Turbines and their components
First Claim
1. An axial flow gas turbine, comprising:
- in axial succession, a turbine and a turbine exhaust section, the turbine comprising a turbine nozzle containing a low pressure turbine stage having an annular row of stator vanes followed in axial succession by an annular row of rotor blades, wherein the low pressure turbine stage is characterized by the following parameters;
a ratio of vane airfoil pitch to vane airfoil axial width at a root end of a vane airfoil (P/W) is in a region of 1.0 to 1.2;
a ratio of blade airfoil pitch to blade airfoil axial width at a root end of a blade airfoil (P/W) is in the region of 0.6;
a ratio of blade diameter at a tip end of the blade airfoil to blade diameter at the root end of the blade airfoil is in a region of 1.6-1.8; and
a ratio of a axial length of the exhaust section to the blade airfoil height (L/H) is no greater than a value in a region of 4;
1;
said parameters being subject to a predetermined amount of variation.
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Accused Products
Abstract
An axial flow gas turbine comprises a turbine and a turbine exhaust section. The turbine comprises a turbine nozzle containing a low pressure turbine stage having an annular row of stator vanes (V2) followed in axial succession by an annular row of rotor blades (B2). The low pressure turbine stage is characterized by the following parameters: the ratio of vane airfoil pitch to vane airfoil axial width (P/W) at the root end of the vane airfoil (V2) is in the region of 1.0 to 1.2, preferably about 1.12; the ratio of blade airfoil pitch to blade airfoil axial width (P/W)at the root end of the blade airfoil (B2) is in the region of 0.6; the ratio of blade diameter at the tip end of the blade airfoil to blade diameter at the root end of the blade airfoil (blade tip/hub diameter ratio) is in the region of 1.6-1.8, preferably about 1.72; and the ratio of the axial length of the exhaust section to the blade airfoil height (L/H) is no greater than a value in the region of 4:1, preferably 3:1. These parameters are subject to a permitted variation of up to ±10%, preferably up to ±5%. Dimensions of example airfoils are given and are scaleable to produce turbines of any chosen power.
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Citations
25 Claims
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1. An axial flow gas turbine, comprising:
- in axial succession, a turbine and a turbine exhaust section, the turbine comprising a turbine nozzle containing a low pressure turbine stage having an annular row of stator vanes followed in axial succession by an annular row of rotor blades, wherein the low pressure turbine stage is characterized by the following parameters;
a ratio of vane airfoil pitch to vane airfoil axial width at a root end of a vane airfoil (P/W) is in a region of 1.0 to 1.2;
a ratio of blade airfoil pitch to blade airfoil axial width at a root end of a blade airfoil (P/W) is in the region of 0.6;
a ratio of blade diameter at a tip end of the blade airfoil to blade diameter at the root end of the blade airfoil is in a region of 1.6-1.8; and
a ratio of a axial length of the exhaust section to the blade airfoil height (L/H) is no greater than a value in a region of 4;
1;
said parameters being subject to a predetermined amount of variation. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17)
- in axial succession, a turbine and a turbine exhaust section, the turbine comprising a turbine nozzle containing a low pressure turbine stage having an annular row of stator vanes followed in axial succession by an annular row of rotor blades, wherein the low pressure turbine stage is characterized by the following parameters;
- 18. A blade airfoil for a low pressure turbine stage of a gas turbine, the airfoil having cross-sectional profiles at a root, mid-height, and tip as defined in Tables 1A to 1C respectively, subject to a predetermined level of variation.
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21. A blade airfoil for a low pressure turbine stage of a gas turbine, the blade airfoil'"'"'s configuration being defined by the application of a scaling factor to the x, y and z values in Tables 1A to 1C to obtain scaled x, y and z values, said scaling factor being chosen to obtain a predetermined power output from the low pressure turbine, the scaled x, y and z values being subject to said predetermined level of variation.
- 22. A vane airfoil for a low pressure turbine stage of a gas turbine, the vane having cross-sectional profiles at a root, mid-height, and tip as defined in Tables 2A to 2C respectively, subject to a predetermined level of variation.
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25. A vane airfoil for a low pressure turbine stage of a gas turbine, the vane airfoil'"'"'s configuration being defined by the application of a scaling factor to the x, y and z values in Tables 2A to 2C to obtain scaled x, y and z values, said scaling factor being chosen to obtain a predetermined power output from the low pressure turbine, the scaled x, y and z values being subject to said predetermined level of variation.
Specification