Effect of tip clearance on gas phase distribution of a gas-liquid two-phase pump

2021 ◽  
Author(s):  
Peng Wang ◽  
Hang Xie ◽  
Xingqi Luo ◽  
Runan Mo ◽  
Jinling Lu ◽  
...  
Keyword(s):  
Gas Phase ◽  
Phase Distribution ◽  
Tip Clearance ◽  
Two Phase

scholarly journals Phase Distribution in the Tip Clearance of a Multiphase Pump at Multiple Operating Points and Its Effect on the Pressure Fluctuation Intensity

Processes ◽  
2021 ◽  
Vol 9 (3) ◽  
pp. 556
Author(s):  
Guangtai Shi ◽  
Zongku Liu ◽  
Xiaobing Liu ◽  
Yexiang Xiao ◽  
Xuelin Tang
Keyword(s):  
Phase Velocity ◽  
Pressure Fluctuation ◽  
Phase Distribution ◽  
Tip Clearance ◽  
Tip Leakage Flow ◽  
Two Phase ◽  
Multiphase Pump ◽  
Fluctuation Intensity ◽  
Operating Points ◽  
Multiple Operating Points

Tip clearance has a great effect on the flow and pressure fluctuation characteristics in a multiphase pump, especially at multiple operating points. The phase distribution and pressure fluctuation in tip clearance in a multiphase pump are revealed using the CFD (computational fluid dynamics) technology and high-speed photography methods. In this paper, the phase distribution, the gas-liquid two-phase velocity slip, and the pressure fluctuation intensity are comprehensively analyzed. Results show with the increase of the tip clearance, the multiphase pump pressurization performance is obviously deteriorated. In the meantime, the gas accumulation mainly occurs at the hub, the blade suction side (SS), and the tip clearance, and the maximum gas-liquid two-phase velocity difference is near the impeller streamwise of 0.4. In addition, the tip clearance improves the gas-liquid two-phase distribution in the pump, that is, the larger the tip clearance is, the more uniform the gas-liquid distribution becomes. Furthermore, the gas leads to the maximum pressure fluctuation intensity in the tip clearance which is closer to the tip leakage flow (TLF) outlet, and has a greater effect on the degree of flow separation in the tip clearance.

Gas Phase Distribution Effects on Heat Transfer in Upward Vertical Bubbly Channel Flows

2016 ◽  
Author(s):  
Haden Hinkle ◽  
Deify Law
Keyword(s):  
Heat Transfer ◽  
Gas Phase ◽  
Bubble Size ◽  
Single Phase ◽  
Volume Fraction ◽  
Phase Distribution ◽  
Vertical Channel ◽  
Channel Flows ◽  
Two Phase ◽  
Ansys Fluent

Two-phase (non-boiling) flows have been shown to increase heat transfer in channel flows as compared with single-phase flows. The present work explores the effects of gas phase distribution such as volume fraction and bubble size on the heat transfer in upward vertical channel flows. A two-dimensional (2D) channel flow of 10 cm wide by 100 cm high is studied numerically. Numerical simulations are performed using the commercial computational fluid dynamics (CFD) code ANSYS FLUENT. The bubble size is characterized by the Eötvös number. The volume fraction and the Eötvö number are varied parametrically to investigate their effects on Nusselt number of the two-phase flows. All simulations are compared with a single-phase flow condition.

scholarly journals Complexity of phase distribution in two-phase flow using composite multiscale entropy

2020 ◽  
Vol 135 (8) ◽  
Author(s):  
Gabriela Rafałko ◽  
Romuald Mosdorf ◽  
Grzegorz Litak ◽  
Grzegorz Górski
Keyword(s):  
Gas Phase ◽  
Two Phase Flow ◽  
Phase Distribution ◽  
Digital Camera ◽  
Flow Distribution ◽  
Multiscale Entropy ◽  
Phase Flow ◽  
Two Phase ◽  
Flow Rates ◽  
Water Glycerol

AbstractMultiphase flow in a minichannel is a complex phenomenon which shows various patterns dynamics including slugs and bubbles depending on gas/fluid component flow rates. In this paper, air and water–glycerol mixed fluid flow has been studied. In the experiment, the volume flow rates of air and water–glycerol were changing. We studied transition of bubbles to slugs two-phase flow patterns by using multiscale entropy approach to digital camera signals and identified various patterns. The results clearly indicate that the multiscale entropy is an important complexity measure dependent on the flow distribution of the gas phase in a water–glycerol content.

