Claims:We claim:
1) A high pressure blade (120) of a fluid flow machine comprising an air foil portion formed by a convex suction side (122) and a concave pressure side (124) bounded at extreme ends by a leading edge (126) and a trailing edge (128), wherein the geometry defining parameters of the high pressure blade (120) profile are according to the following table:
Parameter Hub Section(H-H)
Chord 19.56 mm
Inlet Angle 4 deg
Exit Angle -72.8 deg
Leading edge radius 2.5 mm
Stagger Angle -40.86 deg
Trailing edge radius 0.125 mm
Unguided turning 27.08 deg
Angle of Attack -40.86 deg
Area 7.67 mm2
Axial chord(width) 13.4 mm
Camber 76.8 deg
Maximum Thickness 5.18 mm
Pitch/Chord 0.8757
Radius at CG 300 mm
Solidity 1.141
Throat/Pitch 0.3097
Tmax/Chord 0.2596

2) A high pressure nozzle (140) of a fluid flow machine comprising an air foil portion formed by a convex suction side (142) and a concave pressure side (144) bounded at extreme ends by a leading edge (146) and a trailing edge (148), wherein the geometry defining parameters of the high pressure nozzle (140) profile are according to the following table:

Parameter Hub Section(H-H)
Chord 19.56 mm
Inlet Angle - 4 deg
Exit Angle 72.8 deg
Leading edge radius 2.5 mm
Stagger Angle 40.86 deg
Trailing edge radius 0.125 mm
Unguided turning 27.08 deg
Angle of Attack 40.86 deg
Area 7.67 mm2
Axial chord(width) 13.4 mm
Camber -76.8 deg
Maximum Thickness 5.18 mm
Pitch/Chord 0.8757
Radius at CG 300 mm
Solidity 1.141
Throat/Pitch 0.3097
Tmax/Chord 0.2596

3) A high pressure blade (120) of a fluid flow machine as claimed in claim 1, wherein said high pressure blade (120) has an elliptical nose shape at said leading edge (126).

4) A high pressure blade (120) of a fluid flow machine as claimed in claim 1, wherein said high pressure blade (120) works efficiently and suitable for use in low pressure ranges of steam turbines.

5) A high pressure blade (120) of a fluid flow machine as claimed in claim 1, wherein said high pressure blade (120) performs better and suitable for use in conditions of high salt deposition.

6) A high pressure blade (120) of a fluid flow machine as claimed in claim 1 or 3, wherein said elliptical nose shape of said high pressure blade (120) facilitates in lower salt deposition at said leading edge (126).

7) A high pressure nozzle (140) of a fluid flow machine as claimed in claim 2, wherein said high pressure nozzle (140) has an elliptical nose shape at said leading edge (146).

8) A high pressure nozzle (140) of a fluid flow machine as claimed in claim 2, wherein said high pressure nozzle (140) works efficiently and suitable for use in low pressure ranges of steam turbines.

9) A high pressure blade (140) of a fluid flow machine as claimed in claim 2, wherein said high pressure blade (140) performs better and suitable for use in conditions of high salt deposition.

10) A high pressure blade (140) of a fluid flow machine as claimed in claim 2 or 7, wherein said elliptical nose shape of said high pressure blade (140) facilitates in lower salt deposition at said leading edge (146).
, Description:FIELD OF THE INVENTION:
The present invention relates to the field of a blade of a fluid flow machine. Particularly, the present invention relates to a high pressure blade of a steam turbine.

TERMINOLOGY AND FORMULAS USED:
U-Peripheral velocity of rotor;
C-Steam velocity;
Ct-Tangential steam velocity;
Ca-Axial Steam velocity; and
Delta h- Enthalpy change.

The formulas employed in doing mean line calculations are as follows:
1) Loading factor-Delta h/U2
2) Peripheral velocity of rotor (U)= 3.147*D*N/60000 m/s
Where D=Rotor Hub Dia; N=speed of rotor in rpm.
3) Steam velocity C- 44.7 *(Delta h)0.5
4) Height of the blades in a stage (H)= 2 Q/3.147*D*sina*e*C
Where Q=Volumetric flow rate in each stage (m3/sec);
D= Rotor Hub Dia;
a= Blade or Nozzle Inlet angle;
e=Degree of admission(Projected Area of nozzles/Total area of moving
blades);
C=Steam velocity.
5) Flow Coefficient= Ca/U

DEFINITIONS OF TERMS USED:
Incidence: Incidence is defined as an optimum point on the blade for the flow to hit in order to generate maximum efficiency.

