Inscrição na biblioteca: Guest

ISSN Online: 2377-424X

ISBN Print: 978-1-56700-474-8

ISBN Online: 978-1-56700-473-1

International Heat Transfer Conference 16
August, 10-15, 2018, Beijing, China

DIRECT NUMERICAL SIMULATION OF THE LONG-TERM BEHAVIOUR OF WEAK FOUNTAINS IN A HOMOGENEOUS FLUID

Get access (open in a dialog) DOI: 10.1615/IHTC16.cov.022953
pages 2869-2876

Resumo

The long-term behavior of weak fountains in a cylindrical container, produced by the injection of dense fluid upwards into a homogeneous ambient fluid of lesser density, is studied numerically. Three-dimensional direct numerical simulations have been carried out to simulate the transient flow behavior of weak fountains with Re and Fr in the ranges of 20 ≤ Re ≤ 800 and 0.5 ≤ Fr ≤ 3.0, with Re and Fr defined in the main manuscript. The development of the fountain flow consists of three stages; the initial formation of the fountain, followed by the intrusion formed by the outflow of fountain fluid, and finally the establishment of stratification in the ambient fluid which takes relatively a much longer time. This study focuses on the latter two stages. The intrusion stage can be further divided into two parts; the radial outflow of fountain fluid along the base of the container, and the up-flow on the sidewall, which can be treated as a forced radial density current and a line fountain respectively. It is observed that convection and thermal conduction are the main mechanisms at both the intrusion and stratification stages. The time series of the location of the intrusion front, the characteristic height of the line fountain on the sidewall, and the characteristic time scales are analyzed and scaling relations are developed from the numerical results to characterize the flow behavior in terms of the radial length scale, Re and Fr.