Study of Isothermal Pressure Drop and Non-boiling Heat Transfer in Vertical Downward Two Phase Flow

In the past few decades, the application areas of two-phase flow have increased due to technological advancement. The main applications of two-phase flow can be seen in chemical, oil and nuclear industry. Pressure drop and heat transfer are two important phenomena and essential in terms of engineering design. There is no doubt that the flow orientation has a significant influence on these phenomena due to the large density difference between phases. For this purpose, the pressure drop and the heat transfer characteristics of downward two-phase flow and the effect of different flow patterns on these characteristics were experimentally investigated by using air-water mixture as the fluid combination in a 0.01252 m I.D. pipe in the present study. It was seen that both the pressure drop and the heat transfer were greatly dependent on the flow patterns. The slug and the falling film regimes were the most distinctive ones due to their unpredictable behaviors. High frictional pressure drop and heat transfer rate values were observed for the downward flow in general. It was seen that the buoyancy had a great impact on the flow especially at the lower flow rates. Moreover, some of the well known two-phase pressure drop and heat transfer correlations were tested against the data. Consequently, the available pressure drop and heat transfer correlations were able to produce only limited results. Therefore, further work is still needed.Mechanical & Aerospace Engineerin