ranges from 0. This range is normalized based on axial chord Y of airfoil For example, the mean gage distance can be approximately 0.

The pitch distance D between respective leading edges of two of airfoils ranges from 1. For example, the pitch distance D can be approximately 1. The ranges described above are both normalized based on axial chord Y of airfoil The plane extends normal from concave surface of one airfoil , until it meets the other airfoil. The mean gage area is the average of all gage areas between two airfoils over a given range. The range for mean gage area is similar to the range for mean gage distance, described above and as shown in FIG.

The mean gage area between two airfoils ranges from 0. For example, the mean gage area can be approximately 0.