FIELD OF THE INVENTION:
The present invention relates to the field of steam turbines. Particularly  the present invention relates to high pressure module blade profile of steam turbines.

TERMINOLOGY AND FORMULAS USED:
U-Peripheral velocity of rotor;
C-Steam velocity;
Cs-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.

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 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 and moving blades are mounted on rotor and configured in opposite direction and project outwards.

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.

The design concern herein is to achieve an optimized high pressure module reaction blade profile with mid span reaction of 50% and able to operate efficiently in off design conditions. In sugar industries during the peak crushing season  the amount of steam extracted from the turbine to be used for process purposes is very high. In contrary  during off-season  there will be no crushing and amount of extraction will be very low and most of the steam is used only for power generation purpose. So  the steam turbines in sugar industries are subjected to variable volumetric flow conditions. Typically  the volumetric flow varies between 85% to 130% of design volumetric flow. These high pressure module blade profiles are typically employed in sugar plant applications wherein the blades should be capable of withstanding wide angle of incidence due to variable volumetric flows without compromising much on efficiency.

Therefore  there is a felt need for development of advanced profile for high pressure module blade to overcome the drawbacks of the prior art and thereby producing a high efficient steam turbine high pressure module blade profile with 50% mid span reaction.

OBJECTS OF THE INVENTION:
An object of the present invention is to provide a high efficient steam turbine high pressure module blade profile capable of accepting wider incidence angles and achieving flat efficiencies over a wide range of operation.

Another object of the present invention is to provide a steam turbine high pressure module blade profile with mid span reaction of 50%.

One more object of the present invention is to provide a steam turbine high pressure module blade profile capable of operating efficiently at variable volumetric flows.

Still another object of the present invention is to provide a steam turbine high pressure module blade profile capable of operating efficiently at variable inlet and exit pressures.

Further another object of the present invention is to achieve an advanced airfoil geometry to minimize frictional losses  boundary layer separation losses  secondary flow losses and tip leakage losees.

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 blades depicting typical blade features;

Figure 2 illustrates a top sectional view of analytical model of hypothetical high pressure module blade base profile obtained according to predefined input and set of predefined constraints in accordance with the present invention;

Figure 3 illustrates a top sectional view of final model of high pressure module blade refined profile achieved after aerodynamic and thermodynamic optimization in accordance with the present invention;

Figure 4(a) illustrates an isometric view of blade of figure 3;

Figure 4(b) illustrates a front view of blade of figure 3;

Figure 4(c) illustrates a left side view of blade of figure 3;

Figure 4(d) illustrates a right side view of blade of figure 3;

Figure 4(e) illustrates a back view of blade of figure 3;

Figure 4(f) illustrates a top view of blade of figure 3;

Figure 5 illustrates a high pressure module with a plurality of stages having a blade profile of figure 3;

Figure 6 illustrates a convergent passage width between adjacent blade profiles of figure 3;

Figure 7 illustrates a relative mach number distribution to identify the flow phenomenon across the blade profile of figure 3;

Figure 8 illustrates a plot to identify the location of the loading across the blade profile of figure 3;

Figure 9 illustrates a plot showing that the thermodynamic loading and axial velocity of steam flow/peripheral velocity of the rotor are within the predefined constraints across the stages of high pressure module of figure 5 at design conditions;

Figure 10 illustrates a plot of degree of reaction at hub  mean and tip of the stationary blades and moving blades of high pressure module of figure 5 at design conditions;

Figure 11 illustrates a plot showing that the blade profiles in accordance with the present invention accepting wider incidence angles across the stages of high pressure module of figure5 at design conditions;

Figure 12 illustrates a plot showing the incidences across the stages of high pressure module at design conditions deployed with blade profiles of figure 2;

Figure 13 illustrates a plot showing flat efficiencies across the stages of the high pressure module of figure 5 at design conditions;

Figure 14 illustrates a plot showing the incidences at mean of the blades across the stages of high pressure module at off design conditions deployed with blade profiles of figure 2;

Figure 15 illustrates a plot showing efficiencies across the stages of high pressure module at off design conditions deployed with blade profiles of figure 2;

Figure 16 illustrates a plot of degree of reaction at mean of the stationary blades and moving blades of high pressure module of figure 5 at off design conditions;

Figure 17 illustrates a plot showing that the blade profiles in accordance with the present invention accepting wider incidence angles across the stages of high pressure module of figure5 at off design conditions; and

Figure 18 illustrates a plot showing flat efficiencies across the stages of the high pressure module of figure 5 at off design conditions.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS:
Figure 1 illustrates a sectional view of two adjacent blades depicting typical blade features.

