Thesis (M.Eng.)--Chulalongkorn University, 2001

To develop a computer program for predicting flow pattern and pressure loss in two-phase flow systems (gas-liquid) in isothermal cases of horizontal, vertical upward and vertical downward piping system. Visual Basic version 6.0 language was used for development of the two-phase program. Two-phase program was developed by using two-phase flow pattern models proposed by Taitel Y. and Duckler (1976), Taitel, Bornea and Duckler (1980), and Barnea, Shoham and Taitel (1981) for horizontal, vertical upward and vertical downward flow respectively. Two-phase pressure loss calculations were based on the studies of Taitel and Duckler (1980), Duckle and Hubbard (1975), Duckler, Wick and Cleveland (1964), Fernandes, Semiat and Duckler (1983) and Martin (1988). Program results were tested against experimental data from other researchers for air and water in 0.75-3 inch under atmospheric pressure to 5 barG. The results of flow pattern prediction were consistent with the experimental data except some flow conditions close to the transition between flow patterns. Calculated pressure losses are over predicted by more than 50% for stratified flow under 1 BarA to 5 BarG, in 0.75-3 inch pipe, gas superficial velocity 0.28 - 0.56 ft/s, liquid superficial velocity 5-33 ft/s. Calculated pressure losses for slug flow are within +-30% of the experimental value at 1 barA to 15 barG, in 3 inch pipe, air superficial velocity 17-25 ft/s, water superficial velocity 1-5 ft/s.