CFD Modeling of Storm Sewer Geysers in Partially Filled Dropshafts
Conference
Zanje, SR, Mahyawansi, P, Leon, AS et al. (2022). CFD Modeling of Storm Sewer Geysers in Partially Filled Dropshafts
. 1187-1195. 10.1061/9780784484258.110
Zanje, SR, Mahyawansi, P, Leon, AS et al. (2022). CFD Modeling of Storm Sewer Geysers in Partially Filled Dropshafts
. 1187-1195. 10.1061/9780784484258.110
Geysers in storm sewer systems occur due to the uncontrolled release of trapped air through dropshafts. This study presents an unsteady three-dimensional (3D) computational fluid dynamics (CFD) model to simulate the two-phase flow dynamics of geysers starting with partially filled dropshafts. The CompressibleInterFoam (CIF) solver of OpenFOAM is used in the geyser simulations due to its suitability for modeling two compressible and immiscible fluids. The successive mixing of air and water entering the dropshaft causes a reduction in the density of the air-water mixture. Also, the non-uniform and chaotic mix of air and water in the dropshaft may lead to small bursts in the dropshaft that may cause depressurization in the dropshaft. This, in turn, could lead to rapid changes in the velocity of mostly the air and in a lesser degree of the water in the horizontal pipe. The increase in the relative velocities of air and water inside the horizontal pipe causes the transition from stratified to wavy and ultimately to slug flow. This results in successive eruptions as a result of the blowout of slugs through the dropshaft. Besides providing insights into the geyser processes, the present study provides criteria for performing a computationally efficient numerical simulation of geysers.
