Flow Control Insert for Turbine Vane Cooling Efficiency
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Solution Overview
Problem
Combustion gas turbines face inefficiencies due to high cooling air flow requirements, which consume significant energy and reduce turbine efficiency, despite the need to maintain vane temperatures within specified ranges to prevent damage.
Innovation Solution
A flow control insert is designed to be placed in the cooling passages of turbine vanes, reducing cooling air flow while increasing heat transfer from the vane to the air, using designs such as a flow metering plate and flow control inserts like a twisted strip to achieve this, allowing existing vane designs to be used without modification.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If cooling air flow is increased to maintain vane temperature within specification, then vane temperature control is improved, but turbine efficiency deteriorates due to increased parasitic losses
Solution Approach 1:
The flow control insert introduces a porous screen structure within the cooling passage that creates controlled flow resistance. The porous material allows cooling air to pass through while maintaining a pressure drop that reduces the overall cooling air flow requirement from the turbine, thereby reducing parasitic losses while still achieving adequate cooling of the vane.
Solution Approach 2:
The flow control insert changes the flow parameters (velocity, pressure, distribution) of the cooling air within the passage. By introducing the insert, the cooling air flow rate is reduced while the heat transfer coefficient is enhanced through improved flow distribution and turbulence promotion, achieving the same cooling effect with less air and lower energy losses.
2Loss of energy
If cooling air flow is reduced to improve turbine efficiency, then parasitic losses are reduced, but vane temperature control deteriorates
Solution Approach 1:
The porous screen structure provides flow resistance that maintains adequate cooling air distribution throughout the passage even at reduced overall flow rates. The porous material ensures that cooling air reaches all critical areas of the vane while the pressure drop across the insert reduces the total cooling air requirement, thus maintaining temperature control with lower parasitic losses.
Solution Approach 2:
The flow control insert promotes turbulence and chaotic flow patterns within the cooling passage, which enhances convective heat transfer. This increased turbulence ensures that even reduced volumes of cooling air can effectively remove heat from the vane surfaces, maintaining temperature control while allowing for reduced cooling air flow and lower energy losses.
3Ease of manufacture
If existing vane design is used without modification, then manufacturing cost is reduced, but cooling air flow efficiency deteriorates
Solution Approach 1:
The solution segments the cooling system into two independent parts: the existing vane casting design and the separate flow control insert. This allows the proven, expensive-to-redesign vane to remain unchanged while the insert—a simpler, lower-cost component—is added to improve cooling efficiency and reduce parasitic losses.
Solution Approach 2:
The flow control insert acts as an intermediary component between the cooling air source and the vane. This mediator device modifies the cooling air flow characteristics without requiring changes to the vane itself, enabling efficiency improvements while avoiding the high costs associated with redesigning and revalidating the existing vane casting.
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 the volume of cooling air required, thereby enhancing turbine efficiency by minimizing parasitic losses while maintaining vane temperatures within specifications, thus improving overall engine performance without the need for redesigning expensive and validated vane components.
Implementation Method 1
increase heat transfer from the vane to the cooling air
Data Source
AI summary
A flow control insert for a turbine vane is disclosed. The flow control insert is designed to be placed in a trailing edge cooling passage of the turbine vane to simultaneously reduce cooling air flow and increase heat transfer from the vane to the cooling air, thereby improving efficiency of the turbine via reduced cooling air flow requirement while maintaining vane temperature within a specified range. Two different flow control insert designs are disclosed, where either design fits inside the cooling passage opening and allows an existing vane casting design to be used.