High-precision two-phase fluid interface capturing method

Abstract

The invention discloses a high-precision two-phase fluid interface capturing method, comprising the steps of: modeling a computation region and generating an initial high-quality unstructured triangular grid; setting computation parameters and initializing the VOF (Volume Of Fluid) phase function value F for different fluid phases; firstly predicating and computing the distribution of fluid phasefunctions by adopting 'prediction-correction', performing self-adaptive subdivision on a grid unit at the phase interface according to the phase function values, then re-computing the distribution offluid phase functions on the subdivided grid unit; after the computation on the subdivided grid unit is completed, remerging sub-grid units, with the specified phase fluid completely flowing out or completely filled therein, into the grid unit before subdivision and obtaining the phase function value F of the grid, and constructing the phase interface by adopting a PLIC (Piecewise Linear Interface Construction) method. The method of the invention can improve the phase interface capturing precision with no need of massively increasing the number of the grid unit, and simultaneously, as the time and the phase interface vary, the method has no need of regenerating all of the grids, so the algorithm executing efficiency is high.

Description

technical field [0001] The invention relates to a self-adaptive unstructured triangular mesh generation method and a two-phase interface construction method, in particular to a high-precision two-phase fluid interface capture method. Background technique [0002] Two-phase or multiphase flow widely exists in nature and engineering. With the rapid development of computer technology, numerical simulation has become an effective method for studying multiphase flow. When studying gas-liquid / liquid-liquid two-phase flow, since there is a moving phase interface, and the fluid physical and flow state may change drastically on the free interface, it is very important to consider the deformation and displacement of the phase interface and the treatment of the interface Whether the two-phase interface can be accurately captured is related to the correctness and rationality of the entire flow field calculation. The VOF (Volume of Fluid) method, as an interface capture method, has been...

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Problems solved by technology

The construction of the interface is the premise of computing fluid transport and visualization. Nowadays, it is more common to use a line segment with an arbitrary slope to approximate the real interface line. In 1995, Barth proposed a method to iteratively calculate the position of the line segment using the least square method, and obtained It is widely used, but every time the interface is constructed, several iterative calculations must be performed on the grid, and the accuracy is limited; for the calculation of fluid transport, in view of the irregularity of the unstructured grid, many scholars avoid Open the Euler format calculation of the flow rate and use the Euler-Lagrangian combination method proposed by Mosso in 1997 to calculate the flow rate. formats, in addition to involving complex geometric calculations

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