Jet fans produce a highly anisotropic turbulent flow regime and cause severe entrainment of the ambient fluid. Additionally, the placement of jet fans near or away from walls has a significant impact on throw and spread of the fan. This paper proposes a RSM based numerical technique to accurately predict the throw and spread of jet fans in an industrial setting while accounting for both the near wall effects and anisotropic nature of turbulence. The RSM based numerical technique described in this study allows for accurate prediction of the axial throw termination distances for jet fans in an industrial setting. The RSM approach also overcomes the limitations imposed by the free jet theory by accounting for wall effect on flow as well as other physical or temporal limitations imposed by various numerical methods such as RANS and SRS.
The Free Jet Theory proposes a classification method for turbulent jet decay problems, where the jet decay domain is classified into three flow domains and one terminal region. The terminal region of turbulent jet decay is not understood well physically and is neglected for the purpose of throw and spread calculations. The technique put forth in this paper draws from the fundamentals presented by the free jet theory and is then modified and applied to account for Coanda effects seen due to the proximity of walls to the flow when the jet fan is mounted close to the ceiling. Finally, experimental data is recorded by placing the jet fan in proximity with the floor in a closed room. The data thus generated is subsequently used to validate numerical results.Copyright © 2016 by ASME