Assessment of Common Turbulence Models under Conditions of Temporal Acceleration in a Pipe

چکیده مقاله

In this paper, transient flow in a pipe at Reynolds numbers (based on bulk velocity and diameter) ranged from 7000 to 45200 is numerically simulated using four common turbulence models. The models considered are the BaldwinLomax algebraic model, the N-H model with wall correction of Lam and Bremhorst, the N-Z model and the N-H-Q 2 model of Durbin. The results of these models are compared with those of the recent experiments reported in the literature. The predicted velocity and delay period using the models compared well with measured values for short and long ramp-up flow excursions. The delay period of the calculated turbulence kinetic energy close to the pipe centerline is around 4 sec which agrees with the experiments. The N-H-Q 2 model was found to provide the best results compared to the measured data in the region away from the wall. At the end of the excursion near the wall, however, the results of this model differs from those of the experiments