EFFECTS OF GRID SPACER WITH MIXING VANE ON ENTRAINMENTS AND DEPOSITIONS IN TWO-PHASE ANNULAR FLOWS

다국어 초록 (Multilingual Abstract)

The effects of mixing vanes (MVs) attached to a grid spacer on the characteristics of airewater annular flows were experimentally investigated. To know the effects, a grid spacerwith or without MV was inserted in a vertical circular pipe of 16-mm internal diameter. Forthree cases (i.e., no spacer, spacer without MV, and spacer with MV), the liquid filmthickness, liquid entrainment fraction, and deposition rate were measured by the constantcurrent method, single liquid film extraction method, and double liquid film extractionmethod, respectively. The MVs significantly promote the re-deposition of liquid droplets inthe gas core flow into the liquid film on the channel walls. The deposition mass transfercoefficient is three times higher for the spacer with MV than for the spacer without MV,even for cases 0.3-m downstream from the spacer. The liquid film thickness becomesthicker upstream and downstream for the spacer with MV, compared with the thicknessfor the spacer without MV and for the case with no spacer.

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