The airfoil sections of two adjacent 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 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 ‘P’. The axial length of the blade typically referred to as width is indicated by a letter ‘W’. The inlet and exit blade angles are indicated by letters a1 and ß1 respectively. The 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 ‘T’. The angle between the chord line 21 and turbine axial direction (meridional direction) typically referred to as stagger angle is indicated by a letter ‘S’.

Figure 2 illustrates a top sectional view of analytical model of hypothetical high pressure module blade base profile obtained according to predefined input and set of predefined constraints.

In accordance with the present invention  the base profile is obtained initially by giving the predefined input and set of predefined constraints in the blade generating software (“Axial”). The predefined input and set of predefined constraints are governed by standard design rules employed in steam turbine industry.
Hypothetical operational input data and a set of predefined constraints are as follows:
1) Operational Input Data:
Inlet pressure at reaction stage 53.5 bar
Exit Pressure 30 bar
Inlet Temperature 4500c
Mass flow 140 Tons per hour or 38.88 kg/sec
Speed of Rotor Drum (N) 5625 rpm
Hub Radius 210 mm

2) Set of predefined constraints:
Achieve thermodynamic loading(delta h/U2)- (change in enthalpy/square of peripheral velocity of rotor) 1.1 to 1.2
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
Hblade/Diahub Less than or equal to 0.14
Pitch/ Chord(At Hub) 0.83 to 0.864
Efficiency 90%

In real time applications  the inlet pressure  exit pressure  temperature and volumetric flow stated in the above operational input data table will vary rapidly during off- design conditions.

Table 1 elucidates the geometry defining parameters at hub of moving blade profile of figure 2. As the 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 1
Parameter Hub Section(H-H)
Chord 14.86 mm
Inlet Angle 5.54 deg
Exit Angle -73.22 deg
Leading edge radius 0.421 mm
Stagger Angle -47.19 deg
Trailing edge radius 0.06 mm
Unguided turning 13.92 deg
Angle of Attack -47.19 deg
Area 26.89 mm2
Axial chord(width) 10.09 mm
Camber 78.76 deg
Maximum Thickness 2.736 mm
Pitch/Chord 0.688
Radius at CG 210 mm
Solidity 1.468
Throat/Pitch 0.279
Tmax/Chord 0.184

Figure 3 illustrates a top sectional view of final model of high pressure module blade refined profile achieved after aerodynamic and thermodynamic optimization.

Figure 4(a) illustrates an isometric view of blade of figure 3.

Figure 4(b) illustrates a front view of blade of figure 3.

Figure 4(c) illustrates a left side view of blade of figure 3.

Figure 4(d) illustrates a right side view of blade of figure 3.

Figure 4(e) illustrates a top view of blade of figure 3.

Figure 5 illustrates a high pressure module with a plurality of stages having a blade profile of figure 3.

In accordance with the present invention  there is provided a high pressure module blade profile comprising a convex suction side 34  a concave pressure side 36  a leading edge 38 and a trailing edge 40.

Table 2 elucidates the geometry defining parameters at hub of moving blade profile of figure 3. As the 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 2
Parameter Hub Section(H-H)
Chord 18 mm
Inlet Angle 10 deg
Exit Angle -72.8 deg
Leading edge radius 4 mm
Stagger Angle -38 deg
Trailing edge radius 0.25 mm
Unguided turning 20 deg
Angle of Attack -38 deg
Area 10.0683 mm2
Axial chord(width) 14.18 mm
Camber 82.8 deg
Maximum Thickness 4.824 mm
Pitch/Chord 0.7635
Radius at CG 210 mm
Solidity 1.36605
Throat/Pitch 0.2672
Tmax/Chord 0.268

