OpenFOAM을 이용한 평판 팬 형상 막냉각 홀 하류에서의 막냉각 특성 연구

Abstract

In this study, a numerical analysis was performed for a 7-7-7 fan-shaped film cooling hole on a flat plate using OpenFOAM, a well-known open source CFD code. To assess the availability of compressible flow solver in the OpenFOAM, a numerical analysis using Ansys CFX under the same conditions was also performed. The OpenFOAM results using RANS with κ-ω SST model confirmed the influence of the spatial discretization schemes, such as Upwind, linearUpwind and LUST, and compared with the CFX result. A comparative analysis using OpenFOAM with linearUpwind scheme according to the blowing ratio ranged between 0.5 and 2.0 was performed and the OpenFOAM results were compared with the CFX results under the same conditions. In addition, the numerical analysis results were compared with the experimental results. The distribution of film cooling effectiveness in the OpenFOAM result becomes thinner than that of the CFX result as the blowing ratio increases. It shows that the coolant flow is lifted off from the adiabatic wall at the high blowing ratio and the OpenFOAM results have more interaction between mainstream and coolant flow than the CFX results due to difference between spatial discretization schemes. In overall, the distribution patterns of film cooling effectiveness are different between the numerical results and experimental results and the results of the laterally averaged film cooling effectiveness both from OpenFOAM and Ansys CFX are higher than those of the experiments. In term of calculating the averaged effectiveness for the lateral direction and the specific area, the result of the OpenFOAM shows closer to the experimental result as the blowing ratio increased. Current numerical study using the OpenFOAM shows the feasibility for resolving the film cooling flow behavior over the flat plate and demonstrates possibility of replacing commercial codes.