A unified lattice Boltzmann framework for combined radiation-conduction heat transfer

•An effective numerical method for combined radiation-conduction heat transfer under unified lattice Boltzmann framework.•Applicable for situations from single dimension to muti-dimension.•Both steady and transient problems are accurately solved.•The effects of several variable conditions such as coupled parameter, scattering and emission are considered. As the wider application of combined radiation-conduction heat transfer, effective numerical framework is required to precisely predict the heat transfer process. In this paper, a unified lattice Boltzmann framework is proposed for combined radiation-conduction heat transfer problem. As a complete form of lattice Boltzmann framework, the radiative transfer equation (RTE) and energy equation are both solved under the versatile, consistent D1Q3, D2Q9 and D3Q15 lattice model to construct a combined LB framework. Through several numerical cases from 1-D to 3-D problems for both steady and transient problems, we validated the applicability and accuracy of our framework. Besides, taking account of various parameters, we discuss the effects of different medium properties and anisotropic scattering condition. Our unified LB framework for radiation-conduction transfer is tested to be available for muti-dimensional problems through 1-D to 3-D cases. Furthermore, the anisotropic scattering condition is considered as an extension of our framework. The present work is expected to provide an effective numerical tool for various of combined radiation-conduction heat transfer questions.