Table 3 elucidates the geometry defining parameters at hub of stationary blade profile of figure 3.
Table 3
Parameter Hub Section(H-H)
Chord 18 mm
Inlet Angle - 10 deg
Exit Angle 72.8 deg
Leading edge radius 4 mm
Stagger Angle 38 deg
Trailing edge radius 0.25 mm
Unguided turning 20 deg
Angle of Attack 38 deg
Area 10.0683 mm2
Axial chord(width) 14.18 mm
Camber 82.8 deg
Maximum Thickness 4.824 mm
Pitch/Chord 0.7635
Radius at CG 210 mm
Solidity 1.36605
Throat/Pitch 0.2672
Tmax/Chord 0.268

The aerofoil shape (geometry) is same for both moving blade and stationary blade. However  the moving blade and stationary blades are configured in opposite direction by means of assembling T-root R in the slot provided on the rotor drum D as shown in figure 4(a) and figure 5 respectively. The claim of the application in question is only with respect to optimized profile shape of the blades. As the profile developer will not be able to analyze the flow phenomenon on a single blade  a high pressure module as shown in figure 5 with a plurality of stages having a blade profile of figure 3 is developed based on standard mean line calculations employed in turbine industry (i.e.  parameters like blade heights  no. stages etc are calculated based operational input data). The mean line calculations yielded blade heights in the range of 30mm to 55mm across the stages and number of stages as seven. However  the blade heights and no. stages in the HP stage of the turbine will not have any effect on study of aerodynamic performance of the blade profiles but to assess the performance of the blade profiles  simulations should be conducted on the overall high pressure module wherein the blade profiles of figure 3 are deployed.

TEST RESULTS:
Simulations were run on high pressure module of figure 5 and results are analyzed by means of plots obtained from test runs.

Figure 6 illustrates a convergent passage width between adjacent blade profiles of figure 3. The x-axis of the plot represents axial span wise of the blade profiles and y-axis of the plot indicates passage width between adjacent blade profiles. It is evident from the plot that the passage width decreases towards the trailing edge of the blade profiles which in turn conveys that flows accelerates towards the exit of the blades and minimizes the separation of boundary layer across the surface of the blade profiles.

Figure 7 illustrates a relative Mach number distribution to identify the flow phenomenon across the blade profile of figure 3 of a stationary blade 42 and moving blade 44. The colour scale indicates the relative mach number distribution and the location of red colour in the plot on the suction side 34 of the stationary blade 42 and moving blade 44 signifies the growth of boundary layer at the specified location and also indicates that the flow is slowly becoming turbulent from the specified location.

The general rule employed in analyzing flow phenomenon is as follows:
If Mach number < 1  then the flow is subsonic and the blade profiles are acceptable.
If Mach number =1  then the flow is sonic and the blade profiles are not acceptable as the flow will be turbulent and separation of boundary layer begins.
If Mach number > 1  then the flow is supersonic and the blade profiles are not acceptable as the flow will be highly turbulent and separation of boundary layer will be rampant.

Figure 8 illustrates a plot to identify the location of the loading across the blade profile of figure 3 of a stationary blade 42 and moving blade 44. The x-axis of the plot represents axial span wise of the blade profiles and y-axis of the plot indicates static pressure in KPa. The steep change in the curvature on the suction side 34 of the stationary blade 42 and moving blade 44 indicates that the location of aerodynamic loading is in the middle of the blade profile which in turn signifies that the profile losses are less.

Figure 9 illustrates a plot showing that the thermodynamic loading and axial velocity of steam flow/ peripheral velocity of the rotor are within the predefined constraints across the stages of high pressure module of figure 5. The green legend plot indicates that the thermodynamic loading (Delta H/ U2) across the stages is within the specified constraint range of 1.1 to 1.2. The blue legend plot and red legend plot indicates that the Axial velocity of steam/ Peripheral velocity of the rotor (Ca/U) at inlet of steam and exit of steam across the stages is within the specified constraint range of 0.32 to 0.35.

Figure 10 illustrates a plot of degree of reaction at hub  mean and tip of the stationary blades and moving blades of high pressure module of figure 5. The x-axis represents rows of stationary blades 42 and moving blades 44 with odd numbers indicating stationary blades 42 and even numbers indicating moving blades 44. The y-axis represents percentage of degree of reaction. The green legend plot indicates degree of reaction at hub  the blue legend plot indicates degree of reaction at tip and the red legend plot indicates degree of reaction at mean of stationary blades 42 and moving blades 44. It is evident from the plot that the stationary blades 42 and moving blades 44 achieved a mean reaction of 50%.

