A new real-gas model to characterize and predict gas leakage for high-pressure gas pipeline

Abstract

High-pressure gas pipe leakage is a topic of great concern in the risk assessment and safety management of pipeline systems. Traditional ideal-gas models with the assumption of fully ruptured leak loss are valid for a large leak hole in low-pressure gas pipelines (3–14 bar). This paper developed a new model for small leaks in high-pressure gas pipelines, which improves the traditional models in two aspects: the introduction of a mass fraction to characterize the proportion of leaked gas flow to in-pipe gas flow, and the integration of the real-gas thermodynamics into the fundamental governing equations to include the gas compressibility factor in the high-pressure conditions (>14 bar). To examine the validity and practicality of the new real-gas model, comprehensive comparison tests were carried out with the results of the benchmark numerical simulations and the hazard modelling software ALOHA, respectively. In the light of prediction accuracy, the new real-gas model shows its advantage over the traditional ideal-gas model, the improved ideal-gas model, and the semi-empirical correlation proposed by previous research. The virtues of high accuracy and short computational time confirmed the effectiveness of the new real-gas model in the responsive evaluation of high-pressure gas pipe leakage with small leak holes.