Статті в журналах: "Expansion de la vapeur"

1

Davydenkov, I. A., A. B. Davydov, and G. A. Perestoronin. "Vapor-liquid turbine expansion engines." Chemical and Petroleum Engineering 31, no. 2 (February 1995): 114–15. http://dx.doi.org/10.1007/bf01147389.

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2

Wright, Gavin. "Les Fondements Historiques de la Domination Economique Américaine." Annales. Histoire, Sciences Sociales 53, no. 3 (June 1998): 537–67. http://dx.doi.org/10.3406/ahess.1998.279684.

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La prééminence économique des États-Unis est l'un des traits marquants de l'histoire mondiale du 20e siècle. La domination américaine a été si nette et si évidente qu'elle semble souvent ne requérir aucune explication. L'historien Paul Kennedy écrit quant à lui, dans son étude très appréciée, The Rise and the Fall of the Great Powers:Les États-Unis semblaient posséder tous les avantages économiques dont certaines autres puissances détenaient une partie, mais ils ne comptaient aucun des handicaps de celles-ci… A la fin de la guerre de Sécession, les États-Unis ont pu exploiter, pour se transformer à une cadence stupefiante, les nombreux avantages dont ils étaient dotés: riches etendues cultivables, importantes quantites de matieres premieres, et possibilite de developper ces ressources grace a revolution particulierement heureuse de la technologie moderne (rail, machine a vapeur, equipement minier); faibles contraintes sociales ou geographiques ; absence de menace etrangere importante ; flux d'investissements etrangers et, progressivement, nationaux... Etant donne ces avantages, tout le processus de developpement etait virtuellement inévitable. C'est-à-dire que seule une opiniatre betise humaine, une guerre civile presque incessante ou une catastrophe naturelle auraient pu hypothequer cette expansion ou dissuader des millions d'immigrants de traverser l'Atlantique pour obtenir leur part d'or et grossir la main-d'œuvre.

3

Ahmed, Aram Mohammed, and Attila R. Imre. "The effect of recuperator on the efficiency of ORC and TFC with very dry working fluid." MATEC Web of Conferences 345 (2021): 00012. http://dx.doi.org/10.1051/matecconf/202134500012.

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Organic Rankine Cycles (ORC) and Trilateral Flash Cycles (TFC) are very similar power cycles; ideally, they have a reversible adiabatic (isentropic) compression, an isobaric heating, an isentropic expansion and an isobaric cooling. The main difference is that for ORC, the heating includes the full evaporation of the working fluid (prior expansion); therefore, the expansion starts in a saturated or dry vapour state, while for TFC, the heating terminates upon reaching the saturated liquid states. Therefore, for TFT, expansion liquid/vapour state (in bubbly liquid or in vapour dispersed with droplets), requiring a special two-phase expander. Being ORC a more “complete” cycle, one would expect that its thermodynamic efficiency is always higher than for a TFC, between the same temperatures and using the same working fluids. Surprisingly, it was shown that for very dry working fluids, the efficiency of TFC can exceed the efficiency of basic (i.e. recuperator- and superheater-free) ORC, choosing sufficiently high (but still subcritical) maximal cycle temperature. Therefore in these cases, TFC (having a simpler heat exchange unit for heating) can be a better choice than ORC. The presence of a recuperator can influence the situation; by recovering the proper percentage of the remaining heat (after the expansion), the efficiency of ORC can reach and even pass the efficiency of TFC.

4

Damanik, Jhon Berry Finn, Bambang Admadi Harsujuwono, and Lutfi Suhendra. "Pengaruh Konsentrasi Asam Stearat dan Suhu Gelatinisasi terhadap Karakteristik Komposit Bioplastik Tapioka dan Glukomanan." JURNAL REKAYASA DAN MANAJEMEN AGROINDUSTRI 10, no. 1 (March 28, 2022): 44. http://dx.doi.org/10.24843/jrma.2022.v10.i01.p05.

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This study aims to determine the effect of stearic acid concentration and gelatinization temperature and the interaction of the two treatments on the characteristics of tapioca and glucomannan bioplastic composites, and determine the concentration of stearic acid and gelatinization temperature which can produce bioplastic composites with the best characteristics. This study used a randomized block design with two factors. The first factor is the concentration of stearic acid which consists of 0.2%, 0.4%, 0.6%, 0.8%. The second factor is the gelatinization temperature which consists of 4 temperatures, namely 70±1°C, 75±1°C, 80±1°C, 85±1°C. The variables observed in this study were tensile strength, elongation at break, elasticity, thickness expansion, water vapor transmission rate, biodegradation and functional group analysis. The data were analyzed for diversity and continued with Duncan's Multiple Comparison. The results showed that the concentration of stearic acid and gelatinization temperature had a very significant effect on tensile strength, thickness expansion, water vapor transmission rate and biodegradation. The interaction between treatments had a very significant effect on tensile strength, thickness expansion, water vapor transmission rate and biodegradation and significantly affected elongation at break and elasticity. The best tapioca and glucomannan bioplastic composites used a stearic acid concentration of 0.4% and a gelatinization temperature of 80±1°C which had the characteristics of a tensile strength of 23.86 MPa, elongation at break 8.70%, elasticity 274.40 MPa, thickness expansion 111.52%, water vapour transmission rate 1.05 g/m2.hour, biodegradation rate with 7 days old. Tapioca and glucomannan bioplastic composites contain functional groups of hydroxyl (O-H), alkyne (C?H), aldehyde (C=O), carboxylic acid (C-O), alkene (C-H) and hydroxyl hydrocarbon (CH2)n. Keywords : bioplastic composite, tapioca, glucomannan, stearic acid, gelatinization temperature

5

Saini, D. K., A. Baruah, and G. Sachdeva. "Vapour compression system analysis undergoing expansion in an ejector." Journal of Physics: Conference Series 1240 (July 2019): 012131. http://dx.doi.org/10.1088/1742-6596/1240/1/012131.