Study on Gas-Liquid Two-Phase Flow Distribution Inside a Flute Header

2020 ◽  
Author(s):  
Liping Pang ◽  
Shangmin Li ◽  
Hu Yuan ◽  
Liqiang Duan
Keyword(s):  
Liquid Phase ◽  
Gas Phase ◽  
Liquid Flow ◽  
Two Phase Flow ◽  
Phase Distribution ◽  
Flow Distribution ◽  
Phase Flow ◽  
Two Phase ◽  
Parallel Channels ◽  
Gas Liquid Flow

Abstract When the supercritical boiler is working at low load during flexible operation, the uneven distribution of the gas-liquid flow at the intermediate header may affect the safety of the water-cooled wall at the vertical parallel panels. In order to improve the uniformity of gas-liquid flow distribution in the water-cooled wall of intermediate header and study the internal flow mechanism, a flute inside the header is applied with parallel vertical parallel channels and experiments under different operating conditions are conducted to verify the effectiveness of this geometrical structure. The flow pattern in the experiment belongs to stratified and wavy flow. Computational fluid dynamic (CFD) simulation is conducted in order to investigate two-phase flow distribution behavior inside a flute header. It was found that the radial gas phase distribution in the flute tube shows a symmetrical relationship, and there are two vortexes in opposite directions. With the increasing distance from the inlet, the uniformity of the gas phase distribution becomes even. The gravity is greater than the drag force, which has effect on the two-phase flow distribution. The gas phase velocity has been improved inside flute section and liquid phase flow has more even flow distribution along annular section. It makes liquid phase sent to far end of flute header. That benefits two-phase flow distribution along 10 parallel channels equally.

Measurement of Gas Phase Distribution Using Multifiber Optical Probes in a Two-Phase Flow

2020 ◽  
Vol 20 (12) ◽  
pp. 6642-6651
Author(s):  
Qiuyi Yang ◽  
Ningde Jin ◽  
Fan Wang ◽  
Weikai Ren
Keyword(s):  
Gas Phase ◽  
Two Phase Flow ◽  
Phase Distribution ◽  
Phase Flow ◽  
Optical Probes ◽  
Two Phase

Numerical modeling of the influence of bubbles on flow and heat transfer in the descending gas-liquid flow in a pipe

2012 ◽  
Vol 9 (1) ◽  
pp. 131-135
Author(s):  
M.A. Pakhomov
Keyword(s):  
Heat Transfer ◽  
Gas Phase ◽  
Liquid Flow ◽  
Bubble Diameter ◽  
Gas Content ◽  
Two Phase ◽  
Eulerian Description ◽  
Flow And Heat Transfer ◽  
Gas Liquid Flow ◽  
The Mathematical Model

The paper presents the results of modeling the dynamics of flow, friction and heat transfer in a descending gas-liquid flow in the pipe. The mathematical model is based on the use of the Eulerian description for both phases. The effect of a change in the degree of dispersion of the gas phase at the input, flow rate, initial liquid temperature and its friction and heat transfer rate in a two-phase flow. Addition of the gas phase causes an increase in heat transfer and friction on the wall, and these effects become more noticeable with increasing gas content and bubble diameter.

Numerical Analysis of Two-Phase Pipe Flow of Liquid Helium Using Multi-Fluid Model

2001 ◽  
Vol 123 (4) ◽  
pp. 811-818 ◽  
Author(s):  
Jun Ishimoto ◽  
Mamoru Oike ◽  
Kenjiro Kamijo
Keyword(s):  
Phase Transition ◽  
Gas Phase ◽  
Liquid Helium ◽  
Two Phase Flow ◽  
Fluid Model ◽  
Numerical Results ◽  
Phase Flow ◽  
Two Dimensional ◽  
Two Phase ◽  
Normal Fluid

