Fuel System Thermal Management to Prevent Gas Turbine Coking
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Solution Overview
Problem
Coking in the fuel system of gas turbine engines occurs during shutdown and is caused by residual fuel in the fuel nozzles and neighboring fuel lines, compromising fuel nozzle performance and requiring frequent maintenance.
Innovation Solution
An electrically powered compressor is integrated within the gas turbine engine's core compartment, which directs air from the bypass flow path to cool the turbine and combustion sections during operation and post-shutdown to prevent fuel from overheating and forming coke.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If fuel flow is halted at shutdown, then fuel consumption stops, but heat from the combustor and case structure soaks into the fuel system causing coking
Solution Approach 1:
The system applies preliminary cooling action to the fuel system before and during shutdown to prevent coking. The cooling system is activated to counteract the heat soaking that would otherwise cause fuel decomposition and coke formation in the fuel nozzles and lines.
Solution Approach 2:
The cooling system is activated in advance during the shutdown sequence to prevent coking before it can occur. By initiating cooling early in the shutdown process, the system prevents thermal damage to the fuel system components.
2Temperature
If an electric compressor is added to the core compartment, then active cooling capability is improved, but device complexity increases
Solution Approach 1:
The electric compressor installed in the core compartment serves multiple functions: it provides active cooling to the fuel system during shutdown, maintains engine cooling capabilities, and can support various operational modes. This multi-functionality justifies the added complexity by delivering multiple benefits from a single component.
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 solution effectively prevents coking in the fuel system, maintaining fuel injector performance and enhancing the reliability and operational time of the gas turbine engine.
Implementation Method 1
An electrically powered compressor is integrated within the gas turbine engine's core compartment, which directs air from the bypass flow path to cool the turbine and combustion sections during operation and post-shutdown to prevent fuel from overheating and forming coke.
Data Source
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AI summary
A gas turbine engine (10) includes an engine core with a compressor section (14), a combustion section (16) downstream of the compressor section (14) relative to a core flow path (C), and a turbine section (18) downstream of the combustion section (16) relative to the core flow path (C). A core casing (20) extends around the compressor section (14), the combustion section (16), and the turbine section (18). A second casing extends around the core casing (20) and a core compartment (48) is between the core casing (20) and the second casing. An electric compressor (50) is in the core compartment (48). A first port (52) is formed in the second casing and fluidically is connected to the electric compressor (50) via first valve. A bleed line is fluidically connecting the first valve to the core flow path proximate the compressor section. A second port (54) is formed in the core casing (20) in the combustion section (16) and is fluidically connected to the electric compressor (50) via a second valve. A turbine cooling line is fluidically connecting the second valve to at least one turbine cooling passage in the turbine section.