Gas Turbine Heat Shield Securing Element Cooling
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Solution Overview
Problem
Existing heat shields in gas turbines face challenges in efficiently cooling securing elements, leading to increased cooling air consumption and adverse effects on NOx emissions and thermal stress, due to inefficient sealing and cooling of gaps between heat shield elements.
Innovation Solution
The introduction of a securing element with a through opening in the fixing section allows direct supply of cooling fluid to the grip section, enabling effective cooling of the securing elements without sealing the entire gap, and the use of a heat-insulating coating on the hot surface further reduces cooling fluid demand.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If gaps are left between adjacent heat shield elements to allow thermal expansion, then thermal expansion is enabled, but hot gas can penetrate through the gaps into the heat shield
Solution Approach 1:
The heat shield is divided into multiple discrete heat shield elements with gaps between them, allowing each element to expand independently while the overall structure remains segmented and manageable
Solution Approach 2:
A cooling fluid is introduced as an intermediary substance that flows through channels in the supporting structure and securing elements to cool the heat shield elements, preventing hot gas penetration without requiring complete gap sealing
2Strength
If metal securing elements are used to fix heat shield elements, then securing is achieved, but cooling of the securing elements becomes problematic due to their exposure to hot gas
Solution Approach 1:
The securing elements are designed with localized cooling channels that allow cooling fluid to flow directly through the fixing section, providing targeted cooling where the metal is most vulnerable to thermal loading while maintaining securing capability
Solution Approach 2:
Cooling fluid serves as an intermediary that transfers heat away from the metal securing elements through dedicated cooling channels, protecting the securing elements from thermal damage without compromising their structural function
3Object-affected harmful factors
If gaps are flushed with cooling air to seal against hot gas penetration, then hot gas penetration is prevented, but cooling air consumption increases and combustion performance deteriorates
Solution Approach 1:
The cooling function is extracted from the general gap sealing function and implemented through dedicated cooling channels in the securing elements, allowing cooling without requiring large volumes of cooling air to flush gaps
Solution Approach 2:
A cooling fluid circulation system is implemented that uses pressurized cooling fluid flowing through channels in the supporting structure and securing elements, replacing the need for large volumes of cooling air to seal gaps
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 approach reduces cooling air consumption, decreases thermal stress on heat shield elements, and lowers NOx emissions, allowing for either reduced emissions or increased output while maintaining current emissions levels, and enhances the durability of the heat shield by improving cooling efficiency.
Implementation Method 1
it is possible for the cooling fluid to be supplied directly to the grip section through the through opening from the supporting structure
Implementation Method 2
the use of a heat-insulating coating on the hot surface further reduces cooling fluid demand
Data Source
AI summary
A heat shield is provided on a supporting structure with a number of heat shield elements, which are fixed to a large area of the supporting structure leaving gaps between adjacent heat shield elements, a number of securing elements with which the heat shield elements are fixed to the supporting structure and which have a grip section engaging in the heat shield elements and a cooling system for cooling the securing elements, the cooling system being designed such that cooling fluid can be supplied directly to the grip sections of the securing elements.