CN-121997804-A - LSMPS-based high density ratio bubble rising behavior numerical calculation method

Abstract

The invention discloses a high density ratio bubble rising behavior numerical calculation method based on LSMPS, which is implemented according to the following steps of step 1, establishing a two-dimensional axisymmetric single bubble rising calculation model based on a mesh-free moving particle semi-implicit method, step 2, calculating the temporary speed of particles, step 3, calculating the pressure of gas particles and interface node particles, step 4, calculating the pressure jump of interface node particles, step 5, calculating the pressure of liquid particles, step 6, correcting the speed of particles, step 7, updating the positions of particles and interface node particles, and step 8, simulating calculation and result derivation. According to the invention, an axisymmetric model is adopted, the rising behavior of air bubbles in water and nitrogen bubbles in lead-bismuth alloy is numerically simulated, the evolution of bubble interfaces can be accurately captured, the total rising speed of bubbles and the change rule of the speeds of the top and the bottom of the bubbles are analyzed, and the evolution process of the height, the volume, the surface area and the aspect ratio of the barycenter of the bubbles along with the time is obtained.

Inventors

• ZUO JUANLI

Assignees

• 西安理工大学

Dates

Publication Date

20260508

Application Date

20251226

Claims (8)

1. 1. The numerical calculation method for the rising behavior of the high density ratio bubble based on LSMPS is characterized by comprising the following steps of: step 1, establishing a two-dimensional axisymmetric single-bubble ascending calculation model based on a gridless moving particle semi-implicit method; step 2, calculating the temporary speed of the particles; step 3, calculating the pressure of the gas particles and the interface node particles; Step 4, calculating pressure jump of interface node particles; step 5, calculating the pressure of the liquid particles; Step 6, correcting the speed of the particles; Step 7, updating the positions of the particles and the interface node particles; and 8, simulating calculation and result derivation.
2. 2. The LSMPS-based high density ratio bubble rising behavior numerical calculation method as claimed in claim 1, wherein in the initial layout of the gas phase and the liquid phase particles in the step 1, the layout of the particles near the phase interface adopts a multi-resolution technique, that is, different regions adopt different inter-particle distances and different resolutions, and the smaller the inter-particle distance is, the denser the particle distribution is, and the larger the inter-particle distance is, the more sparse the particle distribution is.
3. 3. The method for calculating the numerical value of the rising behavior of the high density ratio bubble based on LSMPS according to claim 1, wherein the temporary speed in the step 2 is calculated explicitly, and a particle movement speed correction term and an artificial viscosity term are added: (1) in the formula, Is the step of the time that is required, Is the temporary speed at which the vehicle is traveling, Is the convection term, velocity correction Is the speed of movement of the particles, Is an artificial viscosity term, superscript The calculation step is indicated and the subscript i indicates the particle i.
4. 4. The method for calculating the rising behavior value of the bubble based on the high density ratio of LSMPS according to claim 1, wherein for the gas particles and the interface node in the step 3, the following pressure equation is considered: For gas particles: (2) for interface nodes: (3)。
5. 5. The method for calculating the rising behavior value of bubbles based on LSMPS according to claim 1, wherein in the step 4, there is a pressure jump at an interface node between the gas phase and the liquid phase, and a pressure jump calculation formula is adopted: (4) Wherein, the Is the pressure at the gas interface node i, Is the pressure of the liquid interface node i, superscript And All represent calculation steps.
6. 6. The method for calculating the rising behavior value of the high density ratio bubble based on LSMPS according to claim 1, wherein in the step 5, the pressure jump calculated in the step 4 is used as a Dirichlet boundary condition for calculating the pressure of the liquid phase particles, and the pressure of the liquid phase particles is calculated by using the following formula: (5)。
7. 7. The method for calculating the numerical value of the rising behavior of the high density ratio bubble based on LSMPS according to claim 1, wherein the particle velocity correction calculation formula in step 6 uses the following formula: (6)。
8. 8. the method for calculating the rising behavior value of the high density ratio bubble based on LSMPS according to claim 1, wherein the calculation formula for updating the positions of the particles and the interface node particles in the step 7 adopts the following formula: (7)。

