Experimental study on air-water two-phase flow patterns and pressure drop in pebble beds

It was discovered that five different flow patterns occurred in the experimental parameter ranges. Compared with Tung and Dhir's model, the modified Tung and Dhir's model of the flow pattern transition was in better agreement with the experimental results. A new correlation for the prediction of single-phase flow pressure drops is proposed based on the two-regime model. The pressure drop for the two-phase co-current flow was interpreted by the concept of relative permeability. A new correlation was presented for predicting two-phase flow pressure drops over a wide range of operation conditions. The correlation produced desirable result when compared with experimental data.