Analysis of the impact force by a transient liquid slug flowing out of a horizontal pipe

An abrupt increase in the gas flow rate in a horizontal gas-liquid two-phase stratified or wavy flow induces a transient slug flow. When this transient liquid slug flows out of a pipe, it applies a large impact force by its impingement on a structure located outside the pipe. The shape of this impact force-time curve is characterized by such quantities as initial impact force, maximum force, acting period of force and total momentum. The influences of each volumetric flux of two phases and of the pipe diameter on the impact force-time curves and the dynamic behavior of the transient liquid slug are experimentally studied and theoretically analyzed on the basis of Dukler-Hubbard's model by applying equations of the integral balance of mass and momentum to the transient liquid slug. The calculated results agree well with the experimental results of the dynamic behavior of the transient liquid slug and of the impact force. (orig.)