Multi-vane segment design and casting method
View Patent ↗Provided is an industrial gas turbine multi vane segment, which can be cast in one piece using a wax pattern method. The multi vane segment includes a platform; at least three airfoils, extending radially from the platform, having a combined airfoil volume, a chord length and an airfoil thickness; and a shroud with a shroud volume, disposed on an end of said airfoils radially distant from the platform. The ratio of the shroud volume to the combined airfoil volume defines a first ratio, while the multi vane segment has a first ratio greater or equal to 1.4:1. This ratio enables preferential solidification, during casting, of the airfoils before the shroud.
1. An industrial gas turbine multi vane segment, which can be cast in one piece using a wax pattern method, comprising:
a platform;
at least three airfoils extending radially from said platform having a combined airfoil volume, a chord length and an airfoil thickness; and
a shroud, disposed on an end of said airfoils radially distant from said platform, having a shroud volume,
wherein a ratio of the shroud volume to the combined airfoil volume defines a first ratio greater than or equal to 1.4:1.
2. The multi vane segment of claim 1 , wherein said first ratio is less than 2:1.
3. The multi vane segment of claim 2 , wherein a second ratio, defined as the ratio of the airfoils chord length to airfoil thickness, is greater than or equal to 7:1.
4. The multi vane segment of claim 3 , wherein the multi vane segment weighs more than 55 kg.
5. The multi vane segment of claim 3 , wherein the multi vane segment weighs more than 65 kg.
6. The multi vane segment of claim 5 , wherein the multi vane segment comprises no more than three airfoils.
7. The multi vane segment of claim 1 , wherein a second ratio, defined as a ratio of the airfoils chord length to airfoil thickness, is greater than or equal to 7:1.
8. The multi vane segment of claim 7 , wherein the multi vane segment weighs more than 55 kg.
9. The multi vane segment of claim 7 , wherein the multi vane segment weighs more than 65 kg.
10. The multi vane segment of claim 7 , wherein the multi vane segment comprises no more than three airfoils.
11. The multi vane segment of claim 1 , wherein the multi vane segment weighs more than 55 kg.
12. The multi vane segment of claim 1 , wherein the multi vane segment weighs more than 65 kg.
13. The multi vane segment of claim 1 , wherein the multi vane segment comprises no more than three airfoils.
14. A process for casting an industrial gas turbine multi vane segment weighing more than 55 kg suitable for casting as one piece and having:
a platform;
at least three airfoils extending radially from said platform having a combined airfoil volume, a chord length and a airfoil thickness; and
a shroud, disposed on an end of said airfoils radially distant from said platform, having a shroud volume, the process comprising:
selecting the multi vane segment with a first ratio defined by a ratio of the shroud volume to combined airfoil volume, and a second ratio defined by a ratio of chord length to airfoil thickness; and
casting, by a wax pattern method, said multi vane segment with a first ratio of greater than or equal to 1.4:1 and a second ratio of greater than or equal to 7:1.