Turbine Cooling System with Dual Flow Paths and Heat Exchanger
Solution Overview
Problem
The extraction of cooling air from the compressor for gas turbine engines reduces engine efficiency, as it is used to cool turbine components, and existing systems lack robustness in case of heat exchanger failure, potentially leading to rotor blade overheating.
Innovation Solution
A dual cooling air flow path system with a heat exchanger and preswirler, where one path is cooled and then routed through nozzle guide vanes to reduce temperature and pressure, allowing for effective cooling while maintaining robustness by ensuring cooling air reaches the rotor even if one path fails.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If cooling air is extracted from the compressor to cool turbine components, then the turbine components are protected from overheating, but engine efficiency is reduced
Solution Approach 1:
The cooling air flow is divided into two separate paths: a first path through a heat exchanger that cools the air, and a second path that bypasses the heat exchanger. This segmentation allows partial cooling of cooling air to reduce turbine component temperatures while minimizing the overall impact on engine efficiency by not cooling all cooling air.
Solution Approach 2:
The temperature parameter of the cooling air is changed by passing it through a heat exchanger in the first flow path. The heat exchanger reduces the temperature of the cooling air from its original state (over 700°C) to a lower temperature, making it more effective for cooling turbine components while reducing the quantity of cooling air needed.
2Temperature
If a single heat exchanger is used to cool cooling air, then cooling effectiveness is improved, but system reliability is reduced due to vulnerability to heat exchanger failure
Solution Approach 1:
The cooling air supply system is segmented into two independent flow paths: a first path through the heat exchanger and a second path that bypasses it. This segmentation creates redundancy, ensuring that if the heat exchanger fails, cooling air can still reach the turbine rotor through the second path, thereby maintaining system reliability.
Solution Approach 2:
The second flow path acts as a pre-prepared backup or cushion against heat exchanger failure. By having this alternative path in place beforehand, the system is protected against the harmful effect of heat exchanger failure, ensuring continuous cooling air supply to the turbine rotor without interruption.
3Quantity of substance
If cooling air temperature is reduced to eliminate film cooling, then cooling air quantity is reduced and efficiency improves, but cooling effectiveness may be compromised
Solution Approach 1:
The temperature parameter of the cooling air is reduced by passing it through the heat exchanger in the first flow path. This temperature reduction increases the cooling effectiveness per unit volume of cooling air, potentially allowing reduction in the total quantity of cooling air needed while maintaining or improving 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 system reduces the amount of cooling air needed, potentially eliminating film cooling of rotor blades, improves engine efficiency, and maintains cooling effectiveness by ensuring continuous airflow to the turbine rotor even if one heat exchanger fails.
Implementation Method 1
a heat exchanger which cools the cooling air guided by the first flow path relative to the cooling air guided by the second flow path
Implementation Method 2
a preswirler for receiving the cooling air at the ends of the two flow paths, swirling the cooling air tangentially to the engine axis, and delivering the swirled cooling air to a rotor of the turbine
Data Source
AI summary
A cooling system is provided for cooling a turbine of a gas turbine engine. The system has first and second flow paths for guiding cooling air received from the compressor of the engine. The routes of both flow paths bypass the combustor of the engine. The system also has a preswirler for receiving the cooling air at the ends of the two flow paths, swirling the cooling air tangentially to the engine axis, and delivering the swirled cooling air to a rotor of the turbine. The first flow path is routed through a heat exchanger which cools the cooling air guided by the first flow path relative to the cooling air guided by the second flow path.