Meridional Plane: A plane cutting the turbo machine through diametric line and longitudinal axis.

Pitch: Circumference of the blade (2*Pi*r)/No.of blades in a row. Circumference of the blade depends on blade height (i.e., at hub, mean or tip).

Stage: Stage herein refers to a combination of rows of blades and nozzles.

Reaction: Enthalpy drop across the rows of blades/ Enthalpy drop across the stage.

Spanwise Reaction: Reaction across different cross-section of blade length.

BACKGROUND OF THE INVENTION:
Steam turbines comprises a plurality of blades typically configured in three modules viz High pressure module (HP), Intermediate pressure module (IP) and Low pressure module (LP). High pressure module (HP) of a steam turbine typically contributes to one-third of power generation and comes immediately after control stage (nozzle chest- a row of nozzles and a row of impulse blades). Typically, conventional steam turbines employ either a straight parallel-sided blades (cylindrical) or tapered and twisted blades configuration. The criteria for selection of cylindrical blade or tapered and twisted blade depend on the height of the blade. The general design rule traditionally followed in the industry is that, if the height of the blade exceeds 110mm, taper and twist is required for the blade to achieve good efficiency and better incidence respectively. The number of rows of blades in each module of the turbine is determined depending on various factors like space, pressure ratio, power output and efficiency.

High Pressure (HP) Module, Intermediate Pressure (IP) module and Low Pressure (LP) module can be of impulse type or reaction type or combination of impulse and reaction type. In impulse stage type, pressure drop occurs only in nozzles and moving blades facilitates in changing the direction of fluid flow, thereby increasing the velocity of the flow and no pressure drop occurs in moving blades. In impulse-reaction stage type, pressure drop occurs in both nozzles and moving blades resulting in the generation of kinetic energy. In reaction stage type, flow enters the moving blades, changes its direction resulting in the increase of velocity and also undergoes a pressure drop. Generally speaking, reaction type stage is more efficient than impulse type stage due to less frictional losses, boundary layer separation losses, secondary flow losses and tip leakage losses. In impulse stage, nozzles are mounted in nozzle diaphragms and project inwards from the casing towards rotor and moving blades are mounted in rotor disc and project upwards from the rotor whereas in reaction stage, nozzles are mounted on guide blade carriers projecting inwards and moving blades are mounted on rotor projecting outwards such that the nozzles and moving blades are configured in opposite direction.

Figure 1 illustrates a sectional view of two adjacent moving blades depicting typical blade features.
The airfoil sections of two adjacent moving blades (10 and 12) is disclosed wherein the blades include a convex suction side (14 and 16), a concave pressure side (18 and 20), a leading edge (22 and 24) and a trailing edge (26 and 28).

The parameters which define the geometry and configuration of the moving blades in a row are as follows: The distance between trailing edges (26 and 28) of two adjacent blades (10 and 12) typically referred to as pitch is indicated by a letter ‘P1’. The axial length of the blade typically referred to as width is indicated by a letter ‘W1’. The inlet and exit blade angles are indicated by letters a1 and ß1 respectively. The shortest distance between trailing edge 26 of blade 10 to convex suction surface 16 of blade 12 typically referred to as throat is indicated by a letter ‘D1’. The angle between the chord line 21 and turbine axial direction (meridional direction) typically referred to as stagger angle is indicated by a letter ‘S1’.

Figure 2 illustrates sectional view of two adjacent nozzles depicting typical nozzle features.
The airfoil sections of two adjacent nozzles (30 and 32) is disclosed wherein the nozzles include a convex suction side (34 and 36), a concave pressure side (38 and 40), a leading edge (42 and 44) and a trailing edge (46 and 48).

The parameters which define the geometry and configuration of the nozzles in a stage are as follows: The distance between trailing edges (46 and 48) of two adjacent nozzles (30 and 32) typically referred to as pitch is indicated by a letter ‘P2’. The axial length of the nozzle typically referred to as width is indicated by a letter ‘W2’. The inlet and exit nozzle angles are indicated by letters a2 and ß2 respectively. The distance between trailing edge 46 of blade 30 to convex suction surface 36 of blade 32 typically referred to as throat is indicated by a letter ‘D2’. The angle between the chord line 41 and turbine axial direction (meridional direction) typically referred to as stagger angle is indicated by a letter ‘S2’.

