The 1991 Max Jakob Memorial Award Lecture: Image-Forming Optical Techniques in Heat Transfer: Revival by Computer-Aided Data Processing

Abstract

Increasing possibilities of computer-aided data processing have fostered a revival of image-forming optical techniques in heat and mass transfer as well as in fluid dynamics. Optical measuring techniques can provide comprehensive and detailed information on the formation of phase interfaces, particle movement, or the size distribution of droplet swarms. Holographic interferograms contain full information, not only about boundary layers restricting transport processes, but also on local coefficients of heat and mass transfer. Laser-induced fluorescence promotes a better understanding of combustion processes by conveying insights into the concentration and the temperature in and around a flame. For describing complicated phenomena in fluid dynamics or in heat transfer by computer programs, global experimental information is not sufficient. Optical techniques provide local data without disturbing the process and with a high temporal resolution. By using the results of optical measuring techniques, it is possible to improve computer programs that describe physical processes. Optical techniques are also very sensitive touchstones for checking the quality of such programs.