Internal cooling is one of the effective techniques to
cool turbine blades from inside. This internal cooling is achieved
by pumping a relatively cold fluid through the internal-cooling
channels. These channels are fed through short channels placed at
the root of the turbine blade, usually called entrance region
channels. The entrance region at the root of the turbine blade
usually has a different geometry than the internal-cooling channel
of the blade. This study investigates numerically the fluid flow
and heat transfer in one-pass smooth isothermally heated channel
using the RNG k−ε model. The effect of Reynolds
number on the flow and heat transfer characteristics has been
studied for two mass flow rate ratios (1/1 and 1/2) for the
same cooling channel. The Reynolds number was varied between
10 000 and 50 000. The study has shown that the cooling
channel goes through hydrodynamic and thermal development which
necessitates a detailed flow and heat transfer study to evaluate
the pressure drop and heat transfer rates. For the case of
unbalanced mass flow rate ratio, a maximum difference of 8.9%
in the heat transfer rate between the top and bottom surfaces
occurs at Re=10 000 while the total heat transfer rate from
both surfaces is the same for the balanced mass flow rate case.
The effect of temperature-dependent property variation showed a
small change in the heat transfer rates when all properties were
allowed to vary with temperature. However, individual effects can
be significant such as the effect of density variation, which
resulted in as much as 9.6% reduction in the heat transfer
rate.