Several techniques have been disclosed in the prior art illustrating the optimization of nozzle and blade profiles based on various parameters.

US Patent Publication No: 20080063530 published on March 13th, 2008 titled “HP Turbine Blade Airfoil Profile” discloses optimization of first stage blade in a two stage high pressure gas turbine to achieve maximum work, minimize secondary flow losses, flow separation losses and tip leakage losses.

US Patent No: 5277549 filed on March 16, 1992 titled “Controlled Reaction L-2R Steam Turbine” teaches about high performance tapered and twisted turbine blade deployed in low pressure module of a steam turbine to minimize energy loss through row of blades and control the radial distribution of degree of reaction.

Non Patent Literature published in Journal of Computational and Applied Mechanics, Vol.5., No.2., (2004), pp. 311-321 titled “Numerical optimization of a high pressure steam turbine stage” disclosed optimization of HP impulse stage of a 200 MW steam turbine having cylindrical stator blades and tapered and twisted rotor blades with an objective to minimize enthalpy loss of the stage. In this the blade profile hasn’t been changed but other parameters like stator and rotor blade numbers, stagger angles, rotor blade twist angle and stator blade compound lean at root and tip are optimized.

Generally, In prior art, optimization is done on blades for design requirements meeting design constraints considering minimum boundary layer separation losses, secondary flow losses, tip leakage losses etc., The blades thus developed operates at targeted efficiency at design conditions and operates at below the targeted efficiency at off design conditions (i.e., Mass flow varies). The primary design requirement herein is to develop a high pressure blade profile having high efficiency than the existing blade profiles available in the market for a given set of boundary conditions.

Further, it is understood based on the empirical evidence that in the operating pressure range of inlet pressure of 18.05 bar and exit pressure of 13.47 bar, the high pressure blades of the turbine are more subjected to salt deposition resulting in the change of profile shape of the high pressure blades and spoiling of the surface smoothness of the high pressure blades which ultimately results in loss of efficiency of the high pressure blades.

Figure 3(a) illustrates a top sectional view of an optimized high pressure blade profile obtained after aerodynamic and thermodynamic optimization according to the prior art.

Table 1 elucidates the geometry defining parameters at hub of the optimized high pressure blade of figure 1(a). As the high pressure blade profile herein is of cylindrical blade, the geometry parameters will not be varying spanwise across Hub, Mean and Tip except parameters associated with radius from axis of rotor drum like pitch etc.
Table 1
Parameter Hub Section(H-H)
Chord 19.78 mm
Inlet Angle 11.68 deg
Exit Angle -72.8 deg
Leading edge radius 3 mm
Stagger Angle -38.66 deg
Trailing edge radius 0.098 mm
Unguided turning 14.56 deg
Angle of Attack -38.66 deg
Area 9.26 mm2
Axial chord(width) 14.18 mm
Camber 84.48 deg
Maximum Thickness 4.88 mm
Pitch/Chord 0.8214
Radius at CG 300 mm
Solidity 1.217
Throat/Pitch 0.2879
Tmax/Chord 0.2485

Figure 3(b) illustrates a top sectional view of an optimized high pressure nozzle profile obtained after aerodynamic and thermodynamic optimization according to the prior art.

Table 2 elucidates the geometry defining parameters at hub of high pressure nozzle of figure 1(b).
Table 2
Parameter Hub Section(H-H)
Chord 19.78 mm
Inlet Angle - 11.68 deg
Exit Angle 72.8 deg
Leading edge radius 3 mm
Stagger Angle 38.66 deg
Trailing edge radius 0.098 mm
Unguided turning 14.56 deg
Angle of Attack 38.66 deg
Area 9.26 mm2
Axial chord(width) 14.18 mm
Camber -84.48 deg
Maximum Thickness 4.88 mm
Pitch/Chord 0.8214
Radius at CG 300 mm
Solidity 1.217
Throat/Pitch 0.2879
Tmax/Chord 0.2485

Figure 4 illustrates an efficiency plot across the stages of a high pressure module using high pressure nozzles of figure 3(b) and high pressure blades of figure 3(a) for a simulation run at a predefined input and set of predefined constraints.
The predefined input and set of predefined constraints are governed by standard design rules employed in steam turbine industry.
The operational input data and set of predefined constraints are as follows:
1) Operational input data:
Inlet Pressure 18.05 bar
Exit Pressure 13.47 bar
Inlet Temperature 3300 C
Mass Flow 38 Kg/Sec
Speed of Rotor Drum (N) 5625 rpm
Hub Radius 300 mm