Figure 11 illustrates a plot showing that the blade profiles in accordance with the present invention accepting wider incidence angles across the stages of high pressure module of figure5 at design conditions. The x-axis represents rows of stationary blades 42 and moving blades 44 with odd numbers indicating stationary blades 42 and even numbers indicating moving blades 44. The y-axis represents incidence angle in degrees. The green legend plot with downward triangle indicates incidence angle at hub  the blue legend plot indicates optimum incidence angle at mean  the red legend plot indicates incidence angle at tip and the green legend plot with upward triangle indicates actual deviated incidence angle at mean of stationary blades 42 and moving blades 44. It is evident from the plot that the actual incidence deviation from the optimum incidence at mean is in the range of +10 to -10 degrees.

Figure 12 illustrates a plot showing the incidences of blade profiles of figure 2 at design conditions. The x-axis represents rows of stationary blades 42 and moving blades 44 with odd numbers indicating stationary blades 42 and even numbers indicating moving blades 44. The y-axis represents incidence angle in degrees at various sections like hub  mean and tip of the stationary blades 42 and moving blades 44. The green legend plot with downward triangle indicates incidence angles at the hub of the blades (42 and 44) across the stages. The green legend plot with upward triangle indicates incidence angles at the mean of the blades (42 and 44) across the stages. The red legend plot indicates incidence angles at the tip of the blades (42 and 44) across the stages. The blue legend plot indicates optimum angle of incidence at the mean of the blades (42 and 44) across the stages. It is evident from figure 12 that the blue legend plot and green legend plot with upward triangle are intermingling on over the other which signifies blade profiles of figure 2 are not in a position to accept wider incidence angles at design conditions.

Figure 13 illustrates a plot showing flat efficiencies across the stages of the high pressure module of figure 5 at design conditions. It is evident from the blue legend plot and red legend plot that the high pressure module achieved a total to total efficiency of 88.5% and total to static efficiency of 87.8% which is quite acceptable with respect to predefined requirement of 90% efficiency. Further  it can be observed from the plot that the variations in the efficiencies across the stages are minute.

Figure 14 illustrates a plot showing the incidences at mean of the blades across the stages of high pressure module at off design conditions deployed with blade profiles of figure 2. Two simulations at off design conditions of 85% and 130% of design volumetric flow are performed on the blade profiles of figure 2. The x-axis represents rows of stationary blades 42 and moving blades 44 with odd numbers indicating stationary blades 42 and even numbers indicating moving blades 44. The y-axis represents incidence angles in degrees at mean of the stationary blades 42 and moving blades 44. The dotted red colour plot indicates incidence at mean for 130% design volumetric flow test run. The continuous red colour plot indicates incidence at mean for 85% design volumetric flow run. The dotted and continuous blue color plot indicates optimum incidence at mean for 130% and 85% design volumetric flow runs respectively. It can be inferred from the plot that the blade profiles of figure 2 exhibited a deviation from optimum incidences in the range of +25 to -22 degrees.

Figure 15 illustrates a plot showing efficiencies across the stages of high pressure module at off design conditions deployed with blade profiles of figure 2. Two simulations at off design conditions of 85% and 130% of design volumetric flow are performed on the blade profiles of figure 2. The x-axis of the plot represents stages of high pressure module and y-axis of the plot represents efficiency. The continuous blue legend plot indicates total to total efficiency at 85% of design volumetric flow run whereas the dotted blue legend plot indicates total to total efficiency at 130% of design volumetric flow run. The continuous red legend plot indicates total to static efficiency at 85% of design volumetric flow run whereas the dotted red legend plot indicates total to static efficiency at 130% of design volumetric flow run. It is evident from the plot that at 130% of design volumetric flow run variations in both the total to total efficiency (efficiency drop is from 99% to 88%) and total to static efficiency (efficiency drop is from 93% to 82%) across the stages are predominant.

Figure 16 illustrates a plot of degree of reaction at mean of the stationary blades and moving blades of high pressure module of figure 5 at off design conditions. Simulations are run at various volumetric flows from 85% to 130% of design volumetric flow by increasing the volumetric flow up by 5% and the results are plotted. The x-axis represents rows of stationary blades 42 and moving blades 44 with odd numbers indicating stationary blades 42 and even numbers indicating moving blades 44. The y-axis represents percentage of degree of reaction. It is evident from the figure 15 that at all off design conditions  the degree of reaction is within the range of 48.5% to 51.5% achieving a mid span reaction of approximately 50%.

