Effect of Mild Sway on the Interfacial Mass Transfer Rate of Stored Liquids

2015 ◽  
Vol 137 (11) ◽  
Author(s):  
Dibakar Rakshit ◽  
K. P. Thiagarajan ◽  
R. Narayanaswamy
Keyword(s):  
Mass Transfer ◽  
Transfer Rate ◽  
Degrees Of Freedom ◽  
Mass Transfer Rate ◽  
Constant Amplitude ◽  
Two Phase ◽  
Interfacial Mass Transfer ◽  
Different Temperatures ◽  
Slow Moving ◽  
Liquid Vapor

An exploratory study of two-phase physics was undertaken in a slow moving tank containing liquid. This study is under the regime of conjugate heat and mass transfer phenomena. An experiment was designed and performed to estimate the interfacial mass transfer characteristics of a slowly moving tank. The tank was swayed at varying frequencies and constant amplitude. The experiments were conducted for a range of liquid temperatures and filling levels. The experimental setup consisted of a tank partially filled with water at different temperatures, being swayed using a six degrees-of-freedom (DOF) motion actuator. The experiments were conducted for a frequency range of 0.7–1.6 Hz with constant amplitude of 0.025 m. The evaporation of liquid from the interface and the gaseous condensation was quantified by calculating the instantaneous interfacial mass transfer rate of the slow moving tank. The dependence of interfacial mass transfer rate on the liquid–vapor interfacial temperature, the fractional concentration of the evaporating liquid, the surface area of the liquid vapor interface and the filling level of the liquid was established. As sway frequency, filling levels, and liquid temperature increased, the interfacial mass transfer rate also increased. The interfacial mass transfer rate estimated for the swaying tank compared with the interfacial mass transfer rate of stationary tank shows that vibration increases the mass transfer.

Characterization of Interfacial Mass Transfer Rate of Stored Liquids

2015 ◽  
Vol 7 (2) ◽  
Author(s):  
Dibakar Rakshit ◽  
R. Narayanaswamy ◽  
K. P. Thiagarajan
Keyword(s):  
Mass Transfer ◽  
Transfer Rate ◽  
Mass Transfer Rate ◽  
Two Phase ◽  
Interfacial Mass Transfer ◽  
Different Temperatures ◽  
Interfacial Temperature ◽  
Fill Level ◽  
Liquid Vapor

A thermodynamic analysis of the two-phase physics involving a liquid–vapor combination has been studied under the regime of conjugate heat and mass transfer phenomena. An experiment has been designed and performed to estimate the interfacial mass transfer characteristics of a liquid–vapor system by varying the liquid temperature. The experimental setup consists of an instrumented tank partially filled with water and maintained at different temperatures. The evaporation of liquid from the interface and the gaseous condensation has been quantified by calculating the interfacial mass transfer rate for both covered and uncovered tanks. The dependence of interfacial mass transfer rate on the liquid–vapor interfacial temperature, fractional concentration of the evaporating liquid, the surface area of the liquid vapor interface, and the fill level of the liquid has been established through the present experimental study. An estimation of the overall mass transfer rate from the interface due to a concentration gradient shows an analogy with the multiphase heat transfer that takes place across the interface due to temperature gradient. It was seen that at low fill levels and with a temperature difference of about 30 °C between liquid and ullage, the mass transfer rate of a closed system was nearly doubled when compared to its open system counterpart.

scholarly journals An Experimental Study on the Mass Transfer Rate of Droplets in Annular Two-Phase Flow

2006 ◽  
Vol 49 (2) ◽  
pp. 271-278 ◽  
Author(s):  
Tomio OKAWA ◽  
Naoya SHIMADA ◽  
Akio KOTANI ◽  
Isao KATAOKA
Keyword(s):  
Mass Transfer ◽  
Experimental Study ◽  
Transfer Rate ◽  
Two Phase Flow ◽  
Mass Transfer Rate ◽  
Phase Flow ◽  
Two Phase

scholarly journals Effect of surface contamination on interfacial mass transfer rate

2017 ◽  
Vol 830 ◽  
pp. 5-34 ◽  
Author(s):  
J. G. Wissink ◽  
H. Herlina ◽  
Y. Akar ◽  
M. Uhlmann
Keyword(s):  
Mass Transfer ◽  
Transfer Rate ◽  
Isotropic Turbulence ◽  
Mass Transfer Rate ◽  
Surface Contamination ◽  
Gas Transfer ◽  
Clean Surface ◽  
Transfer Velocity ◽  
Surface Fraction ◽  
Interfacial Mass Transfer

The influence of surface contamination upon the mass transfer rate of a low diffusivity gas across a flat surface is studied using direct numerical simulations. The interfacial mass transfer is driven by isotropic turbulence diffusing from below. Similar to Shen et al. (J. Fluid Mech., vol. 506, 2004, pp. 79–115) the surface contamination is modelled by relating the normal gradient of the horizontal velocities at the top to the horizontal gradients of the surfactant concentrations. A broad range of contamination levels is considered, including clean to severely contaminated conditions. The time-averaged results show a strong correlation between the gas transfer velocity and the clean surface fraction of the surface area. In the presence of surface contamination the mass transfer velocity $K_{L}$ is found to scale as a power of the Schmidt number, i.e. $Sc^{-q}$, where $q$ smoothly transitions from $q=1/2$ for clean surfaces to $q=2/3$ for very dirty interfaces. A power law $K_{L}\propto Sc^{-q}$ is proposed in which both the exponent $q$ and the constant of proportionality become functions of the clean surface fraction.