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6

Mielczarek, Z. A., and T. J. Trojanowski. "Refrigerant vapour superheat in direct-expansion air cooling coils." International Communications in Heat and Mass Transfer 14, no. 3 (May 1987): 341–46. http://dx.doi.org/10.1016/0735-1933(87)90035-2.

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7

Goyal, Kunal, R. V. Nanditta, Potteli Dharma Teja, S. Malarmannan, and G. Manikandaraja. "Analysis of vapor compression refrigeration system employing tetrafluroethane and difluroethane as refrigerants." Journal of Physics: Conference Series 2054, no. 1 (October 1, 2021): 012054. http://dx.doi.org/10.1088/1742-6596/2054/1/012054.

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Abstract The axiomatic effects of ozone layer depletion have caused additional damage in the last few decades. The accretion in greenhouse gases has transformed to take cardinal steps immediately. The concoct blend of 1,1,1,2 Tetrafluroethane (R134a) and 1,1, Difluroethane (R152) a was tested in a vapour compression refrigeration system as these are non-toxic, eco-friendly, non-flammable and non-corrosive. Experimental performance analysis of vapor compression refrigeration system using R134a and blends of R152a and R134a is done for different dimensions of expansion valves. Various parameters like coefficient of performance (COP), refrigerating effect and compressor work were analyzed. Refrigeration effect and compressor work of R134a was higher than R152a. COP value was reliable for 60/40 ratio of R152a and R134a and maximum COP was achieved with the blend of 90/10 ratio in the first expansive coil. These aberrant results could be overcome by amalgamation of R134a and R152a as the discharge temperature of R152a is effectively controlled by blending.

8

Morin, Richard, Ghfran Al Chami, Richard Gagné, and Benoit Bissonnette. "Design Considerations and Innovative Approach for Restoration of Historic Landmarks in Old Montreal." MATEC Web of Conferences 199 (2018): 07003. http://dx.doi.org/10.1051/matecconf/201819907003.

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Restoration of some streets in Old Montreal is achieved using granite pavers bonded with a mortar bed to a concrete slab. The technique was originally used for the pavement of St-Paul Street with stone bricks back in the 1800's. A similar approach is being used in 2016 to renovate the very same street, except for the materials used in casting the foundation slab. In order to space out the expansion joints and prevent drying shrinkage cracking, fibre reinforcement and an expansive component are incorporated in the concrete. The concept was successfully used in bridge deck rehabilitation projects such as Girouard Overpass deck overlay. The basic principle of this approach is to generate a chemical expansion in the concrete (200 to 300 gm/m) using an expansive component, and to restrain the generated expansion through the combined action of ordinary peripheral steel reinforcement in the slab and steel fibre reinforcement in the concrete. The objective is to mitigate shrinkage stresses by keeping the strain balance as low as possible and allowing the concrete additional time to develop sufficient tensile strength, such that the stresses induced in the concrete slabs will remain lower than the concrete tensile strength.Restraint of expansion by the steel fibres and the peripheral reinforcement induces an initial compressive stress in the concrete slab. A part of this stress is used to compensate for the drying shrinkage, whereas the remaining part (if any) is used to resist incidental restrained deformation (e.g. thermal strains) cracking. Concrete mixture proportioning, placement, and curing need to be optimized in order to achieve enough expansion to adequately control cracking due to restrained shrinkage. After proper moist curing of the slab, the pavers are bonded to its top surface using a latex-modified mortar (latex to cement ratio of about 11% by mass). The latex-modified mortar used as a levelling bed underneath the pavers has a low vapour permeability that partially seals the concrete surface and further contributes to minimize drying shrinkage cracking. Since 2011, various historic landmarks in the City of Montreal have been restored using concrete containing an expansive component. To this date, monitoring and performance reports have showed that the chemical prestress approach is quite effective in decreasing shrinkage cracking in paved street foundations, thereby allowing the placement of longer slabs with significantly fewer expansion joints.

9

Kudryashov, N. A., and An A. Tutnov. "Modeling unsteady vapor condensation by rapid expansion." Fluid Dynamics 27, no. 3 (1993): 363–67. http://dx.doi.org/10.1007/bf01051184.

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10

NIIHARA, Koichi, and Toshio HIRAI. "Thermal Expansion of Chemically Vapor-Deposited Si3N4." Journal of the Ceramic Association, Japan 94, no. 1085 (1986): 156–58. http://dx.doi.org/10.2109/jcersj1950.94.156.

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11

Niihara, Koichi, and Toshio Hirai. "Thermal expansion of chemically vapor-deposited Si3N4." International Journal of High Technology Ceramics 2, no. 3 (January 1986): 242. http://dx.doi.org/10.1016/0267-3762(86)90069-x.

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12

Schnerr, G. H., and S. Adam. "Visualization of unsteady gas/vapor expansion flows." Journal of Thermal Science 6, no. 3 (September 1997): 171–80. http://dx.doi.org/10.1007/s11630-997-0033-2.

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13

Chen, Xu, Shu Feng Zhao, and Linda Zhai. "Interface Cracking of Plastic Electronic Package under Temperature and Humidity Environment." Key Engineering Materials 353-358 (September 2007): 2940–43. http://dx.doi.org/10.4028/www.scientific.net/kem.353-358.2940.

