In this paper a new hybrid numerical algorithm is developed to solve coupled convection-radiation heat transfer in a two dimensional cavity containing an absorbing, emitting and scattering medium. The radiative information is obtained by solving the radiative transfer equation (RTE) using the control volume finite element method (CVFEM) and the density, velocity and temperature fields are calculated using the two double population lattice Boltzmann equation (LBE). To the knowledge of the authors, this hybrid numerical method is applied at the first time to simulate combined transient convective radiative heat transfer in 2D participating media. In order to test the efficiency of the developed method two configurations are examined: (i) free convection with radiation in a square cavity bounded by two horizontal insulating sides and two vertical isothermal walls and (ii) Rayleigh Benard convection with and without radiative heat transfer. The obtained results are validated against available works in literature and the proposed method is found to be efficient, accurate and numerically stable.