Oscillatory fluid motion unlocks plug flow operation in helical tube reactors at lower Reynolds numbers (Re ≤ 10)

摘要: Abstract Flow in helical tubes exhibits plug flow characteristics above a critical rate due to the formation of Dean vortices. In this study, we report novel use oscillatory inside coiled achieve high degrees at lower rates. The enhancement appeared ‘switch-on’ then ‘switch-off’ as oscillation intensity was increased, corresponding ‘oscillatory numbers’ Deo = 70–200, where secondary instabilities are expected. It is believed that motion leads periodic and unravelling For 5 mm tube diameter, effects radius curvature (12.5–32.5 mm), pitch (7.5–12.5 mm), net (Ren = 10–50), frequency (2–8 Hz) amplitude (1–8 mm) were studied. prototype coil reactors rapidly manufactured using 3D printing. optimal conditions for corresponded Deo/Ren = 2–8, Strouhal numbers range St = 1–2. Plug observed Reynolds least low Ren = 10, compared Ren = 70–300 literature subjected steady flows.