Post-Shutdown Combustor Suction Cooling 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 in fuel nozzles and other components, resulting in costly issues like engine start problems and inefficient combustion.
Innovation Solution
A suction enabled post shutdown combustor cooling and ventilation system that draws cooling air from the core flow path and combustor cavity, using pumps and valves to redirect airflow to prevent coking by dumping hot air to the fan bypass stream.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the engine is shutdown and cooling systems stop operating, then energy consumption is reduced, but residual heat causes temperature increases leading to carbon deposits in fuel nozzles
Solution Approach 1:
The system activates cooling airflow immediately upon engine shutdown to prevent carbon deposits before they can form. The pump and valves are configured to automatically initiate post-shutdown cooling, addressing the coking problem before it occurs rather than treating it after formation.
Solution Approach 2:
The system extracts hot air from the combustor cavity and fuel nozzle areas using the pump, removing the harmful thermal environment that causes carbon deposition. This targeted extraction of hot air from critical areas prevents coking while minimizing overall system complexity.
2Temperature
If cooling systems operate continuously to prevent carbon deposits, then component temperature is controlled, but energy consumption increases
Solution Approach 1:
The system dynamically adjusts cooling airflow based on engine operational state. During normal operation, cooling valves remain closed to conserve energy. Upon shutdown detection, the pump activates and valves open to provide targeted cooling only when thermal management is critical, optimizing the balance between temperature control and energy consumption.
Solution Approach 2:
The cooling system applies airflow selectively to specific high-risk areas (fuel nozzles, combustor cavity) rather than uniformly cooling the entire engine. The pump draws air from and directs it to critical zones where carbon deposition risk is highest, providing localized thermal management with minimal energy expenditure.
3Object-affected harmful factors
If a suction enabled cooling system with pump and valves is implemented, then carbon deposit prevention is improved, but device complexity increases
Solution Approach 1:
The pump serves multiple functions: it draws cooling air from the combustor cavity, creates suction to direct airflow through fuel nozzle areas, and provides the driving force for the entire post-shutdown cooling system. This multi-functionality reduces the need for separate components, managing system complexity while maintaining effective carbon deposit prevention.
Solution Approach 2:
The system utilizes the engine's own shutdown state to trigger cooling activation. The pump and valves are configured to automatically respond to shutdown conditions, eliminating the need for complex external control systems. The system essentially self-activates when needed, reducing control complexity while maintaining protective functionality.
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 carbon deposits in fuel nozzles and other components, preventing costly failures and ensuring efficient engine operation post-shutdown.
Implementation Method 1
A pump is fluidly coupled with a suction line, wherein the suction line is fluidly coupled with bleed ports
Implementation Method 2
residual heat in certain engine components can be transferred (i.e.; 'soakback') from the bore area, gas path, and cases
Data Source
Figure 1
Figure 2
AI summary
A post shutdown combustor cooling system (10) including a pump (34) with a suction line (36) coupled with bleed ports (38); a bleed port line (40) coupled with the suction line; a pump suction valve (42) positioned in the suction line upstream of the pump; a bleed valve (44) positioned in the bleed port line; a pump discharge line (48) coupled with the pump, a core compartment supply line (56) coupled with a turbine cooling air port (58), a core compartment inlet (64) located within a core compartment (28) coupled with the core compartment, the core compartment supply line having a core compartment supply valve (70); a turbine cooling air supply line (60) coupled to the core compartment supply line and the high pressure turbine cooling air port, the turbine cooling air supply line comprising a turbine cooling air valve (68); and an engine core flow path (30) coupled with the bleed ports and turbine cooling air port.