626 Development of Numerical Simulation Method of Dispersed Two-Phase Flow Using a Euler-Lagrange Model

Forced convective flow boiling in a single microchannel with different channel heights was studied through a numerical simulation method to investigate bubble dynamics, two-phase flow patterns, and boiling heat transfer. The momentum and energy equations were solved using a finite volume (FV) numerical method, while the liquid–vapor interface of a bubble is captured using the volume of fluid (VOF) technique. The effects of different constant wall heat fluxes and different channel heights on the boiling mechanisms were investigated. The effects of liquid velocity on the bubble departure diameter were also analyzed. The predicted bubble shapes and distribution profiles together with two-phase flow patterns are also provided.

Download Full-text

Simulation Analysis of Capacitance Method in Two-Phase Flow Concentration Measurement by Coupled Fields

10.20944/preprints201608.0234.v1 ◽

2016 ◽

Author(s):

Xiaoxin Wang ◽

Hongli Hu ◽

Lin Li ◽

Bo Wang

Keyword(s):

Numerical Simulation ◽

Two Phase Flow ◽

Simulation Analysis ◽

Three Dimensional ◽

Flow Characteristics ◽

Simulation Method ◽

Concentration Measurement ◽

Phase Flow ◽

Two Phase ◽

Time Dynamic

This paper proposed three-dimensional numerical simulation method by coupling of electrostatic and fluid fields to evaluating the performance of electrical sensor in the concentration measurement of gas/solid two-phase flow. Compared with the static numerical simulation, this real-time dynamic 3-D simulation method can research on a designed capacitance sensor combining the dynamic characteristics of the two-phase flows for concentration measurement. Several fluid-electrostatic models of transmission pipes with different sensor structures are built. Under different test positions and different particle concentrations, the flow characteristics and the corresponding electric signals can be obtained, and the correlation coefficient between the concentration values and the capacitance values are used for performance evaluation of the sensors. The effects of flow regimes on concentration measurement are also been investigated in this paper. To validate the results of simulation, an experimental platform with horizontal straight pipe for phase volume concentration measurement of solid/air two-phase flow is built, and the experimental results agree well with simulation conclusions. The simulation and test results show that the coupling models can give constructive reference opinions for the sensor design and collection of installation position in different transmission pipelines, which are very important for the practical process of pneumatic conveying system.

Download Full-text

Study on the prediction method and the flow characteristics of gas-liquid two-phase flow patterns in the suction chamber

International Journal of Numerical Methods for Heat &amp Fluid Flow ◽

10.1108/hff-08-2021-0588 ◽

2021 ◽

Vol ahead-of-print (ahead-of-print) ◽

Author(s):

Chunlei Shao ◽

Ning Bao ◽

Sheng Wang ◽

Jianfeng Zhou

Keyword(s):

Numerical Simulation ◽

Flow Rate ◽

Two Phase Flow ◽

Flow Characteristics ◽

Prediction Method ◽

Simulation Method ◽

Flow Patterns ◽

Phase Flow ◽

Two Phase ◽

Content Type

Purpose The purpose of this paper is to propose a prediction method of gas-liquid two-phase flow patterns and reveal the flow characteristics in the suction chamber of a centrifugal pump. Design/methodology/approach A transparent model pump was experimentally studied, and the gas-liquid two-phase flow in the pump was numerically simulated based on the Eulerian–Eulerian heterogeneous flow model. The numerical simulation method was verified from three aspects: the flow pattern in the suction chamber, the gas spiral length and the external characteristics of the pump. The two-phase flow in the suction chamber was studied in detail by using the numerical simulation method. Findings There are up to eight flow patterns in the suction chamber. However, at a certain rotational speed, only six flow patterns are observed at the most. At some rotational speeds, only four flow patterns appear. The gas spiral length has little relationship with the gas flow rate. It decreases with the increase of the liquid flow rate and increases with the increase of the rotational speed. The spiral flow greatly increases the turbulence intensity in the suction chamber. Originality/value A method for predicting the flow pattern was proposed. Eight flow patterns in the suction chamber were identified. The mechanism of gas-liquid two-phase flow in the suction chamber was revealed. The research results have reference values for the stable operation of two-phase flow pumps and the optimization of suction chambers.

Download Full-text

Numerical Simulation of Two Phase Flow and Heat Transfer in CPL Condenser With Porous Wick

ASME 2008 First International Conference on Micro/Nanoscale Heat Transfer, Parts A and B ◽

10.1115/mnht2008-52129 ◽

2008 ◽

Author(s):

ZhiChun Liu ◽

Wei Liu ◽

JinGuo Yang

Keyword(s):

Heat Transfer ◽

Numerical Simulation ◽

Phase Change ◽

Two Phase Flow ◽

Pressure Oscillation ◽

Simulation Method ◽

Phase Flow ◽

Two Phase ◽

Porous Wick ◽

Flow And Heat Transfer

In the present paper, the Volume of Fluid (VOF) method is introduce to model the two phase flow and heat transfer with phase change in CPL condenser with porous element and the effect of different wall temperature and inlet vapor velocity to condensation phase change interface was studied with numerical simulation method. The results present that a fixed condensation physical interface can be formed on the face of porous wick, which can restrain, even eliminate the pressure oscillation. The reason of the effects are also analysed in this paper.

Download Full-text