2) Set of Predefined Constraints:
Achieve thermodynamic loading(delta h/U2)- (Change in Enthalpy/Square of Peripheral Velocity of Rotor) 1.05-1.4 bar
Achieve Mean Reaction 50%
Optimum Peripheral velocity of rotor/Tangential velocity of steam flow (U/Cs) 0.6 to 0.7
Optimum Swirl 10 to 20 deg
Axial velocity of steam flow/peripheral velocity of the rotor (Ca/U) 0.32 to 0.35
Pitch/Chord (At Hub) 0.86 to 0.984
Efficiency 95%

The x-axis of the plot indicates stage number and the y-axis of the plot indicates efficiency in percentage. It can be inferred from the figure 4 that efficiency drops from 95.13% at first stage to 94.72% at third stage showing linear drop across the three stages. The optimized blade & nozzle profile disclosed in Patent Application 2776/CHE/2015 yielded a total to total module efficiency of 94.95% for a given set of predefined operational input and set of predefined constraints. Though the optimized profile herein question is not an improvement or modification over the optimized blade profile of Patent Application 2776/CHE/2015 and developed independently by not tweaking the blade profile of Patent Application 2776/CHE/2015 but an effective comparison can be drawn as the simulation for both the profiles is run at same boundary conditions.

Therefore, there is a felt need for development of a high pressure blade profile to overcome the drawbacks of the prior art and thereby provide an efficient high pressure blade profile suitable for use in pressure ranges of high salt deposition.

OBJECTS OF THE INVENTION:
An object of the present invention is to provide an efficient high pressure blade suitable for use in low pressure ranges of steam turbines.

Another object of the present invention is to provide a high pressure blade suitable for use in conditions of high salt deposition.

One more object of the present invention is to provide a high pressure blade having better loading diagram.

Still another object of the present invention is to provide advanced airfoil geometry for a high pressure blade to minimize frictional losses, boundary layer separation losses, and secondary flow losses.

Further another object of the present invention is to provide a high pressure blade having mean reaction of 50%.

Yet one more object of the present invention is to develop a high pressure blade which facilitates in lower salt deposition on its surface especially at leading edge.

SUMMARY OF THE INVENTION:
In accordance with the present invention a high pressure blade (120) of a fluid flow machine is provided, the high pressure blade (120) comprising an air foil portion formed by a convex suction side (122) and a concave pressure side (124) bounded at extreme ends by a leading edge (126) and a trailing edge (128), wherein the geometry defining parameters of the high pressure blade (120) profile are according to the following table:
Parameter Hub Section(H-H)
Chord 19.56 mm
Inlet Angle 4 deg
Exit Angle -72.8 deg
Leading edge radius 2.5 mm
Stagger Angle -40.86 deg
Trailing edge radius 0.125 mm
Unguided turning 27.08 deg
Angle of Attack -40.86 deg
Area 7.67 mm2
Axial chord(width) 13.4 mm
Camber 76.8 deg
Maximum Thickness 5.18 mm
Pitch/Chord 0.8757
Radius at CG 300 mm
Solidity 1.141
Throat/Pitch 0.3097
Tmax/Chord 0.2596

Typically, the high pressure blade (120) has an elliptical nose shape at the leading edge (126).

Typically, the high pressure blade (120) performs better and suitable for use in conditions of high salt deposition.

BRIEF DESCRIPTION OF THE DRAWINGS:
The invention will now be described with reference to the accompanying drawings in which:
Figure 1 illustrates a sectional view of two adjacent moving blades depicting typical blade features;

Figure 2 illustrates sectional view of two adjacent nozzles depicting typical nozzle features;

Figure 3(a) illustrates a top sectional view of an optimized high pressure blade profile obtained after aerodynamic and thermodynamic optimization according to the prior art;

Figure 3(b) illustrates a top sectional view of an optimized high pressure nozzle profile obtained after aerodynamic and thermodynamic optimization according to the prior art;

Figure 4 illustrates an efficiency plot across the stages of a high pressure module using high pressure nozzles of figure 3(b) and high pressure blades of figure 3(a) for a simulation run at a predefined input and set of predefined constraints;

