Abstract:
This study focuses on the influence of the internal flow
condition on turbine blade showerhead region film cooling. The
elliptical leading edge model has five rows of film cooling holes
with 15 holes each at fixed hole-to-hole spacing of 4-diameter
and located along the stagnation line (0o), at ±30o and at ±60o
measured from the stagnation line. Two inlet flow conditions,
channel flow, and impinging flow are investigated separately,
and the effects of coolant-to-mainstream density ratios (DR =
1.0, 1.5 and 2.0) with three different coolant-to-mainstream
blowing ratios (M = 0.5, 1.0 and 1.5) are tested using pressure
sensitive paint measurement technique. Experiments were
conducted in a suction type low-speed wind-tunnel facility at a
flow Reynolds number around 100,000 based on the oncoming
mainstream velocity and leading edge diameter. The mainstream
turbulence intensity near the leading edge model is about 7%.
Results indicate that overall the impingement inlet configuration
provides better film effectiveness for all the DRs. However, the
difference is found to be minimum at M = 0.5 and 1.0 for heavier
density coolant (DR = 2.0). Additionally, computational
simulations have been performed to understand the flow physics
of these two inlet flow configurations using a realizable k-epsilon
turbulence model.
Description:
Papers presented at the 13th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Portoroz, Slovenia on 17-19 July 2017 .
