Estimation of the local loss coefficient in gradual conical expansions for oil using CFD

Abstract

In long-distance fluid transport, the use of expansion fittings is crucial for increasing efficiency, which is affected by geometry and phase interaction. With the increase in oil and oil sands extraction, projected the global supply of these fluids increases significantly from 5.4 mb/d in 2022 to around 10.6 by 2045 according to OPEP data, the continuous improvement of these processes is of great importance for enhancing energy efficiency and reducing their environmental impact. This aligns with the Sustainable Development Goals, particularly goals 12 (responsible production and consumption) and 9 (industry, innovation, and infrastructure). To address this challenge, a numerical analysis of fluid behavior through the fitting was performed, varying parameters such as the diameter ratio (1,5, 2,0, 3,0), the expansion angle (7, 15, 30), the fluid velocity (1,5; 2,0; 2,5; 3,0), and the fluid itself (water, API 30,7 oil). All of this was done using computational fluid dynamics (CFD) simulations in ANSYS Fluent®. These simulations aim to evaluate the loss coefficient (K) of this fitting commonly used in heavy crude oil transport, in order to reduce pressure losses in pipelines and erosion in flows containing sand or sediment.