Film condensation of steam on a vertical tube is investigated numerically and experimentally, in the present work. A mathematical model was set based on the basic conservation laws of mass and energy, Nusselts analysis of film condensation, and empirical equations available in the literature. Then, a simulation program in FORTRAN language was developed which simulates the film condensation of steam on a vertical tube. A complete steam tables subprogram was also developed and incorporated with the main program. The experimental work was carried out using a steam condensation test bench. The inlet and outlet cooling water temperatures, steam temperature and pressure, tube surface temperature at center, and cooling water flow rate are recorded during each experimental test run. The inlet cooling water temperature, steam temperature, and cooling water flow rate are used as an input for the numerical program, then the program calculates tube surface temperature distribution, cooling water temperature distribution, local heat transfer rate, local condensation heat transfer coefficient, condensate boundary layer thickness distribution, total heat transfer rate, and average condensation heat transfer coefficient. The effect of various parameters on the condensation heat transfer coefficient, such as steam temperature, steam-surface temperature difference, and the presence of non-condensable gas were investigated and reported graphically. It was found that increasing (steam-surface) temperature difference while keeping the steam temperature constant results in an increase in condensate boundary layer thickness, which in turn causes a decrease in condensation heat transfer coefficient. On the other hand, increasing steam temperature and keeping the (steam-surface) temperature difference constant leads to an increase in condensation heat transfer coefficient. In addition, the presence of non-condensable gas with different concentrations was also investigated and it was shown that it causes a noticeable reduction in the average condensation heat transfer coefficient. An equation for calculating average condensation heat transfer coefficient on a vertical tube was also developed. The experimental data obtained from the test runs were compared with numerical results and showed good agreement. Thus, it can be concluded that the present computational program is suitable for simulating steam condensation on a vertical tube.
Green biosynthesized selenium nanoparticles from
The study aims to provide a Suggested model for the application of Virtual Private Network is a tool that used to protect the transmitted data through the Web-based information system, and the research included using case study methodology in order to collect the data about the research area ( Al-Rasheed Bank) by using Visio to design and draw the diagrams of the suggested models and adopting the data that have been collected by the interviews with the bank's employees, and the research used the modulation of data in order to find solutions for the research's problem.
The importance of the study Lies in dealing with one of the vital topics at the moment, namely, how to make the information transmitted via
... Show MoreModern French novel has gained a distinctive status in the history of French literature during the first half of the twentieth century. This is due to many factors including the new literary descriptive objective style adopted by novelists like Alain Robbe – Grillet that has long been regarded as the outstanding writer of the nouveau roman, as well as its major spokesman, a representative writer and a leading theoretician of the new novel that has broken the classical rules of the one hero and evolved, through questioning the relationship of man and the world and reevaluating the limits of contemporary fiction , into creating a new form of narrative.
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... Show MoreThis study describes the preparation of new series of tetra-dentate N2O2 dinuclear complexes (Cr3+, Co2+, Cu2+) of the Schiff base derived from condensation of 1-Hydroxy-naphthalene-2-carbaldehyde with 2-amino-5-(2-hydroxy-phenyl)-1,3,4-thiadiazole. The structures of the ligands were identified using IR, UV-Vis , mass, elemental analysis and 1H-NMR techniques. All prepared complexes have been characterized by conductance measurement, magnetic susceptibility, electronic spectra, infrared spectrum, theromgravimatric analysis (TGA) and metal analysis by atomic absorption. From stoichiometry of metal to ligand and all measurements show a octahedral geometry proposed for all
... Show MoreThe reaction of methyldopa with o-vanillin in refluxing ethanol afforded Schiff base and characterized through physical analysis with a number of spectra also the study of biological activity. The geometry of the Schiff base was identified through using (C.H.N) analysis, Mass, 1H-NMR, FT-IR, UV-Vis spectroscopy. Metal complexes of Cr3+, Mn2+, Co2+, Ni2+, Cu2+, Zn2+, Cd2+ and Hg2+ with Schiff base have been prepared in the molar ratio 2:1 (Metal:L), (L = Schiff base ligand) except Hg2+ at molar ratio 1:1 (Hg:L). The prepared complexes were characterized by using Mass, FT-IR and UV-Vis spectral studies, on other than magnetic properties and flame atomic absorption, conductivity measurements. According to the results a dinuclear octahe
... Show MoreThe reaction of methyldopa with o-vanillin in refluxing ethanol afforded Schiff base and characterized through physical analysis with a number of spectra also the study of biological activity. The geometry of the Schiff base was identified through using (C.H.N) analysis, Mass, 1H-NMR, FT-IR, UV-Vis spectroscopy. Metal complexes of Cr3+, Mn2+, Co2+, Ni2+, Cu2+, Zn2+, Cd2+ and Hg2+ with Schiff base have been prepared in the molar ratio 2:1 (Metal:L), (L = Schiff base ligand) except Hg2+ at molar ratio 1:1 (Hg:L). The prepared complexes were characterized by using Mass, FT-IR and UV-Vis spectral studies, on other than magnetic properties and flame atomic absorption, conductivity measurements. According to the results a dinuclear octahedral geo
... Show MoreThrough this article, we studied the peristaltic motion of “Hyperbolic Tangent” fluid in the geometry of curvature channel by using the analysis of large wavelength and less of Reynolds number. The matter has controlled mathematically by the partial differential equations of continuity, motion, heat transfer. In the study, we used the impact of radial magnetic force. The obtained coupled non-linear equations of above equations have solved by an approximation technical. Locked formula solutions of the stream function, axial velocity, heat function has evaluated. The influence of curvature is analysed and took it into account. The impact of sundry variables on the inflow features ha
This work includes the synthesis and identification of ligand {3-((4-acetylphenyl)amino)-5,5-dimethylcyclohex2-en-1-one} (HL* ) by the treatment of 5,5-dimethylcyclohexane-1,3-dione with 4-aminoacetophenone under reflux. The ligand (HL* ) was identified via FTIR, Mass spectrum, elemental analysis (C.H.N.), 1H and 13C-NMR spectra, UV-Vis spectroscopy, TGA and melting point. The complexes were synthesized from ligand (HL* ) mixed with 3-aminophenol (A) and metal ion M(II), where M(II) = (Mn, Co, Ni, Cu, Zn and Cd) at alkaline medium to produce complexes of general formula [M(L* )(A)] with (1:1:1) molar ratio. These complexes were detected via FT-IR spectra, UV-Vis spectroscopy as well as elemental analysis (A.A) and melting point, conductivit
... Show MoreEvolution has become a feature of this era because of the speed that makes it open multiple horizons and many to identify everything that is new in different areas and also characterized by the competitive position of emotional attitudes changing depending on the positions of winning and defeat, and the use of training methods are the most important pillars of the game of wrestling, The methods contribute to raising the level of the wrestler and refining his physical and skill potential. The problem of the research is that the shooting exercises from above the chest are very important in Roman wrestling and can be terminated by the player. Through very personal interviews for coaches and concluded that there is a weakness in the level of fl
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