Compressor Impeller Cooling Air Sinks for Gas Turbine Efficiency
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Solution Overview
Problem
Gas turbine engines face challenges in effectively utilizing bleed air for cooling compressor impellers, as the cooling air is typically discarded, leading to inefficiencies in operational efficiency and impeller life.
Innovation Solution
A bleed circuit is introduced to reuse the cooling air from compressor impellers by directing it through a transport section and depositing it into a junction within the turbine, where it can cool turbine vanes or pressurize the forward wheel cavity, thereby increasing engine efficiency and impeller life.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of stationary object
If cooling air is bled from the impeller to cool the impeller, then impeller life is improved, but operational efficiency deteriorates due to discarding the cooling air
Solution Approach 1:
The patent recovers the cooling air that would otherwise be discarded from the impeller. The bleed circuit captures cooling air at the impeller tip and redirects it through transport passages to the turbine section, where it is reused for cooling turbine vanes or pressurizing the forward wheel cavity. This recovery approach eliminates the waste of pre-cooled air while maintaining impeller cooling benefits.
Solution Approach 2:
The cooling air serves multiple functions: it cools the impeller at the source, then is redirected to cool turbine vanes or pressurize the forward wheel cavity in the turbine section. This multi-functional use of the same air stream maximizes the utility of the bled air, improving overall engine efficiency while maintaining component life.
2Loss of energy
If a bleed circuit is implemented to reuse cooling air, then operational efficiency is improved, but device complexity increases
Solution Approach 1:
The bleed circuit is integrated with the existing compressor and turbine structures. The transport passages are formed within the diffuser and turbine housing, merging the cooling air recovery function with the existing flow path components. This integration approach minimizes additional complexity while achieving air reuse.
Solution Approach 2:
The diffuser serves as an intermediary structure that houses the transport passages for moving cooling air from the impeller to the turbine section. By utilizing the diffuser as the mediator for air transport, the patent avoids creating separate dedicated piping systems, thereby reducing overall system 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
The reuse of bleed air enhances the operational efficiency of gas turbine engines by maintaining improved impeller operation and life while minimizing the impact on engine performance.
Implementation Method 1
a compressor having an impeller arranged to rotate about the axis to compress air
Implementation Method 2
a diffuser for collecting compressed air from the impeller tip
Implementation Method 3
a bleed circuit fluidly connected between the compressor and the turbine for communicating a stream of impeller air from the impeller to the turbine
Implementation Method 4
where it can cool turbine vanes or pressurize the forward wheel cavity
Data Source
Figure 1~2
Figure 3
Figure 4~5
AI summary
A gas turbine engine includes devices, systems, and methods for providing bleed air from the compressor impeller to the turbine for cooling and/or other use. The bleed air may include compressor cooling air that is routed through the diffuser and external to an outer bypass duct and/or internally to a forward wheel cavity of the turbine.