ISSN Online: 2688-7231
ISBN Online: 978-1-56700-524-0
Proceedings of the 26thNational and 4th International ISHMT-ASTFE Heat and Mass Transfer Conference December 17-20, 2021, IIT Madras, Chennai-600036, Tamil Nadu, India
Comparison of Various RANS Models for Predicting Near-wall Flow and Heat Transfer Characteristics of a Turbulent Wall Jet
In this work the relative performance of various RANS models in predicting the near wall flow and heat transfer characteristics of a plane turbulent wall jet is numerically investigated. Three different k-ε models, namely the Standard, the Re-Normalised Group (RNG) and the Realisable model, are considered with two distinct wall treatments, like the Standard Wall Function (SWF) with Yp+~26 for the near wall node and the Enhanced Wall Treatment (EWT) with Yp+~1 for the near wall node. Additionally, two different Y+-independent k-ω models such as, the Shear Stress Transport (SST) and the Standard k-ω models, which require no wall treatment, have been employed. All the simulations have been done using commercially available ANSYS-Fluent software (version 17) for the jet exit Reynolds number of 9600 with an isothermally heated wall. Numerical study reveals that the implementation of EWT as a near wall treatment, in general, gives more accurate predictions for fluid flow as well as heat transfer characteristics, particularly at near wall region, than k-ε with SWF and k-ω models. With an improved near wall shear stress and heat transfer prediction capability than the SWF, the EWT scheme with the Realizable and the RNG k-ε models may be considered as viable low cost alternative to DNS or LES for analysis of wall jet characteristics.