Gas Turbine Exhaust Plenum Cooling via Segmented Airflow
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Solution Overview
Problem
The increasing temperature of working gas in gas turbines leads to a significant increase in compressed air consumption for cooling, which contradicts the goal of improving efficiency, and using high-temperature resistant materials is costly and impractical.
Innovation Solution
A dual cooling system is implemented in the gas turbine installation, where compressed air is used for cooling the outer exhaust diffuser and ambient air is used for cooling the inner diffuser, reducing the overall compressed air consumption and increasing energy efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the temperature of working gas is raised to improve efficiency, then energy efficiency is improved, but the amount of compressed air consumed for cooling increases
Solution Approach 1:
The exhaust plenum cooling is divided into two separate cooling systems: a first cooling system for the outer exhaust diffuser and a second cooling system for the inner exhaust diffuser. This segmentation allows different cooling air sources to be used for different components, optimizing overall cooling efficiency while reducing compressed air consumption.
Solution Approach 2:
Different cooling strategies are applied to different locations within the exhaust plenum. The outer exhaust diffuser receives cooling air from the first cooling system, while the inner exhaust diffuser receives cooling air from the second cooling system. This local differentiation allows each component to be cooled appropriately based on its specific thermal requirements.
2Temperature
If high-temperature resistant materials are employed to increase working gas temperature capability, then temperature resistance is improved, but production cost increases
Solution Approach 1:
The patent replaces the mechanical/material solution (using high-temperature resistant materials) with a thermal management solution (dual cooling systems). Instead of relying on expensive materials to withstand high temperatures, the invention uses controlled cooling air flow to maintain components within safe temperature ranges, allowing the use of standard materials and reducing production costs.
3Temperature
If compressed air is used for cooling the exhaust plenum, then cooling performance is achieved, but the proportion of compressed air consumed for cooling increases
Solution Approach 1:
The cooling system is segmented into two independent pathways that can operate simultaneously or independently. The first cooling system handles the outer exhaust diffuser while the second cooling system handles the inner exhaust diffuser, allowing optimized air distribution and reduced total compressed air consumption.
Solution Approach 2:
The invention changes the cooling parameters by introducing a second cooling system with different operating characteristics. The second cooling system is designed to operate with different air flow rates and pressure conditions, allowing the overall system to achieve effective cooling with a reduced proportion of compressed air.
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 reduces the amount of compressed air needed for cooling, enhances energy efficiency, and allows for higher working gas temperatures without increasing production costs, while maintaining component temperatures within safe limits, thus improving the reliability and adaptability of the gas turbine.
Implementation Method 1
a first cooling system for introducing, from the outer peripheral side of the outer diffuser, cooling air for cooling the exhaust plenum
Implementation Method 2
a second cooling system for introducing, from the inner peripheral side of the inner diffuser, cooling air for cooling the exhaust plenum
Data Source
AI summary
The invention provides a gas turbine installation, a cooling air supplying method, a method of modifying a gas turbine installation, which can reduce the amount of compressed air extracted for cooling of an exhaust plenum and which can increase energy efficiency. The gas turbine installation comprises an exhaust plenum comprising an exhaust casing connected to the downstream side of a turbine and made up of an outer casing and an inner casing, and an exhaust diffuser made up of an outer diffuser and an inner diffuser, which are disposed between the outer casing and the inner casing; a first cooling system for introducing, from the outer peripheral side of the outer diffuser, cooling air for cooling the exhaust plenum; and a second cooling system for introducing, from the inner peripheral side of the inner diffuser, cooling air for cooling the exhaust plenum.