Effect of the liquid density on a liquid-gas-particle mixture flow in dam break

Kim, Min Il,Yoon, Hyun Sik Elsevier 2020 INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER - Vol.148 No.-

<P><B>Abstract</B></P> <P>The present study numerically investigated the effect of the liquid density on the liquid-gas-particles mixture flow during dam break using the computational fluid dynamics (CFD) and discrete element method (DEM). The successive validation of the adopted CFD-DEM method was performed by comparison with the results of the previous computational and experimental studies. The density ratio (<I>DR</I>) is defined as the ratio of the liquid density to the particle density, leading to 1.04≤<I>DR</I>≤2.5. As <I>DR</I> decreases, the liquid density becomes large and at the smallest D R = 1.04 is as heavy as a particle density. As <I>DR</I> decreases, the motion of the front heads of the liquid and particles becomes faster. The gap between the front head positions of the free surface and the particles becomes larger with decreasing <I>DR</I>. The particle front position is almost proportional to the time without the deflection. However, the time history of the liquid front position was a slightly deflected formation. The time histories of the front head positions of the liquid and particles showed the similar profile, regardless of <I>DR</I>. Thus, we propose empirical models of the normalized front head positions of the liquid and particles as a function of the normalized time based on the present numerical results.</P> <P><B>Highlights</B></P> <P> <UL> <LI> The effect of the liquid density on the liquid-gas-particle mixture flow in dam break is investigated using CFD-DEM coupled method. </LI> <LI> As the density ratio decreases, the front head positions move faster. </LI> <LI> The gap between the front head positions of the liquid and the particle becomes larger with decreasing the density ratio. </LI> <LI> The empirical model of the arrival time for the front head is suggested. </LI> </UL> </P>

Liquid-Liquid Equilibrium and Physical Properties of Aqueous Mixtures of Poly (Ethylene Glycol) 3000 with Tri-Potassium Citrate at Different pH: Experiment, Correlation and Thermodynamic Modeling

Mahnam Ketabi,Mohsen Pirdashti,Poorya Mobalegholeslam 대한화학회 2019 대한화학회지 Vol.63 No.1

The new experimental data of liquid-liquid equilibrium (LLE) of aqueous two-phase system (ATPS) consisting of poly(ethylene glycol) 3000 + tri-potassium citrate at different pH were presented. It was found that an increase in pH resulted in the expansion of the two-phase region. The TLL and STL increased with increasing the pH values. The Merchuk equation can be appropriately employed to correlate the binodal curves and also the tie-line compositions were adjusted to both the Othmer-Tobias and Bancroft equations. In order to calculate the compositions of the phase and the ends of the tie-lines, density and refractive indices as two physical properties were used. Finally, the extended UNIQUAC, UNIFAC, Virial-(Mobalegholeslam & Bakhshi) and modified UNIQUAC-FV were used to measure the phase equilibria at different pH. The results of the models suggested that it can be used quite well to correlate the LLE in an aqueous solution of polymer–salt.

Liquid-Liquid Equilibrium and Physical Properties of Aqueous Mixtures of Poly (Ethylene Glycol) 3000 with Tri-Potassium Citrate at Different pH: Experiment, Correlation and Thermodynamic Modeling

Ketabi, Mahnam,Pirdashti, Mohsen,Mobalegholeslam, Poorya Korean Chemical Society 2019 대한화학회지 Vol.63 No.1

The new experimental data of liquid-liquid equilibrium (LLE) of aqueous two-phase system (ATPS) consisting of poly(ethylene glycol) 3000 + tri-potassium citrate at different pH were presented. It was found that an increase in pH resulted in the expansion of the two-phase region. The TLL and STL increased with increasing the pH values. The Merchuk equation can be appropriately employed to correlate the binodal curves and also the tie-line compositions were adjusted to both the Othmer-Tobias and Bancroft equations. In order to calculate the compositions of the phase and the ends of the tie-lines, density and refractive indices as two physical properties were used. Finally, the extended UNIQUAC, UNIFAC, Virial-(Mobalegholeslam & Bakhshi) and modified UNIQUAC-FV were used to measure the phase equilibria at different pH. The results of the models suggested that it can be used quite well to correlate the LLE in an aqueous solution of polymer-salt.

