Gas Turbine Guide Vane Cooling Air Bore Placement
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In gas turbines, inhomogeneous pressure fields at the leading edges of guide vanes cause hot gas to penetrate annular gaps, leading to inefficiencies in cooling, particularly when existing cooling-air ducts no longer effectively counteract pressure maxima due to changes in vane positions during upgrading or when new guide vanes are installed.
Innovation Solution
The method involves replacing guide vanes of the first guide vane stage with new or reconditioned ones that have cooling-air bores fluidically connected to a supply duct, with more bores positioned radially inward from the leading edges, thereby redirecting cooling air to effectively counteract pressure maxima without requiring on-site machining or altering existing cooling ducts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If existing cooling-air ducts are used to cool annular gaps, then cooling is provided to the supporting structure, but hot gas penetrates the annular gaps in the region of leading edges due to pressure maxima
Solution Approach 1:
The patent applies local quality by providing cooling-air bores specifically in the region of leading edges where pressure maxima occur. The vane platforms are equipped with additional cooling-air bores at radially inner positions that open directly into the annular gaps at the leading edge regions, targeting the specific location where hot gas penetration occurs. This localized cooling approach ensures that cooling air is delivered precisely where the thermal challenge is greatest, rather than using a uniform cooling distribution.
2Adaptability or versatility
If guide vanes are replaced during upgrading, then new guide vanes can be installed, but existing cooling-air ducts no longer effectively counteract pressure maxima due to changes in vane positions
Solution Approach 1:
The patent applies preliminary action by pre-equipping the new guide vanes with cooling-air bores during the manufacturing process. The cooling-air bores are integrated into the vane platforms of the new guide vanes before installation, so that when the new guide vanes are mounted in upgraded positions, the cooling air paths are already correctly positioned to counteract the pressure maxima at the new leading edge locations. This eliminates the need for on-site machining or modification of cooling ducts after the guide vanes are installed.
3Reliability
If more cooling-air bores are positioned radially inward from leading edges, then hot gas penetration is prevented more effectively, but device complexity increases
Solution Approach 1:
The patent applies universality by designing the new guide vanes to serve multiple functions: they perform the primary function of guiding the gas flow while simultaneously incorporating cooling-air bores that provide thermal protection. The vane platforms are designed as multi-functional components that integrate both the flow-guiding geometry and the cooling air distribution system. This allows the guide vanes themselves to provide both aerodynamic and thermal management functions, rather than requiring separate dedicated cooling structures.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution ensures reliable prevention of hot gas penetration into annular gaps without unnecessary contamination or machining, simplifying the upgrading process by using cooling-air bores on new guide vanes to adapt to changing pressure distributions, maintaining cooling efficiency even when the number of guide vanes changes.
Implementation Method 1
inhomogeneous pressure fields are formed in the region of the annular gaps and are primarily caused by the fact that the hot gas flowing out of the combustion chamber into the gas turbine accumulates in the region of the leading edges of the blades of the guide vanes
Implementation Method 2
The cooling air which is conducted through said cooling air ducts therefore enters the corresponding annular gap in each case in the region of the pressure maxima and generates cooling-air flows which prevent hot air from penetrating the annular gap
Data Source
AI summary
A method for upgrading a gas turbine, the method includes: a) removing all guide vanes of the first guide vane stage; b) replacing the removed guide vanes of the first guide vane stage with new or reconditioned guide vanes, wherein blade platforms of the new or reconditioned guide vanes are provided with cooling air bores which fluidically connect a cooling air supply duct to the annular gap and open into the annular gap, and wherein the cooling air bores are arranged in such a manner that more cooling air bores open into regions of an annular gap that are arranged radially inwards from leading edges of the guide vanes than in other regions of the annular gap.