Estimating sonic gas flow rates in pipelines

This paper presents a detailed review and analysis of sonic gas flow in pipelines, adding considerably more detail to the analysis, particularly for long pipelines. Our results show that (1) the mass flow rate is asymptotic as the velocity head pipe loss increases (2) the asymptotic value is identical for both adiabatic and isothermal conditions and (3) a maximum is found in the gas flow, although this maximum is near the asymptotic value. A graphical method for isothermal flows and a simple, shortcut formula is presented using asymptotic analysis which accurately estimates gas flow rates in long pipelines under both adiabatic and isothermal conditions. Process safety applications are provided.