CFD Simulation of Two Phase Leak Flow Through Circular and Rectangular Circumferential Cracks from High Pressure High Temperature Pipelines

Leak flow prediction has become a part and parcel of safe design in high pressure high temperature piping systems. This study investigates the behavior of mass flux, flow velocity and phasic transformation through circumferential cracks with circular and rectangular geometries from high-pressure high temperature pipelines. 3- dimensional computational hydrodynamic simulations were performed to model narrow leaks simulating the conditions of a pressurized water reactor. The simulations examined variations in mass flux and velocity for different crack sizes under a stagnation pressure range of 70 to 100 bar. Results demonstrate that both mass flux and velocity consistently increase with pressure. For circular cracks, mass flux increased by up to 20.2%, while average velocity rose by 20%. In smaller cracks, the increases in mass flux and velocity were around 19.8%. Rectangular cracks exhibited similar trends, with mass flux increasing by up to 19.6% and velocity by 19.7%. These findings demonstrate the strong dependence of leakage behavior on both pressure and crack geometry, which is critical for predicting failure risks in high-pressure systems.