Numerical Analysis of Marangoni Effect on Natural Convection in Two-layer Fluid Structure inside a Two-Dimensional Rectangular Cavity

摘要

Steady natural convection heat transfer inside a rectangular cavity has been investigated numerically. The cavity is filled with two different fluids. The bottom portion of the cavity is filled with water, while the upper portion of the cavity is filled with air. As a result, it forms an interface dividing the two fluids (air and water), where Marangoni convection occurs. The two-dimensional Navier-Stokes and energy equations are used to govern the fluid flow and heat transfer inside the cavity and the Galerkin finite element scheme is adopted to solve these partial differential equations. Numerical simulations are carried out for a fixed range of Rayleigh number (10~4 ≤ Ra ≤ 10~6) and different aspect ratios (AR = 0.375, 0.5, 0.625). The effects of Rayleigh number and aspect ratios on the natural convection heat transfer have been investigated. The thermal and flow field inside the cavity are visualized via isotherm plots and streamline patterns respectively. Finally, the heat transfer performance for different governing parameters has been investigated in terms of overall Nusselt number evaluated on the left portion of heated wall and the non-dimensional average temperature evaluated on the whole cavity. It is found in the result that the heat transfer enhances with the increase of Rayleigh number.