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Архив
Proceedings of the 24th National and 2nd International ISHMT-ASTFE Heat and Mass Transfer Conference (IHMTC-2017)


ISBN Онлайн: 978-1-56700-478-6

RESPONSE OF GAS-LIQUID DOWNWARD ANNULAR FLOW ACROSS DIVERGING PIPE SECTIONS

DOI: 10.1615/IHMTC-2017.1000
pages 713-719

S. Anupriya
Department of Chemical Engineering, IIT Madars

Sreenivas Jayanti
Department of Chemical Engineering Indian Institute of Technology Madras 600 036 India

Аннотация

Gas-liquid downward annular flow through a vertical circular pipe occurs widely in industrial equipment such as steam generators, re-boilers and absorbers. With a well-defined morphology, it can be described in terms of two-phase, three-field formulation representing the gas and two liquid phases, namely, liquid droplets and liquid film, each of which can have distinctly different velocity and temperature profiles, and may have different factors influencing their variation within the flow. Due to intense research over the past several decades, it can be claimed that the primary features of gas-liquid annular flow in vertical tubes are well-understood, especially in upward direction of flow.

The objective of the present work is to extend this knowledge base to the study of annular flow through area change and in vertically downward orientation. The reversal of gravity may have negligible influence on the gas flow; however, the film flow, and as a consequence, the entrainment and deposition processes, can be influenced significantly. In the present study, we report on the experiments conducted to determine pressure losses in sudden expansion at 0.025 m/0.038 m inner diameter pipe junction and a 0.025 m/0.050 m inner diameter pipe junction. Using these results together with a model for downward annular flow and a phenomenological model is proposed for the prediction of expansion loss coefficient in downward annular flow.