Finite Volume Based Numerical Investigation On The Effects Of Internal Cooling And Film Cooling On The Thermal Performance Of Gas Turbine Blades
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Date
2010-05
Authors
Shaker, Sufian Farid
Journal Title
Journal ISSN
Volume Title
Publisher
Universiti Sains Malaysia
Abstract
The inlet temperature of modern gas turbine engines has been increased to
achieve higher thermal efficiency and increased output. The blade surfaces including
the leading edge, suction side and pressure side are exposed to the most extreme
heat loads, and therefore, must be adequately cooled to maintain safety. This thesis
presents steady computational predictions for a three-dimensional numerical
investigation for different cooling arrangement of turbine blade model with both the
internal cooling and combines cooling (film cooling) techniques. The computational
predictions were achieved using FLUENT . The dimension and the airfoil shape
are generated by GAMBIT similar to the actual McDonnell Douglas (A-4 Skyhawk)
blade with the same scale. The unstructured Triangular Pave mesh is used for all the
blade models. The material considered in the analysis is stainless steel alloy-AL
6XN which is highly resistant to temperature. Turbulence was represented using the
k- ω shear-stress transport (SST) model, and the flow was assumed to have a freestream
turbulence intensity of 10%. The heat transfer coefficient, total temperature
distribution, static pressure and velocity vector was investigated. The CFD heat
transfer coefficient predictions compared well with the previous work. The results
showed that heat transfer coefficient was higher with film cooling compared to
without film cooling. For all the cases, the temperature distributions over the blade
surface are obtained and presented. From the results, the CFD simulation has
predicted that the blade with three rows of film cooling holes in the suction side,
three rows in the pressure side and two rows in the leading edge with enternal
channel is the best in terms of cooling performance. Besides these cases, the effect
of coolant injection pressure ratio on temperature distribution , was
investigated. Results showed that the increase in , has led to reduction in the
temperature and moreover the lateral spreading facilitated the best coolant layer.
This CFD code is also capable of handling unsteady flows. The periodic model was
employed to predict the unsteady flow behavior during operation by a twodimensional
numerical investigation for details of film cooling blade at three
rotational speeds of 1800, 2550 and 3000 rpm. Results showed that the temperature
of the rotor blade decreased slightly with the increase in the rotation speed due to the
effect of flow acceleration.
Description
Keywords
The effects of Internal cooling and film cooling , on The thermal performance of gas Turbine blades