Heat and mass transport phenomena under the influence of vibration using a new aided image processing approach

Abstract

In this investigation, the influences of a wide range of Rayleigh vibrations on the measurement of thermodiffusion in a microgravity environment subjected to a constant temperature difference between two walls of cubic cavity are presented for the first time in detail. Particularly, the effects of different parameters of vibrational forces, such as frequency and amplitude, on thermodiffusion experiments are studied. The impact on the separation of the components of the mixture due to the change in the forced vibration from low to high Rayleigh vibration are investigated. The SODI-IVIDIL project gathered together Canadian, European, and Russian researchers with complementary skills to prepare and carry out the experiment, to process the raw data, and perform numerical modeling of the phenomena. The ISS experimental data were obtained using optical digital interferometry in a reduced gravity environment. The experiment was performed in a cubic cell containing an aqueous solution exposed to a 10 K temperature gradient. Nine different runs of a water and isopropanol mixture with a negative Soret coefficient and the same temperature difference were chosen as test cases in this study. In this work, the collected data are analyzed by the use of fast Fourier transform (FFT) image processing. A curve-fitting method based on a genetic algorithm, which is aided by a fast robust version of discretized smoothing, is then used to calculate the Soret coefficient. Results show maximum separation and Soret coefficient for the case with minimum Rayleigh number; however, a linear relation between the Rayleigh vibration and the maximum separation was not detected. This is unexpected since most often the increase in Rayleigh number corresponds to a decrease in the separation of components.