Numerical Investigation of Performance and Flow Characteristics of a Tunnel Ventilation Axial Fan with Thickness Profile Treatments of NACA Airfoil

Yong-In Kim, Sang-Yeol Lee, Kyoung-Yong Lee, Sang-Ho Yang and Young-Seok Choi
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Yong-In Kim: Thermal & Fluid System R&D Group, Korea Institute of Industrial Technology, Cheonan-si 31056, Korea
Sang-Yeol Lee: Research Department, Samwon Environment & Blower Co., Ltd., 233, Siheung-si 15078, Korea
Kyoung-Yong Lee: Thermal & Fluid System R&D Group, Korea Institute of Industrial Technology, Cheonan-si 31056, Korea
Sang-Ho Yang: Research Department, Samwon Environment & Blower Co., Ltd., 233, Siheung-si 15078, Korea
Young-Seok Choi: Thermal & Fluid System R&D Group, Korea Institute of Industrial Technology, Cheonan-si 31056, Korea

Energies, 2020, vol. 13, issue 21, 1-29

Abstract: An axial flow fan, which is applied for ventilation in underground spaces such as tunnels, features a medium–large size, and most of the blades go through the casting process in consideration of mass production and cost. In the casting process, post-work related to roughness treatment is essential, and this is a final operation to determine the thickness profile of an airfoil which is designed from the empirical equation. In this study, the effect of the thickness profile of an airfoil on the performance and aerodynamic characteristics of the axial fan was examined through numerical analysis with the commercial code, ANSYS CFX. In order to conduct the sensitivity analysis on the effect of the maximum thickness position for each span on the performance at the design flow rate, the design of experiments (DOE) method was applied with a full factorial design as an additional attempt. The energy loss near the shroud span was confirmed with a quantified value for the tip leakage flow (TLF) rate through the tip clearance, and the trajectory of the TLF was observed on the two-dimensional (2D) coordinates system. The trajectory of the TLF matched well with the tendency of the calculated angle and correlated with the intensity of the turbulence kinetic energy (TKE) distribution. However, a correlation between the TLF rate and TKE could not be established. Meanwhile, the Q -criterion method was applied to specifically initiate the distribution of flow separation and inlet recirculation. The location accompanying the energy loss was mutually confirmed with the axial coordinates. Additionally, the nonuniform blade loading distribution, which was more severe as the maximum thickness position moved toward the leading edge (LE), could be improved significantly as the thickness near the trailing edge (TE) became thinner. The validation for the numerical analysis results was performed through a model-sized experimental test.

Keywords: axial fan; thickness; performance; tip leakage flow (TLF); inlet recirculation; National Advisory Committee for Aeronautics (NACA) 3512 (search for similar items in EconPapers)
JEL-codes: Q Q0 Q4 Q40 Q41 Q42 Q43 Q47 Q48 Q49 (search for similar items in EconPapers)
Date: 2020
References: View references in EconPapers View complete reference list from CitEc
Citations: View citations in EconPapers (1)

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