New concept for flow regime identification applied to electrical resistance tomography data in a bubble column
Sprache des Vortragstitels:
Englisch
Original Tagungtitel:
GLS-16 International Conference on Gas-Liquid and Gas-Liquid-Solid Reactor Engineering
Sprache des Tagungstitel:
Englisch
Original Kurzfassung:
Bubble columns (BCs) are being frequently used in the chemical industry. The topic of flow regime (FR) identification in
BCs is very important since the degrees of mixing, mass and heat transfer depend on the prevailing FR. In this work, a new
original parameter (called novel hybrid index (NHI)) for identification of the transition velocities Utrans based on electrical
resistance tomography (ERT) data was developed and successfully tested. The ERT data were obtained in an air-deionized
water BC (0.1 m in ID) equipped with a cross sparger (12 orifices ? ? 1 mm, each leg having 3 orifices). Based on the change
of the slope of the NHI values, the end of gas maldistribution zone was identified at a superficial gas velocity Ug of 1.5 ? 10-2
m/s. In the homogeneous FR, the NHI values smoothly decreased up to 4.5 ? 10-2 m/s. At this critical gas velocity, a local NHI
minimum was observed. It identified clearly the onset of the transition FR. i.e. the so-called main Utrans value. It is noteworthy
that our result was also empirically predicted. At Ug = 7.0 ? 10-2 m/s the NHI leveled off and this trend marked the onset of the
churn-turbulent FR
Forschungs-