The Change of Velocity and Pressure of Micro Bubble in Multi-Phases Flow in Mesoscopic Scale

2014 ◽  
Vol 722 ◽  
pp. 97-100 ◽  
Author(s):  
Zai Shuai Ling ◽  
Wei Long ◽  
Zhang Yong Wu
Keyword(s):  
Bubble Velocity ◽  
Dissolution Mechanism ◽  
Flow State ◽  
Mesoscopic Scale ◽  
Vof Model ◽  
Key Factor ◽  
Micro Bubble ◽  
Fluent Software ◽  
Bubble Rising ◽  
Pressure Changes

The dissolution mechanism of air and formation mechanism of bubble in the scopic-scale,and the change rule of the velocity and pressure of bubble in the rising process,made the theoretical analysis and explanation. Be based on VOF model,with the help of Fluent software,For the single bubble rising in the water by numerical simulation;The results show that liquid phase flow state is a key factor affecting the speed of the bubbles rise;Pressure difference is the main reason cause the jets and bubbles deformation.Through the above process in the rising process of the bubble velocity and pressure changes, and a detailed analysis of inquiry, the pressure and velocity of the bubble rising process show up more realistic.

The Formation Mechanism and Simulation of Micro Bubble in Multi-Phases Flow in Mesoscopic Scale

2015 ◽  
Vol 779 ◽  
pp. 141-144
Author(s):  
Wei Long ◽  
Zai Shuai Ling
Keyword(s):  
Formation Mechanism ◽  
Dissolution Mechanism ◽  
Phase Flow ◽  
Flow State ◽  
Mesoscopic Scale ◽  
Vof Model ◽  
Key Factor ◽  
Micro Bubble ◽  
Fluent Software ◽  
Bubble Rising

The dissolution mechanism of air and formation mechanism of bubble in the scopic-scale Be based on VOF model,with the help of Fluent software,For the single bubble rising in the water by numerical simulation;The results show that liquid phase flow state is a key factor affecting the speed of the bubbles rise;Pressure difference is the main reason cause the jets and bubbles deformation.

The Research on the Key Factor Affect the Precision in Stress Analysis for the Rotor of Steam Turbine

2013 ◽  
Vol 275-277 ◽  
pp. 83-86
Author(s):  
Chun Lin Zhang ◽  
Nian Su Hu ◽  
Wen Yang ◽  
Jian Mei Wang ◽  
Min Li ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Numerical Calculation ◽  
Transfer Coefficient ◽  
Stress Analysis ◽  
Surface Heat ◽  
Flow State ◽  
Surface Heat Transfer ◽  
Surface Heat Transfer Coefficient ◽  
Key Factor

With the development of the power grid, the proportion of large capacity unit is increasing rapidly. It requires a more in-depth study on the reliability of the unit, especially for the unit adjusting the peak. This paper concerned on the research of the surface heat transfer coefficient, which is the key factor affect the precision in thermal stress analysis. The surface heat transfer coefficient is obtained via the numerical calculation for the steam’s flow state and the transient heat transfer between rotor. This paper mainly describes the steam’s flow state and the transient heat transfer with the steam seal, and the results show that the direct numerical calculation is resultful in this subject.

Numerical Simulation of High-Aspect-Ratio Micro-Hole Electroforming with External Magnetic Field

2010 ◽  
Vol 42 ◽  
pp. 13-16
Author(s):  
Wei Li ◽  
Ping Mei Ming ◽  
Wu Ji Jiang ◽  
Yin Ding Lv
Keyword(s):  
Magnetic Field ◽  
Numerical Simulation ◽  
Aspect Ratio ◽  
High Aspect Ratio ◽  
Flow State ◽  
Cathode Electrode ◽  
Micro Hole ◽  
Fluent Software ◽  
The Magnetic Field ◽  
Enhance Mass

In this paper, the influences of applied magnetic field on flow state during electroforming of the high-aspect-ratio (HAR) blind micro-hole were numerically analyzed using the Fluent software. The results showed that, when microelectroforming of nickel without external agitation, three vortexes could form due to the magnetohydrodynamic (MHD) effect within the HAR micro-hole with magnetic field in parallel to cathode-electrode surface, and the flow rate in the micro-hole increased with the increase of the magnetic field and current density. The MHD effect helped to enhance mass transfer during the microelectroforming of HAR microstructures.

scholarly journals The non-Darcy characteristics of fault water inrush in karst tunnel based on flow state conversion theory

