Flow pattern in horizontal and vertical two phase flow in small diameter pipes

Abstract New data on flow pattern transition for gas liquid flow in small diameter tubes (4 to 12 mm) is presented. The experimental results are compared with previously published models for horizontal and vertical flows considered to be valid for medium and large diameter pipes. The effect of surface tension which might be expected to be important in small diameter pipe flow has been found to affect only the stratified‐slug transition in horizontal flow. A modification to the model to include this effect is proposed.