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Structural model of plastic electronic package under temperature and humidity is constructed, and the coupling of the thermal and moisture impact on structure field is implemented. The impact of thermal expansion, hygro-swelling and vapor pressure increases with increasing initial defect, especially the impact of vapor pressure. At certain crack length, KI and KII induced by thermal expansion is proportional to temperature difference, and KI and KII induced by vapor is proportional to vapor pressure. The impacts of thermal expansion and hygro-swelling on ERR decrease during crack propagation, but the impact of vapor pressure increases significantly.

14

Rodriguez, Mark A., James F. Browning, Colleen S. Frazer, Clark S. Snow, Ralph G. Tissot, and Elaine P. Boespflug. "Unit cell expansion in ErT2 films." Powder Diffraction 22, no. 2 (June 2007): 118–21. http://dx.doi.org/10.1154/1.2737462.

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XRD analysis of plasma-vapor-deposited ErT2 films during aging (T decay to 3He) reveals an hkl-dependent unit-cell expansion in which (200) grains expand out-of-plane as much as 0.01 Å more than (111) out-of-plane grains. Texture analysis of an aged ErT2 film reveals a bimodal (111)/(200) out-of-plane preferred orientation. sin2 ψ analysis reveals significant in-plane macro-strain due to 3He bubble formation/growth. The mechanistic origins regarding these observations are also discussed.

15

Duplat, Jérôme. "Dynamics of expansion and collapse of explosive two-dimensional bubbles." Journal of Fluid Mechanics 859 (November 22, 2018): 677–90. http://dx.doi.org/10.1017/jfm.2018.804.

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An explosive gas mixture of hydrogen and oxygen is introduced in liquid water between two horizontal walls, forming a flat cylindrical bubble. Ignition and explosion of the bubble lead to a large depressurized cavity that finally implodes. We investigate the dynamics of the bubble collapse, which is qualitatively similar to the collapse of a spherical bubble. It exhibits a slightly weaker singularity than for spherical bubbles. We also analyse the explosion process. Starting with an initial radius $R_{0}$, the bubble reaches a maximal radius $R_{max}$ that depends on the gap thickness $h$ between the two walls: for a thinner gap, the condensation of water vapour is more efficient, the overpressure consecutive to the combustion is weaker, and its duration is shorter. This leads to a smaller maximal radius $R_{max}$. An indirect measurement of the transport coefficient of hot water vapour can be inferred from this observation.

16

PANDA, ANTON, VOLODYMYR MYKOLAJOVYCH ANISIMOV, VOLODYMYR VOLODYMYROVYCH ANISIMOV, IVETA PANDOVA, ANTON KLYMENKO, and PETER ERMAKOV. "CAVITATION NOZZLES WITH EXPANSION CHAMBER." MM Science Journal 2022, no. 4 (November 16, 2022): 6020–25. http://dx.doi.org/10.17973/mmsj.2022_11_2022050.

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An expansion chamber for narrow part of cavitation nozzles is developed. Designs of cavitation nozzles with expansion chamber based on cylindrical nozzle and Venturi nozzle are proposed. The results of calculations of the fluid flow in the presented nozzles show the areas in nozzle, where cavitation is generated, their number, form and power. The plot of volume fraction of vapor phase shows the causes of an increase in the intensity of cavitation in new nozzles with expansion chamber. The main of them is that due to introduction of the expansion chamber, a little area of cavitation generation in the narrow part of cavitation nozzle turns to large one, that causes significant increase in cavitation intensity. The results of comparative experimental studies, which confirm the superiority of cavitation nozzles with the expansion chamber over the basic ones, show that cavitation nozzle with expansion chamber can provide 3 times higher intensity of cavitation, than basic cylindrical nozzle. Also, cavitation nozzle with expansion chamber on the basis of Venturi nozzle can provide 1.5 times higher cavitation intensity, than basic Venturi nozzle.

17

Miyauchi, Masato, Takumi Watanabe, Daiki Hoshi, and Tomonori Ohba. "Irreversible adsorption of acidic, basic, and water gas molecules on calcium-deficient hydroxyapatite." Dalton Transactions 48, no. 47 (2019): 17507–15. http://dx.doi.org/10.1039/c9dt03704g.

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18

Imre, Attila R., Réka Kustán, and Axel Groniewsky. "Thermodynamic Selection of the Optimal Working Fluid for Organic Rankine Cycles." Energies 12, no. 10 (May 27, 2019): 2028. http://dx.doi.org/10.3390/en12102028.

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A novel method proposed to choose the optimal working fluid—solely from the point of view of expansion route—for a given heat source and heat sink (characterized by a maximum and minimum temperature). The basis of this method is the novel classification of working fluids using the sequences of their characteristic points on temperature-entropy space. The most suitable existing working fluid can be selected, where an ideal adiabatic (isentropic) expansion step between a given upper and lower temperature is possible in a way, that the initial and final states are both saturated vapour states and the ideal (isentropic) expansion line runs in the superheated (dry) vapour region all along the expansion. Problems related to the presence of droplets or superheated dry steam in the final expansion state can be avoided or minimized by using the working fluid chosen with this method. Results obtained with real materials are compared with those gained with model (van der Waals) fluids; based on the results obtained with model fluids, erroneous experimental data-sets can be pinpointed. Since most of the known working fluids have optimal expansion routes at low temperatures, presently the method is most suitable to choose working fluids for cryogenic cycles, applied for example for heat recovery during LNG-regasification. Some of the materials, however, can be applied in ranges located at relatively higher temperatures, therefore the method can also be applied in some limited manner for the utilization of other low temperature heat sources (like geothermal or waste heat) as well.

19

Sarkar, Jahar. "Exergy analysis of vortex tube expansion vapour compression refrigeration system." International Journal of Exergy 13, no. 4 (2013): 431. http://dx.doi.org/10.1504/ijex.2013.058101.

