Mathematical modeling of wide-range compressible two-phase flows

2019 ◽  
Vol 78 (2) ◽  
pp. 517-540 ◽  
Author(s):  
A. Serezhkin
Keyword(s):  
Mathematical Modeling ◽  
Two Phase Flows ◽  
Two Phase ◽  
Wide Range

Recent Progress in the Studies of Gas-Liquid Two-Phase Flows at Microgravity Conditions

2003 ◽  
Author(s):  
Tomoji Takamasa ◽  
Takashi Hibiki
Keyword(s):  
Recent Progress ◽  
Interfacial Area ◽  
Phase System ◽  
Two Phase Flows ◽  
Two Phase ◽  
Interfacial Area Transport ◽  
Drift Flux ◽  
Wide Range ◽  
Microgravity Conditions ◽  
Heat Loads

In a thermal system of spacecraft, two-phase flow system now is an excellent alternative to the conventional single-phase system in transporting large amount of thermal energy at a uniform temperature regardless of variations in the heat loads. In addition, two-phase flows exist in a wide range of applications and enabling technologies in space. This report outlines recent progress in the studies of gas-liquid two-phase flows at microgravity conditions, especially for which regarding to interfacial area transport and drift flux.

scholarly journals A general existence result for isothermal two-phase flows with phase transition

2019 ◽  
Vol 16 (04) ◽  
pp. 595-637
Author(s):  
Maren Hantke ◽  
Ferdinand Thein
Keyword(s):  
Phase Transition ◽  
Euler Equations ◽  
Equations Of State ◽  
Linear Equations ◽  
Two Phase Flows ◽  
Kinetic Relation ◽  
Two Phase ◽  
Uniqueness Results ◽  
Wide Range ◽  
Isothermal Euler Equations

Liquid–vapor flows with phase transitions have a wide range of applications. Isothermal two-phase flows described by a single set of isothermal Euler equations, where the mass transfer is modeled by a kinetic relation, have been investigated analytically in [M. Hantke, W. Dreyer and G. Warnecke, Exact solutions to the Riemann problem for compressible isothermal Euler equations for two-phase flows with and without phase transition, Quart. Appl. Math. 71(3) (2013) 509–540]. This work was restricted to liquid water and its vapor modeled by linear equations of state. The focus of this work lies on the generalization of the primary results to arbitrary substances, arbitrary equations of state and thus a more general kinetic relation. We prove existence and uniqueness results for Riemann problems. In particular, nucleation and cavitation are discussed.

Two Phase Pressure Drops for Refrigerants: A Statistical Comparison Among Experimental Data and Correlations

2006 ◽  
Author(s):  
Adriana Greco ◽  
Rita Mastrullo ◽  
Alfonso W. Mauro ◽  
Giuseppe P. Vanoli
Keyword(s):  
Experimental Data ◽  
Horizontal Tube ◽  
Operating Conditions ◽  
Prediction Methods ◽  
Two Phase Flows ◽  
Two Phase ◽  
Pressure Drops ◽  
Statistical Comparison ◽  
Wide Range ◽  
Phase Pressure

A 962 points database for refrigerants two-phase flows by Greco A. and Vanoli G.P. was statistically compared to four widely used prediction methods by Lockhart and Martinelli, Chawla, Theissing and Mu¨ller-Steinhagen and Heck in order to determine the best one. The experimental points are in a wide range of operating conditions for six pure or mixed refrigerants (R134a, R22, R407C, R507A, R410A and R404A) during evaporation in a smooth horizontal tube of 6 m length and 6 mm ID.

scholarly journals Study of Pressure Drops and Heat Transfer of Nonequilibrial Two-Phase Flows

Water ◽  
2021 ◽  
Vol 13 (16) ◽  
pp. 2275
Author(s):  
Aleksandr V. Belyaev ◽  
Alexey V. Dedov ◽  
Ilya I. Krapivin ◽  
Aleksander N. Varava ◽  
Peixue Jiang ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Flow Regime ◽  
Flow Boiling ◽  
Experimental Studies ◽  
High Mass ◽  
Calculation Methods ◽  
Two Phase Flows ◽  
Two Phase ◽  
Pressure Drops ◽  
Wide Range

Currently, there are no universal methods for calculating the heat transfer and pressure drop for a wide range of two-phase flow parameters in mini-channels due to changes in the void fraction and flow regime. Many experimental studies have been carried out, and narrow-range calculation methods have been developed. With increasing pressure, it becomes possible to expand the range of parameters for applying reliable calculation methods as a result of changes in the flow regime. This paper provides an overview of methods for calculating the pressure drops and heat transfer of two-phase flows in small-diameter channels and presents a comparison of calculation methods. For conditions of high reduced pressures pr = p/pcr ≈ 0.4 ÷ 0.6, the results of own experimental studies of pressure drops and flow boiling heat transfer of freons in the region of low and high mass flow rates (G = 200–2000 kg/m2 s) are presented. A description of the experimental stand is given, and a comparison of own experimental data with those obtained using the most reliable calculated relations is carried out.

scholarly journals Structure and dynamics of small-scale turbulence in vaporizing two-phase flows

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Radouan Boukharfane ◽  
Aimad Er-raiy ◽  
Matteo Parsani ◽  
Nilanjan Chakraborty
Keyword(s):  
Strain Rate ◽  
Velocity Gradient ◽  
Liquid Interface ◽  
Small Scale ◽  
Two Phase Flows ◽  
Gradient Tensor ◽  
Two Phase ◽  
Velocity Gradient Tensor ◽  
Carrier Liquid ◽  
Wide Range

AbstractImproving our fundamental understanding of multiphase turbulent flows will be beneficial for analyses of a wide range of industrial and geophysical processes. Herein, we investigate the topology of the local flow in vaporizing forced homogeneous isotropic turbulent two-phase flows. The invariants of the velocity-gradient, rate-of-strain, rate-of-rotation tensors, and scalar gradient were computed and conditioned for different distances from the liquid–gas surface. A Schur decomposition of the velocity gradient tensor into a normal and non-normal parts was undertaken to supplement the classical double decomposition into rotation and strain tensors. Using direct numerical simulations results, we show that the joint probability density functions of the second and third invariants have classical shapes in all carrier-gas regions but gradually change as they approach the carrier-liquid interface. Near the carrier-liquid interface, the distributions of the invariants are remarkably similar to those found in the viscous sublayer of turbulent wall-bounded flows. Furthermore, the alignment of both vorticity and scalar gradient with the strain-rate field changes spatially such that its universal behaviour occurs far from the liquid–gas interface. We found also that the non-normal effects of the velocity gradient tensor play a crucial role in explaining the preferred alignment.

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