Real-Time Optical Coking Sensor for Fuel Heat Control
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Solution Overview
Problem
Gas turbine engines face limitations in utilizing fuel as a heat sink due to the risk of coking at temperatures above 400°F, restricting the amount of heat that can be added to the fuel, which affects engine efficiency.
Innovation Solution
Implementing an optical coking sensor system with UV light sources and sensors to monitor fuel darkening, allowing real-time detection of thermal stress and determining the onset of coking, enabling active control of fuel temperature to prevent coking while maximizing heat transfer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If heat is added to fuel to improve engine efficiency, then fuel temperature increases and heat transfer improves, but fuel coking occurs at temperatures above 400°F
Solution Approach 1:
The optical sensor performs preliminary detection of fuel thermal stress before coking actually occurs. By monitoring fuel color changes in real-time and generating early warnings, the system enables preventive action to be taken before the harmful coking process begins, resolving the contradiction between heat addition and coking prevention.
2Reliability
If fuel temperature is limited to prevent coking, then fuel reliability is maintained, but heat transfer efficiency and engine performance are restricted
Solution Approach 1:
The optical sensor provides continuous real-time feedback on fuel thermal stress conditions by monitoring color changes. This feedback loop enables the control system to dynamically adjust heat addition rates, allowing maximum safe heat transfer while preventing coking, thus resolving the contradiction between reliability and energy efficiency.
Solution Approach 2:
The system changes the monitoring parameter from indirect temperature measurement to direct optical absorption measurement. By using UV light absorption at 254nm wavelength to detect fuel thermal stress, the system can precisely detect early-stage thermal degradation before coking occurs, enabling more accurate control of fuel temperature and heat transfer parameters.
3Reliability
If real-time monitoring of fuel thermal stress is implemented, then coking prevention is improved, but device complexity increases
Solution Approach 1:
The system replaces complex mechanical temperature sensing and coking detection mechanisms with an optical absorption-based detection system. By using UV light absorption measurements, the system achieves accurate real-time thermal stress monitoring with simpler, more reliable optical components rather than complex mechanical or chemical sensing systems.
Solution Approach 2:
The patent introduces UV light at 254nm wavelength as an intermediary to detect fuel thermal stress. The light acts as a mediator that interacts with the fuel molecules to reveal thermal degradation through absorption changes, providing indirect but accurate measurement of fuel condition without requiring direct contact with hot fuel or complex sensing mechanisms.
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
Enables real-time management of fuel temperature to prevent coking, optimizing heat transfer and improving engine efficiency by utilizing Sustainable Aviation Fuels (SAFs) with higher coking temperatures.
Implementation Method 1
a light source configured to deliver light toward the fuel; and a light sensing element configured to detect the light traveling through the fuel
Implementation Method 2
the light sensing element includes one or a combination of, a photodiode, a phototransistor, a charge-coupled device (CCD), and a complementary metal-oxide-semiconductor (CMOS) sensor
Implementation Method 3
The fuel delivery conditioning system includes a fuel/oil cooler that is in fluid communication with the fuel delivery subsystem to receive the fuel and is in fluid communication with the oil cooling subsystem to receive the heated oil. The fuel/oil cooler transfers heat from the oil to the fuel to increase a temperature of the fuel
Data Source
Figure 1
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AI summary
A gas turbine engine fuel system (100) includes a fuel delivery system (102), an oil cooling subsystem (120), a fuel delivery conditioning system (110), and one or more optical coking sensors (150, 160). The fuel delivery subsystem (102) delivers fuel (105) to a gas turbine engine (20) and the oil cooling subsystem (120) receives heated oil (121) from the gas turbine engine (20). The fuel delivery conditioning system (110) includes a fuel/oil cooler (112) that is in fluid communication with the fuel delivery subsystem (102) to receive the fuel (105) and is in fluid communication with the oil cooling subsystem (120) to receive the heated oil (121). The fuel/oil cooler (112) transfers heat from the oil (121) to the fuel (105) to increase a temperature of the fuel (105), and the optical coking sensors (150, 160) output a signal indicating a thermal stress of the fuel (105) that occurs with a changing temperature of the fuel (105). A controller (148) receives the voltage signal and determines an onset of coking in the fuel (105) based on the signal.