Numerical simulation of paraffin melting in circular tube using LBM

Paraffin melting is widely used in the fields of phase change materials (PCMs) energy storage, gathering and transportation pipeline paraffin removal, etc. Analysis of the phase change mechanism and influencing factors of paraffin melting in the circular tube deeply has important guiding significance for improving the heat storage capacity by changing the structure of phase change material storage device and ensuring the safe transportation of crude oil in the pipeline. A double distribution lattice Boltzmann model based on enthalpy method is established to simulate the temperature field and the flow field of paraffin melting in a circular tube in this paper. The influence of different Rayleigh (Ra) number and Prandtl (Pr) number on the paraffin melting process in a circular tube is analyzed. The results show that the natural convection process is strengthened with the increase of the Ra number, and the decrease of the average Nusselt (Nu) number on the wall is smooth in the transition stage of wax melting due to the existence of fuzzy zone. The melting rate of paraffin can be accelerated or reduced by controlling the number Pr, so as to meet the relevant requirements of engineering.