This study presents the effect of thermal radiation on the steady flow in a
vertical micro channel filled with highly absorbing medium. The governing
equations (mass, momentum and energy equation with Rosseland approximation
and slip boundary condition) are solved analytically. The effects of thermal
radiation parameter, the temperature parameter, Reynolds number, Grashof
number, velocity slip length, and temperature jump on the velocity and
temperature profiles, Nusselt number, and skin friction coefficient are
investigated. Results show that the skin friction and the Nusselt number are
increased with increase in Grashof number, velocity slip, and pressure
gradient while temperature jump and Reynolds number have an adverse effect on
them. Furthermore, a criterion for the flow unsteadiness based on the
temperature parameter, thermal radiation parameter, and the temperature jump
is presented.