PHASE INTERFACES IN BUBBLE FLOW .2. LARGE BUBBLES AND PLUGS

In the first part of this article an equation was derived for calculat ion of the specific interfacial area and the size distribution of bubb les in bubble flow, However, its application is limited to gas content s lower than 12%, At higher gas contents, large bubbles and gas plugs occur in the field of flow, These have a very low interfacial area per unit volume compared to small bubbles. Since large bubbles and gas pl ugs contain a large proportion of the gas in the flow, the overall int erfacial area is reduced, In the present contribution, the gas content above which large bubbles and gas plugs occur is calculated. The resu lts are subjected to experimental testing for vertical pipe flow. In a ddition, the volume fraction of the larger bubbles is calculated and t he results verified experimentally by measurements in bubble columns, Subsequently, the specific enterfacial area with and without large bub bles is calculated for high gas contents, The results are in agreement with values measured for bubble columns and column plates.