Study of Diffusion Instability in Ternary Gas Mixtures under Nonisothermal Conditions

¹ Abai Kazakh National Pedagogical University, Almaty 050010, Kazakhstan
² Research Institute of Experimental and Theoretical Physics, Al-Farabi Kazakh National University, Almaty 050040, Kazakhstan

^a Corresponding author: kosov_vlad_nik@list.ru

Abstract

The main objective of this article is to investigate the effect of heating (from below or above) on stability of mechanical equilibrium in binary and ternary gas mixtures. Three series of experiments on instabilities in are reported gaseous diffusion. In one series occurrence of convective flows under diffusive mixing are investigated in the systems N₂O – CO₂ and CO₂ – N₂O heated from below. The temperature difference when the transition between the diffusion and the convective processes happen is higher at the bottom arrangement of N₂O. In the second series the influence of temperature difference are studied in the mixture 0.279 C₃H₈ + 0.721CO₂ – CO₂. The rate of convective mass transfer increases sufficiently. In the third series the convective mass transfer is examined in the system 0.4736 He + 0.5264 Ar – N₂ heated from above. The experimental results reveal that the intensity of unstable process decreases until 420.0 K reaching a minimum value. Linear stability theory is applied to determine the boundary of transition from the state of diffusion to the region of convection. The results of numerical study are in good agreement with the experiments.