Figure 5(a) illustrates a top sectional view of an optimized high pressure blade profile obtained after aerodynamic and thermodynamic optimization in accordance with the present invention;

Figure 5(b) illustrates a top sectional view of an optimized high pressure nozzle profile obtained after aerodynamic and thermodynamic optimization in accordance with the present invention;

Figure 6 illustrates an isometric view of a high pressure blade of figure 5(a);

Figure 7 illustrates an isometric view of a high pressure nozzle of figure 5(b);

Figure 8 illustrates a stream line flow path across a stage of a high pressure module with a high pressure nozzle of figure 5(b) and a high pressure blade of figure 5(a);

Figure 9 illustrates a plot of degree of reaction at high pressure nozzles of figure 5(b) and high pressure blades of figure 5(a) in a high pressure module for a simulation run at a predefined input and set of predefined constraints; and

Figure 10 illustrates an efficiency plot across the stages of a high pressure module using high pressure nozzles of figure 5(b) and high pressure blades of figure 5(a) for a simulation run at a predefined input and set of predefined constraints.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS:
A preferred embodiment will now be described in detail with reference to accompanying drawings. The preferred embodiment does not limit the scope and ambit of the invention. The description provided is purely by way of example and illustration.

Figure 5(a) illustrates a top sectional view of an optimized high pressure blade profile obtained after aerodynamic and thermodynamic optimization.

Figure 5(b) illustrates a top sectional view of an optimized high pressure nozzle profile obtained after aerodynamic and thermodynamic optimization.

It can be inferred from the figures 5(a) and 5(b) that leading edge is of elliptical nose shape when compared to the rounded shape of the leading edge of the figures 3(a) and 3(b) respectively. It is also evident from the figures 5(a) and 5(b) that the shape of the profile of the optimized high pressure blade and the optimized high pressure nozzle is same.

Figure 6 illustrates an isometric view of a high pressure blade of figure 5(a).

In accordance with the present invention, there is provided a high pressure blade 120 comprising a convex suction side 122, a concave pressure side 124, a leading edge 126 and a trailing edge 128. The high pressure blade 120 is provided with an integrally formed root R at its bottom to facilitate in insertion of the high pressure blade 120 in to a rotor disc of a rotor.

Table 3 elucidates the geometry defining parameters at hub of high pressure blade 120 of figure 6. As the high pressure blade profile in question is of cylindrical blade, the geometry parameters will not be varying spanwise across Hub, Mean and Tip except parameters associated with radius from axis of rotor drum like pitch etc.

Table 3
Parameter Hub Section(H-H)
Chord 19.56 mm
Inlet Angle 4 deg
Exit Angle -72.8 deg
Leading edge radius 2.5 mm
Stagger Angle -40.86 deg
Trailing edge radius 0.125 mm
Unguided turning 27.08 deg
Angle of Attack -40.86 deg
Area 7.67 mm2
Axial chord(width) 13.4 mm
Camber 76.8 deg
Maximum Thickness 5.18 mm
Pitch/Chord 0.8757
Radius at CG 300 mm
Solidity 1.141
Throat/Pitch 0.3097
Tmax/Chord 0.2596

Figure 7 illustrates an isometric view of a high pressure nozzle of figure 5(b).

In accordance with the present invention, there is provided a high pressure nozzle 140 comprising a convex suction side 142, a concave pressure side 144, a leading edge 146 and a trailing edge 148. The high pressure nozzle 140 is provided with an integrally formed tenon T at its bottom to facilitate in insertion of the high pressure blade 140 in to a guide blade carrier.

Table 4 elucidates the geometry defining parameters at hub of high pressure blade 140 of figure 7.
Table 4
Parameter Hub Section(H-H)
Chord 19.56 mm
Inlet Angle - 4 deg
Exit Angle 72.8 deg
Leading edge radius 2.5 mm
Stagger Angle 40.86 deg
Trailing edge radius 0.125 mm
Unguided turning 27.08 deg
Angle of Attack 40.86 deg
Area 7.67 mm2
Axial chord(width) 13.4 mm
Camber -76.8 deg
Maximum Thickness 5.18 mm
Pitch/Chord 0.8757
Radius at CG 300 mm
Solidity 1.141
Throat/Pitch 0.3097
Tmax/Chord 0.2596

Figure 8 illustrates a stream line flow path across a stage of a high pressure module with a high pressure nozzle of figure 5(b) and a high pressure blade of figure 5(a).
It can be inferred from the figure 8 that the steam follows a smooth stream line flow path across a stage of a high pressure module without any recirculation.

