Combined Heat and Mass Transfer during Condensation of Vapours Mixture and Non-Condensable Gas in a Vertical Tube

The problem of laminar film condensation from binary vapours mixture with the presence of non-condensable gas (air) flowing in a vertical tube is numerically investigated. The set of the non-linear parabolic equations expressing the mass conservation, momentum, energy, and species diffusion in both phases with the boundary conditions are resolved by using a finite difference numerical scheme. A comparative study between the results obtained for three cases (water-ethanol-air, water-methanol-air, and ethanol-methanol-air) under the same conditions is made. The impact of varying the wall temperature, the inlet vapour mass fractions, and the inlet liquid mass flow rate on the conjugate the heat and mass transfer during the condensation of the studied mixtures are examined. It is found that the condensation of water-methanol-air corresponds to a higher latent heat flux QL2 and accumulated condensation rate Mr2 when compared with water-ethanol-air and ethanol-methanol-air. Moreover, the nature of the fluid plays an important role in the heat and mass exchanges

Comparative Study of Reversal Flow during the Evaporation or Condensation of Water and Ethanol Film in a Vertical Channel

A comparative study of reversal flow is carried out to investigate the effect of thermal and mass buoyancy forces with evaporation or condensation along a vertical channel. The highlight is focused on the effects of phase change of two different liquid films having widely different properties, on heat and mass transfer rates in the channel. The evaporation occurs along isothermal and wetted walls. The induced laminar upward flow consists of a mixture of blowing air and vapour of water or ethanol. Various combinations of thermal and solutal boundary conditions (cooling and heating modes) are considered to investigate extensively their influence on the flow development. A two-dimensional steady state and elliptical flow model is used and the liquid film is assumed extremely thin. The governing equations of the model are solved by FVM and the velocity-pressure fields are treated with the SIMPLER algorithm. The results show that the buoyancy forces have a significant effect on the hydrodynamic, thermal and mass fields of both gas mixtures. In addition, the flow reversal is predicted with a relatively high temperature difference between the air-mixture and the wetted walls

Gas flow humidification enhancement by evaporating seawater liquid film

Dans ce présent travail nous étudions l'humidification d'un flux d'air dans un procédé de dessalement à travers l'évaporation du film liquide tout en considérant l'eau pure et l'eau de mer. Pour atteindre les objectifs, une méthode implicite de différence finie est utilisée pour résoudre les équations gouvernantes couplées dans les phases liquide et gazeuse. L'influence des conditions d'entrée du film liquide, y compris la salinité, sur l'humidification du flux d'air dans un tube vertical est étudiée

Mixed convection heat and mass transfer within a vertical channel

L'objectif de ce travail est d'étudier numériquement le transfert de chaleur et de masse lors de l'évaporation d'un film liquide d'acétone, d'épaisseur négligeable, mouillant les parois d'un canal vertical. Les équations générales de conservation et les conditions aux limites associées sont discrétisées par le bais de la méthode des volumes finis. Le couplage vitesse-pression est traité par l'algorithme SIMPLER. L'étude se focalise sur l'analyse de l'effet de la vitesse et de l'humidité relative de l'air à l'entrée du canal, sur le comportement hydrodynamique, thermique et massique du flux d'air humide

Elaboration, crystal structure, vibrational, optical properties, thermal analysis and theoretical study of a new inorganic-organic hybrid salt [C4H12N2]4·Pb2Cl11·Cl·4H2O

A new organic–inorganic hybrid salt[C4H12N2]4·Pb2Cl11·Cl·4H2O, containing [Pb2Cl11]7−anions, has been synthesized and characterized by several techniques. X-ray diffraction study shows that the compound crystallizes in the orthorhombic system and Pnnm space group with a = 8.210 (5), b = 25.782 (5), c = 9.467 (5) Å and V = 2003.9 (17) Å3.The structure of the title compound can be described by organic-inorganic layers extending parallel to the (a, b) plane at z = 0 and z = ½. These layers are built up by means of hydrogen bonds forming a three-dimensional network. Intermolecular interactions were investigated by Hirshfeld surfaces. Scanning electronic microscopy (SEM) and energy-dispersive X-ray (EDX) were carried out. Vibrational assignments of the title compound are discussed by FT-IR and FT-Raman spectroscopic studies and DFT calculations allowed the attribution of the spectral bands. The optical study was also investigated by UV–Vis absorption and photoluminescence spectroscopy. The thermal behavior was studied by TGA/DTA analysis.Financial support from Spanish MINECO (MAT2016-78155-C2-1-R, MAT2013-40950-R, and FPI grant BES-2011-046948 to MSM.A.), Gobierno del Principado de Asturias (GRUPIN14-060), FEDER, the Secretary of State for Scientific Research and Technology of Tunisia and Department of Chemistry, College of Sciences and Humanities, Shaqra University, 11911, Ad-Dawadmi, Saudi Arabia are acknowledged.Peer reviewe

