Numerical Study of Storm Geyser Mechanism in the Multi-Inlet System at Laboratory and Prototype Scale

Storm geysers increasingly occur in sewer systems under climate change and rapid urbanization. The geyser mechanism in a single-inlet system has been extensively studied, while the geyser mechanism in multi-inlet systems has yet to be discovered. In this study, three-dimensional computational fluid dynamics models with multi-inlets at laboratory and prototype scale were established to investigate geysering induced by rapid filling. The numerical results at laboratory scale indicate that compared to the single-inlet model under identical inflow conditions (rapid increase the same total flow in the same time), the geyser pressure generated in the multi-inlet model is less than that of a single-inlet model, but more water is ejected out, and the geyser process is closer to the actual geyser event. The numerical results of the prototype model show that the equivalent density of the water-air mixture during geysering in the prototype scale model is about 212 kg/m(3), which is less than the equivalent density in the laboratory scale model.