It is found that wall boundary conditions, position the convective heat transfer coefficient between the cavity and the ambient air and effect on the air cavity . At low Rayleigh number, wall boundary conditions have a minimal effect on Nu . However, increasing Ra, the wall boundary conditions have greater effect on the Nusselt number. And the temperature and velocity distribution are variation with location of convection and heat flux also with Rayleigh number .. The construct result used program(ANSYS) to find temperature, velocity and pressure distribution also the vector of velocity inside the air gap for several cases. The results are presented and discussed in this study and compared with other researches.