The furnace exit gas temperature (FEGT) is one of the fundamental parameters necessary to determine the energy balance of the boiler in a coal-fired power plant, and is thus beneficial to the production of reliable thermo-fluid models of its operation and the operation of the systems down and upstream. The continuous measurement of the FEGT would also be a useful indicator to predict, prevent and diagnose faults, optimize boiler operation and aid the design of heat transfer surfaces. Acoustic pyrometry, a technique that measures temperature based on the travel time of an acoustic wave in a gas, is investigated as a viable solution for continuous direct measurement of the FEGT. This study focuses specifically on using acoustic pyrometry to reconstruct the temperature profile at the furnace exit including methods for accurately determining the time of flight (TOF) of acoustic waves. An improved reconstruction technique using radial basis functions (RBF) for interpolation and a least squares algorithm is simulated and its performance was compared to cubic spline interpolation, regression and Lagrange interpolation by evaluating its reconstruction accuracy in terms of mean and root-mean-squared (RMS) error when reconstructing set temperature profiles. Various parameters including transceiver positions, grid divisions and time of flight error, are investigated in terms of how they inform acoustic pyrometry implementation. The improved RBF interpolation function managed to reconstruct complex temperature profiles and had a greater reconstruction accuracy than compared interpolation methods, improving on the accuracy of previous work done. Random acoustic path error was found to not be additive with reconstruction error however repeating acoustic TOF readings improved reconstruction accuracy to mitigate this effect. In general, it was also found that symmetrical transmitter/receiver positions produced more accurate reconstructions as well as positioning receivers/transceivers and grid lines closer to the furnace walls, where the greatest temperature change occurs. In addition to testing reconstruction methods, a low-cost experimental set-up was constructed to measure the time of flight. The focus of this study was on using various signal processing methods to determine the time of flight and evaluating their accuracy in the presence of noise. Methods such as threshold detection with bandpass filtering, cross correlation, generalized cross-correlation (GCC) and a new method developed employing variable notch filters with locations and widths based on repetitive frequencies identified in the noise with cross correlation. The performance of methods was experimentally tested under varying signal to noise ratios (SNR) and noise conditions. These SNR tests showed that cross-correlation methods produced more reliable TOF readings under lower SNRs than threshold detection methods. Under white noise the smooth coherent transform (SCOT) GCC variation proved to produce the most accurate results producing an average TOF error of 0.84 % up until a SNR of 1.4 before reducing in accuracy. In coloured noise (generated based on previous boiler recordings) the variable notch filter method with crosscorrelation was able to identify repetitive noise frequencies filter them out and ultimately produced results with an average TOF error of 1.99 % up until a SNR of 0.67, where the noise level exceeds that of the signal.

No description available.

Thesis (Ph. D.)--University of Nevada, Reno, 2005. / "December, 2005." Includes bibliographical references (leaves 65-66). Online version available on the World Wide Web.

Thesis (Ph. D.)--Cornell University. / Reprinted from the Journal of physical chemistry, vol. 15, 1911. Bibliography: p. 303-305.

Thesis (B.S.)--University of Missouri, School of Mines and Metallurgy, 1928. / The entire thesis text is included in file. Typescript. Illustrated by author. Title from title screen of thesis/dissertation PDF file (viewed October 21, 2009)

Thesis (M.S.)--University of Wisconsin--Madison, 1966. / eContent provider-neutral record in process. Description based on print version record. Bibliography: l. 67-68.

Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Chemical Engineering, 1979. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND SCIENCE. / Bibliography: leaf 93. / by Ronald Alan Dictor. / M.S.

Thesis (B.S.)--University of Missouri, School of Mines and Metallurgy, 1933. / The entire thesis text is included in file. Typescript. Title from title screen of thesis/dissertation PDF file (viewed July 15, 2010)

The study aims to develop an infrared temperature-sensing system by applying to thermal radiation theory. The system consists of an optic unit, a photodetector, and an electronic unit. This system detects thermal radiation at 1310 nm wavelength, the temperature range of the system is 600~4000¢J, rise time 2£gs, spatial resolution 400£gm. The calibration was performed in the temperature low at 1200¢J by using a K-type thermocouple that can gain between temperature and output voltage relations, but beyond the temperature 1200¢J applying to Planck¡¦s law as calculate to predict. In the calibrated temperature range, the measurement error is ¡Ó80¢J for the low temperatures and ¡Ó20¢J for the high temperatures. The system was used to measure temperature variation during Nd:YAG pulse laser welding process. Experiments ware performed with stainless steel plates as specimen radiation by a laser pulse of 7ms duration time and various energy in the rang of 1245~5313mJ. The experimental results show the feasibility of the infrared temperature-sensing system in application of Nd:YAG pulse laser welding process.

No description available.