Infrared thermometry in high temperature materials processing: influence of liquid water and steam

ABSTRACT

The capability of four infrared thermometry techniques (2-colour and 1-colour pyrometers, Pyrolaser and IR camera) was evaluated with respect to the impact of water or steam in the line of sight to determine temperature from two heat sources (blackbody calibration source and steel block inside the furnace). The influence of liquid water on the temperature readings was minimal when using 2-colour pyrometry due to comparable absorption coefficients of water for the measured wavelengths. The signals measured using both the Pyrolaser and the 1-colour pyrometer were decreased due to the partial absorption and resulted in an apparent temperature lower than the actual. Water readily absorbed the IR signal in the range of the IR camera operation, resulting in no signal whenever liquid water was present in the line of sight. Steam caused the most deviation and fluctuation of temperature readings for all techniques due to the large level of light scattering in addition to the absorption of the radiant energy. A technique was developed to determine the transmissivity (apparent emissivity) when water or steam is in the line of sight of measurement. An approximate correction to the measurements based on Planck’s law is discussed for both 2-colour and 1-colour pyrometers.

KEYWORDS:

• 2-colour and 1-colour pyrometry
• infrared (IR) camera
• pyrolaser
• water and steam interference
• blackbody

Acknowledgments

This work was funded by the U.S. DOE’s Office of Energy Efficiency and Renewable Energy’s (EERE) Advanced Manufacturing Office (AMO). The authors would like to express their appreciation to ORNL colleagues such as Beth Armstrong for allowing access to her equipment to troubleshoot the experiments, Gregory Cox and Daniel Moore for their help in performing the experiments involving the industrial box furnace and Dr. S. Suresh Babu for the valuable discussions on materials processing. The authors also thank Scott Nagle from Process Sensors Corp. and Stefan Buschmann from Sensortherm GmbH for the helpful discussions on the 2-color pyrometer.

Author contributions

AAT performed the experiments and data analysis. TRW and TRM advised on experimental work and counselled on the conditions relevant to field measurements and legacy work in this field of study. GMC guided the flash processing development and counselled on the material processing conditions. HW analysed data and contributed to the concept development and testing design. All the authors discussed the results and co-wrote the manuscript.

Disclosure statement

Competing interests. Mr. Gary M. Cola, owner of Flash SteelWorks Inc., Washington, MI, USA, holds several patents related to the flash processing thermal cycle and equipment and offers licensing of the Flash Process.

Notes

1. FLIR SC8200 IR camera, FLIR, Wilsonville, OR, www.flir.com.

2. Pyrolaser, Pyrometer Instrument Company, Inc, Windsor, NJ, www.pyrometer.com.

3. Capella C311, Process Sensors Corporation, Milford, MA USA, www.ProcessSensors.com.

4. Mikron M305, Advanced Energy Industries, Inc., Denver, CO, www.advancedenergy.com/products/temperature-measurement/calibration-sources/medium-temperature-calibration-sources/mikron-m305/.

Additional information

Funding

Research was sponsored by the U. S. DOE, Office of Energy Efficiency and Renewable Energy, Advanced Manufacturing Office, under contract DE-AC05-00OR22725 with UT-Battelle LLC..

Notes on contributors

Artem A. Trofimov

Artem A. Trofimov is the Leader of the Hot Disk Department as well as a Researcher and a Product Specialist in the Instruments Division at Orton Ceramic Foundation. Dr. Trofimov graduated with B.S./M.S. in Physics from Russian State University of Aviation Technology, and an M.S. and Ph.D. in Materials Science & Engineering from Clemson University. He completed a Postdoctoral Fellowship at Oak Ridge National Laboratory (ORNL). His research interests include thermal transport properties of materials, Hot Disk transient plane source, and inorganic scintillators.

Thomas R. Watkins

Thomas R. Watkins is the Leader of the Neutron and X-ray Scattering Group as well as a Senior Research Staff Member in the Materials Science and Technology Division at the Oak Ridge National Laboratory (ORNL). He graduated with a B.S. in Ceramic Engineering from Alfred University, and an M.S. and Ph.D. in Ceramic Science from the Pennsylvania State University. His research interests include residual stresses, x-ray and neutron diffraction and mechanical properties of materials.

Thomas R. Muth

Thomas R. Muth has a 28 year career converting difficult to process metals into useful forms for performance advantage, strategic advantage, and profit in the nuclear, defense, transportation, consumer electronic, medical, and chemical industry, which has been the impetus of many multi-materials processing efforts. Mr. Muth’s current efforts at ORNL are to strengthen the understanding and expand the use of titanium powder metallurgy components, made from particulate titanium emanating from new reduction technologies.

Gary M. Cola

Gary Cola is the founder and CTO of Flash Steelworks. As the developer of Flash Processing for steel, Cola has globally patented the methods to create leading performance steel for military and civilian uses. Unique in their class, Flash steels exhibit great ease in welding while outperforming titanium and aluminum alloys on a per mass basis for many applications.

Hsin Wang

Dr. Hsin Wang, received his BS degree of Solid-State Physics from Tsinghua University in 1989 and his MS and Ph.D. in Ceramic Science from the New York State College of Ceramics at Alfred University in 1991 and 1994. He joined Oak Ridge National Laboratory in 1995 and is currently a distinguished scientist at the Materials Science and Technology Division. His research focuses are on transport properties of materials, advanced thermal imaging, thermal management and reliability of energy storage systems, and effect of neutron irradiation on material properties.