A suitability analysis of transient one-dimensional two-fluid numerical models for simulating two-phase gas-liquid flows based on benchmark problems. (30th October 2021)

• Record Type: Journal Article
• Authors: Sondermann, Carina Nogueira; Viggiano, Raphael; Rachid, Felipe Bastos de Freitas; Bodstein, Gustavo C.R.
• Is Part Of: Computers & fluids. Volume 229(2021)
• Publication Date: 2021-10-30
• Subjects: Two-phase flow -- Two-fluid model -- Transient simulation -- Numerical methods -- Benchmark problems; Fluid dynamics -- Data processing -- Periodicals; 532.050285
• DOI: 10.1016/j.compfluid.2021.105070
• Languages: English
• ISSNs: 0045-7930

Abstract

HIGHLIGHTS: Two mathematical models that can represent two-phase gas-liquid flows in combination with three numerical methods (FCT, FORCE and ModFORCE) are used to simulate benchmark problems: water faucet and shock tube. Hyperbolicity issues are addressed to present advantages and disadvantages of the models herein used. The methods can be tuned to give a better result in terms of accuracy to capture the desired behavior by controlling the numerical diffusion and dispersion in the solution. The ModFORCE method combined with the 5E2P model seems to provide the best results when compared to all the models and methods combinations for the problems analyzed. Each problem has its own particularity that should be considered when choosing the model/method combination. Abstract: Gas-liquid two-phase flows in pipes are present in a variety of engineering applications. These applications require transient one-dimensional mathematical models coupled with robust numerical methods to simulate the flow behavior in time and space. As there exist several possible combinations of models and numerical methods, questions arise as to the suitability of these numerical models to best accommodate the problem features. Aiming to partially answer this question, we present in this work numerical simulations of two well-known gas-liquid benchmarks, the water faucet, and the shock tube problems, carried out with two two-fluid models – 4E1P (four equations and one pressure) and 5E2P (five equations and two pressures) – in association with three numerical methods – FCT (Flux-Corrected Transport method), FORCE (First-Order Centered Scheme) and ModFORCE. The numerical methods used herein are written in a general form and do not require the solution of the associated Riemann problem. The obtained results are sought to serve as a reference to choose the best approaches, among the ones studied, to tackle some transient one-dimensional two-phase flow problems, highlighting the advantages and disadvantages of each model and method combination regarding hyperbolicity, diffusive and dispersive effects. Overall, the combination of the 5E2P model with the ModFORCE numerical method provides the most accurate results compared to the analytical solutions available.