Thermal washing is a common method of wax removal in oil fields. The law of
phase change heat transfer of wax during the thermal washing process is
revealed to be of great significance for improving the melting rate of wax.
The lattice Boltzmann method is used to numerically simulate the process of
phase change heat transfer in pipelines with different angles (90?, 45?, 0?,
-45? and -90?) of wax layers based on the enthalpy-porous medium model in
the present work. The boundary condition between wax and hot water is
considered as convective heat transfer boundary. The effect of the Prandtl
number on the law of phase change heat transfer of the wax at various angles
is investigated. The simulation results indicate a non-linear decrease in
the complete melting time of the wax layer from -90? to 90?. The heat
transfer capacity is enhanced with the decrease of Prandtl number, which
effectively shortens the melting time of wax. The complete melting time of
the wax layer is reduced by 23.78% when the Prandtl number decreases from
79.4 to 59.4. The speed of convective heat transfer is increased with the
decrease of Prandtl number, which means that the solid zone of wax is
accelerated into the loose and porous mushy zone, and the efficiency of wax
removal is improved. The research results can provide a reference for
improving the efficiency of thermal washing.