  In this brief report, a thermal lattice-Boltzmann (LB) model is presented for
axisymmetric thermal flows in the incompressible limit. The model is based on
the double-distribution-function LB method, which has attracted much attention
since its emergence for its excellent numerical stability. Compared with the
existing axisymmetric thermal LB models, the present model is simpler and
retains the inherent features of the standard LB method. Numerical simulations
are carried out for the thermally developing laminar flows in circular ducts
and the natural convection in an annulus between two coaxial vertical
cylinders. The Nusselt number obtained from the simulations agrees well with
the analytical solutions and/or the results reported in previous studies.