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20

Liu, Yefeng, and Jun Yu. "Review of vortex tube expansion in vapour compression refrigeration system." IOP Conference Series: Earth and Environmental Science 153 (May 2018): 032021. http://dx.doi.org/10.1088/1755-1315/153/3/032021.

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21

Arshed, G. M., S. Z. Shuja, B. S. Yilbas, and M. O. Budair. "Transient Helium Jet Expansion Into Stagnant Air in Relation to Laser Drilling." Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 219, no. 7 (July 1, 2005): 667–83. http://dx.doi.org/10.1243/095440605x31517.

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Transient helium jet expansion into a stagnant air environment is modelled to resemble the laser vapour ejection from the cavity during the drilling process. As the metal vapour properties are not known, helium is employed while the previously measured jet inlet velocity profiles are introduced in the simulations. A numerical scheme employing a control volume approach is used to discretize the governing equations of flow. The predictions are validated through a case study associated with an incompressible transient jet flow. It is found that the jet inlet profile influences considerably the self-similar behaviour of the jet. Moreover, the jet expands radially in the early period while as time progresses, the axial penetration of the jet becomes high.

22

Kahn, H., R. Ballarini, and A. H. Heuer. "Thermal Expansion of Low-pressure Chemical Vapor Deposition Polysilicon Films." Journal of Materials Research 17, no. 7 (July 2002): 1855–62. http://dx.doi.org/10.1557/jmr.2002.0274.

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Polysilicon films were deposited using low-pressure chemical vapor deposition (LPCVD) onto oxidized silicon substrates, after which substrate curvature as a function of temperature was measured. The curvatures changed with temperature, implying that the thermal expansion of LPCVD polysilicon differs from that of the single crystal silicon substrate. Further, polysilicon films with tensile residual stresses displayed an increased thermal expansion, while polysilicon films with compressive residual stresses displayed a decreased thermal expansion. Following high temperature annealing, the residual stresses of the polysilicon films were reduced to near zero, and the thermal expansion of the polysilicon films matched that of the single crystal substrate. The apparent change in thermal expansion coefficient due to residual stress was much larger than predicted theoretically.

23

SU, Yongqiang, Jinfa SHI та Yahui WANG. "Numerical Simulation of Cavitation of Water Jet Nozzle Based on Realizable k-ε Model". Mechanics 28, № 1 (17 лютого 2022): 12–18. http://dx.doi.org/10.5755/j02.mech.28583.

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In order to study the cavitation characteristics of water jet nozzles, a realizable model was selected to simulate the flow field inside the nozzle at the inlet pressure of 15 MPa. The pressure at the starting point of the nozzle throat section dropped to the minimum, and the liquid velocity reached the maximum. From the vapor volume distribution map of the nozzle, it can be seen that the vapor fraction is the largest on the wall of the expansion section, and a local reflux is formed in the expansion section, which results in the gradual diffusion of the vapor fraction distribution along the wall of the expansion section. In addition, the influence of nozzle inlet pressure on the vapor fraction and vapor fraction distribution region in the expansion section is analyzed. The results show that the larger vapor fraction and vapor fraction distribution region can be produced under the 25 MPa inlet pressure. At the pressure inlet of 25 MPa, six groups of numerical simulations were carried out with different the length to diameter ratio of the nozzle throat section (L4/d0). The results show that when L4/d0 is 2, it is more conducive to the formation of cavitation and the quality of cavitation is better.

24

Guardone, Alberto, Piero Colonna, Emiliano Casati, and Enrico Rinaldi. "Non-classical gas dynamics of vapour mixtures." Journal of Fluid Mechanics 741 (February 13, 2014): 681–701. http://dx.doi.org/10.1017/jfm.2013.13.

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AbstractThe non-classical gas dynamics of binary mixtures of organic fluids in the vapour phase is investigated for the first time. A predictive thermodynamic model is used to compute the relevant mixture properties, including its critical point coordinates and the local value of the fundamental derivative of gas dynamics $\Gamma $. The considered model is the improved Peng–Robinson Stryjek–Vera cubic equation of state, complemented by the Wong–Sandler mixing rules. A finite thermodynamic region is found where the nonlinearity parameter $\Gamma $ is negative and therefore non-classical gas dynamics phenomena are admissible. A non-monotone dependence of $\Gamma $ on the mixture composition is observed in the case of binary mixtures of siloxane and perfluorocarbon fluids, with the minimum value of $\Gamma $ in the mixture being always larger than that of its more complex component. The observed dependence indicates that non-ideal mixing has a strong influence on the gas dynamics behaviour, either classical or non-classical, of the mixture. Numerical experiments of the supersonic expansion of a mixture flow around a sharp corner show the transition from the classical configuration, exhibiting an isentropic rarefaction fan centred at the expansion corner, to non-classical ones, including mixed expansion waves and rarefaction shock waves, if the mixture composition is changed.

25

Kronberg, Alexander, Maxim Glushenkov, Sander Roosjen, and Sascha Kersten. "Isobaric Expansion Engines–Compressors: Thermodynamic Analysis of Multistage Vapor Driven Compressors." Energies 16, no. 19 (September 24, 2023): 6791. http://dx.doi.org/10.3390/en16196791.

