Fan-shaped holes are widely used to provide better cooling performances than cylindrical holes over a large range of different operating conditions. Main advantages of such solution include a reduced amount of cooling air for the same performance, increased part lifetime and fewer required holes. As the overall cooling performance of such holes is strictly related to the adiabatic effectiveness and heat transfer coefficient (HTC) increase due to the coolant injection, both issues should be investigated. A numerical analysis has been conducted on a laidback fan-shaped film cooling hole onto a flat plate with the aim of investigating the increase of heat transfer. A steady-state RANS analysis was performed at two different blowing ratios (1.25 and 2.5) with imposed heat flux on the heated wall reproducing the same conditions as in the experimental tests presented in the companion paper. Despite no temperature difference was imposed between main gas and coolant flow, adiabatic effectiveness maps were extracted from tracing distribution over the plate. Performances of four different eddy viscosity turbulence models have been tested: the Two-Layer model by Rodi both in the isotropic original formulation and with an anisotropic algebraic correction based on DNS data fitting as firstly proposed by Lakheal, the k–ω SST by Menter and the ν2–f by Durbin. All calculations were conducted with a 3D unstructured pressure-based compressible solver based on the open-source OpenFOAM® CFD platform. A detailed analysis of both the predicted flow field and thermal distribution in the domain was presented. The obtained results were compared with the experimental measurements showed in the companion paper both in terms of wall heat transfer coefficient and adiabatic effectiveness.

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