Study on mixing process of two component gases in a vertical fluid layer

This study is to investigate the onset time of natural circulation through the apparatus under the stable density stratified fluid layer. The experiment has been carried out using two component gases. The experiment apparatus consists of a reverse U-shaped vertical slot and a storage tank. The left side vertical slot consists of the heated wall and the cooled wall. The right side vertical slot consists of the two cooled walls. Temperature difference between the vertical walls was set to 0, 10, 30, 50, 70, and 100 [K]. The combination of the two component gases was set to nitrogen/argon, neon/argon, helium/argon, and helium/nitrogen. The heavy gas was filled with the storage tank and light gas was filled with the reverse U-shaped vertical slot. Before the experiment starts, the localized natural convection was generated in the heated side vertical slot. After the experiment starts, the heavy gas will be transported to the slot by the molecular diffusion and natural convection. And then, natural circulation occurs abruptly through the reverse U-shaped passage. Mixing process of two component gases was affected not only by the localized natural convection but also by the molecular diffusion. The onset of natural circulation has been affected not only by molecular diffusion but also by localized natural convection in the vertical fluid layer.