فهرست مطالب مجتبی مسیحی

In the present research, the behavior and flow pattern of a Counter-current Gas-Liquid Two-Phase Flow in Transparent Vertical pipe made from Plexiglas with inner diameter of 38 mm was experimentally investigated. The considered fluids included the water and the air, and the results were obtained for a total of 125 select cases differing in the apparent velocities of the water and the air. The supperfacial velocities of the air and water in the 38 mm pipe were investigated in the ranges 4.90 – 9.30 m/s and 0.083– 0.139 m/s, respectively. The Entrainment fraction was measured Isokinetic-sampling technique. Provision of the Counter current Gas-Liquid Two-Phase Flow conditions in terms of initial flow orientation and the investigation of the effect of this design on the flow patterns, liquid film thickness, and the Entrainment fraction are the major innovations of the present research.In contrast to previous research works, the present study sets the scene for a more accurate evaluation of the annular flow pattern for calculating the liquid film thickness and the Entrainment fraction by designing the initial inlet orientation. Based on a comparison, as far as the calculation of the Entrainment was concerned, the results of the present research exhibited good agreement with the Wallis model in the 38 mm pipe, and when it came to obtaining the liquid film thickness, the results were consistented to those of the Schubring model.It is shown that the predictions of this new correlation outperform those from previously reported studies.

In the present research, the behavior and flow pattern of a Counter current Gas-Liquid Two-Phase Flow in different Transparent Vertical pipes made from Plexiglas with inner diameters of 26 mm and 44 mm were experimentally investigated. The considered fluids included the water and the air, and the results were obtained for a total of 304 select cases differing in the apparent velocities of the water and the air. The air and the water were flown from separate inlets upward and downward, respectively. The apparent velocities of the air and water in the 26 mm pipe were investigated in the ranges of 10.47 – 26.17 m/s and 0.06 – 0.36 m/s, respectively. The corresponding ranges for the 44 mm pipe were  3.56 – 9.14 m/s and 0.02 – 0.12 m/s, respectively. The liquid film thickness in the annular flow was measured by the Quick shut valve technique. The Entrainment fraction was measured Isokinetic-sampling technique. Provision of the Counter current Gas-Liquid Two-Phase Flow conditions in terms of initial flow orientation and the investigation of the effect of this design on the flow patterns, liquid film thickness, and the Entrainment fraction are the major innovations of the present research.In contrast to previous research works, the present study sets the scene for a more accurate evaluation of the annular flow pattern for calculating the liquid film thickness and the Entrainment fraction by designing the initial inlet orientation. Based on a comparison, as far as the calculation of the Entrainment was concerned, the results of the present research exhibited good agreement with the Oliemans model in the 26 mm pipe and the Wallis model in the 44 mm pipe, and when it came to obtaining the liquid film thickness, the results were consistented to those of the Schubring model.It is shown that the predictions of this new correlation outperform those from previously reported studies.