Baffle Assembly Cooling Air Path Velocity
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Solution Overview
Problem
Gas turbine engine components, such as turbine blades, experience platform distress due to high metal temperatures and low backside heat transfer, which conventional cooling methods fail to adequately address, particularly in areas difficult to cool.
Innovation Solution
A baffle assembly is introduced in gas turbine engines that reduces the cross-sectional area of the cooling air path, increasing the flow velocity of cooling air and enhancing heat transfer by redirecting it through a narrower path between the baffle and the blade platforms, thereby reducing platform temperatures and distress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If conventional cooling air paths are used with large cross-section, then the structure is simpler and easier to manufacture, but the heat transfer efficiency is insufficient and platform temperatures remain too high
Solution Approach 1:
The baffle assembly creates a localized region of reduced cross-section in the cooling air path specifically at the platform cooling areas. This local modification concentrates cooling air flow where it is most needed - at the platform surfaces - rather than uniformly distributing it throughout the entire air path. The baffle structure is positioned to create this targeted effect without requiring complete redesign of the entire cooling system.
Solution Approach 2:
The invention changes the cross-sectional area parameter of the cooling air path by introducing the baffle assembly. This parameter change reduces the effective flow area, which according to fluid dynamics principles increases the velocity of cooling air and enhances the heat transfer coefficient. The parameter modification is achieved through the physical presence of the baffle that partially blocks the cooling air path.
2Reliability
If cooling air flow rate is increased to improve heat transfer, then platform distress is reduced, but the required cooling air path cross-section increases
Solution Approach 1:
The invention changes the flow velocity parameter by reducing the cross-sectional area through the baffle assembly. This creates a higher velocity cooling air flow that delivers more effective heat transfer per unit area. The increased velocity compensates for the reduced cross-section, maintaining or improving overall cooling effectiveness without requiring a larger air path area.
Solution Approach 2:
The baffle assembly creates a localized region of reduced cross-section in the cooling air path specifically at the platform cooling areas. This local modification concentrates cooling air flow where it is most needed - at the platform surfaces - rather than uniformly distributing it throughout the entire air path.
3Ease of manufacture
If filmholes are used for cooling, then the structure is simpler, but heat transfer efficiency is insufficient in difficult-to-cool areas
Solution Approach 1:
The baffle assembly acts as an intermediary element that modifies the cooling air flow characteristics. It serves as a mediator between the cooling air source and the platform surfaces, creating optimized flow patterns that enhance heat transfer. The baffle structure is positioned to redirect and concentrate cooling air toward difficult-to-cool platform areas, improving effectiveness without adding complex cooling features to the platforms themselves.
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
The baffle assembly effectively increases heat transfer coefficients, decreases platform temperatures, and reduces platform distress by enhancing cooling air velocity and heat transfer, from approximately 50 BTU/ft2/Hr/°F to 200-300 BTU/ft2/Hr/°F, lowering temperatures from 2050°F to 1800°F.
Implementation Method 1
a baffle sized and shaped to extend between surfaces of the cooling plenum such that a cooling air path of reduced cross-section is formed between the baffle and the surfaces, the baffle being operative to increase a flow rate of cooling air as the cooling air directed to the cooling air path is redirected through the cooling air path of reduced cross-section
Implementation Method 2
the baffle being operative to increase a flow rate of cooling air as the cooling air directed to the cooling air path is redirected through the cooling air path of reduced cross-section
Implementation Method 3
The baffle assembly effectively increases heat transfer coefficients, decreases platform temperatures
Data Source
AI summary
Gas turbine engine systems involving baffle assemblies are provided. In this regard, a representative baffle assembly for a gas turbine engine includes: a cooling plenum defining a cooling air path; and a baffle sized and shaped to extend between surfaces of the cooling plenum such that a cooling air path of reduced cross-section is formed between the baffle and the surfaces, the baffle being operative to increase a flow rate of cooling air as the cooling air directed to the cooling air path is redirected through the cooling air path of reduced cross-section.