Figure 9 illustrates a plot of degree of reaction at high pressure nozzles of figure 5(b) and high pressure blades of figure 5(a) in a high pressure module for a simulation run at a predefined input and set of predefined constraints.

Figure 10 illustrates an efficiency plot across the stages of a high pressure module using high pressure nozzles of figure 5(b) and high pressure blades of figure 5(a) for a simulation run at a predefined input and set of predefined constraints.

The predefined input and set of predefined constraints are governed by standard design rules employed in steam turbine industry.
The operational input data and set of predefined constraints are as follows:
1) Operational input data:
Inlet Pressure 18.05 bar
Exit Pressure 13.47 bar
Inlet Temperature 3300 C
Mass Flow 38 Kg/Sec
Speed of Rotor Drum (N) 5625 rpm
Hub Radius 300 mm

2) Set of Predefined Constraints:
Achieve thermodynamic loading(delta h/U2)- (Change in Enthalpy/Square of Peripheral Velocity of Rotor) 1.05-1.4 bar
Achieve Mean Reaction 50%
Optimum Peripheral velocity of rotor/Tangential velocity of steam flow (U/Cs) 0.6 to 0.7
Optimum Swirl 10 to 20 deg
Axial velocity of steam flow/peripheral velocity of the rotor (Ca/U) 0.32 to 0.35
Pitch/Chord (At Hub) 0.86 to 0.984
Efficiency 95%

Referring to the figure 9, the odd numbers on the x-axis of the plot represents high pressure nozzles 140 and the even numbers on the x-axis of the plot represents high pressure blades 120. The y-axis of the plot represents percentage of reaction. The green legend, red legend and blue legend in the plot indicates the degree of reaction at hub, mean and tip of nozzles and blades. It is evident from the plot that the mean reaction (red legend) at high pressure nozzles 140 and high pressure blades 120 in a three stage module is almost 50%.

Referring to the figure 10, the x-axis of the plot indicates stage number and the y-axis of the plot indicates efficiency in percentage. It can be inferred from the figure 10 that the efficiency drops from 95.43% at first stage to 95.08% at second stage and again picks up to 95.27% at third stage. The high pressure blade 120 and the high pressure nozzle 140 deployed in a three stage module in accordance with the present invention and for a simulation run at the same boundary conditions as that of the prior art yielded a total to total module efficiency of 95.16% which is 0.21% more than the total to total module efficiency of the prior art.

TEST RESULTS:
The phenomenon of salt deposition can be superimposed in a simulation through application of roughness on the surface of the blades. Various Simulations are run by applying roughness of different values over the surface of the nozzles and the blades of the present invention and the prior art and keeping all the remaining boundary conditions as same. The total to total module efficiency obtained from the simulations on the present invention and the prior art is tabulated herein below.

Sl.No Average Roughness Present Invention Prior Art
1. 1 Micron 94.91 94.44
2. 2 Micron 94.7 94.24
3. 5 Micron 94.53 93.92
4. 0.5 mm 88.03 87.48

It can be deduced from the above table, that in all the cases, the efficiency of the present invention is more than 0.21% when compared to the prior art. So, in a nutshell, it can be inferred that the blades and nozzles of the present invention are performing better when compared to the blades and nozzles of the prior art especially in conditions of salt deposition.

Further, it is also observed that salt deposition at leading edge is less on the blades and nozzles of the present invention due to elliptical nose shape and low contact surface area when compared to the rounded shape blades and nozzles of the prior art.

TECHNICAL ADVANCEMENTS:
A high pressure blade of a fluid flow machine has several technical advantages including but not limited to the realization of :
• an efficient high pressure blade suitable for use in low pressure ranges of steam turbines ;
• a high pressure blade suitable for use in conditions of high salt deposition ;
• a high pressure blade having better loading diagram ;
• a high pressure blade with advanced air foil geometry to minimize frictional losses, boundary layer separation losses, and secondary flow losses ;
• a high pressure blade having mean reaction of 50% ; and
• a high pressure blade which facilitates in lower salt deposition on its surface especially at leading edge.

Although the invention has been described herein above with reference to the embodiments of the invention, the invention is not limited to the embodiments described herein above. It is to be understood that modifications and variations of the embodiments can be made without departing from the spirit and scope of the invention.