Description

LSMPS-based high density ratio bubble rising behavior numerical calculation method Technical Field The invention belongs to the technical field of fluid mechanics, and particularly relates to a numerical calculation method for rising behavior of bubbles with high density ratio based on LSMPS. Background The rising motion of bubbles is widely found in various engineering fields such as ocean engineering, chemical engineering, energy engineering, and environmental engineering. The phenomenon of high density ratio of gas-liquid two-phase flow often occurs during the rising of bubbles. For example, air bubbles rising in water and inert gas bubbles rising in liquid metal systems have gas-to-liquid densities approaching thousands and tens of thousands of times. Under these conditions, sharp jumps/drops in density and pressure typically occur at the interface due to discontinuities in fluid properties, bubble dynamics become highly nonlinear due to the combined effects of buoyancy, inertial forces, viscous forces, and surface tension, making the interface prone to destabilization and severe deformation. Therefore, the intensive research on the motion law of bubbles with high density ratio is of great significance for revealing the basic mechanism of multiphase flow. Disclosure of Invention The invention aims to provide a high density ratio bubble rising behavior numerical value calculation method based on LSMPS, which can accurately capture the evolution of a bubble interface. The technical scheme adopted by the invention is that the numerical calculation method for the rising behavior of the bubbles based on LSMPS high density ratio is implemented according to the following steps: step 1, establishing a two-dimensional axisymmetric single-bubble ascending calculation model based on a gridless moving particle semi-implicit method; step 2, calculating the temporary speed of the particles; step 3, calculating the pressure of the gas particles and the interface node particles; Step 4, calculating pressure jump of interface node particles; step 5, calculating the pressure of the liquid particles; Step 6, correcting the speed of the particles; Step 7, updating the positions of the particles and the interface node particles; and 8, simulating calculation and result derivation. The invention is also characterized in that: In the step 1, when gas phase and liquid phase particles are initially laid out, a multi-resolution technology is adopted for particle layout near a phase interface, namely different areas adopt different particle intervals and different resolutions, the smaller the particle intervals are at the position closer to the phase interface, the denser the particle distribution is, the larger the particle intervals are at the position farther from the phase interface, and the more sparse the particle distribution is. In the step 2, an explicit calculation method is adopted for the temporary speed, and a particle movement speed correction term and a manual viscosity term are added: (1) in the formula, Is the step of the time that is required,Is the temporary speed at which the vehicle is traveling,Is the convection term, velocity correctionIs the speed of movement of the particles,Is an artificial viscosity term, superscriptThe calculation step is indicated and the subscript i indicates the particle i. For gas particles and interface nodes in step 3, consider the following pressure equation: For gas particles: (2) for interface nodes: (3)。 In the step 4, pressure jump exists at an interface node between the gas phase and the liquid phase, and a pressure jump calculation formula adopts: (4) Wherein, the Is the pressure at the gas interface node i,Is the pressure of the liquid interface node i, superscriptAndAll represent calculation steps. In step 5, the pressure jump calculated in step 4 is used as a Dirichlet boundary condition for calculating the liquid phase particle pressure, and the liquid phase particle pressure is calculated by the following formula: (5)。 In the step 6, the particle velocity correction calculation formula adopts the following formula: (6)。 In the step 7, the calculation formula of the positions of the updated particles and the interface node particles adopts the following formula: (7)。 the beneficial effects of the invention are as follows: According to the numerical calculation method for the rising behavior of the high-density ratio bubbles based on LSMPS, the rising behavior of the bubbles under the high-density ratio is researched by adopting a two-dimensional axisymmetric model, and the simulation calculation can be carried out on the bubble motion in the air-water and nitrogen-lead bismuth alloy system and other gas-liquid two-phase flows under the high-density ratio. The numerical algorithm of the invention can accurately capture the evolution of the bubble interface, and the calculated data can analyze the rising characteristics of the bubble, including the total rising speed, t