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Oxygen absorption from air into water and axial dispersion in the aqueous phase have been measured in a 5 cm diameter reciprocating plate bubble column. The volumetric mass transfer coefficients in semi‐batch conditions were found to increase with agitation and were correlated with the specific power input and air flow rate. Under countercurrent conditions, it was found that axial mixing had little effect and conditions approached plug flow. The volumetric mass transfer coefficients were correlated with specific power input, air and water flow rates. Mass transfer coefficients were estimated using holdup and bubble diameter results. Comparison of the coefficients with the literature values indicated that the bubble surfaces were partially mobile.

scillatory Flow Mixing (OFM in short) is a relatively recent development in mixing technology, which has been researched 0 over the past decade (Mackley, 1987; Howes, 1988; Brunold et al., 1989; Dickens et al .

The hydrodynamics of countercurrent air/water flow in a 5 cm diameter reciprocating plate bubble column have been studied; the plates contained 14 mm diameter perforations and had a fractional open area of 0.57. The ranges of superficial velocities of air and water were respectively 0‐0.99 cm/s and 0‐3.95 cm/s. The stroke was in most cases 4.5 cm and the reciprocation frequency was in the range 0–5 Hz. The pressure drops were measured in the absence of reciprocation for single phase and two phase flow conditions. Pressure fluctuations and time‐averaged pressure drops were measured with plate reciprocation under single and two‐phase conditions. The results were described in terms of the simple quasi‐steady state model; the effective orifice coefficients of the perforations were within the range 0.4 to 0.97 depending on the reciprocation conditions. The Sauter mean diameters of the bubbles decreased with agitation; they were about twice the values predicted from an earlier correlation developed for liquid‐liquid systems. The gas holdups were also substantially greater than predicted from correlations based on liquid‐liquid systems. Both these effects were explained as due to the tendency for bubbles to cluster in the plate region.

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