Simulation of Adiabatic Flow Patterns and Flow Pattern Map of R134a in Vertical Micro Tubes

Abstract:

The current research paper presents an investigation into the behavior of two-phase flow of liquid-vapour R134a within vertical circular channels with a 1 mm diameter, utilizing the Volume of Fluid (VOF) method. The main objective of these simulations was to create a numerical flow regime map to delineate the boundaries of different flow patterns for liquid-gas R134a. The injection of vapor was performed through an annular (concentric) nozzle configuration. To optimize computational efficiency, a two-dimensional axisymmetric assumption was made. The results of this study led to the identification of four fundamental flow patterns: bubbly flow/confined bubble flow, slug flow, churn flow, and annular flow. The accuracy of these findings was confirmed by comparing them with experimental flow visualization results, demonstrating a strong agreement. This study highlights the effectiveness of Computational Fluid Dynamics in establishing a reliable two-phase flow pattern map.

• Periodical: Defect and Diffusion Forum (Volume 442)
• Pages: 63-69
• DOI: https://doi.org/10.4028/p-9U6ccz
• Online since: May 2025
• Authors: Amirah Mohamad Sahar, Mohamad Shaiful Ashrul Ishak*, Yahaya Nor Zaiazmin
• Keywords: CFD, Flow Pattern, Flow Pattern Maps, Microchannel, R134a, Two-Phase

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