Доступ предоставлен для: Guest

ISSN Online: 2377-424X

ISBN Print: 0-85295-345-3

International Heat Transfer Conference 10
August, 14-18, 1994, Brighton, UK

NUMERICAL STUDY ON EFFECT OF INITIAL CONCENTRATION DIFFERENCE ON ONSET OF ROLLOVER

Get access (open in a dialog) DOI: 10.1615/IHTC10.240
pages 333-338

Аннотация

Momentum, heat and mass transport processes leading to rollover of density-stratified liquid layers in a vessel are investigated numerically. The main purpose of the study is to clarify the effect of initial concentration difference on the onset of rollover. The transport processes in a vessel are modelled as follows. Two fluids with different initial concentrations are stratified in a container Both the upper and the lower fluids are assumed to have the same thermophysical properties except for their densities. Then the vertical wall of the container is heated and convective Hows start developing in the fluids. We have calculated a number of cases in which the upper and lower fluids have initially different concentrations and different heating conditions. The result reveals that the initial concentration difference greatly influences the time elapsed before rollover onset. Under the same Nusselt number, if the initial concentration difference is small, the rollover onset time is shortened. When the initial concentration difference is the same and the Nusselt number is changed, the rollover onset time is shortened with the increasing Nusselt number. The processes leading to rollover are as follows. Initially two convection rolls are induced in the upper and lower fluids separately, this situation being continued for a certain period, while the concentration is diffused with the convection. At least a great amount of the lower high-density fluid reaches the top surface, and then the fluids are suddenly mixed together