Gas turbine combustion diagnostic device using ultrasonic waves

Device for Direct Measurement of Gas Turbine Combustor Flame Temperature Based on Ultrasonic Reflection Delay Time

This technology is a combustion diagnostic device that installs an ultrasonic transmitter and receiver in a combustion diagnostic tube connected to the interior of a gas turbine combustor. It calculates the flame temperature based on the time difference between the transmitted ultrasonic wave and the reflected wave returning from the inner surface of the combustor. The control unit determines the ultrasonic speed within the combustor using the delay time and separation distance, then calculates the flame temperature using a velocity-temperature correlation formula.

Conventional gas turbines monitor the magnitude and frequency of combustion dynamic pressure using dynamic pressure sensors. However, due to various factors such as fuel quality imbalances, changes in atmospheric temperature and humidity, and equipment aging, it has been difficult to accurately diagnose combustion instability based on dynamic pressure alone. As the use of syngas and new fuels increases, the need for precise combustion diagnostics has grown, but existing methods, which rely on adding multiple sensors without direct flame temperature measurement, suffer from complex structures and cumbersome maintenance.

This technology directly calculates flame temperature by measuring the speed of ultrasonic waves crossing the flame using only one transmitter that sends waves toward the flame and up to two receivers, resulting in high measurement precision and a simple component configuration. If the calculated temperature is below 1300℃, it generates a carbon monoxide risk signal, and if it is above 1600℃, it generates a nitrogen oxide risk signal, allowing for real-time response to incomplete combustion and hazardous gas emissions. This technology can be applied to combustion monitoring in gas turbine power plants and integrated gasification combined cycle (IGCC) facilities, improving both combustion efficiency and emission management by being retrofitted onto existing diagnostic tubes without requiring structural changes or replacements.

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Key Features:

• A combustion diagnostic tube with one end opening into the interior space of a gas turbine combustor and the other end protruding outward
• An ultrasonic transmitter provided at the other end of the diagnostic tube to generate transmitted ultrasonic waves toward the combustor, and ultrasonic receivers to receive the transmitted waves and reflected waves from inside the combustor, respectively
• A control unit that calculates the delay time from the reception of the transmitted ultrasonic wave to the reception of the reflected wave from the received signals, and determines the ultrasonic speed within the combustor using the separation distance
• A control function that generates a carbon monoxide risk signal if the calculated flame temperature is 1300℃ or lower, and a nitrogen oxide risk signal if it is 1600℃ or higher

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