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Isobaric expansion (IE) engines can directly convert heat into mechanical energy, making them particularly attractive for applications such as vapor-driven pumps and compressors. A recent initial assessment investigating the utilization of IE engines as vapor-driven reciprocating compressors has revealed that the vapor use efficiency is inherently low in the case of the simplest direct-acting compressor designs. Based on this analysis, it was anticipated that multistage compression can offer significant advantages for vapor-driven compressors. Therefore, this paper aims to conduct a comprehensive analytical thermodynamic analysis of direct vapor-driven multistage reciprocating compressors. The analysis considers processes without intercooling and processes with intercooling of the compressed gas between stages. The findings demonstrate that, for vapor-driven compression, the benefits of multistage compression are superior to those known for conventional compression processes. Multistage vapor-driven compression not only reduces compression work and temperature elevation but, more importantly, mitigates the adverse effects on vapor compression of the driving vapor, thereby enabling a substantial improvement in vapor utilization efficiency. Furthermore, the total volume of the IE engine compressor experiences a significant decrease with an increasing number of stages. Consequently, under specific process parameters, the overall dimensions of the engine-compressor system may also decrease as the number of stages increases. The results offer significant opportunities for energy savings in energy-intensive compression processes by replacing electrical energy with readily available low-grade heat sources (<100 °C). Such processes include hydrogen, air, and ethylene compression at high pressure.

26

Liu, Liming, Zhao Yuan, Lixue Chen, and Shan Liu. "Experimental investigation on the velocity of cathode spots in a vacuum arc with high di/dt." Journal of Physics D: Applied Physics 55, no. 19 (February 14, 2022): 195202. http://dx.doi.org/10.1088/1361-6463/ac507e.

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Abstract With the development of DC transmission and aerospace technology, the demands on the breaking capacity of vacuum circuit breakers (VCBs) under high d i d t condition are getting higher and higher. The breaking capacity of VCBs is determined by cathode spots, which provide electrons and metal vapor to maintain the arc. In this paper, the experiments of cathode spot observation were carried out based on the detachable vacuum interrupter and the cup-shaped axial magnetic field contacts. The images of cathode spot distribution were obtained by an ultra high-speed camera. In the initial expansion stage of arcing, it was discovered that the distribution of cathode spots is ring-shaped and symmetrical. The initial expansion velocity of cathode spot ring is approximately proportional to the value of d i d t and is independent of frequency. During the whole arcing process, the expansion velocity of cathode spot ring rises first and then drops with arcing time. The effects of the magnetic field and metal vapor density on the expansion process of cathode spot were analyzed. Based on the experimental conditions and results, the values of magnetic field and metal vapor density were calculated which can reasonably explain the variation of expansion velocity of cathode spot.

27

Gouin, Henri, and Pierre Seppecher. "Temperature profile in a liquid–vapour interface near the critical point." Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences 473, no. 2204 (August 2017): 20170229. http://dx.doi.org/10.1098/rspa.2017.0229.

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Thanks to an expansion with respect to densities of energy, mass and entropy, we discuss the concept of thermocapillary fluid for inhomogeneous fluids. The non-convex state law valid for homogeneous fluids is modified by adding terms taking account of the gradients of these densities. This seems more realistic than Cahn and Hilliard’s model which uses a density expansion in mass-density gradient only. Indeed, through liquid–vapour interfaces, realistic potentials in molecular theories show that entropy density and temperature do not vary with the mass density as it would do in bulk phases. In this paper, we prove using a rescaling process near the critical point, that liquid–vapour interfaces behave essentially in the same way as in Cahn and Hilliard’s model.

28

Al Horr, Yousef, Bourhan Tashtoush, Nelson Chilengwe, and Mohamed Musthafa. "Performance Assessment of a Hybrid Vapor Compression and Evaporative Cooling Fresh-Air-Handling Unit Operating in Hot Climates." Processes 7, no. 12 (November 21, 2019): 872. http://dx.doi.org/10.3390/pr7120872.

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Evaporative cooling can be integrated into fresh-air-handling units, to reduce cooling demand. This study considers a hybrid fresh-air-handling unit which incorporates a vapor-compression cooling cycle and indirect evaporative cooling to condition an ambient primary airstream to a desired supply air state. The cooling effects of using various modes (vapor compression only; direct expansion with mist; direct expansion with water shower; and direct expansion with mist and water shower) are compared when the fresh-air-handling unit operates in harsh (hot and humid) climatic conditions experienced in Qatar. Experimental analysis is based on actual ambient conditions measured from August 2018 to July 2019. It is found that the best-performing wet mode of operation saves more than 60% of the energy required by a conventional direct expansion cooling system operating under the same ambient conditions. In hot, dry conditions, the coefficient of performance of the fresh-air-handling unit when using the indirect evaporative mode of operation is double the coefficient of performance when operating with direct expansion mode only.

29

Hamadi, Farida, and El Hachemi Amara. "Effect of Argon Ambient Gas Pressure on Plume Expansion Dynamics." Advanced Materials Research 227 (April 2011): 129–33. http://dx.doi.org/10.4028/www.scientific.net/amr.227.129.

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In this paper we present a numerical modeling of a nanosecond laser pulse interaction with a titanium target. We investigate the vapor plume formation and the influence of the ambient gas pressure on plume expansion dynamics. The vapor plume formation depends on the results of the heat transfer in the solid target modeling. The solid-liquid phase change is modeled by a two dimensional approach using an enthalpy formulation. The resulting plume expansion in the argon background gas is studied using the species transport model. The algebraic equations are discretized by the finite volume method implemented by Fluent CFD software [1]. The calculation results of plume expansion velocity, density, temperature and degree of ionization in the plume are presented.

30

Miller, T. C., W. D. Gubler, S. Geng, and D. M. Rizzo. "Effects of Temperature and Water Vapor Pressure on Conidial Germination and Lesion Expansion of Sphaerotheca macularis f. sp. fragariae." Plant Disease 87, no. 5 (May 2003): 484–92. http://dx.doi.org/10.1094/pdis.2003.87.5.484.

