Two-phase flow is typically observed in gas-liquid pipelines across diverse domains, including nuclear, petroleum, and chemical industries. As accurate prediction of flow characteristics is crucial for engineering app...
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Two-phase flow is typically observed in gas-liquid pipelines across diverse domains, including nuclear, petroleum, and chemical industries. As accurate prediction of flow characteristics is crucial for engineering applications, one-dimensional two-fluid models with various treatments have been extensively employed to mathematically describe the gas-liquid variations in the pipelines through a set of non-linear partial differential equations (PDEs). This paper presents a modularly designed algorithm that incorporates an implicit scheme coupled with the finite element method (FEM) to solve the one-dimensional two-fluid model with gas-liquid stratified calculation. To validate the accuracy of this algorithm, four cases utilizing varying mesh sizes, inlet flows, and outlet pressures are conducted to scrutinize numerical steady-state gas-liquid flow characteristics, and the consistency between the numerical variations computed through this algorithm and those from OLGA simulator is used to analyze transient gas-liquid behaviors. The steady-state flow fields reveal two distinct zones along the pipe: an intense momentum exchange zone influenced by the inlet nonequilibrium state and a gentle momentum exchange zone influenced by the gas compressibility. Notably, a finer mesh will yield more accurate descriptions of flow parameters in the intense zone, while a relatively sparser mesh suffices for the gentle zone. Additionally, the transient results reveal that the gas-liquid variations in the pipe under initial condition of single-phase gas can be divided into three stages: the gas expansion stage determined by gas compressibility, the gas spread stage influenced by the gas propulsion, and the liquid filling stage decided by the liquid kinetic motion. The consistent identification of the three stages in gas-liquid variations under initial conditions of different static fluids highlights the effectiveness and accuracy of the proposed numerical method in describing transient fe
In this paper,the quasi-static large deformation,wrinkling and fracture behaviors of bimodular structures and membranes are studied with an implicit bond-based peridynamic computational ***,the constant and tangential...
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In this paper,the quasi-static large deformation,wrinkling and fracture behaviors of bimodular structures and membranes are studied with an implicit bond-based peridynamic computational ***,the constant and tangential stiffness matrices of the implicit peridynamic formulations for the nonlinear problems are derived,*** former is con structed from the linearization of the bond strain on the basis of the geometric approximation while the latter is established according to the linearization of the pairwise force by using first-order Taylor’s ***,a bimodular material model in peridynamics is developed,in which the tensile or compressive behavior of the material at each point is conveniently described by the tensile or compressive states of the bonds in its ***,the bimodular material model is extended to deal with the wrinkling and fracture problems of membranes by setting the compressive micro-modulus to be *** addition,the incremental-iterative algorithm is adopted to obtain the convergent solutions of the nonlinear ***,several representative numerical examples are presented and the results demonstrate the accuracy and efficiency of the proposed method for the large deformation,wrinkling and fracture analyses of bimodular structures and membranes.
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