Effect of flow obstruction on two-phase pressure drops in both horizontal and vertical annular flows.

Two phase pressure drops due to friction and obstruction were studied for various blockages in both horizontal and vertical annular flows. These pressure drops are evaluated from the pressure distribution obtained along the test section with the aid of eight Meriam 33KB35 well type manometers. The frictional pressure drop in the channel upstream of the blockage was found to depend upon either the presence or the size of blockage, but it is not influenced by the changes in location. The pressure drop in the channel downstream of the blockage is influenced by the obstruction, with the location of blockage being the dominant factor. A comparison of the drop results between horizontal and vertical flows indictaes that the frictional pressure is larger in vertical flow. (from authors' abstract)