Resonant Frequency based Ultra-High Temperature Sensors for Harsh Environments

Ultra-high temperature and pressure measurement is critical to achieve high efficiency and reliability of gas turbine engines. In topic 19b, the DOE seeks novel sensors that are minimally intrusive and capable of long-term monitoring to improve efficiency and reduce emissions in conventional gas turbines, pressure gain combustion, and super critical power cycles. From providing real-time monitoring of hot gas path temperatures and pressure can help increase reliability of combustion turbines by extending times between engine overhauls by providing more accurate part lifing models from understanding the impact of radial temperature changes and pressure differentials across turbine stages. Furthermore, real-time monitoring of combustion hot gas flow can help increase the efficiency of the combustion turbine by enabling the increase of the turbine inlet temperature from having a more accurate measurement of combustion firing temperatures. Sensatek is proposing a resonant frequency (RF) based temperature sensor using a dielectric resonator for ultra-high temperature sensing, integrated RF transmission antenna, and a pressure sensor based on evanescent-mode resonator structure. These sensors are comprised of polymer derived ceramic materials suitable for harsh environments characterized by high temperatures (1200C –1700C) and corrosive gases. The principle for these sensors is that the dielectric constant of ceramic materials monotonically increases versus temperature/pressure. Therefore, by designing the sensor as a resonator and by detecting its resonant frequency, the temperature & pressure of the sensor can be extracted to provide continuous real-time monitoring. Our main objectives in Phase I are to 1) demonstrate an RF based ultra- high temperature sensor up to 1,700C, 2) demonstrate an RF based ultra-high temperature pressure sensor up to 1,700C, and 3) and prototype machine learning software and electronics for real-time monitoring of sensing system. The largest proportion of U.S. electricity generation (65%) still comes from fossil fuels-powered plants. Nitrous oxides (NOx) and sulfur oxides (SOx) are harmful byproducts that result from combustion instabilities inside gas turbines used in power generation. According to Environmental Protection Agency (EPA) Air Markets Program Data, power generation gas turbines accounted for 1.3 million tons of NOx and SOx. According to the U.S. Department of Energy, NOx levels can become increased as a result of an increased flame temperature inside a combustor chamber of a gas turbine. Ultra-high temperature and pressure sensors can reveal when combustors are over firing and enable operators to take corrective measures to prevent increased NOx levels that levy fines. According to gas turbine manufacturers the average savings from a predictive outage would eliminate $3.2 million/turbine/year from unplanned outage costs in parts and loss revenue, Based on data from BCC Research (Gupta, 2017) this amounts to $109.7 Billion in annual repair cost and lost revenue from downtime over 35,371 turbines installed worldwide.