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Conidial germination in vitro and foliar lesion expansion were studied for Sphaerotheca macularis f. sp. fragariae. Detached strawberry (Fragaria × ananassa) leaves were inoculated, then held in controlled environments of constant temperatures (4 to 36°C) and relative humidity (RH, 32 to 100%) representing the range of these variables observed under California commercial production conditions. Percent germination and lesion expansion rate were determined by destructive subsampling over time. Conidia germinated at all temperatures by 6 h and reached a maximum by 48 h, with the optimum near 20°C. Lesions were marked with the aid of a microscope and measured by computer-assisted image-analysis to determine expansion rate. Maximal rates occurred at 25°C. Several growth models were fit to the expansion rate data with high significance. Predicted optima from these models ranged from 22 to 27°C and/or 17 to 27 mm Hg VPwater@100%RH. Neither RH, partial vapor pressure of water (VPwater), nor vapor pressure deficit (VPD) correlated with lesion expansion rate, adding to studies minimizing the importance of RH and VPD as determinants of asexual phase powdery mildew growth other than specifically at spore germination.

31

Wu, Weifeng, Qi Wang, Zhao Zhang, Zhijun Wu, Xiaotian Yang, and Liangcong Xu. "Influence of evaporating rate on two-phase expansion in the piston expander with cyclone separator." Thermal Science 24, no. 3 Part B (2020): 2077–88. http://dx.doi.org/10.2298/tsci180903322w.

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The trilateral flash cycle shows a greater potentiality in moderate to low grade heat utilization systems due to its potentiality of obtaining high exergy efficiency, compared to the conventional thermodynamic cycles such as the organic Rankine cycles and the Kalina cycle. The main difference between the trilateral flash cycle and the conventional thermodynamic cycles is that the superheated vapor expansion process is replaced by the two-phase expansion process. The two-phase expansion process actually consists of a flashing of the inlet stream into a vapor and a liquid phase. Most simulations assume an equilibrium model with an instantaneous flashing. Yet, the experiments of pool flashing indicate that there is a flash evaporating rate. The mechanism of this process still remains unclear. In this paper, the flash evaporating rate is introduced into the model of the two-phase expansion process in the reciprocating expander with a cyclone separator. As such, the obtained results reveal the influence of evaporating rate on the efficiency of the two-phase expander.

32

Oh, M. D., and M. L. Corradini. "A Propagation/Expansion Model for Large Scale Vapor Explosions." Nuclear Science and Engineering 95, no. 3 (March 1987): 225–40. http://dx.doi.org/10.13182/nse87-a20452.

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33

Qadri, S. B., C. Kim, E. F. Skelton, T. Hahn, and J. E. Butler. "Thermal expansion of chemical vapor deposition grown diamond films." Thin Solid Films 236, no. 1-2 (December 1993): 103–5. http://dx.doi.org/10.1016/0040-6090(93)90651-5.

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34

Krumdieck, S. P., H. M. Cave, S. Baluti, M. Jermy, and A. Peled. "Expansion transport regime in pulsed-pressure chemical vapor deposition." Chemical Engineering Science 62, no. 22 (November 2007): 6121–28. http://dx.doi.org/10.1016/j.ces.2007.07.003.

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35

Menon, S. V. G. "Convergence of Coupling-Parameter Expansion-Based Solutions to Ornstein–Zernike Equation in Liquid State Theory." Condensed Matter 6, no. 3 (August 5, 2021): 29. http://dx.doi.org/10.3390/condmat6030029.

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The objective of this paper is to investigate the convergence of coupling-parameter expansion-based solutions to the Ornstein–Zernike equation in liquid state theory. The analytically solved Baxter’s adhesive hard sphere model is analyzed first by using coupling-parameter expansion. It was found that the expansion provides accurate approximations to solutions—including the liquid-vapor phase diagram—in most parts of the phase plane. However, it fails to converge in the region where the model has only complex solutions. Similar analysis and results are obtained using analytical solutions within the mean spherical approximation for the hardcore Yukawa potential. However, numerical results indicate that the expansion converges in all regions in this model. Next, the convergence of the expansion is analyzed for the Lennard-Jones potential by using an accurate density-dependent bridge function in the closure relation. Numerical results are presented which show convergence of correlation functions, compressibility versus density profiles, etc., in the single as well as two-phase regions. Computed liquid-vapor phase diagrams, using two independent schemes employing the converged profiles, compare excellently with simulation data. The results obtained for the generalized Lennard-Jones potential, with varying repulsive exponent, also compare well with the simulation data. Solution-spaces and the bifurcation of the solutions of the Ornstein–Zernike equation that are relevant to coupling-parameter expansion are also briefly discussed. All of these results taken together establish the coupling-parameter expansion as a practical tool for studying single component fluid phases modeled via general pair-potentials.

36

Sarkar, J. "Performance characteristics of natural-refrigerants- based ejector expansion refrigeration cycles." Proceedings of the Institution of Mechanical Engineers, Part A: Journal of Power and Energy 223, no. 5 (May 22, 2009): 543–50. http://dx.doi.org/10.1243/09576509jpe753.

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The thermodynamic analyses and comparison of three natural-refrigerants-based vapour compression refrigeration cycles (ammonia, isobutane, and propane) are presented in this article using a constant pressure mixing ejector as an expansion device. Optimization of the area ratio of the ejector is done based on maximum cooling coefficient of performance (COP) and performance improvement for different operating conditions. The effect of using an internal heat exchanger is studied as well. Results show that optimum area ratio and cooling COP increases with a decrease in cycle temperature lift, whereas the COP improvement over basic expansion cycle increases with the increase in cycle temperature lift. Study shows that the optimum parameters, as well as performance using the ejector as an expansion device, are strongly dependent on the refrigerant properties as well as the operating conditions. The optimum area ratio is maximum for ammonia and minimum for propane, whereas maximum cooling COPs are similar. Using the ejector as an expansion device, propane yields a maximum COP improvement of 26.1 per cent followed by isobutane (22.8 per cent) and ammonia (11.7 per cent) for studies ranges. The effect of using an internal heat exchanger in the ejector expansion refrigeration cycle is found to be not profitable.

