Numerical study on mitigating severe slugging in pipeline/riser system with wavy pipe

Assessment of Premoli et al. Correlation Predictions in Horizontal Stratified-Wavy Two-Phase Flow Encountered at Small Diameter T-Junction

“…The Realizable k-ε turbulence model constitutes a common practice according to literature since it is both adequate to capture the generated turbulence structures and less computationally expensive in comparison with other available turbulence models such as the Standard k-ω and the SST k-ω models. Moreover, it has been proven that the choice of turbulence model affects less the accurate prediction of phases' redistribution and consequently the value of important two-phase flow parameters such as void fraction [12], [13]. Concerning the discretization schemes, the Body Force Weighted and the Compressive schemes were utilised for the pressure discretization and for the volume of fluid, respectively, whereas the Second Order Upwind scheme was used for the remaining variables.…”

“…The average gas and liquid phase velocities are used to calculate the slip ratio, S, and thereby to characterize the two-phase flow, whereas the two-phase mixture density is required in calculation of two-phase pressure drop which in turn is a key parameter for the proper design and safe operation of processes involving two-phase flow. The air and water average velocities, u a and u w , can be defined as the ratio of either corresponding air or water superficial velocity divided by the void fraction or the liquid holdup, respectively, and they can be calculated as show in (13) and (14), whereas the two-phase mixture density, ρ m , is given in (15) and it constitutes the standard calculation approach according to literature [14].…”

Modeling and Experiments of Severe Slugging in a Riser System

“…Li et al [14] developed a transient model using OLGA to study the dynamic behavior of severe slugging in a pipeline-riser system and compared the simulation results with the experimental data. Xing et al [15,16] carried out 2D CFD simulations for severe slugging and attempted to develop a 3D-1D coupling simulation, that is, STAR-OLGA coupling, for mitigating hydrodynamic slug flows with a wave pipe, where the 1D simulation for the entire pipeline coupled with the 3D simulation of the partial flow field was implemented to control the scale of calculation. Looking through current literatures, numerical simulation methods are mainly divided into two categories: (1) numerical simulation of the whole flow field based on CFD; (2) simplified one-dimensional transient model.…”

Estudo experimental de intermitência severa em um sistema água-ar.

“…Xing propôs um dispositivo para condicionar o escoamento próximo à base do riser para mudar o padrão de escoamento nessa região. O estudo foi realizado experimentalmente (Xing et al, 2013a) e numericamente (Xing et al, 2013b).…”

“…A motivação veio do fato de que a intermitência severa ocorre com escoamento em padrão estratificado no pipeline e o uso de seções de tubulações não lineares acaba por modificar o padrão de escoamento multifásico na região. Em Xing et al (2013b) foi realizado um estudo numérico bidimensional em que se verificou que fatores como posição e amplitude (razão da área pelo diâmetro) das tubulações em onda afetam os resultados. Para maiores amplitudes foi verificado que há uma maior redução no comprimento de slug severo, porém isso aumenta as forças de arrasto e empuxo.…”