## The Volume of Fluid VOF algorithm was implemented to model

Fig. 4. Typical upside view for pure ethanol two-phase flow through sudden contraction σA = 0.51. (Flow rate condition: jL,d = 0.26 m/s and jG,d = 0.48 m/s). (a) Experimental (b) Numerical.Figure optionsDownload full-size imageDownload as PowerPoint slide

From Fig. 4(b), it AMG 548 is found that the present numerical simulation result offers an accurate representation of the experimental two-phase flow configuration with the same flow conditions.

4.2. Bubble velocity

Fig. 5 shows the bubble velocity data in the upstream channel with contraction of σA = 0.51. The data are plotted against the total volumetric flux, j (= jL + jG). The solid and broken lines represent respectively calculations by uG = j (homogeneous flow) and uG = 1.61j by the drift flux model of Zuber and Findlay [19].equation(9)uG=C0j+VGjuG=C0j+VGjHere, the drift velocity, VGj was taken as zero because of horizontal flow. The distribution parameter, C0, was determined by Mishima-Hibiki’s correlation [20].equation(10)C0=1.2+0.510exp(-0.691D)C0=1.2+0.510exp(-0.691D)Here, D is the inner diameter of tube in mm. The uG data for all liquids are higher than the solid line, and tight junctions for HFE-7200, having both the lowest surface tension and viscosity, show the highest value.