The Effects of Coolant Pipe Geometry and Flow Conditions on Turbine Blade Film Cooling

Year 2017, , 1196 - 1210, 01.07.2017

Muhammad Akbar

https://doi.org/10.18186/journal-of-thermal-engineering.314165

Cited By: 3

Abstract

The performance of gas turbine engines can be improved by increasing the inlet gas temperature. Turbine blades
can be damaged by high gas temperature, unless additional cooling mechanisms are incorporated to maintain the
blades below an acceptable temperature limit. Film cooling techniques are often used to cool the blades to avoid
damages. The performance of film cooling depends on several parameters, however. In this paper past research
on film cooling is reviewed and areas in need of further investigation are identified. Computational fluid dynamics
(CFD) simulations are then conducted on the widely-used single-hole film cooling arrangements in which coolant
jets are injected into air flows inside a straight channel before issuing onto the blades. Cooling pipe-blade
configurations and flow conditions are varied and the resulting flow hydrodynamics are examined. Counter
rotating vortex pairs (CRVPs) formed in the flow strongly influence the film cooling performance. Small coolant
inclination angles, exit holes enlargement in span wise direction, higher injected fluid density, and higher injectedambient
fluid velocity ratios are all found to maintain the CRVPs away from each other and close to wall - both of
which promote cooling. Pipe curvature can be used for enhancing cooling by exploiting the centrifugal force effect.

Keywords

Numerical Study, Gas Turbine Blade, Counter Rotating Vortex Pairs, Recirculation Zone, Flow Hydrodynamics, Film Cooling Effectiveness

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