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Hill, P. G., K. Miyagawa, and J. D. Denton. "Fast and accurate inclusion of steam properties in two- and three-dimensional steam turbine flow calculations." Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 214, no. 7 (July 1, 2000): 903–19. http://dx.doi.org/10.1243/0954406001523146.

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The Denton time-marching method for turbomachinery flow calculation has been modified for rapid and accurate access to the properties of steam in equilibrium dry and wet states and in the metastable dry region. Transition between metastable dry and equilibrium wet states is accomplished either at the stable equilibrium boundary or by allowing metastable equilibrium expansion followed by a condensation shock whose location depends on the local degree of subcooling of the metastable vapour and the local expansion rate. Steam properties and their derivatives are obtained from a wide-ranging Helmholtz representation of equilibrium (stable and metastable) thermodynamic properties and stored for use in an accurate Taylor series representation. Comparisons have been made of flow development in a low-pressure steam turbine blade row for three expansion assumptions: equilibrium stable and metastable dry, stable equilibrium, dry and wet, and dry expansion prior to a condensation ‘shock’ which is followed by equilibrium wet expansion. Inclusion of real steam properties extends calculation time for one iteration cycle by about 5 per cent and has little effect on the number of cycles required for convergence in the absence of a condensation shock; however, inclusion of the shock may double the time required for convergence.

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Richardson, R. N., and J. S. Butterworth. "A Novel Vapour-Compression Refrigeration Circuit Employing a Computer-Controlled Expansion Valve." International Journal of Mechanical Engineering Education 23, no. 1 (January 1995): 1–7. http://dx.doi.org/10.1177/030641909502300103.

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39

Igobo, Opubo N., and Philip A. Davies. "Review of low-temperature vapour power cycle engines with quasi-isothermal expansion." Energy 70 (June 2014): 22–34. http://dx.doi.org/10.1016/j.energy.2014.03.123.

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40

You, Qinglong, Jinzhong Min, Shichang Kang, and Nick Pepin. "Poleward expansion of the tropical belt derived from upper tropospheric water vapour." International Journal of Climatology 35, no. 9 (August 12, 2014): 2237–42. http://dx.doi.org/10.1002/joc.4125.

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41

Kosowski, Krzysztof, and Marian Piwowarski. "Subcritical Thermodynamic Cycles with Organic Medium and Isothermal Expansion." Energies 13, no. 17 (August 21, 2020): 4340. http://dx.doi.org/10.3390/en13174340.

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The efficiencies of the Organic Rankine Cycle (ORC) are not very high and only very seldom do they exceed 20%. The increase and optimization of initial parameters and certain modifications of the thermodynamic cycle make it possible to overcome these drawbacks. A new modified cycle has been described and analyzed in detail in the paper. Similarly to the Ericsson cycle for gas turbines, isothermal expansion in the turbine is suggested for the power plant with organic media. The new cycle and the typical ORC power plants have the same block diagram. The only difference is that expansion in the proposed cycle occurs not adiabatically but as an isothermal process. The thermodynamic calculations have been carried out for 11 various fluids and 4 different cycles. The obtained results have clearly shown that cycles with isothermal expansion (isothermal turbines) are characterized by remarkably higher efficiency than typical power plants with adiabatic turbines. The increase in efficiency varies from 6 to 12 percent points for cycles with saturated live vapor and from 4 to 7 percent points for cycles with superheated live vapor. The performed analyses have shown that it is possible to achieve a very high efficiency (over 45%) of organic cycle, which is a very competitive value. In such cases the proposed power plants can achieve an efficiency which is higher than that of modern steam turbine plants with supercritical parameters.

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CHENG, WAN, XISHENG LUO, and M. E. H. van DONGEN. "On condensation-induced waves." Journal of Fluid Mechanics 651 (March 24, 2010): 145–64. http://dx.doi.org/10.1017/s0022112009993879.

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Complex wave patterns caused by unsteady heat release due to cloud formation in confined compressible flows are discussed. Two detailed numerical studies of condensation-induced waves are carried out. First, the response of a flow of nitrogen in a slender Laval nozzle to a sudden addition of water vapour at the nozzle entrance is considered. Condensation occurs just downstream of the nozzle throat, which initially leads to upstream- and downstream-moving shocks and an expansion fan downstream of the condensation front. Then, the flow becomes oscillatory and the expansion fan disappears, while upstream and much weaker downstream shocks are repeatedly generated. For a lower initial humidity, only a downstream starting shock is formed and a steady flow is established. Second, homogeneous condensation in an unsteady expansion fan in humid nitrogen is considered. In the initial phase, two condensation-induced shocks are found, moving upstream and downstream. The upstream-moving shock changes the shape of the expansion fan and has a strong influence on the condensation process itself. It is even quenching the nucleation process locally, which leads to a renewed condensation process more downstream. This process is repeated with asymptotically decreasing strength. The repeated interaction of the condensation-induced shocks with the main expansion wave leads to a distortion of the expansion wave towards its shape that can be expected on the basis of phase equilibrium, i.e. a self-similar wave structure consisting of dry part, a plateau of constant state and a wet part. The strengths of the condensation-induced waves, as well for the Laval nozzle flow as for the expansion fan, appear to be in qualitative agreement with the results from the analytical Rayleigh–Bartlmä model.

