Isothermal flow distribution in coupled manifolds: comparison of results from cfd and an integral model

摘要

Isothermal, incompressible flow distribution in the coupled manifold continues to be of interest to the industrial, engineering, and scientific communities. Several investigations carried out in the past have considered the suitability of a CFD code (Fluent) for predicting detailed velocity and pressure distributions for three dimensional dividing flow in a 90 deg tee junction. Results from these cast doubt on the successful use of CFD to model the complex flow in a tee. The focus of the present work is to determine if the same code can accurately predict the larger scale features of three dimensional branching flows and in a coupled manifold having three risers. Simulations were performed for flow in the coupled manifold and for both laminar and turbulent, dividing and combining flow in a tee section for a brad range of fow branching conditions. The ratio of riser diameter to manifold diameter is fixed at 0.75 for this study. The turbulent models used are the standard and renormalization group k- epsilon models. All constants in tehse models are set tto their respective default values. Static pressure re-gain factors are calculated from the results of CFD simulations nad are favorably compared with the data of others. These data are then used in an existing integral model for flow in coupled manifolds. The good agreement between the results from the integral model and the CFD model for flow in the coupled manifold attests to the suitabliity of the integral model for this problem. The advantage of the integral approach is the speed at which the problem can be solved by the computer, and the fact that there is no need for the time-consuming and expensive geometrical modeling and mesh generation normally associated with finite element and finite difference models.