Numerical Investigation of Swirling Pipe Flows

Swirling flow is a common phenomenon in engineering applications. It has been shown that swirling flow increases heat and mass transfer, and reduces power requirements in certain engineering applications. A numerical study of the swirling flow inside a straight pipe was carried out in the present work with the aid of the commercial CFD code Fluent. Two-dimensional simulations were performed, and two turbulence models were used, namely, the RNG k-ε model and the Reynolds stress model. Results at various swirling numbers were obtained and compared with available experimental data to determine if the numerical method is valid when modeling swirling flows. It has been shown that the RNG k-ε model is in better agreement with experimental velocity profiles for low swirl, while the Reynolds stress model becomes more appropriate as the swirl is increased. However, both turbulence models predict an unrealistic decay of the turbulence quantities for the flows considered here, indicating the inadequacy of such models in simulating developing pipe flows with swirl.