Abstract
Film cooling has been extensively used to provide thermal protection for the external surfaces of gas turbine components. For the past 40 years, numerous number of film cooling hole designs and arrangements have been introduced. Due to broad designs and arrangements of film cooling, numerical investigation has been utilized to provide initial insight on the aerodynamics and thermal performance of the new film cooling designs or arrangements. The present work focuses on the numerical investigation of RANS and URANS analyses on a flat plate film cooling. The investigation aims to provide comparison between various turbulent models available for the Reynolds Average Navier Stokes (RANS) analyses and extended to unsteady Reynolds Average Navier Stokes (URANS). The numerical investigations make used of ANSYS CFX ver. 14 and were carried out at Reynolds Number, Re = 7,000 based on the hole diameter at blowing ratio, BR = 0.5. The results of the RANS analyses show significant influence of the turbulent models on the predicted aerodynamics and thermal performance of the film cooling. The result of URANS indicates limitation of RANS analyses to provide details on the eddied and vortices formation in film cooling flow structure.
Highlights
The modern gas turbine works at the temperature range of 1800K- 2000K [1], which is higher than the melting temperature of the turbine components materials
The present work focuses on the numerical investigation of Reynolds Average Navier Stokes (RANS) and U-RANS analyses on a flat plate film cooling, aiming to evaluate the capability of different turbulence models to provide accurate prediction of aerodynamics and thermal performance of the film cooling phenomena
All the turbulence models of RANS producing the same pattern of results with high u-velocity region sandwiched by a low velocity region at the hole center and cooling hole wall
Summary
The modern gas turbine works at the temperature range of 1800K- 2000K [1], which is higher than the melting temperature of the turbine components materials. Such high operating temperature of the turbine became possible because of application of cooling scheme on the turbine components which includes film cooling. The main feature of jet in cross flow is the existent of counter rotating vortex pair which lift the jet away from the surface and hindering the film cooling protection provided by the secondary jet. Various numerical schemes of computational fluid dynamics are available in
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