Boost Compressor for Gas Turbine Cooling Air Pressure
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Solution Overview
Problem
The geared gas turbine engine faces challenges in efficiently delivering cooling air to the turbine section due to higher temperatures and pressures, where using fully compressed air from downstream locations is inefficient, and there is a need for a more effective method to increase the pressure of cooling air for effective cooling.
Innovation Solution
The cooling air is tapped from an upstream location in the compressor and passed through a boost compressor to increase its pressure, with a mixing chamber and variable control systems to tailor the air delivery, ensuring sufficient pressure and flow for cooling, and the boost compressor is controlled to match operational conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stress or pressure
If cooling air is tapped from downstream end of compressor section, then cooling air pressure is sufficient to move into turbine section, but air usage efficiency deteriorates due to having already fully compressed the air
Solution Approach 1:
The cooling air is tapped from an upstream location in the compressor section before full compression is achieved, and then a boost compressor is used to increase the pressure to the required level. This preliminary action of tapping air earlier in the compression process, combined with subsequent compression, avoids the energy waste of fully compressing air that will only be used for cooling.
2Speed
If fan rotor rotates at slower speeds with gear reduction, then fan drive turbine speed increases, but turbine section temperatures rise creating higher cooling challenges
Solution Approach 1:
The system changes the parameters of the cooling air by using a boost compressor to increase its pressure and by potentially adjusting temperature through the compression process. This allows the cooling air to effectively counteract the higher turbine section temperatures resulting from increased fan drive turbine speed.
3Stress or pressure
If boost compressor is used to increase cooling air pressure from upstream compressor location, then cooling air can effectively reach turbine section, but device complexity increases
Solution Approach 1:
The boost compressor is designed to serve multiple functions: it increases the pressure of cooling air to enable it to reach the turbine section, and it can be controlled to match various operational conditions. This multi-functionality justifies the added complexity by providing a versatile solution for cooling air delivery.
4Reliability
If variable control systems are added to tailor air delivery, then cooling effectiveness is optimized, but device complexity increases
Solution Approach 1:
Variable control systems are implemented to dynamically adjust the cooling air delivery parameters such as flow rate and pressure. This allows the system to adapt to changing operational conditions and optimize cooling effectiveness, with the control complexity being justified by the significant improvement in cooling performance.
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 allows for efficient delivery of cooling air to the turbine section, optimizing air usage and matching compressor operations across a range of conditions, thereby enhancing cooling effectiveness and reducing parasitic losses.
Implementation Method 1
This air is then passed through a boost compressor, which increases its pressure such that it now can move into the turbine section.
Implementation Method 2
with a mixing chamber and variable control systems to tailor the air delivery, ensuring sufficient pressure and flow for cooling
Data Source
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AI summary
A gas turbine engine (100) comprises a compressor section having a downstream most end (113) and a cooling air tap (120) at a location spaced upstream from the downstream most end (113). The cooling air tap (120) is passed through at least one boost compressor (118) and at least one heat exchanger (124, 130), and then passed to a turbine section to cool the turbine section, the boost compressor (118) being controlled to provide a desired pressure to the turbine section.