Effect of roughness on air core vortexing phenomenon during draining of liquids from cylindrical tanks: An experimental investigation. (2023) - Gokul, G.
Abstract: This work investigates the effect of surface roughness on the development of air core vortex when liquid inside a cylindrical tank is rotated and subsequently drained. Surface roughness was applied on both the lateral and base surfaces of the cylindrical tank. When vortex air core forms in drain tanks, the drain port may become blocked, and this can immediately restrict the amount of draining liquid that is discharged. The development of such a vortex will result in the underutilization of propellants and may drastically impact the performance of rocket engines in the propellant tanks of spacecraft and rockets. Ingestion of air core vortex in metal casting process can affect the mechanical properties of casted metals. So, in the disciplines of aviation, metal casting, and other hydraulic engineering systems, air core vortex suppression is inevitable. The properties of the air core vortex have been studied experimentally for various values of roughness height and initial fluid rotation. It has been observed that using surface roughness, air core vortexing can be reduced by up to 50% at the highest value of initial rotation given to the liquid. In the light of the results obtained, current study recommends drain tank manufacturers not to smoothen the tank surface spending time at extra cost.