Mass flow measurement absorption, mechanism

Mass transfer controlled by diffusion in the gas phase (ammonia in water) has been studied by Anderson et al. (A5) for horizontal annular flow. In spite of the obvious analogy of this case with countercurrent wetted-wall towers, gas velocities in the cocurrent case exceed these used in any reported wetted-wall-tower investigations. In cocurrent annular flow, smooth liquid films free of ripples are not attainable, and entrainment and deposition of liquid droplets presents an additional transfer mechanism. By measuring solute concentrations of liquid in the film and in entrained drops, as well as flow rates, and by assuming absorption equilibrium between droplets and gas, Anderson et al. were able to separate the two contributing mechanisms of transfer. The agreement of their entrainment values (based on the assumption of transfer equilibrium in the droplets) with those of Wicks and Dukler (W2) was taken as supporting evidence for this supposition. 

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