2021 ◽  
Vol 25 (6 Part B) ◽  
pp. 4415-4421
Author(s):  
Zheng-Zheng Cao ◽  
Yu-Feng Xue ◽  
Hao Wang ◽  
Jia-Rui Chen ◽  
Yu-Lou Ren
Keyword(s):  
Flow Velocity ◽  
Water Inrush ◽  
Coupled Model ◽  
Flow Fields ◽  
Darcy Law ◽  
Brinkman Equation ◽  
Flow State ◽  
Navier Stokes Equation ◽  
Velocity Change ◽  
Key Factor

The fault water inrush is a key factor which leads to tunnel construction in karst regions. Based on the fluid mechanics principles, the paper addresses a numer?ical coupled model for karst fault tunnel with COMSOL Multiphysics software. Besides, the Darcy law equation, Brinkman equation, and Navier-Stokes equation are inserted to stimulate the steady flow of aquifer, the non-linear seepage of fault and the free flow in tunnel excavating area in software, respectively. Then, the pres?sure and flow velocity in three flow fields are analyzed under different permeability ratios in numerical model. It is shown that the fault permeability is the key factor affecting water inrush, and that the pressure and flow velocity change visibly in adjacent domains between two flow fields.

Simulation of Bubbles Aggregation Process Base on Interface Compression Method

2012 ◽  
Vol 569 ◽  
pp. 277-281
Author(s):  
Yong Guang Nie ◽  
Yu Mao ◽  
Juan Wang ◽  
Jiang Yun Wang
Keyword(s):  
Open Source ◽  
Aggregation Process ◽  
Compression Method ◽  
Vof Model ◽  
Key Factor ◽  
The Difference

Interface compression method is a VOF model presented in recent years. In this paper, the difference between interface compression method and classic acceptor-donor methods was revealed. The advection test shown the interface compression method was more accurate than HRIC scheme. The bubble aggregation process was simulated by this method using open source CFD tool OpenFOAM. Simulation shown the method can accurately capture the interface in the process of bubble aggregation and the loop flow is a key factor in the process.

scholarly journals Simulation of Printer Nozzle for 3D Printing TNT/HMX Based Melt-Cast Explosive

2021 ◽  
Author(s):  
Huzeng Zong ◽  
Qilun Cong ◽  
Tengyue Zhang ◽  
Yanjun Hao ◽  
Lei Xiao ◽  
...  
Keyword(s):  
3D Printing ◽  
Channel Model ◽  
Energetic Material ◽  
Element Model ◽  
Fused Deposition Modelling ◽  
3D Printer ◽  
Flow State ◽  
Fused Deposition ◽  
Fluent Software ◽  
Velocity Pressure

Abstract Fused deposition modelling (FDM) has been one of the most widely used rapid prototyping (RP) technologies, which has been attracted increasing attentions in the world. However, existing literatures about energetic material flow inside the 3D printer nozzle are sparse. For plunger 3D printer, we summarized the experimental and related literatures, finding that viscosity, temperature, outlet velocity, pressure, and nozzle diameter are the main factors to affect the flow state in the nozzle. Based on the actual printer nozzle structure, in this paper, a finite element model was established by SOLIDWORKS software firstly, meanwhile, the flow channel model of the nozzle was extracted and simplified. Secondly, the factors influencing the printing results were researched and analysed. In the end, numerical simulation on velocity field and temperature field was carried out by FLUENT software. Moreover, the printing test of HMX/TNT was also carried out by using EAM-D-1 3D printer. The printed sample shows that 3D printing is more satisfactory than conventional melt-casting ways to prepare high viscocity and unconventional structure explosives

Cavitation Bubble Collapse Near a Heated Wall and Its Effect on the Heat Transfer

2013 ◽  
Vol 136 (2) ◽  
Author(s):  
Bin Liu ◽  
Jun Cai ◽  
Xiulan Huai ◽  
Fengchao Li
Keyword(s):  
Heat Transfer ◽  
Cavitation Bubble ◽  
Stokes Equations ◽  
Saturated Vapor ◽  
Bubble Diameter ◽  
Bubble Radius ◽  
Heated Wall ◽  
Bubble Collapse ◽  
Flow State ◽  
Vof Model

In the present work, a numerical investigation on the mechanism of heat transfer enhancement by a cavitation bubble collapsing near a heated wall has been presented. The Navier–Stokes equations and volume of fluid (VOF) model are employed to predict the flow state and capture the liquid-gas interface. The model was validated by comparing with the experimental data. The results show that the microjet violently impinges on the heated wall after the bubble collapses completely. In the meantime, the thickness of the thermal boundary layer and the wall temperature decrease significantly within the active scope of the microjet. The fresh low-temperature liquid and the impingement brought by the microjet should be responsible for the heat transfer reinforcement between the heated wall and the liquid. In addition, it is found that the impingement width of the microjet on the heated wall always keeps 20% of the bubble diameter. And, the enhancement degree of heat transfer significantly depends on such factors as stand-off distance, saturated vapor pressure, and initial bubble radius.

