Countercurrent gas–liquid flow in inclined and vertical ducts — I: Flow patterns, pressure drop characteristics and flooding
TL;DR: In this article, an experimental investigation into adiabatic gas-liquid counterflow in inclined and vertical rectangular ducts with a square-edged gas inlet is conducted, where water, methanol, propanol, air, argon, helium and hydrogen are used as working fluids.
About: This article is published in International Journal of Multiphase Flow.The article was published on 2000-09-01. It has received 90 citations till now. The article focuses on the topics: Froude number & Reynolds number.
Citations
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TL;DR: In this article, the authors presented a method to detect the presence of viruses in the human brain using the Web of Science Record created on 2010-03-19, modified on 2017-05-10.
Abstract: Reference EPFL-ARTICLE-147393doi:10.1115/1.2955990View record in Web of Science Record created on 2010-03-19, modified on 2017-05-10
263 citations
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TL;DR: In this paper, the authors investigated the dynamics of a thin laminar liquid film flowing under gravity down the lower wall of an inclined channel when turbulent gas flows above the film.
Abstract: We investigate the dynamics of a thin laminar liquid film flowing under gravity
down the lower wall of an inclined channel when turbulent gas flows above the
film. The solution of the full system of equations describing the gas–liquid flow faces
serious technical difficulties. However, a number of assumptions allow isolating the
gas problem and solving it independently by treating the interface as a solid wall.
This permits finding the perturbations to pressure and tangential stresses at the
interface imposed by the turbulent gas in closed form. We then analyse the liquid
film flow under the influence of these perturbations and derive a hierarchy of model
equations describing the dynamics of the interface, i.e. boundary-layer equations, a
long-wave model and a weakly nonlinear model, which turns out to be the Kuramoto–
Sivashinsky equation with an additional term due to the presence of the turbulent
gas. This additional term is dispersive and destabilising (for the counter-current case;
stabilizing in the co-current case). We also combine the long-wave approximation with
a weighted-residual technique to obtain an integral-boundary-layer approximation
that is valid for moderately large values of the Reynolds number. This model is
then used for a systematic investigation of the flooding phenomenon observed in
various experiments: as the gas flow rate is increased, the initially downward-falling
film starts to travel upwards while just before the wave reversal the amplitude of the
waves grows rapidly. We confirm the existence of large-amplitude stationary waves by
computing periodic travelling waves for the integral-boundary-layer approximation
and we corroborate our travelling-wave results by time-dependent computations.
74 citations
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TL;DR: In this article, an experimental investigation of gas-liquid counter-current flow in a vertical rectangular channel with 10 mm gap, at rather short distances from liquid entry, is reported.
72 citations
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TL;DR: In this article, a physical model for laminar reflux condensation of a pure saturated vapour in an inclined small diameter tube is presented, and the theoretical results for the film thickness and the heat transfer are compared with the experimental data.
54 citations
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TL;DR: In this paper, an experimental investigation on the air/water counter-current two-phase flow in a horizontal rectangular channel connected to an inclined riser has been conducted, where a high-speed camera in the bended region of the hot leg, delivering a detailed view of the stratified interface as well as of dispersed structures like bubbles and droplets.
50 citations
References
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01 Jan 1974
TL;DR: In this article, the stability of Laminar Boundary Layer Flow Appendices has been investigated in Cylindrical and Spherical Coordinates of Incompressible Newtonian Fluids.
Abstract: 1 Preliminary Concepts 2 Fundamental Equations of Compressible Viscous Flow 3 Solutions of the Newtonian Viscous-Flow Equations 4 Laminar Boundary Layers 5 The Stability of Laminar Flows 6 Incompressible Turbulent Mean Flow 7 Compressible Boundary Layer Flow Appendices A Transport Properties of Various Newtonian Fluids B Equations of Motion of Incompressible Newtonian Fluids in Cylindrical and Spherical Coordinates C A Runge-Kutta Subroutine for N Simultaneous Differential Equations Bibliography Index
6,569 citations
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TL;DR: In this paper, a 32 mm dia vertical pipe with various forms of liquid outlet, namely a porous wall, a tapered outlet, and a square-edged outlet, was used to investigate the effect of churn flow on the penetration rate.
103 citations
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TL;DR: In this paper, an envelope theory for onset of flooding in inclined stratified flow is developed, which agrees better than the experimental data than other theories. And some basic flow parameters, such as mean film thickness and interfacial friction factor in the roll-wave regime (near-flooding) have been measured.
Abstract: Flooding of stratified countercurrent steam-water flow in nearly-horizontal and in inclined flat-plate geometries is investigated. An envelope theory for onset of flooding in inclined stratified flow is developed, which agrees better than the experimental data than other theories. In addition, some basic flow parameters, such as mean film thickness and interfacial friction factor in the roll-wave regime (near-flooding) have been measured. Empirical correlations for these parameters were sought, which are essential in the flooding analysis.
88 citations
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TL;DR: In this article, an improved flooding correlation is proposed which accurately correlates the data of three previous investigations, and the results clearly show that some flooding data had been misinterpreted in the past.
76 citations