Numerical modelling of natural convection of binary mixtures: case of a helium buoyant jet in an air-filled enclosure
type: Dataset
description: This study focuses on the understanding of the dispersing and mixing mechanisms of helium in air in a semi-confined cavity. This phenomena is an example of a low-density fluid injected in a high-density ambient fluid which results in a buoyant plume. This is an important safety issue for all hydrogen-based systems. A numerical model has been developed combining the appropriate boundary conditions with the conservation equations for the mixture mass, species mass, momentum and the state law of the mixture as well as the variation laws of the physical properties. First a laminar starting plume of a glycerol-water mixture is considered as a validation test-case by comparison with experimental data [Rogers & Morris 09]. The propagation of the axisymmetric buoyant-jet is modeled for large Grashof numbers and small injection Reynolds numbers. A good agreement has been found for the ascent velocity as well as the two types of head shape. A modified scaling law of the ascent velocity versus a modified Reynolds number is proposed to take into account for the kinetic viscosities of both fluids. For the helium-air mixture, a 2D planar air-filled cavity was first considered. The auto-similar scaling laws for steady plane plumes in unconfined environment [Gebhart et al. 88] have been reproduced for the vertical velocity and the density profiles along the vertical centerline, when considering moments before the plume impact on the top wall. Then a cylindrical container is considered to model the CEA experiment [Cariteau & Tkatschenko 12]. Numerical results are compared to experimental data and to a numerical benchmark. The effect of the axisymmetry assumption is evident.
issued: 2026-05-07T18:01:16.707668
language: en
modified: 2026-05-07T18:01:16.707673
contact point: Organization
  fn: CCSD
keyword: binary-mixture
keyword: buoyant-jet
keyword: glycerol-water
keyword: helium-air
keyword: infoeu-reposemanticsdoctoralthesis
keyword: jet
keyword: melange-binaire
keyword: melange-eau-glycerol
keyword: melange-helium-air
keyword: panache
keyword: physmecameflphysics-physicsmechanics-physicsfluid-mechanics-physicsclass-ph
keyword: simulation
keyword: spimecameflengineering-sciences-physicsmechanics-physicsmed-phfluids-mechanics-physicsc
keyword: starting-plume
keyword: theses
landing page: https://theses.hal.science/tel-00920867

Numerical modelling of natural convection of binary mixtures: case of a helium buoyant jet in an air-filled enclosure
type: Distribution
format: HTML
issued: 2026-05-07T18:01:16.716235
modified: 2026-05-07T18:01:16.693621
access URL: https://theses.hal.science/tel-00920867

test_moissonnage_selune
type: Agent