Release:2016, Vol. 2. №4
About the authors:Andrey A. Sedlov, Post-Graduate Student, Department of Gas Turbine and Nonconventional Power Plants, Bauman Moscow State Technical University; firstname.lastname@example.org
CFD analysis for heat transfer and pressure losses was performed for various impingement enchantment features: cylindrical, prismatic (diamond and drop section) pins in the wide range of geometric parameters and Reynolds numbers from 104 up to 3·104. Unlike typical ambient experimental conditions, the current study performs the analysis for the conditions applicable for gas turbine engine in the coupled setting (air-intensifiers). This allowed considering the effect of increased heat transfer surface and summarizing the obtained results.
CFD modelling was performed using commercial code ANSYS Fluent 14.0, based on finite volume approach for solving the gas dynamic and heat transfer equations. The system of equations including Navier–Stokes equation, energy and continuity equations and Reynolds averaged was calculated for steady state conditions accounting for compressibility and non-isothermality of the flow.
Realizable k-ε turbulence model combined with Wolfstein model for the near wall layer was chosen for the calculations based on conducted validation according to criterial correlations for the main equation system locking.
The conducted analysis showed the possibility for heat transfer enhancement by 100-150% for mid row holes, while the general intensification level for the 10 studied rows consisted by 50%, if normalized by flat impingent surface. The installation of high blockage features with D/d > 1.0 allows to prevent the running flow from the negative impact of the cross flow and at the same time to increase the heat transfer area, what leads to the increase of cooling efficiency.
The installation of high blockage features causes also significant redistributions of the heat transfer intensity along the impingement surface, leading to the first rows intensity being decreased by up to 30%. It may lead to the local overheating, so it should be considered in the projection of highly loaded cooled turbine parts.