Review of potential flow solutions for velocity and shape of long isolated bubbles in vertical pipes

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Alexandre Boucher ◽  
Roel Belt ◽  
Alain Liné
Keyword(s):  
Potential Flow ◽  
Bubble Velocity ◽  
Past Century ◽  
Theory Approach ◽  
Total Derivative ◽  
Power Series Method ◽  
Derivative Method ◽  
Bubble Rising ◽  
Analytical Tools ◽  
Moving Liquid

Abstract The motion of elongated gas bubbles in vertical pipes has been studied extensively over the past century. A number of empirical and numerical correlations have emerged out of this curiosity; amongst them, analytical solutions have been proposed. A review of the major results and resolution methods based on a potential flow theory approach is presented in this article. The governing equations of a single elongated gas bubble rising in a stagnant or moving liquid are given in the potential flow formalism. Two different resolution methods (the power series method and the total derivative method) are studied in detail. The results (velocity and shape) are investigated with respect to the surface tension effect. The use of a new multi-objective solver coupled with the total derivative method improves the research of solutions and demonstrates its validity for determining the bubble velocity. This review aims to highlight the power of analytical tools, resolution methods and their associated limitations behind often well-known and wide-spread results in the literature.

Rising Velocity of a Gas Plug in Vertical-Rectangular-Narrow Channels

2008 ◽  
Author(s):  
Tohru Miyashita ◽  
Yasuo Koizumi
Keyword(s):  
Open Space ◽  
Bubble Velocity ◽  
Stagnant Water ◽  
Short Side ◽  
Narrow Channels ◽  
Flow Channels ◽  
Rectangular Channels ◽  
Bubble Rising ◽  
Bubble Rising Velocity ◽  
Gap Spacing

A bubble rising velocity in stagnant water in rectangular channels was examined. The width of the flow channels and the gap space between parallel walls were varied from 10 mm through 150 and from 1 mm through 10 mm, respectively. When the bubble had plug shape in the long side and also the short side, the bubble velocity took the same velocity as that in a circular pipe that had the same periphery. When the bubble lost the plug shape in the long side, the rising velocity became fast as the long side shape departed from the plug shape. When the long side was large enough for the bubble to have the shape of a bubble in open space, the bubble rising velocity was expressed well with the expression for the bubble rising velocity in open space. As the long side became narrow, the bubble rising velocity became slower than that for open space. When the gap spacing was quite narrow; 1 mm, and the long side was less than 20mm, the bubble stopped rising halfway in the flow channel.

Simulation Study for the Effect of Oil Viscosityon Performance of Full Metal Single Screw Pump

2013 ◽  
Vol 561 ◽  
pp. 362-367
Author(s):  
Jun Fei Wu ◽  
Xiao Wei ◽  
Xue Zheng Yang ◽  
Ying Yu
Keyword(s):  
Pressure Change ◽  
Oil Viscosity ◽  
Screw Pump ◽  
Outlet Pressure ◽  
Single Screw ◽  
Pump Output ◽  
Fluent Software ◽  
Volume Method ◽  
Pressure Changes ◽  
Filling Coefficient

Abstract: The oil viscosity affects the pump filling coefficient, so it is the important parameter affecting lifting performance of metal screw pump. Firstly using the finite volume method to establish a full-metal single screw pump 3D model, secondly using FLUENT software to calculate outlet pressure changes with different series of oil viscosity in condition of the same inlet pressure.Lastly Drawing outlet pressure change curves to evaluate the concrete effect of oil viscosity on the performance of the pump . The results indicate that the oil viscosity affects liquid filling coefficient of pump. As the viscosity increases, the outlet pressure of the pump increases, the leakage of the pump output decreases, thereby lifting capacity and volumetric efficiency of the pump improve.

Sign in / Sign up

Export Citation Format

Share Document