An Experimental Study on Air-Water Two-Phase Flow in Pebble Beds

An experimental study was conducted on the air-water two-phase flow patterns and pressure drop in the bed of rectangular cross section containing spheres of regular distribution. Three kinds of glass spheres with different diameters (3mm, 6mm and 8mm) were used for the establishment of the test section. By means of visual observations of the two-phase flow through the test section, it was discovered that five different flow patterns occur in the experimental parameter ranges, namely bubbly flow, bubbly-slug flow, slug flow, slug-annular flow and annular flow. A correlation for bubble and slug diameter in packed beds was proposed, which is an extension of the Tung/Dhir model, Jamialahmadi’s model and Schmidt’s model. Three correlations were proposed to calculate the void friction of flow regime transition in bubble flow, slug flow and annular flow based on the bubble model in the pore region. The experimental result shows that the modified Tung and Dhir’s model of flow pattern transition is a better agreement with the experimental data compared with Tung and Dhir’s model.