A. K. Mitra

Experimental studies on a co-current gas-liquid downflow bubble column

Abstract Two-phase co-current vertical downflow systems offer some distinct advantages, like uniform and finer bubbles, greater residence time, negligible coalescence of the bubles etc. In the present work the hydrodynamics of a vertical downflow bubble column fitted with an ejector have been evaluated. Experimental studies have been carried out to evaluate the total pressure gradient and gas holdup. Similarity analysis was used for analysing the data in order to overcome the complex flow behaviour in the system. Correlations have been developed to predict pressure drop and holdup of gas as a function of different physical and dynamic variables.

Non-newtonian liquid flow in bends

Abstract Experimental data on the pressure drop across different types of bend in the horizontal plane, for non-newtonian pseudoplastic fluid in laminar flow, h

Phase distribution of gas–liquid mixtures in concentric annuli-inception and termination of asymmetry

Abstract A very interesting phenomenon occurs during the simultaneous flow of gas and liquid through a vertical concentric annulus. Although the geometry is axially symmetric, the two phases distribute themselves asymmetrically over a wide range of phase velocities. The present work has attempted to investigate this asymmetric phase distribution across a cross-section through extensive experimentation by using the conductivity probe technique. The probe signals and their probability density function analysis have indicated that this feature is initiated in the bubbly-slug flow regime and persists in the entire range of slug and slug-churn flow patterns. The interfacial configuration is symmetric in bubbly, fully formed churn and the annular flow patterns. Finally, the reason for this asymmetry has been attributed to the formation of cap and Taylor bubbles which are never symmetric with respect to the axis since they always form open annular rings.

Gas-Newtonian and Gas-Non-Newtonian Slug Flow in Vertical Pipe, Part I: Gas Holdup Characteristics

Studies on two-phase gas-liquid co-current flow with non-Newtonian liquid system has attracted the attention of researchers over the years due to its wide-spread applications and importance in various different processes in chemical and biochemical industries, such as the process of two-phase in oil and gas wells, transportation systems of crude and refined products, and food processing in biochemical engineering and bio-reactors. This article examines the sole objective of experimental studies on gas holdup in Newtonian and non-Newtonian liquid slug flow within a range of gas and liquid flowrate of 0.5×10-4 to 1.92×10-4 m3/s and 1.6×10-4 to 6.7×10-4 m3/s, respectively. The present data was analyzed with different models. To predict gas holdup, correlations have been developed for individual system with Newtonian and non-Newtonian liquid. A general correlation was also developed to predict the gas holdup combing both the Newtonian and non-Newtonian liquid systems. The study of the gas holdup characteristics in gas-Newtonian and non-Newtonian liquid systems may give insight into a further understanding and modeling of this slug flow characteristics in industrial applications.

Two phase heat transfer in horizontal tube with jet mixing

Abstract The paper deals with experimental studies on heat transfer coefficients in two phase cocurrent flow in a horizontal tube where liquid jet momentum has been used for gas-liquid dispersion and heat transfer. Empirical equations have been developed to predict augmentation ratio of heat transfer as a function of various physical and dynamic variables of the system.

Frictional Pressure Drop of Gas-Newtonian and Gas-Non Newtonian Slug Flow in Vertical Pipe

Experimental study on two-phase pressure drop in a vertical pipe with air-Newtonian and non-Newtonian liquid in slug flow regime has been carried out within a range of gas and liquid flowrate of 0.5×10-4 to 1.92×10-4 m-3/s and 1.6×10-4 to 6.7×10-4 m3/s respectively. In the present study air and four types of liquids such as water, amyl alcohol, glycerin (two different concentrations), and CMC (Sodium Carboxymethyl Cellulose) are used. The present data were analyzed by two-phase friction method. To predict the two-phase pressure drop, correlations have been developed with Newtonian and non-Newtonian liquid. A general correlation was also developed to predict the two-phase pressure drop in a vertical column of diameter 0.01905 m and 3.4 m height combining both the Newtonian and non-Newtonian liquid systems.