Analysis of effect of geometric parameters on stability of natural convection in porous media

In the present work the stability of natural convection in porous media is studied. The computation analysis of effect of geometric parameters of rectangular duct on the transition Rayleigh number Ra*,which means the convective model from stationary state transiting to periodic or chaotic solution. The duct has filled a porous medium saturated with the fluid, in which there is uniform internal heat generation q per unit volume. The geometric parameters include the aspect ratio r and the tilt angle phi. The results show that the transition Rayleigh number Ra* decreases as the aspect ratio r increases; and Ra* rises as the tilt angle phi increases. The curves Ra*similar to r and Ra*similar to phi are given in this paper.