Simulation on Flow Pattern Transition With Liquid Nitrogen and Its Vapor Using a Droplet Entrainment Model

2021 ◽  
Author(s):  
Rui Zhou ◽  
Tao Xia ◽  
Xiaobin Zhang
Keyword(s):  
Flow Pattern ◽  
Liquid Nitrogen ◽  
Droplet Entrainment ◽  
Flow Pattern Transition

Simulation on Flow Pattern Transition With Liquid Nitrogen and its Vapor Using a Droplet Entrainment Model

2020 ◽  
Author(s):  
Rui Zhou ◽  
Tao Xia ◽  
Xiaobin Zhang
Keyword(s):  
Flow Pattern ◽  
Liquid Nitrogen ◽  
Slug Flow ◽  
Flow Patterns ◽  
Eulerian Model ◽  
Ansys Fluent ◽  
Droplet Entrainment ◽  
Flow Pattern Transition ◽  
Churn Flow ◽  
Two Fluid

Abstract A droplet entrainment model was applied to characterize the flow pattern transition in the countercurrent horizontal flow with liquid nitrogen (LN2) and vapor nitrogen (VN2). A two-fluid three-field model consisting of liquid film, gas, and droplet was implemented based on the Eulerian-Eulerian model in ANSYS Fluent®. In the droplet entrainment model, the condition and position of the droplet generation were realized by calculating the velocity gradient in the normal direction of the interface towards the gas core. The droplet entrainment and deposition rates were also included and validated according to the available data of water/air in the literature. Three flow patterns, including stratified-wavy flow, churn flow, and pseudo-slug flow, were identified in simulation results with LN2/VN2. Furthermore, ligament breakup was found to be the main droplet entrainment mechanism in the churn and pseudo-slug flow, and there can be a high probability of the occurrence of bubble burst as well. Compared with water/air, the droplets are more easily to be entrained in LN2/VN2 due to the smaller viscosity and surface tension according to the results of droplet mass flow rate. Pressure drop signals of the three flow patterns were also obtained and analyzed.

GAS-LIQUID FLOW-PATTERN TRANSITION IN HORIZONTAL PIPES – ANALYSIS OF REPORTED MODELS

2018 ◽  
Author(s):  
André Mendes Quintino ◽  
Davi Lotfi Lavor Navarro da Rocha ◽  
Oscar Mauricio Hernandez Rodriguez
Keyword(s):  
Flow Pattern ◽  
Liquid Flow ◽  
Horizontal Pipes ◽  
Flow Pattern Transition ◽  
Gas Liquid Flow

Spool Valve Hydraulic Measurement Flow Pattern Error Based on Variable Discharge Coefficient

2015 ◽  
Vol 667 ◽  
pp. 444-448
Author(s):  
Zhuo Lin
Keyword(s):  
Flow Pattern ◽  
Discharge Coefficient ◽  
Compensation Method ◽  
Measuring Process ◽  
Important Method ◽  
Flow Pattern Transition ◽  
Spool Valves ◽  
Spool Valve ◽  
Submerged Discharge

Spool valves are the main elements in electro-hydro servo valves. Hydraulic measurement is an important method for spool valve’s null cutting measuring process. Because of the flow pattern transition, the discharge coefficient is a variable. This phenomenon causes errors if we assume the discharge coefficient is a constant as we always do. In this paper, the variable discharge coefficient is considered to the submerged discharge equation, and the flow pattern error is defined. For improving the precision of overlap values measurements, a compensation method of flow pattern error is presented in this paper.

CFD study on double- to single-loop flow pattern transition and its influence on macro mixing efficiency in fully baffled tank stirred by a Rushton turbine

2019 ◽  
Vol 27 (5) ◽  
pp. 993-1000 ◽  
Author(s):  
Quanhong Zhu ◽  
Hang Xiao ◽  
Aqiang Chen ◽  
Shujun Geng ◽  
Qingshan Huang
Keyword(s):  
Flow Pattern ◽  
Mixing Efficiency ◽  
Single Loop ◽  
Rushton Turbine ◽  
Flow Pattern Transition

Flow-Pattern Transition and Hydrodynamic Modeling of Churn Flow

SPE Journal ◽  
1999 ◽  
Vol 4 (12) ◽  
Author(s):  
J. Tengesdal ◽  
A.S. Kaya ◽  
Cem Sarica
Keyword(s):  
Flow Pattern ◽  
Hydrodynamic Modeling ◽  
Flow Pattern Transition ◽  
Churn Flow

Detecting the Flow Pattern Transition in the Gas-Liquid Two-Phase Flow Using Multivariate Multi-Scale Entropy Analysis

2019 ◽  
Vol 74 (10) ◽  
pp. 837-848 ◽  
Author(s):  
Yudong Liu ◽  
Dayang Wang ◽  
Yingyu Ren ◽  
Ningde Jin
Keyword(s):  
Flow Pattern ◽  
Two Phase Flow ◽  
Flow Patterns ◽  
Mean Value ◽  
Entropy Rate ◽  
Permutation Entropy ◽  
Phase Flow ◽  
Two Phase ◽  
Multi Scale ◽  
Flow Pattern Transition

AbstractDue to the complex flow structure and non-uniform phase distribution in the vertical upward gas-liquid two-phase flow, an eight-electrode rotating electric field conductance sensor is used to obtain multi-channel conductance signals. The flow patterns of the vertical upward gas-liquid two-phase flow are classified according to the images obtained from a high-speed camera. Then, we employ the multivariate weighted multi-scale permutation entropy (MWMPE) to detect the instability of flow pattern transition in the gas-liquid two-phase flow. Afterwards, we compare the results of the MWMPE with those of the single-channel weighted multi-scale permutation entropy (SCWMPE) and multivariate multi-scale sample entropy (MMSE). The comparison results indicate that, compared with the SCWMPE and MMSE, the MWMPE has superior performance in terms of the high-resolution presentation of flow instability in the gas-liquid two-phase flow. Finally, we extract the mean value of the MWMPE in whole scales and the entropy rate of the MWMPE in the small scales. The results indicate that the normalized mean value and normalized entropy rate of MWMPE are very sensitive to the transitions of flow patterns, thus allowing the detection of the instability of flow pattern transition.

The bubble-slug flow pattern transition and instabilities of void fraction waves

1987 ◽  
Vol 13 (2) ◽  
pp. 199-217 ◽  
Author(s):  
A. Matuszkiewicz ◽  
J.C. Flamand ◽  
J.A. Bouré
Keyword(s):  
Flow Pattern ◽  
Void Fraction ◽  
Slug Flow ◽  
Flow Pattern Transition
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