Figure 17 illustrates a plot showing that the blade profiles in accordance with the present invention accepting wider incidence angles across the stages of high pressure module of figure5 at off design conditions. Simulations are run at various volumetric flows from 85% to 130% of design volumetric flow by increasing the volumetric flow up by 5% and the results are plotted. The x-axis represents rows of stationary blades 42 and moving blades 44 with odd numbers indicating stationary blades 42 and even numbers indicating moving blades 44. The y-axis represents incidence angles in degrees. The green legend plot with upward triangle indicates incidence at mean of the blades at various volumetric flow runs. The red legend plot indicates incidences at tip of the blades at various volumetric flow runs. The green legend plot with downward triangle indicate incidence at hub of the blades at various volumetric flow runs. The blue legend plot indicates optimum incidences at mean of the blades at various volumetric flow runs. It can be inferred from the plot that the blade profiles of figure 2 exhibited a deviation from optimum incidences in the range of +25 to -22 degrees.
Figure 18 illustrates a plot showing flat efficiencies across the stages of the high pressure module of figure 5 at off design conditions. . Simulations are run at various volumetric flows from 85% to 130% of design volumetric flow by increasing the volumetric flow up by 5% and the results are plotted. The x-axis of the plot represents stages of high pressure module and y-axis of the plot represents efficiency. It is evident from the blue legend plot and red legend plot that the high pressure module achieved a total to total efficiency of 85% and total to static efficiency of 80% at off design conditions. Further  it can be observed from the plot that the variations in the efficiencies across the stages are minute.

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.

We claim:
1) A fifty percent reaction high pressure module blade of a steam turbine comprising an airfoil portion formed by a convex suction side and a concave pressure side bounded at the extreme ends by a leading edge and a trailing edge  wherein the geometry defining parameters of a moving blade profile are according to the following table:
Parameter Hub Section(H-H)
Chord 18 mm
Inlet Angle 10 deg
Exit Angle -72.8 deg
Leading edge radius 4 mm
Stagger Angle -38 deg
Trailing edge radius 0.25 mm
Unguided turning 20 deg
Angle of Attack -38 deg
Area 10.0683 mm2
Axial chord(width) 14.18 mm
Camber 82.8 deg
Maximum Thickness 4.824 mm
Pitch/Chord 0.7635
Radius at CG 210 mm
Solidity 1.36605
Throat/Pitch 0.2672
Tmax/Chord 0.268

2) A fifty percent reaction high pressure module blade of a steam turbine comprising an airfoil portion formed by a convex suction side and a concave pressure side bounded at the extreme ends by a leading edge and a trailing edge  wherein the geometry defining parameters of a stationary blade profile are according to the following table:
Parameter Hub Section(H-H)
Chord 18 mm
Inlet Angle - 10 deg
Exit Angle 72.8 deg
Leading edge radius 4 mm
Stagger Angle 38 deg
Trailing edge radius 0.25 mm
Unguided turning 20 deg
Angle of Attack 38 deg
Area 10.0683 mm2
Axial chord(width) 14.18 mm
Camber 82.8 deg
Maximum Thickness 4.824 mm
Pitch/Chord 0.7635
Radius at CG 210 mm
Solidity 1.36605
Throat/Pitch 0.2672
Tmax/Chord 0.268

3) A fifty percent reaction high pressure module blade of a steam turbine as claimed in claim 1  wherein the leading edge radius of said moving blade is of 4mm.

4) A fifty percent reaction high pressure module blade of a steam turbine as claimed in claim 2  wherein the leading edge radius of said stationary blade is of 4mm.

5) A fifty percent reaction high pressure module blade of a steam turbine as claimed in claim 1  wherein said moving blade is a cylindrical blade.

6) A fifty percent reaction high pressure module blade of a steam turbine as claimed in claim 2  wherein said stationary blade is a cylindrical blade.

7) A fifty percent reaction high pressure module blade of a steam turbine as described herein the description and accompanying drawings.

Dated this 8th day of Sept  2011 (for Triveni Turbine Ltd)


Dr.Sunil Jajit
GM-IPR