Synthesis, crystal structure, physico-chemical characterization and theoretical study of a new Pb(II) complex = C 10 H 22 N 2 3 ·PbCl 5 ·3Cl·3H 2 O

A novel hybrid material, [C10H22N2]3·PbCl5·3Cl·3H2O, has been synthesized and its structure was determined by single-crystal X-ray diffraction. In the atomic arrangement, the different entities are held together through NH⋯Cl, OH⋯Cl and OH⋯O hydrogen bonds to form a three-dimensional network. Intermolecular interactions were investigated by Hirshfeld surfaces. The powder XRD data confirms the phase purity of the crystalline sample. The resulting IR spectrum calculated by the DFT/B3LYP/LanL2DZ method, is similar to the experimental spectrum allowing a good correlation between the experimental and theoretical wavenumbers. The optical properties in the UV–visible region have been explored by the UV–visible absorption. The photoluminescence (PL) spectroscopy, which was investigated at room temperature, exhibited one emission at 426 nm. Thermal analysis discloses a phase transition at 435 K and the decomposition of the sample starts from 554 K.Financial support from Spanish MINECO (MAT2016-78155-C2-1-R, MAT2013-40950-R, and FPI grant BES-2011-046948 to MSM.A.), Gobierno del Principado de Asturias (GRUPIN14-060), FEDER, and the Secretary of State for Scientific Research and Technology of Tunisia, are acknowledged

Elaboration, crystal structure, characterization and DFT calculation of a new Hg(II) inorganic-organic hybrid salt [C6H16N2O]HgCl4

The crystal structure of new organic-inorganic hybrid (2-hydroxyethyl)piperazine-1,4-diiumtetrachloromercurate (II), [C6H16N2O]HgCl4, was determined by X-ray diffraction analysis. In the atomic arrangement, the different entities are held together through N-H⋯Cl, C-H⋯Cl and O-H⋯Cl hydrogen bonds to form ribbons. The powder XRD pattern was in good relation with the results of single crystal structure analysis. This compound was also investigated by scanning electronic microscopy, energy-dispersive X-ray, infrared spectroscopy and differential thermal analysis. DFT calculations allowed the attribution of the IR bands. Intermolecular interactions were investigated by Hirshfeld surfaces. The thermal analysis shows that this compound is stable below 380 ​K.The financial support from Spanish MINECO (MAT2016-78155-C2-1-R, MAT2013- 40950-R, and FPI grant BES-2011-046948 to MSM.A.), Gobierno del Principado de Asturias (GRUPIN14-060), FEDER, the Secretary of State for Scientific Research and Technology of Tunisia and Department of Chemistry, College of Sciences and Humanities, Shaqra University, 11911, Ad-Dawadmi, Saudi Arabia are acknowledged.Peer reviewe

Synthesis, crystal structure, vibrational spectroscopy, DFT, optical study and thermal analysis of a new stannate(IV) complex based on 2-ethyl-6-methylanilinium (C9H14N)2[SnCl6]

The new organic-inorganic compound, (C9H14N)2[SnCl6], has been synthesized and characterized by single-crystal X-ray diffraction at room temperature. Structural analysis indicates that this compound crystallizes in the monoclinic system with C2/m space group. The NH⋯Cl hydrogen bonds between (C9H14N)+ cations and [SnCl6]2- dianions contribute to the cohesion and the stability of the atomic arrangement. Hirshfeld surface analysis was used to investigate intermolecular interactions, as well 2D finger plots were conducted to reveal the contribution of these interactions in the crystal structure quantitatively. Furthermore, the room temperature Infrared (IR) spectrum of the title compound was analyzed on the basis of data found in the literature. The optical properties of the crystal were studied using optical absorption UV–visible and photoluminescence (PL) spectroscopy, which were investigated at room temperature exhibited one band at 237 nm and a photoluminescence emission at 407 nm. Experimental room-temperature X-ray studies were supported by theoretical methods using the DFT/B3LYP methods with the LanL2DZ basis set. The X-ray powder is in agreement with the X-ray structure. To determine molecular electrical transport properties we studied the energy difference between Occupied, HOMO, and Lowest Unoccupied, LUMO orbitals. Moreover, this compound was characterized by thermal analysis between 300 and 750 K and shows that the compound remains stable up to the temperature 383 K. Finally, X-ray photoelectron spectroscopy (XPS) analysis is reported to determine the degree of oxidation of tin in this compound and analyze the surface chemistry of (C9H14N)2[SnCl6].Financial support from Spanish MINECO (MAT2016-78155-C2-1-R, MAT2013-40950-R, and FPI grant BES-2011-046948 to MSM.A.), GobiernodelPrincipado de Asturias (GRUPIN14-060), FEDER, and the Secretary of State for Scientific Research and Technology of Tunisia, are acknowledged