Liquid-liquid extraction of lithium using lipophilic dibenzo-14-crown-4 ether carboxylic acid in hydrophobic room temperature ionic liquid

Torrejos, Rey Eliseo C.,Nisola, Grace M.,Song, Ho Seong,Han, Jeong Woo,Lawagon, Chosel P.,Seo, Jeong Gil,Koo, Sangho,Kim, Hern,Chung, Wook-Jin Elsevier 2016 Hydrometallurgy Vol.164 No.-

<P><B>Abstract</B></P> <P>A green liquid-liquid extraction (LLE) system was developed for the recovery of lithium (Li<SUP>+</SUP>) from sodium and potassium ions, which are typically present at high concentrations in seawater. Dibenzo-14-crown-4ether (DB14C4) was functionalized with a long lipophilic alkyl C18 chain and a pendent proton ionizable carboxylic acid group to obtain a lithium (Li<SUP>+</SUP>) carrier system (DB14C4-C18-COOH) with high Li<SUP>+</SUP> extraction performance and good stability in the room temperature ionic liquid diluent, CYPHOSIL 109. The Li<SUP>+</SUP> extraction efficiency of DB14C4-C18-COOH/CYPHOSIL 109 can be enhanced by increasing the solution pH and DB14C4-C18-COOH concentration. Further examination of extraction results reveal 1:1 coordination between DB14C4-C18-COOH and Li<SUP>+</SUP> which was also supported by density functional theory calculations. At room temperature, the developed LLE system effectively extracted dilute Li<SUP>+</SUP> from Na<SUP>+</SUP> (selectivity α<SUB>Li</SUB> <SUP>+</SUP> <SUB>/Na</SUB> <SUP>+</SUP> =1954) and K<SUP>+</SUP> (α<SUB>Li</SUB> <SUP>+</SUP> <SUB>/K</SUB> <SUP>+</SUP> =138). Kinetic and thermodynamic parameters were evaluated for optimum Li<SUP>+</SUP> extraction conditions. Sequestered Li<SUP>+</SUP> can be easily recovered from the LLE system using dilute hydrochloric acid. Results from recycling tests showed stable Li<SUP>+</SUP> extraction performance hence it can be used for long term application. Overall results indicate the potential application of DB14C4-C18-COOH/CYPHOSIL 109 as a treatment step to recover Li<SUP>+</SUP> from brine or seawater.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Crown ether in RTIL CYPHOSIL 109 LLE system was developed for Li<SUP>+</SUP> recovery. </LI> <LI> Ligand lipophilic dibenzo14C4 crown ether with ionizable COOH group was synthesized. </LI> <LI> Highly selective LLE towards Li<SUP>+</SUP> in the presence of high Na<SUP>+</SUP> and K<SUP>+</SUP> concentration </LI> <LI> Ligand concentration, solution pH and temperature affected Li<SUP>+</SUP> extraction. </LI> <LI> Convenient Li<SUP>+</SUP> recovery and LLE reusability via dilute acid stripping treatment </LI> </UL> </P>

Liquid-liquid equilibrium and physical properties of aqueous mixtures of poly(vinyl pyrrolidone) with potassium phosphate at different pH: Experiments and modeling

Abbas Rahmani,Abbas Ali Rostami,Mohsen Pirdashti,Poorya Mobalegholeslam 한국화학공학회 2017 Korean Journal of Chemical Engineering Vol.34 No.4

Liquid-liquid equilibrium data for poly vinyl pyrrolidone (PVP) K30+K2HPO4+H2O system were measured at 298.15 K and different pH values (7.54, 8.05, and 9.47). A binodal curve was fitted to the Merchuk equation and the tie line compositions were fitted to both the Othmer-Tobias and Bancroft equations. The refractive indices and densities of several homogeneous binary and ternary solutions used for calibration were also measured within a range of 0-30 mass% of PVP and 0-50 mass% of K2HPO4. Then, the viscosities, densities, electrical conductivities, and refractive indices of binary (PVP K30+water; potassium phosphate+water) and ternary (PVP K30+potassium phosphate+ water) systems were measured and correlated at different pH values. The density data showed a linear variation of the polymer and salt mass fractions. The viscosity data of PVP K30 solutions were correlated as a function of the mass fractions by using a nonlinear equation. The effects of the tie line lengths on the densities and viscosities of the aqueous two-phase systems were represented. Also, the modified UNIFAC-NRF is used to calculate the phase equilibria of the mention system. The fitted binary interaction parameters of the model were reported.

A high resolution numerical scheme for a high speed gas-liquid two-phase flow

신병록 대한기계학회 2011 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.25 No.5

A high resolution numerical method for solving high speed gas-liquid two-phase flow is proposed and applied to the two-phase shock tube problem. The present method employs a finite-difference 4th-order Runge-Kutta method and Roe's flux difference splitting approximation with the MUSCL TVD scheme. A homogeneous equilibrium gas-liquid two-phase model that takes account of the compressibility of mixed media is used. Therefore, the present density-based numerical method permits simple treatment of the whole gasliquid two-phase flow field, including wave propagation, large density changes and incompressible flow characteristics at the low Mach number. The speed of sound of above two-phase media has been derived on the basis of thermodynamic relations. By this method, a Riemann problem for the Euler equations of a one-dimensional shock tube was computed. Numerical results such as detailed observations of shock and expansion wave propagations through the gas-liquid two-phase media at thermal and isothermal conditions, and some features related to computational efficiency are made. Comparisons of predicted results with exact solutions are provided and discussed.

