  We have calculated several representative models of vertical structure of an
accretion disk around a supermassive Kerr black hole. The interaction of
radiation and matter is treated self-consistently, taking into account
departures from LTE for calculating both the disk structure and the radiation
field. The structural equations are described in detail, and various
approximations are discussed. We have demonstrated that departures from LTE are
very important for determining the disk structure, even at the midplane, as
well as the emergent radiation, particularly for hot and electron--scattering--
dominated disks. We have shown that at least for the disk parameters studied in
this paper, NLTE effects tend to reduce the value of the Lyman jump with
respect to the LTE predictions, regardless whether LTE predicts an emission or
absorption jump. We have studied the effects of various values of viscosity on
the model structure and predicted spectral energy distribution. The viscosity
is parameterized through a parameter $\alpha_0$ which describes the
vertically-averaged viscous stress, two power-law exponents $\zeta_0$ and
$\zeta_1$, and the division point $m_{d}$ between these two forms. The disk
structure and emergent radiation is sensitive mainly to the values of
$\alpha_0$, while the other parameters influence the disk structure to a much
lesser extent. However, although the detailed shape of the predicted spectrum
is sensitive to adopted value of $\alpha_0$, the overall appearance of the
spectrum is quite similar.
