Research Article
Post-Extrapolation Method for Simulating Unsteady Multiphase Flow in Oil and Gas Transport Pipelines
Abdalla Ali Estuti*
Issue:
Volume 13, Issue 5, October 2025
Pages:
74-83
Received:
20 May 2025
Accepted:
11 June 2025
Published:
24 December 2025
Abstract: Transient multiphase flow phenomena—such as cavitation, gas release, and pressure wave propagation—are critical challenges in oil and gas pipeline operations. These events, often triggered by sudden pump shutdowns or valve operations, can lead to equipment damage, production losses, and safety hazards. Accurate and stable simulation of such transients is essential for flow assurance, system design, and real-time decision-making in hydrocarbon transport networks. This study introduces a simulation framework based on the Post-Extrapolation Method (PEM), a numerical scheme developed to compute pressure and void fraction at specified time steps without requiring interpolation. PEM is applied to simulate one-dimensional, isothermal, transient multiphase flow representative of upstream and midstream oil and gas pipeline systems. Model validation is conducted against a well-established experimental benchmark involving cavitation and gas release phenomena. The results from PEM confirm its accuracy, stability, and suitability for modeling complex multiphase transients in oil and gas pipelines, offering a robust tool for engineers and operators.
Abstract: Transient multiphase flow phenomena—such as cavitation, gas release, and pressure wave propagation—are critical challenges in oil and gas pipeline operations. These events, often triggered by sudden pump shutdowns or valve operations, can lead to equipment damage, production losses, and safety hazards. Accurate and stable simulation of such transie...
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Research Article
Determinants of Ethiopia Export Performances: Evidence from an Auto Regressive Distributive Lag Model
Abdi Alemayehu*
Issue:
Volume 13, Issue 5, October 2025
Pages:
84-93
Received:
6 November 2025
Accepted:
18 November 2025
Published:
26 December 2025
DOI:
10.11648/j.ogce.20251305.12
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Abstract: Export was to drive productive capacity of domestic businesses, employment generation, better source of resource allocation and distribution. As a result, export to be an engine for economic growth and development. The objective of this study was to identify determinants of export in Ethiopia for the period 1996-2023 by applying auto regressive distributive lag model with bound testing approach of co-integration and error correction model. The Error Correction Term is negative (-0.889642) and is significant at 1% confidence level which indicates that any deviation from the long run equilibrium between variables is corrected about 88.96% each year. As evidenced from the estimation result of Auto Regressive Distributive Lag Model with bound testing approach of co-integration and error correction model, foreign direct investment, inflation rate, institutional quality index, taxes on international trade and trade openness of Ethiopia positively and statistically significantly affect the Ethiopian exports performance both in short-run and long-run. However, first lag of real exchange rate positively and statistically significantly affect Ethiopian exports performance only short run. Hence, government should encourage infrastructures attract foreign investors to directing produce exportable goods, reducing export duties to improve competitiveness on international trade improving the institutional quality through respect rule of law, government effectiveness, legal voice and accountability, regulatory quality and lowering corruption boost Ethiopian exports performance.
Abstract: Export was to drive productive capacity of domestic businesses, employment generation, better source of resource allocation and distribution. As a result, export to be an engine for economic growth and development. The objective of this study was to identify determinants of export in Ethiopia for the period 1996-2023 by applying auto regressive dis...
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