Energy conversion often takes place in processes occurring at extreme conditions of high temperatures, pressures, chemical aggressiveness, mechanical abrasion, and other factors. In extreme environments, even the most hardened insertion sensors do not perform reliably over an extended period of operation. To overcome the difficulties in obtaining reliable temperature measurements in extreme environments, we have developed a noninvasive ultrasound method for measuring spatial distribution of temperatures in solid materials and, specifically, across containments of extreme processes, such as gasification refectories.
This presentation describes a novel approach that uses noninvasive ultrasound (US) to measure the temperature distribution in solid materials. We use the ultrasound propagation path that is structured to contain engineered or naturally occurring echogenic features which redirect a fraction of the energy of each ultrasound excitation pulse back to the transducer as a train of echoes. Their time of flight is used to determine the speed of sound in different segments of the US propagation path. Then, by using the relationship between the velocity of the ultrasound propagation and the temperature, the time of flight measurements are used to estimate the temperature distribution across the sample.
During this presentation, we will describe the results of successful laboratory demonstration and pilot-scale oxy-fuel combustor testing of this new technology. The experimental validation of the developed method shows that the estimated temperature profile is correctly captures, and that the measurement accuracy is often comparable with the traditional insertion sensors. We will discuss the advantages this approach, which include its suitability for in-situ and non-destructive measurements over a broad range of temperatures, the applicability to the measurements of conductive heat fluxes in solids, and the spatially resolved characterization of their elastic properties.
Y. Jia, M. Puga, A. Butterfield, D. Christensen, K. Whitty, and M. Skliar, Ultrasound Measurements of Temperature Profile Across Gasifier Refractories: Method and Initial Validation, Energy & Fuels 2013 27 (8), 4270-4277
M. Skliar, K. Whitty, and A. Butterfield, Ultrasonic temperature measurement device, US Patent 8,801,277 B2, August 12, 2014.