Digital twin framework for pipeline systems using the Post-Extrapolation Method (PEM): Real-time prediction of water air two phase transients with experimental and OLGA Validation

Title : Digital twin framework for pipeline systems using the Post-Extrapolation Method (PEM): Real-time prediction of water air two phase transients with experimental and OLGA Validation

Abstract:

This paper presents an integrated Digital Twin framework for real-time monitoring and prediction of two-phase transient flow in pipeline systems, with specific relevance to the operational environment of the National Oil Corporation (NOC) of Libya. The proposed framework incorporates the Post-Extrapolation Method (PEM) into a Method of Characteristics (MOC) structure to overcome the numerical interpolation limitations typically encountered in conventional transient solvers. The PEM-enhanced formulation allows accurate prediction of water–air transient behavior over a regular computational grid while maintaining numerical stability under variable wave celerity conditions.

Model validation was conducted using comprehensive experimental data from the National University of Singapore (NUS) air–water multiphase flow loop, demonstrating strong agreement across a broad range of gas volume fractions (GVF = 0%–90%). Comparative analysis against industry-standard OLGA simulations further confirmed the effectiveness of PEM, achieving a Mean Absolute Percent Error (MAPE) below 4% across all test scenarios while reducing computational runtime by approximately 60%. These results position PEM as a computationally efficient alternative that retains physical fidelity without the intensive computational demands of full multiphase solvers.

The Digital Twin implementation highlights significant potential for improving pipeline integrity management, enabling early detection of surge events, tracking of flow-regime transitions, and real-time operational optimization. The framework is readily adaptable to oil–gas systems through fluid-property mapping and provides a practical pathway for real-time deployment within NOC’s pipeline infrastructure.

Keywords: Digital Twin; Transient Two-Phase Flow; Post-Extrapolation Method (PEM); Pipeline Integrity; OLGA Simulation; Real-Time Monitoring; National Oil Corporation (NOC)

Biography:

Abdalla Ali Estuti is a senior engineering consultant and researcher with more than four decades of professional experience across a broad range of engineering disciplines. His expertise includes engineering analysis, numerical modelling , infrastructure systems, fluid mechanics, and applied computational methods, with involvement in energy, industrial, and large-scale infrastructure projects. He is the developer of the Post-Extrapolation Method (PEM), an advanced numerical approach for simulating unsteady single- and two-phase flow, with applications in real-time prediction and digital twin frameworks for engineering systems. His research interests focus on transient phenomena, numerical stability, and the integration of physics-based models with operational and decision-support environments. Mr. Estuti has contributed to international conferences and peer-reviewed publications and continues to bridge advanced engineering theory with real-world applications.