Unmasking the mystery: The path to accurate liquid slug holdup prediction

Abstract

Slug flow modeling relies on various correlations for predicting liquid slug holdup (HLS). These correlations, developed from specific experimental ranges, sometimes fail to predict HLS accurately when applied outside their original operational conditions and other times result in strange behavior. The common belief is that these failures are due to limited experimental data ranges, but another significant factor is the inconsistency in HLS values for the same superficial liquid to gas velocity ratio (VSL/VSG). This ratio has not been adequately considered in existing correlations. This study investigates the hypothesis that HLS should remain constant for a given VSL/VSG ratio, assuming the flow regime remains within slug flow. By analyzing different correlations, we identify discrepancies in HLS predictions for identical VSL/VSG values, challenging the assumption that liquid content should be consistent within a stable flow regime. The paper provides evidence supporting this hypothesis and proposes a new approach for more accurate HLS predictions. Our findings highlight the necessity of considering the VSL/VSG ratio to enhance the reliability of liquid slug correlations and models.