The analysis of two-dimensional two-phase flow in horizontal heated tube bundles using drift flux model

This paper presents the experimental study and numerical simulation of two- dimensional two-phase flow in horizontal heated tube bundles. In the experi ments, two advanced measuring systems with a single-fibre optical probe and a tri-fibre-optical-probe were developed to measure respectively the local void fraction and vapor bubble velocities among the heated tube bundles. I n accordance with the internal circulation characteristics of two-phase flo w in the tube bundles, a mathematical model of two-dimensional two-phase lo w Reynolds number turbulent flow based on the modified drift flux model and the numerical simulation method to analyze the two-phase flow structures h ave been developed. The modified drift flux model in which both the acceler ation by gravity and the acceleration of the average volumetric flow are ta ken into account for the calculation of the drift Velocities enables its ap plication to the analysis of multi-dimensional two-phase flow. In the analy sis the distributions of the vapor-phase velocity, liquid-phase velocity an d void fraction were numerically obtained by using the modified drift flux model and conventional drift flux model respectively and compared with the experimental results. The numerical analysis results by using the modified drift flux model agree reasonably well with the experimental investigation. It is confirmed that the modified drift flux model has the capability of c orrectly simulating the two-dimensional two-phase flow.