Thermally Isolated Cooling Plenum for Gas Turbine Thermal Management
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Solution Overview
Problem
Existing gas turbine engines face thermal degradation and premature wear due to thermal gradients caused by air leakage from the primary flow path into the cooling region, leading to uneven temperature distribution across turbine stages.
Innovation Solution
A thermally isolated cooling plenum is implemented with axial non-contact seals and a segmented seal along the inner diameter of the primary flow path to prevent fluid transfer between the primary flow path and the cooling plenum, ensuring that cooling air from a single source is evenly distributed and maintains thermal isolation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If air is allowed to leak from the primary flow path into the cooling region, then cooling air is replenished, but thermal gradients increase causing premature wear and breakage
Solution Approach 1:
The cooling plenum is segmented into thermally isolated regions using seals (radial seal at the inner diameter flow path wall and axial seal at the forward wall). This segmentation prevents hot air leakage from the primary flow path into the cooling region, maintaining uniform temperature distribution and eliminating thermal gradients that cause component wear and breakage.
2Temperature
If cooling air is drawn from compressor bleed and piped through TOBI system, then active cooling is achieved, but thermal gradients still occur due to air leakage
Solution Approach 1:
A thermally isolated cooling plenum acts as an intermediary chamber between the TOBI cooling air source and the turbine stages. The plenum with its sealing system (radial seal and axial seal) mediates the cooling air distribution, preventing hot air intrusion and ensuring uniform thermal conditions while maintaining effective cooling of the turbine stages.
3Reliability
If seals are installed to prevent air leakage, then thermal isolation is improved, but device complexity increases
Solution Approach 1:
Instead of implementing a complex sealed system throughout the entire cooling plenum, the invention applies sealing only at critical locations: the radial seal at the inner diameter flow path wall and the axial seal at the forward wall. This localized sealing approach achieves effective thermal isolation with minimal additional complexity.
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 reduces thermal gradients across the turbine stages, minimizing wear and extending the lifespan of components by maintaining consistent cooling temperatures and preventing hot air from entering the cooling plenum.
Implementation Method 1
a flow path inner diameter seal is disposed in the inner diameter flow path wall adjacent at least one of the at least one turbine stages, thereby preventing fluid transfer between the primary flow path and the thermally isolated cooling plenum
Implementation Method 2
a fore seal disposed between the forward wall and a rotor structure, wherein the fore seal prevents fluid flow between the thermally isolated cooling plenum and an adjacent plenum
Implementation Method 3
the cooling airflow is distributed throughout the thermally isolated cooling plenum
Implementation Method 4
thermally isolated cooling plenum supplied with a single source of cooling airflow... maintaining consistent cooling temperatures
Data Source
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AI summary
A gas turbine engine includes a turbine section (54) fluidly connected to a combustor (56) by a primary flow path (C). The turbine section (54) includes a first portion at a high pressure relative to a second portion. A thermally isolated cooling plenum (180) is positioned radially inward of the primary flow path (C). The cooling plenum (180) is defined by a forward wall (150), a shaft structure (170), an aft wall (160), and an inner diameter wall of the primary flow path (C). Air in the thermally isolated cooling plenum (180) is thermally isolated from air in the primary flow path (C). At least one cooling air system is operable to provide cooling air to the thermally isolated cooling plenum (180).