Auxiliary Compressor Cooling Air for Turbine Vane Temperature Control
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Solution Overview
Problem
Gas turbine engines face inefficiencies due to the high operating temperatures of turbine nozzles, which require significant cooling air from the compressor, leading to lost energy and reduced thermal efficiency, as the existing cooling methods often dilute the hot combustion gases and result in limited pressure margin for effective cooling.
Innovation Solution
An auxiliary source of compressed air, heated by a separate engine and processed through a recuperator, is used to provide a dedicated supply of cooling air to the turbine vanes, reducing the quantity of cooling air required and improving overall efficiency by maintaining higher pressure and temperature than traditional designs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If traditional compressor cooling air is used for turbine nozzle cooling, then cooling effectiveness is achieved, but thermal efficiency decreases due to dilution of hot combustion gases and loss of pressure margin
Solution Approach 1:
The invention extracts the cooling air supply function from the main gas turbine compressor and places it in a separate auxiliary compressor system. This extraction allows the main compressor to focus solely on providing combustion air, eliminating the dilution effect on hot combustion gases while maintaining effective turbine nozzle cooling through the dedicated auxiliary cooling air supply.
Solution Approach 2:
The cooling air supply system is segmented into a separate auxiliary compressor, heat exchanger, and cooling air delivery system independent from the main compressor. This segmentation enables independent optimization of cooling air parameters (pressure, temperature, flow rate) without affecting the main combustion process, thereby improving thermal efficiency while maintaining cooling effectiveness.
2Temperature
If more cooling air is supplied to turbine nozzles, then metal temperature control is improved, but power output decreases due to reduced mass flow through combustor
Solution Approach 1:
The cooling air demand is extracted from the main combustion air flow and satisfied by a separate auxiliary compressor. This allows the main compressor to deliver maximum mass flow to the combustor for optimal power output, while the auxiliary compressor independently provides sufficient cooling air to maintain turbine nozzle metal temperatures within safe operating limits.
3Stress or pressure
If higher pressure cooling air is used, then cooling effectiveness increases, but the pressure margin available for cooling is limited by compressor design
Solution Approach 1:
The air compression function is segmented into two independent systems: the main compressor for combustion air and an auxiliary compressor for cooling air. This segmentation allows the auxiliary compressor to be specifically designed and optimized for delivering high-pressure cooling air to turbine nozzles without being constrained by the design requirements of the main combustion air compressor, thereby achieving higher cooling air pressure and improved cooling effectiveness.
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 enhances cooling effectiveness, reduces the amount of cooling air needed, and increases power output by up to 2.4% and efficiency by approximately 10%, while maintaining metal temperature control and extending component life.
Implementation Method 1
a heat exchanger cooling the compressed air from the auxiliary compressor
Data Source
AI summary
The present invention discloses a novel apparatus and methods for providing a flow of cooling air to one or more turbine nozzles or turbine blade outer air seals. The flow of cooling air is provided by an external source and regulated in order to improve turbine nozzle and air seal cooling efficiency and component life.