Gas Turbine Vane Ring Convex Contour Burn-back
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Solution Overview
Problem
Aerodynamic designs for turbine guide wheels in gas turbines often compromise between efficiency and burn-back capability, leading to reduced turbine efficiency and increased specific fuel consumption due to the inability to maintain constant flow capacity during thermal stress-induced burn-back.
Innovation Solution
The design incorporates a convex pressure-side contour on the guide vanes, creating a constant passage section between adjacent vanes, which maintains the passage cross-section during burn-back, allowing for optimal aerodynamic efficiency and mechanical stability without compromising the burn-back criterion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If guide vanes are designed with strong aerodynamic loading in the rear suction side area (rear-loaded design), then aerodynamic efficiency is improved, but burn-back capability is violated
Solution Approach 1:
The pressure side contour is designed with different curvature characteristics in different regions: a first region with positive curvature (convex) and a second region with negative or zero curvature (concave or straight). This local differentiation allows the rear suction side area to maintain strong aerodynamic loading while the pressure side geometry ensures burn-back capability by controlling passage width changes during thermal degradation.
2Reliability
If guide vanes are designed to maintain constant passage cross-section during burn-back, then flow capacity is preserved, but aerodynamic loading is reduced
Solution Approach 1:
The pressure side contour is designed with different curvature characteristics in different regions: a first region with positive curvature (convex) and a second region with negative or zero curvature (concave or straight). This local differentiation allows the rear suction side area to maintain strong aerodynamic loading while the pressure side geometry ensures burn-back capability by controlling passage width changes during thermal degradation.
3Reliability
If a compromise is made in aerodynamic design to ensure burn-back capability, then reliability is improved, but turbine efficiency decreases
Solution Approach 1:
The pressure side contour is designed with different curvature characteristics in different regions: a first region with positive curvature (convex) and a second region with negative or zero curvature (concave or straight). This local differentiation allows the rear suction side area to maintain strong aerodynamic loading while the pressure side geometry ensures burn-back capability by controlling passage width changes during thermal degradation.
Data Source
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AI summary
The invention relates to a turbine guide wheel of a gas turbine with several guide vanes arranged at circumferential intervals. It is provided that two adjacent guide vanes (23) each form a passage (29) between the suction side (31) of one guide vane (23) and the pressure side (30) of the other guide vane, starting from the trailing edge (32) of the blade. This passage comprises a constant passage section (29a) in which the passage (29) has a substantially constant cross-sectional area (37). The constant passage section (29a) has an inlet region (38) and an outlet region (36). Each guide vane (23) forms a rear section (320) on the pressure side, which extends from the vane trailing edge (32) adjacent to the constant passage section (29a) to the inlet section (38) of the passage section (29), and forms a front section (310) on the pressure side, which extends upstream of the rear section (320).It is provided that each guide vane (23) has a convex pressure side contour (33) on the pressure side (30) that creates a transition from the rear area (320) of the guide vane (23) to the front area (310) of the guide vane (23).