Numerical Investigation of Adiabatic and Conjugate Film Cooling Effectiveness on a Single Cylindrical Film-Cooling Hole

Abstract

This paper documents a computational investigation of the film-cooling effectiveness of a 3-D gas turbine endwall with one cylindrical cooling hole. The simulations were performed for an adiabatic and conjugate heat transfer models. Turbulence closure was investigated using five different turbulence models; the standard k-ε model, the RNG k-ε model, the realizable k-ε model, the standard k-ε model, as well as the SST k-ω model. Results were obtained for a blowing ratio of 2.0, and a coolant-to-mainflow temperature ratio of 0.54. The simulations used a dense, high quality, O-type, hexahedral grid. The computed flow/temperature fields are presented, in addition to local, two-dimensional distribution of film cooling effectiveness for the adiabatic and conjugate cases. Results are compared to experimental data in terms of centerline film cooling effectiveness downstream cooling-hole, the predictions with realizable k-ε turbulence model exhibited the best agreement especially in the region for (x/D ≤ 6). All turbulence models predicted the jet lift-off. Also, the results show the effect of the conjugate heat transfer on the temperature (effectiveness) field in the film-cooling hole region and, thus, the additional heating up of the cooling jet itself.

Film Cooling Effectiveness From a Single Scaled-Up Fan-Shaped Hole: A CFD Simulation of Adiabatic and Conjugate Heat Transfer Models

“…These models were adopted in this study due to ease of implementation and computational economy, and due to the fact that they showed good agreement in predicted film effectiveness for the 2D slot cooling and single cylindrical film-cooling holes [ ]. 20,21 Alternative flow modeling such as DNS or models relying on subgrid turbulence models such as LES are not considered in this study because they are computationally very expensive and not suitable for practical industrial computations. The impact of each of the three turbulence models on the prediction of film cooling effectiveness is compared to experimental data [10] in the results section below.…”

Film cooling effectiveness: Comparison of adiabatic and conjugate heat transfer CFD models

“…Recently, Silieti et al [20,21] investigated the numerical prediction of film cooling effectiveness in two and three dimensional gas turbine endwall/shroud for the cases of conjugate and adiabatic heat transfer models. They considered cooling slots, and cylindrical cooling holes at different blowing ratios.…”

Computational analysis of span-wise hole locations on fluid flow and film cooling of internal channels with crescent ribs

“…To well simulate the considered turbulent flow behavior, a turbulence model should first be elaborately selected. Silieti et al (2004) examined the performances of five turbulence models, i.e. the standard k - ε model, the Renormalization Group k - ε model, the realizable k-ε model, the standard k - ω model and the shear-stress transport k - ω model, in prediction of film cooling effectiveness.…”