Modelling vaporous cavitation on fluid transients

TL;DR

This paper presents a new vaporous cavitation model for fluid transients in transmission lines, addressing limitations of traditional models by incorporating frequency-dependent friction and aligning well with experimental data.

Contribution

The study introduces a homogeneous equilibrium vaporous cavitation model that improves prediction accuracy over conventional column separation models, especially regarding pressure spikes and cavity sizes.

Findings

The new model avoids unrealistically high pressure predictions.

Frequency-dependent friction improves model accuracy.

Predictions closely match experimental cavitation data.

Abstract

A comprehensive study of the problem of modelling vaporous cavitation in transmission lines is presented. The two-phase homogeneous equilibrium vaporous cavitation model which has been developed is compared with the conventional column separation model. The latter predicts unrealistically high pressure spikes because of a conflict arising from the prediction of negative cavity sizes if the pressure is not permitted to fall below the vapour pressure, or the prediction of negative absolute pressures if the cavity size remains positive. This is verified by a comparison of predictions with previously published experimental results on upstream, midstream and downstream cavitation. The new model has been extended to include frequency-dependent friction. The characteristics predicted by the frequency-dependent friction model show close correspondence with experimental data.