A SATURATED LIQUID DENSITY CORRELATION FOR PURE REFRIGERANTS AND OTHER SUBSTANCES

박경근 대한설비공학회 2012 International Journal Of Air-Conditioning and Refr Vol.20 No.2

A modification is proposed of the Chouaieb-Ghazouani-Bellagi (CGB) correlation for the saturated liquid density. After we examined the values of the critical exponent, which is a nonlinear parameter for the CGB correlation, we assumed that the exponent deviates by a small amount from the theoretical value of 0.325. Then, a Taylor-series expansion was conducted for the CGB correlation in order to develop a new correlation with two linear adjustable parameters. Data on the saturated liquid density for 70 pure fluids including 43 refrigerants from the NIST Chemistry WebBook in the whole vapor-liquid saturation range were fitted to the new and existing correlations. The results show that the new correlation yields better performance for substances of which reduced triple point temperature is higher than 0.4. Excellent performance (i.e., AAD < 0.1%) can be achieved with the modified CGB for 14 fluids but only for four fluids with the modified Guggenheim model.

캐비테이션 유동해석을 위한 기-액 2상 국소균질 모델

신병록(Byeong Rog Shin) 한국전산유체공학회 2007 한국전산유체공학회지 Vol.12 No.2

A high resolution numerical method aimed at solving cavitating flow is proposed and applied to gas-liquid two-phase shock tube problem. The present method employs a finite-difference 4th-order Runge-Kutta method and Roe's flux difference splitting approximation with the MUSCL TVD scheme. By applying the homogeneous equilibrium cavitation model, the present density-based numerical method permits simple treatment of the whole gas-liquid two-phase flow field, including wave propagation and large density changes. The speed of sound for gas-liquid two-phase media is derived on the basis of thermodynamic relations and compared with that by eigenvalues. By this method, a Riemann problem for Euler equations of one dimensional shock tube was computed Numerical results such as detailed observations of shock and expansion wave propagations through the gas-liquid two-phase media at isothermal condition and some data related to computational efficiency are made. Comparisons of predicted results and exact solutions are provided and discussed.

Ionic liquid-catalyzed isomerization of tetrahydrotricyclopentadiene using various chloroaluminate complexes

Kim, S.G.,Han, J.,Jeon, J.K.,Yim, J.H. Butterworths [etc.] ; Elsevier Science Ltd 2014 Fuel Vol.137 No.-

Isomerization of tetrahydrotricyclopentadiene (THTCPD) was conducted using three kinds of chloroaluminate ionic liquid (IL) catalysts to compare catalytic behavior of the IL catalysts. The effect of various reaction parameters and types of IL catalysts on the THTCPD isomerization has been explored to optimize the reaction process. The conversion of isomerization of THTCPD using IL catalyst strongly dependent on the molar fraction of AlCl<SUB>3</SUB> regardless of the type of IL catalyst, due to an acidity variation. The characterization of the IL catalysts was also performed by means of FT-IR to elucidate the nature of acidic active species on the THTCPD isomerization. It was found that Lewis acidity can be controlled using different types of cationic species as well as by altering the molar fraction of AlCl<SUB>3</SUB>. Moreover, the conversion of THTCPD isomerization was strongly correlated with the Lewis acidity of IL catalyst as well.

Theoretical Study on Interactions between N-Butylpyridinium Nitrate and Thiophenic Compounds

Lu, Renqing,Liu, Dong,Wang, Shutao,Lu, Yukun Korean Chemical Society 2013 Bulletin of the Korean Chemical Society Vol.34 No.6

By using density functional theory calculations, we have performed a systemic study on the electronic structures and topological properties of interactions between N-butylpyridinium nitrate ($[BPY]^+[NO_3]^-$) and thiophene (TS), benzothiophene (BT), dibenzothiophene (DBT), naphthalene (NAP). The most stable structure of $[BPY]^+[NO_3]^-$ ion pair indicates that hydrogen bonding interactions between oxygen atoms on $[NO_3]^-$ anion and C2-H2 on pyridinium ring play a dominating role in the formation of ion pair. The occurrence of hydrogen bonding, ${\pi}{\cdots}$H-C, and ${\pi}{\cdots}{\pi}$ interactions between $[BPY]^+[NO_3]^-$ and TS, BT, DBT, NAP has been corroborated at the molecular level. But hydrogen bonding and ${\pi}{\cdots}{\pi}$ interactions between $[BPY]^+[NO_3]^-$ and NAP are weak in terms of structural properties and NBO, AIM analyses. DBT is prior to adsorption on N-butylpyridinium nitrate ionic liquid.