BLACKBODY TEMPERATURE CALCULATIONS FROM VISIBLE AND NEAR-IR SPECTRA FOR GAS-FIRED FURNACES A Dissertation presented to the Faculty of the Graduate School University Of Missouri-Colimbia In Partial Fulfillment of the Requirements for the Degree Doctor Of Philosophy by RODNEY ALLEN ROSSOW Dr. Shahla Keyvan, Dissertation Supervisor JULY 2005 Copyright 2005 by Rodney Allen Rossow All Rights Reserved ACKNOWLEDGEMENTS Special thanks go to my advisor, Dr. Shahla Keyvan, for without her help this dissertation would not have been possible. Thanks also to the other members of my doctoral committee, Dr. Sherif El-Gizawy, Dr. Yuyi Lin, Dr. Carlos Romero, and Dr. James Thompson for their support. Special thanks also go to my friend, Tim Walker, for his assistance in this work. Thanks also to my fellow graduate students, Handi Cokroyjoyo, Scott Hixson, and Dong Li. Finally, thanks to my family for the emotional support they have supplied me over all these years in school. This work is dedicated to my mother, Pauline Rossow, who has supported me throughout the long journey that has brought me to this day. In addition, a special dedication goes to the memory of my sister, Lillian Yeargan, who has been such an inspiration to me all these years. The Department of Energy (DOE) under contract DE-FC07-00CH11032 provided support for this work. I would also like to thank the Department of Education for their support provided through the Graduate Area of National Needs (GANN) Fellowship. ii TABLE OF CONTENTS ACKNOWLEDGEMENTS ......................................................................................... ii NOMENCLATURE.................................................................................................. xiv ABSTRACT.............................................................................................................. xvi 1 INTRODUCTION.......................................................................................................... 1 1.1 MOTIVATION .................................................................................................. 1 1.2 OVERVIEW OF SPECTROMETER AND PROBE SYSTEM ........................ 2 1.3 OVERVIEW OF DISSERTATION................................................................... 6 2 BACKGROUND............................................................................................................ 8 2.1 COMBUSTION.................................................................................................. 8 2.1.1 Basic Flames Types ................................................................................. 9 2.1.2 Reaction Zone ........................................................................................ 10 2.1.3 Chemical Reactions during the Combustion Process ............................ 10 2.2 ELECTROMAGNETIC RADIATION SPECTRA ......................................... 13 2.2.1 Background Radiation........................................................................... 13 2.2.1.1 Blackbody Radiation.................................................................. 13 2.2.1.2 Non-Blackbody Radiation ......................................................... 15 2.2.2 Emission/Absorption Lines.................................................................... 15 2.3 NOISE .............................................................................................................. 20 2.3.1 Photon Noise.......................................................................................... 20 2.3.2 Detector and Processor Generated Noises ............................................. 21 2.3.3 CCD Array Noises................................................................................. 22 3 TEMPERATURE MEASUREMENT METHODS ..................................................... 24 3.1 TEMPERATURE SCALES............................................................................. 24 iii 3.2 CONTACT METHODS................................................................................... 25 3.2.1 Thermocouples....................................................................................... 26 3.2.2 Resistance Thermometry ....................................................................... 26 3.2.3 Fiber-Optic Probes................................................................................. 27 3.3 NON-CONTACT METHODS......................................................................... 27 3.3.1 Radiation Absorption Methods.............................................................. 28 3.3.2 IR Guns.................................................................................................. 28 3.3.3 Laser Scattering Methods ...................................................................... 29 3.3.4 Pyrometers ............................................................................................. 30 3.4 COMPARISON OF CONTACT VS. NON-CONTACT METHODS ............ 30 3.5 CALIBRATION TECHNIQUES..................................................................... 30 3.5.1 Classifications of Standardization.......................................................... 31 3.5.2 Thermocouples....................................................................................... 31 3.5.3 Light Pipes............................................................................................. 32 3.5.4 Halogen Lamp........................................................................................ 32 3.6 PRECISON OF MEASUERMENTS............................................................... 32 4 DEVELOPMENT OF AN ADVANCED TWO-COLOR METHOD ......................... 34 4.1 THE TWO-COLOR METHOD ....................................................................... 34 4.2 SIMPLE CORRECTIONS FOR THE TWO-COLOR METHOD .................. 35 4.2.1 Corrections Using a Halogen Lamp....................................................... 36 4.2.1.1 Derivation Of The Temperature Equation ................................. 37 4.2.1.2 Wavelength Selection ................................................................ 38 4.2.1.2.1 Difference in Wavelengths Used ....................... 40 iv 4.2.1.2.2 Best Region........................................................ 41 4.2.1.3 Noise Correction Methods ......................................................... 42 4.2.2 The Simple Attenuation Correction Factor............................................ 46 4.2.2.1 Path Length ................................................................................ 46 4.2.2.2 Development of the Linear Model............................................. 47 4.3 ADVANCED CORRECTIONS FOR THE TWO-COLOR METHOD .......... 49 4.3.1 Referenced Correction with a Known Temperature .............................. 50 4.3.1.1 Halogen Correction Curve ......................................................... 50 4.3.1.2 Blackbody Referenced Correction Curves................................. 52 4.3.1.3 Dynamic Empirical Correction Model....................................... 58 4.3.1.4 Ratio Determination and Smoothing ......................................... 59 4.3.1.5 Distance and Wavelength Effects .............................................. 61 5 LABORATORY DATA ACQUISITION AND RESULTS........................................ 66 5.1 HALOGEN LAMP........................................................................................... 66 5.1.1 Intensity Profile...................................................................................... 67 5.1.2 Calculated Temperatures ....................................................................... 67 5.2 ELECTRIC FURNACE................................................................................... 70 5.2.1 Intensity Profile...................................................................................... 70 5.2.2 Calculated Temperatures ....................................................................... 71 5.3 PILOT SCALE GLASS FURNACE................................................................ 75 5.3.1 Intensity Profile...................................................................................... 75 5.3.2 Temperature Measurements................................................................... 76 5.3.3 Correlations to the OH Radical.............................................................. 80 v 5.3.3.1 OH Correlation to NOx.............................................................. 83 5.3.3.2 OH Correlation to Changes in Stoichiometry............................ 85 5.4 RESEARCH BOILER...................................................................................... 86 5.4.1 Intensity Profile...................................................................................... 87 5.4.2 Temperature Measurements................................................................... 88 5.5 COMPARISON OF LABRATORY RESULTS.............................................. 93 6 COMMERCIAL DATA ACQUISITION AND RESULTS........................................ 94 6.1 MULTI-BURNER GLASS FURNACE.......................................................... 94 6.1.1 Visible Temperature Calculations.......................................................... 95 6.1.1.1 Intensity Profile.......................................................................... 96 6.1.1.2 Temperature Calculations with φd.............................................. 97 6.1.1.3 Temperature Calculations with Advanced Corrections ............. 99 6.1.2 Near IR Temperature Comparisons ....................................................