Numerical Simulations For The Laminar And The Turbulent Natural Convection Of High Rayleigh Number(Ra) In An Enclosure

The problem of natural convection flow and heat transfer in a cavity has extensive applicative background in application engineering, such as heat shield of building, safe design of nuclear reactor, microelectronic device cooling etc, so it is noticed more and more widely. A lot of here and overseas scholars do much work in experiment study and numerical simulation。In this paper, The method for solving the unsteady equations of stream function and vorticity has been used to the case of non-uniform grid analysis。The calculations is stable. Detailed computation is conducted for this cases at high Rayleigh numbers (), and their streamlines and isotherms are presented. With the computation results, the relation between and grid number,grid density has been given. Comparison with the paper of the past, under the high Rayleigh number ,the astringency and the accuracy of the computation results are closely related with grid number,grid density ,relaxation factor and time step width。Because the restrict of inside saves and the precision of computer,under the situation of , along with increasing of the grid number, the computation results deviates the true value on the contrary.In order to calculate the higher Rayleigh number, the turbulence model must be joined。In this paper,with the model,. use the turbulence viscosity coefficient method to study two-dimensional turbulent boundary layer by numerical simulation。With the computation results,the curve of nearby boundary layer are given and match with the experiment data very good。...