ISSN Online: 2377-424X
ISBN Print: 0-85295-345-3
International Heat Transfer Conference 10
SIMULTANEOUS HEAT AND MASS TRANSFER IN UNSTEADY TURBULENT NATURAL CONVECTION. APPLICATION TO LIQUIFIED NATURAL GAS STORAGE
摘要
The phenomena of double-diffusive natural convection caused by wall thermal fluxes are numerically studied in a 2D cavity containing a fluid which is initially stratified in temperature and in concentration. The equations, registering such movements, linked to the opposition of the mass buoyancy and thermal forces, are solved in the unsteady case using the Boussinesq approximation and the stream function-vorticity formalism. The standard model k-ε in LRN form that includes interactions between gravity and gradients of temperature and concentration is used. A finite-difference technique using the A.D.I, method is implemented. The convection term is discretized using a hybrid scheme based on the mesh Reynolds number and adapted to a non uniform grid. The time step is determined to ensure stability and to optimize the computation time. The results are obtained for Grth ≤ 1014 and | Grm| ≤ 1015 in the case of liquified natural gas (LNG). The evolution of significant problem variables (temperature, concentration, velocity, turbulent kinetic energy and turbulent dissipation) allow one to follow the fluid destratification.