Post-Shutdown Combustor Ventilation to Prevent Fuel Nozzle Coking
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Solution Overview
Problem
During gas turbine engine shutdown, residual heat causes temperature increases leading to carbon deposits (coking) in fuel nozzles and other components, which can result in engine start issues, inefficient combustion, and component distress.
Innovation Solution
A suction enabled post shutdown combustor cooling and ventilation system that draws in air from the core flow path and promotes airflow through the combustor to dump hot air to an open environment, using pumps and valves to manage airflow during shutdown conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the engine is shutdown, then fuel consumption is reduced, but residual heat causes temperature increases leading to carbon deposits (coking) in fuel nozzles and other components
Solution Approach 1:
The system uses the residual heat and airflow that would otherwise be wasted after engine shutdown to create a beneficial cooling effect. By activating the pump and opening the suction valve, ambient air is drawn through the fuel nozzle area, utilizing the existing thermal energy gradient to prevent coking without requiring additional fuel consumption.
Solution Approach 2:
The pump and valve system is activated immediately upon engine shutdown to prevent coking before it can occur. The suction valve opens in advance to allow cooling airflow to reach the fuel nozzles and other vulnerable components, addressing the thermal problem before carbon deposits have time to form.
2Temperature
If cooling systems operate continuously, then component temperatures are maintained within allowable limits, but system complexity and energy consumption increase
Solution Approach 1:
The cooling system transitions from a static, continuously operating design to a dynamic, on-demand system. The pump and suction valve are activated only when needed (during shutdown conditions), allowing the system to adapt its operation to actual thermal requirements and reduce overall complexity.
Solution Approach 2:
The system uses the engine's own residual heat and airflow patterns to drive the cooling process after shutdown. By leveraging the natural thermal gradient and using the pump to draw ambient air through the fuel system, the design eliminates the need for external cooling infrastructure.
3Object-affected harmful factors
If a suction system is activated post shutdown, then coking risk is reduced, but additional components (pump, valve) and energy consumption are required
Solution Approach 1:
The suction valve acts as an intermediary component that controls airflow to the fuel nozzles. By positioning the valve in the suction line, the system can precisely regulate when and how cooling air reaches vulnerable components, providing targeted protection without requiring complex cooling infrastructure throughout the entire fuel system.
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
Reduces the risk of coking in fuel nozzles and other components, preventing costly failures and ensuring efficient engine operation upon restart.
Implementation Method 1
a pump fluidly coupled with a suction line, wherein the suction line is fluidly coupled with suction ports proximate a fuel system component near a combustor
Implementation Method 2
temperatures of gas turbine engine components are maintained within allowable limits by a plurality of cooling processes that transfer heat from the components to one or more heat sinks
Implementation Method 3
residual heat in certain engine components can be transferred (i.e.; 'soakback') from the bore area, gas path, and cases and subsequently increase the temperature of other engine components beyond allowable limits
Data Source
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AI summary
A suction enabled post shutdown combustor cooling and ventilation system including a pump fluidly coupled with a suction line, wherein the suction line is fluidly coupled with suction ports proximate a compressor; a pump suction valve positioned in the suction line upstream of the pump; a pump discharge line fluidly coupled with the pump, an outlet fluidly coupled with the pump discharge line; and an engine core flow path fluidly coupled with the suction ports.