Vortex bifurcation and air entrainment mitigation using multi-point intakes

• Published in: Physics of fluids (1994) 2024-04, Vol.36 (4)
• Main Authors: Mondal, Rahul Kumar, Rohilla, Lokesh, Kumar, Parmod
• Format: Article
• Language: English
• Subjects: Air entrainment; Annular flow; Flow distribution; Froude number; High speed photography; Hydrocyclones; Nuclear electric power generation; Nuclear power plants; Slug flow; Turbines; Water treatment plants
• ISSN: 1070-6631; 1089-7666
• DOI: 10.1063/5.0203199

Air entrainment is a concern of paramount importance in the process industries, including nuclear power plant, hydraulic machines, water treatment plants, hydrocyclones, and power generation turbines. The ingression of the air into the equipment results in the reduction of the hydraulic efficiency. In the current paper, a combined experimental and numerical investigation has been performed using the commensurate high-speed photography and volume of fluid-based numerical simulations. The mitigation strategies for the reduction of the air ingression include the reduction of the critical height by increasing the number of intakes and changing the intake configuration. The viability of these solutions and the hydrodynamics behind the interfacial evolution leading to the air entrainment have been studied in detail. The air ingression progresses with the establishment of the flow patterns ranging from bubbly flow, slug flow, to the annular flow. The reduction of the critical height can be accomplished by increasing the number of intakes for the same cross-sectional area leading to the reduction in the Froude number F r = V down / g H local < 1. Further increasing the number of intakes beyond four leads to the minimal reduction in the critical height in the tank.