Coagulation studies of cellulose/NaOH/thiourea/urea/H2O fiber spinning system

e-Polymers ◽  
2009 ◽  
Vol 9 (1) ◽  
Author(s):  
Shuai Zhang ◽  
Fa-xue Li ◽  
Jian-yong Yu ◽  
Li-xia Gu
Keyword(s):  
Mass Transfer ◽  
Transfer Rate ◽  
Mass Transfer Rate ◽  
Fiber Spinning ◽  
Coagulation Bath ◽  
Coagulation Rate ◽  
Two Phase ◽  
Time Model ◽  
Rate Difference ◽  
Coagulation Process

AbstractThe coagulation properties of cellulose from cellulose//NaOH/thiourea/ urea/H2O solutions were investigated with the goal of determining the optimal coagulation conditions for the spinning of cellulose fibers. The present study was concentrated on the effect of the coagulation variables upon the coagulation process. It was observed that at the start of the process, the thickness of the solidified layer ε was proportional to the square root of time. Model experiments were performed on gelled solutions of cellulose/NaOH/thiourea/urea/H2O in a coagulation bath to determine the coagulation rate,e / t , and mass transfer rate difference between the solvent and the coagulant, Dk . The influence of coagulant compositions, coagulation time and temperature, and cellulose concentrations on coagulation rate and mass transfer rate difference performed on cellulose samples had been demonstrated by microscopic observations, which was important for understanding and controlling the process of cellulose shaping from NaOH/thiourea/urea/H2O solutions. The data were analyzed by means of the diffusion model based on Fick's law, thereby depicting the mechanism of the coagulation process, which could be described as a two-phase separation, namely a cellulose-rich phase in the coagulated layer and a cellulose-poor phase in uncoagulated layer.

Numerical study on gas–liquid two-phase flow and mass transfer in a microchannel

2021 ◽  
Vol 19 (3) ◽  
pp. 295-308
Author(s):  
Jin Zunlong ◽  
Liu Yonghao ◽  
Dong Rui ◽  
Wang Dingbiao ◽  
Chen Xiaotang
Keyword(s):  
Mass Transfer ◽  
Surface Tension ◽  
Slug Flow ◽  
Transfer Rate ◽  
Numerical Study ◽  
Mass Transfer Rate ◽  
Flow Patterns ◽  
Phase Flow ◽  
Two Phase ◽  
Liquid Plug

Abstract A numerical study of the gas–liquid two-phase flow and mass transfer in a square microchannel with a T-junction is carried out in this work. Through numerical simulation methods, the flow patterns of bubble flow, slug flow and annular flow are determined. By proposing a new flow pattern conversion relationship with different media and different speeds, 100 sets of CO2-water flow patterns and 100 sets of CO2-ethanol flow patterns are obtained. The effects of surface tension on flow pattern, bubble length and liquid plug length are studied. The pressure distribution and pressure drop are analyzed, and mass transfer is obtained through slug flow simulation, and the influencing factors of gas–liquid mass transfer are studied. The results show that the effect of surface tension on the length of the bubble and the length of the liquid plug is completely opposite, the pressure distribution is stepped, and the pressure drop increases with the increase of the gas–liquid velocity. In addition, it was found that the volumetric mass transfer coefficients of the bubble cap and the liquid film gradually decreased with time, and eventually stabilized. The increase in bubble velocity accelerates the mass transfer rate, while the increase in unit cell length slows the mass transfer rate. However, the influence of film thickness and liquid film length on mass transfer varies with time.

Hydrogen Recovery from Organic Wastes: Reactor Development and Improvement

2010 ◽  
Vol 113-116 ◽  
pp. 1040-1044
Author(s):  
Zi Rui Guo ◽  
Yi Sun ◽  
Li Ran Yue ◽  
Yong Feng Li
Keyword(s):  
Mass Transfer ◽  
Acetic Acid ◽  
Interfacial Layer ◽  
Transfer Rate ◽  
Feedback Inhibition ◽  
Anaerobic Fermentation ◽  
Mass Transfer Rate ◽  
Target Product ◽  
Two Phase ◽  
Hydrogen Recovery

The paper reviewed hydrogen production biotechnology on reactor development and design aspects. Biological hydrogen-producing reactor as acid-producing phase of two-phase anaerobic organism treatment system plays an important role in the following aspects: Reactor was developed as the follow ideas: a. CSTR-type anaerobic fermentation reactor is selected to reduce the substrate concentration in reactor and increase target product operational yield and selectivity in the reactor; b. mixture liquid in reaction area is stirred by the stirrer to reach a turbulent state in order to reduce interfacial layer thickness and temperature gradient in a floc unit particle and increase mass transfer rate; c. H2 in the particle and Liquid phase is accelerated to release to prevent accumulated H2 from bringing feedback inhibition to organism metabolism, and H2/CO2conversion to acetic acid; d. A sector turbine agitator with hoisting capacity and mixing power is selected to facilitate sludge to flow back through a effluence seam.

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