Hybrid Lattice Boltzmann-meshless Strategy For The Coupled Radiation And Convection Heat Transfer

Thermal radiation with simultaneous buoyancy and forced convection is an importantissue for applications such as the design of solar collectors, combustion process, electroniccooling, aeronautics, crystal growth, nuclear engineering, etc. In such systems, heat transferresulting from coupled processes, in general, cannot be calculated separately. When concernedabout a participating medium, its complex absorption and emission spectra introduce a majordifficulty in the simulation of these flows. Viskanta, in a literature overview on coupled heattransfer in high temperature flows, pointed out the difficulties in modeling these problems andthe resulting non-complete understanding of these coupled processes. Due to its greatimportance, convection with surface and volumetric radiation has been extensively analyzed byusing numerical simulations and experiments in recent years.The lattice Boltzmann method (LBM) is a powerful numerical technique based on kinetictheory for simulating fluid flows and modeling the physical process in fluids. Owing to itsmesoscopic origin, in comparison with conventional fluid dynamics solvers, it offers suchadvantages as simple calculation procedure, simple and efficient implementation for parallelcomputation, and easy and robust handling of complex geometries. In1998, Chen and Doolenfirst applied the LBM to the fluid flow problems. Then, it was developed to solve a wide rangeof heat transfer problems. Quite recently, natural convection problems have also beeninvestigated by the LBM.In the present work, a numerical investigation has been made of the interaction of thermalradiation with laminar mixed convection in eccentric annulus filled with participating media.As a hybrid approach based on a common multi-scale Boltzmann-type model, the combinationof lattice Boltzmann and direct collocation meshless method (LB-DCM) is developed to solvethe coupled problem of radiation and convection. Numerical results are presented for differenteccentricities, Rayleigh number, Reynolds number, convection-radiation parameter and opticalthickness. Results show that the LB-DCM combination is stable and accurate. Besides, thishybrid approach is easy to implement and has an excellent flexibility in dealing with irregulargeometries.