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A.R. Balakrishnan

Bio: A.R. Balakrishnan is an academic researcher from Indian Institutes of Technology. The author has contributed to research in topics: Pressure drop & Countercurrent exchange. The author has an hindex of 2, co-authored 2 publications receiving 66 citations.

Papers
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Journal ArticleDOI
TL;DR: In this article, the effect of tube diameter on the mechanism of flooding in vertical gas-liquid countercurrent annular flow was investigated. But the results indicated that the mechanism was qualitatively different in the small and the large diameter test sections.

56 citations

Journal ArticleDOI
TL;DR: In this article, measurements of the pressure gradient, film thickness and down flow rate were made for a range of air and water flow rates under pre- and post-flooding conditions.

14 citations


Cited by
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Journal ArticleDOI
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

Journal ArticleDOI
TL;DR: In this article, the effect of pipe diameter on flow characteristics of two-phase flow is investigated from various aspects, particularly focusing on the periodic structures of twophase flow, and it is found that the suggested value of Pearce coefficient 0.8 is reasonable for lower liquid flow rates but becomes insufficient for higher liquid flow rate.

63 citations

Journal ArticleDOI
TL;DR: In this article, the authors investigated the dynamics of separated two-phase flow of basaltic magmas in cylindrical conduits and calculated vesicularity and pressure gradient for a range of gas superficial velocities (volume flow rates/pipe area, 10−2-102 m/s).
Abstract: [1] The dynamics of separated two-phase flow of basaltic magmas in cylindrical conduits has been explored combining large-scale experiments and theoretical studies. Experiments consisted of the continuous injection of air into water or glucose syrup in a 0.24 m diameter, 6.5 m long bubble column. The model calculates vesicularity and pressure gradient for a range of gas superficial velocities (volume flow rates/pipe area, 10−2–102 m/s), conduit diameters (100–2 m), and magma viscosities (3–300 Pa s). The model is calibrated with the experimental results to extrapolate key flow parameters such as Co (distribution parameter) and Froude number, which control the maximum vesicularity of the magma in the column, and the gas rise speed of gas slugs. It predicts that magma vesicularity increases with increasing gas volume flow rate and decreases with increasing conduit diameter, until a threshold value (45 vol.%), which characterizes churn and annular flow regimes. Transition to annular flow regimes is expected to occur at minimum gas volume flow rates of 103–104 m3/s. The vertical pressure gradient decreases with increasing gas flow rates and is controlled by magma vesicularity (in bubbly flows) or the length and spacing of gas slugs. This study also shows that until conditions for separated flow are met, increases in magma viscosity favor stability of slug flow over bubbly flow but suggests coexistence between gas slugs and small bubbles, which contribute to a small fraction of the total gas outflux. Gas flow promotes effective convection of the liquid, favoring magma homogeneity and stable conditions.

45 citations

Journal ArticleDOI
TL;DR: In this article, a three-dimensional CFD model that considers the local absorption and the local momentum transfer mechanism is developed for a film flow on a small plate with a counter-current gas flow.
Abstract: Structured packed columns are widely used in the chemical industry for distillation and absorption. However, the understanding of the transfer mechanism behind the counter-current gas-liquid flow in structured packed columns is still limited. In this work, a three-dimensional CFD model that considers the local absorption and the local momentum transfer mechanism is developed for a film flow on a small plate with a counter-current gas flow. The model, based on the Volume of Fluid (VOF) method, is built up on the basis of a pressure drop model and the penetration theory to quantitatively investigate the instantaneous hydrodynamics and mass transfer characteristics of the liquid phase. Simulations and experiments are carried out for a system consisting of propane and toluene. A comparison of the simulation results with the experimental data for the outlet concentrations shows good agreement.

42 citations

Journal ArticleDOI
TL;DR: In this article, the authors investigated the liquid film characteristics at the onset of flooding in an inclined pipe (16 mm i.d. and 2.2 m in length) using a constant electric current method and visual observation.

33 citations