The two-dimensional characteristics of the vapor-liquid two-phase flow of liquid helium in a pipe are numerically investigated to realize the further development and high performance of new cryogenic engineering applications. First, the governing equations of the two-phase flow of liquid helium based on the unsteady thermal nonequilibrium multi-fluid model are presented and several flow characteristics are numerically calculated, taking into account the effect of superfluidity. Based on the numerical results, the two-dimensional structure of the two-phase flow of liquid helium is shown in detail, and it is also found that the phase transition of the normal fluid to the superfluid and the generation of superfluid counterflow against normal fluid flow are conspicuous in the large gas phase volume fraction region where the liquid to gas phase change actively occurs. Furthermore, it is clarified that the mechanism of the He I to He II phase transition caused by the temperature decrease is due to the deprivation of latent heat for vaporization from the liquid phase. According to these theoretical results, the fundamental characteristics of the cryogenic two-phase flow are predicted. The numerical results obtained should contribute to the realization of advanced cryogenic industrial applications.

Effect of Particle Residence Time on Particle Dispersion in a Plane Mixing Layer

1993 ◽  
Vol 115 (4) ◽  
pp. 751-759 ◽  
Author(s):  
Tsuneaki Ishima ◽  
Koichi Hishida ◽  
Masanobu Maeda
Keyword(s):  
Gas Phase ◽  
Residence Time ◽  
Time Scale ◽  
Characteristic Time ◽  
Mixing Layer ◽  
Particle Dispersion ◽  
Laser Doppler Velocimeter ◽  
Characteristic Time Scale ◽  
Two Phase ◽  
Particle Residence Time

A particle dispersion has been experimentally investigated in a two-dimensional mixing layer with a large relative velocity between particle and gas-phase in order to clarify the effect of particle residence time on particle dispersion. Spherical glass particles 42, 72, and 135 μm in diameter were loaded directly into the origin of the shear layer. Particle number density and the velocities of both particle and gas phase were measured by a laser Doppler velocimeter with modified signal processing for two-phase flow. The results confirmed that the characteristic time scale of the coherent eddy apparently became equivalent to a shorter characteristic time scale due to a less residence time. The particle dispersion coefficients were well correlated to the extended Stokes number defined as the ratio of the particle relaxation time to the substantial eddy characteristic time scale which was evaluated by taking account of the particle residence time.

A Developed Numerical Method for Turbulent Unsteady Fluid Flow in Two-Phase Systems with Moving Interface

2017 ◽  
Vol 14 (06) ◽  
pp. 1750063 ◽  
Author(s):  
A. M. Hegab ◽  
S. A. Gutub ◽  
A. Balabel
Keyword(s):  
Numerical Model ◽  
Gas Phase ◽  
Level Set ◽  
The Body ◽  
Phase System ◽  
Computational Domain ◽  
Two Phase ◽  
Moving Interface ◽  
Level Set Function ◽  
Gas System

This paper presents the development of an accurate and robust numerical modeling of instability of an interface separating two-phase system, such as liquid–gas and/or solid–gas systems. The instability of the interface can be refereed to the buoyancy and capillary effects in liquid–gas system. The governing unsteady Navier–Stokes along with the stress balance and kinematic conditions at the interface are solved separately in each fluid using the finite-volume approach for the liquid–gas system and the Hamilton–Jacobi equation for the solid–gas phase. The developed numerical model represents the surface and the body forces as boundary value conditions on the interface. The adapted approaches enable accurate modeling of fluid flows driven by either body or surface forces. The moving interface is tracked and captured using the level set function that initially defined for both fluids in the computational domain. To asses the developed numerical model and its versatility, a selection of different unsteady test cases including oscillation of a capillary wave, sloshing in a rectangular tank, the broken-dam problem involving different density fluids, simulation of air/water flow, and finally the moving interface between the solid and gas phases of solid rocket propellant combustion were examined. The latter case model allowed for the complete coupling between the gas-phase physics, the condensed-phase physics, and the unsteady nonuniform regression of either liquid or the propellant solid surfaces. The propagation of the unsteady nonplanar regression surface is described, using the Essentially-Non-Oscillatory (ENO) scheme with the aid of the level set strategy. The computational results demonstrate a remarkable capability of the developed numerical model to predict the dynamical characteristics of the liquid–gas and solid–gas flows, which is of great importance in many civilian and military industrial and engineering applications.

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