Quasi One-Dimensional Steady-State Models for Gas Leakage Part II: Improvement of the Viscous Modeling

A comparison between four quasi one-dimensional steady-state gas leakage models, presented in a parallel paper, showed that none of them proved to be satisfactory. The results suggest that the modeling of the wall shear stress is the main flaw in the models. By fitting the shear stress to experimental data, an attempt was made to find a more acceptable model. For this a flow model was combined with an optimization algorithm. A second set of experimental data was used to validate the results. The optimized model gives a much better prediction for the set of experimental data used in the optimization. Application of the new model to another, quite different set of experimental data shows a slight improvement in comparison to the original. This gives some confidence in the improvement. Simulations show that choking, and thereby the occurrence of shock waves, is a realistic possibility in leakage.