Numerical study of R134a liquid-vapor flow in a vertical header for phase separation with low inlet quality

2021 ◽  
Author(s):  
Jun Li ◽  
Pega Hrnjak
Keyword(s):  
Phase Separation ◽  
Numerical Study ◽  
Vapor Flow ◽  
Liquid Vapor

scholarly journals Numerical study on inertial effects on liquid-vapor flow using lattice Boltzmann method

2019 ◽  
Vol 160 ◽  
pp. 428-435
Author(s):  
Shurong Lei ◽  
Yong Shi ◽  
Yuying Yan ◽  
Xingxing Zhang
Keyword(s):  
Lattice Boltzmann Method ◽  
Lattice Boltzmann ◽  
Numerical Study ◽  
Vapor Flow ◽  
Inertial Effects ◽  
Boltzmann Method ◽  
Liquid Vapor

scholarly journals Simulating liquid-vapor phase separation under shear with lattice Boltzmann method

2009 ◽  
Vol 52 (9) ◽  
pp. 1337-1344 ◽  
Author(s):  
Ce Wang ◽  
AiGuo Xu ◽  
GuangCai Zhang ◽  
YingJun Li
Keyword(s):  
Phase Separation ◽  
Lattice Boltzmann Method ◽  
Vapor Phase ◽  
Lattice Boltzmann ◽  
Boltzmann Method ◽  
Liquid Vapor

scholarly journals Phase separation of binary mixtures in shear flow: A numerical study

2000 ◽  
Vol 62 (6) ◽  
pp. 8064-8070 ◽  
Author(s):  
F. Corberi ◽  
G. Gonnella ◽  
A. Lamura
Keyword(s):  
Phase Separation ◽  
Shear Flow ◽  
Binary Mixtures ◽  
Numerical Study

Approximate Riemann solver for compressible liquid vapor flow with phase transition and surface tension

2018 ◽  
Vol 169 ◽  
pp. 169-185 ◽  
Author(s):  
Stefan Fechter ◽  
Claus-Dieter Munz ◽  
Christian Rohde ◽  
Christoph Zeiler
Keyword(s):  
Phase Transition ◽  
Surface Tension ◽  
Compressible Liquid ◽  
Vapor Flow ◽  
Riemann Solver ◽  
Approximate Riemann Solver ◽  
Liquid Vapor

Prediction of Laminar Flow in a Microchannel With Transverse Ultrahydrophobic Ribs

2005 ◽  
Author(s):  
J. Davies ◽  
B. Woolford ◽  
D. Maynes ◽  
B. W. Webb
Keyword(s):  
Friction Factor ◽  
Liquid Flow ◽  
Frictional Resistance ◽  
Vapor Flow ◽  
Flowing Liquid ◽  
Vapor Cavity ◽  
Vapor Interface ◽  
Smooth Channel ◽  
The Impact ◽  
Liquid Vapor

One approach recently proposed for reducing the frictional resistance to liquid flow in microchannels is the patterning of micro-ribs and cavities on the channel walls. When treated with a hydrophobic coating, the liquid flowing in the microchannel wets only the surfaces of the ribs, and does not penetrate the cavities, provided the pressure is not too high. The net result is a reduction in the surface contact area between channel walls and the flowing liquid. For micro-ribs and cavities that are aligned normal to the channel axis (principal flow direction), these micro-patterns form a repeating, periodic structure. This paper presents experimental and numerical results of a study exploring the momentum transport in a parallel plate microchannel with such microengineered walls. The liquid-vapor interface (meniscus) in the cavity regions is treated as ideal in the numerical analysis (flat). Two conditions are explored with regard to the cavity region: 1) The liquid flow at the liquid-vapor interface is treated as shear-free (vanishing viscosity in the vapor region), and 2) the liquid flow in the microchannel core and the vapor flow within the cavity are coupled through the velocity and shear stress matching at the interface. Predictions and measurements reveal that significant reductions in the frictional pressure drop can be achieved relative to the classical smooth channel Stokes flow. Reductions in the friction factor are greater as the cavity-to-rib length ratio is increased (increasing shear-free fraction) and as the channel hydraulic diameter is decreased. The results also show that the average friction factor – Reynolds number product exhibits a flow Reynolds dependence. Furthermore, the predictions reveal the impact of the vapor cavity regions on the overall frictional resistance.

Liquid-Vapor Interactions in a Constant-Area Condensing Ejector

1972 ◽  
Vol 94 (1) ◽  
pp. 169-179 ◽  
Author(s):  
E. K. Levy ◽  
G. A. Brown
Keyword(s):  
Heat Transfer ◽  
Liquid Velocity ◽  
Vapor Flow ◽  
Interfacial Heat Transfer ◽  
Transfer Coefficients ◽  
Transfer Rates ◽  
Constant Area ◽  
Wide Range ◽  
Condensation Shock ◽  
Liquid Vapor

The performance of a condensing ejector depends on the interactions occurring between the liquid and vapor streams in the mixing section. Axial static and liquid-vapor stagnation pressure profiles were measured in a constant-area mixing section using steam and water over a limited range of inlet vapor conditions and a wide range of inlet liquid velocities. Three flow regimes were identified based on inlet liquid velocity. Complete vapor condensation due to a “condensation shock” occurred only in the High Inlet Liquid Velocity Regime. The presence of supersonic vapor flow was found to be a necessary but not a sufficient condition for the existence of the “condensation shock.” In addition, breakup of the liquid jet was found to play an important role in the mixing section processes. A quasi one-dimensional analytical model of the annular liquid-vapor flow patterns occurring in the upstream portion of the mixing section was formulated. Though it was not possible to predict sufficiently accurately the interfacial heat transfer rates from any currently available analyses or data, interfacial heat transfer coefficients of approximately 100 Btu/sec ft2 deg F were found to produce good agreement between the experimentally measured and computed analytical axial static pressure variations. These values compare favorably with other data on the heat transfer rates to turbulent water jets with condensation.

Enhancement of flow boiling heat transfer using liquid-vapor flow separation and capillary liquid supply

2019 ◽  
Vol 2019 (0) ◽  
pp. J05405
Author(s):  
Kyoshiro KAWANO ◽  
Tomotaka UEKI ◽  
Koji MIYAZAKI ◽  
Massoud KAVIANY ◽  
Tomohide YABUKI
Keyword(s):  
Heat Transfer ◽  
Flow Separation ◽  
Boiling Heat Transfer ◽  
Flow Boiling ◽  
Vapor Flow ◽  
Flow Boiling Heat Transfer ◽  
Capillary Liquid ◽  
Liquid Vapor

Thick-Film Phenomenon in High-Heat-Flux Evaporation From Cylindrical Pores

1997 ◽  
Vol 119 (2) ◽  
pp. 272-278 ◽  
Author(s):  
D. Khrustalev ◽  
A. Faghri
Keyword(s):  
Thick Film ◽  
High Heat ◽  
Liquid Films ◽  
Momentum Conservation ◽  
Vapor Flow ◽  
High Heat Flux ◽  
Operational Conditions ◽  
Flux Evaporation ◽  
Cylindrical Pores ◽  
Liquid Vapor

A physical and mathematical model of the evaporating thick liquid film, attached to the liquid-vapor meniscus in a circular micropore, has been developed. The liquid flow has been coupled with the vapor flow along the liquid-vapor interface. The model includes quasi-one-dimensional compressible steady-state momentum conservation for the vapor and also a simplified description of the microfilm at the end of the thick film. The numerical results, obtained for water, demonstrate that formation of extended thick liquid films in micropores can take place due to high-velocity vapor flow under high rates of vaporization. The model has also predicted that the available capillary pressure significantly changes with the wall-vapor superheat and other operational conditions.

Sign in / Sign up

Export Citation Format

Share Document