43

Kronberg, Alexander, Maxim Glushenkov, Sander Roosjen, and Sascha Kersten. "Isobaric Expansion Engine Compressors: Thermodynamic Analysis of the Simplest Direct Vapor-Driven Compressors." Energies 15, no. 14 (July 9, 2022): 5028. http://dx.doi.org/10.3390/en15145028.

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Isobaric expansion (IE) technology is a promising solution for mini- and medium-scale low-grade heat utilization. IE engines directly convert heat to mechanical energy and are particularly interesting as direct-acting, vapor-driven pumps and compressors. The elimination of multiple energy transformations, technical simplicity and the ability to use widely available low-grade heat (<100 °C) instead of fossil fuels are attractive features of this technology. The purpose of this paper was to present a new compression technology based on IE Worthington type engines, analyze the process analytically and numerically, and provide a first assessment of its potential. The simplest single- and double-acting schemes were considered for arbitrary low and high pressures of the compressed gas/vapor and driving vapor. In these schemes, the compressor piston was rigidly connected to that of an engine/driver. The vapor use efficiency of the driver process was characterized by the ratio of the network carried out in the cycle to the consumed mass of the driving vapor. The performed thermodynamic analysis showed how the vapor use efficiency depends on the process parameters. It was found that the efficiency of vapor use in the simplest schemes was low in comparison with the efficiency in pumps if the compressor work was much less than the pump work at the same pressure ratio. This occurred because the energy of the driving vapor was spent on the compression of the vapor itself. As a result, the thermal efficiency of the IE engine compressors was lower than that of the IE engine pumps. The difference was very large if the work of the engine feed pump was significant and no heat regeneration is applied. The results obtained are very useful for achieving improvements in this interesting technology, which will be reported in subsequent publications.

44

Gracie, A. J., and P. H. Brown. "Effects of climatic factors, fluctuating water availability and partial defoliation on the diurnal radial growth pattern of carrot (Daucus carota) taproots." Australian Journal of Experimental Agriculture 44, no. 12 (2004): 1231. http://dx.doi.org/10.1071/ea03040.

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Carrot taproots are prone to radial longitudinal tissue fractures (splitting). The longitudinal alignment of the fractures is consistent with the tangential stress induced by radial growth in the annular cambium. In this study linear variable differential transformers were used to monitor the diurnal radial growth pattern of mature carrot taproots. The diurnal growth pattern was characterised by rapid expansion during the night (dark) period and small shrinkage during the light period. The magnitude of the daily shrinkage was positively correlated with both vapour pressure deficit and global radiation. A positive correlation between the rate of taproot expansion during the night period and global radiation level the preceding day was also recorded. Water stress reduced the taproot night time expansion rate, but the taproot of water stressed plants expanded rapidly when watered to field capacity. Partial defoliation of plants at midday resulted in immediate expansion of the taproot, however, the daily growth rates of the partially defoliated plants was less than untreated control plants over the following 3 days. It was concluded that the short-term changes in taproot diameter could be used to infer changes in tangential stresses and therefore taproot splitting propensity.

45

Zhalehrajabi, Ehsan, and Nejat Rahmanian. "Nucleation and Condensation Modeling of Metal Vapor in Laval Nozzle." Advanced Materials Research 925 (April 2014): 185–89. http://dx.doi.org/10.4028/www.scientific.net/amr.925.185.

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Nucleation and condensation of mercury vapor has been investigated in various divergent angle and operating condition. Divergent angle has a great effect on droplet size at the end of nozzle. Influence of operating condition such as pressure and temperature on the size of droplet has been investigated. A one-dimensional mathematical model based on classical nucleation and growth has been developed to calculate the nucleation and condensation of mercury vapor. A mercury vapour turbine has been used in conjunction with a steam turbine for generating electricity. The mercury cycle offers an efficiency increase compared to a steam-only cycle because energy can be injected into the Rankine Cycle at higher temperature. The target of modeling is predicting the droplet size of mercury nanoparticles during rapid expansion. The results are verified by accurate experimental data available in the literature. The governing equations were solved using Runge-Kutta third-order numerical method in MATLAB software.

46

Habibova, N. "ANALYSIS OF LOW-TEMPERATURE EXPANSION PROCESSES OF NON-IDEAL GASES." East European Scientific Journal 2, no. 11(75) (December 16, 2021): 53–63. http://dx.doi.org/10.31618/essa.2782-1994.2021.2.75.161.

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An energy analysis of the processes of obtaining and using artificial cold in chemical technology is presented. The most well-known methods of obtaining and applying the cooling effect are considered: adiabatic expansion of vapor and gaseous bodies in expanders, throttling. Special attention is paid to the effect of object deviation from the ideal gas model.

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Pickrell, D. J., K. A. Kline, and R. E. Taylor. "Thermal expansion of polycrystalline diamond produced by chemical vapor deposition." Applied Physics Letters 64, no. 18 (May 2, 1994): 2353–55. http://dx.doi.org/10.1063/1.111612.

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48

K. Muthukumarappan and S. Gunasekaran. "VAPOR DIFFUSIVITY AND HYGROSCOPIC EXPANSION OF CORN KERNELS DURING ADSORPTION." Transactions of the ASAE 33, no. 5 (1990): 1637. http://dx.doi.org/10.13031/2013.31520.

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49

Kadono, Toshihiko, Akira Fujiwara, and Akiko M. Nakamura. "Measurement of expansion velocity of an impact-generated vapor cloud." Geophysical Research Letters 20, no. 15 (August 6, 1993): 1595–98. http://dx.doi.org/10.1029/93gl01255.

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50

Sumeru, Kasni, Luga Martin, Farid Nasir Ani, Henry Nasution, and Farid Nasir Ani. "Energy Savings in Air Conditioning System Using Ejector: An Overview." Applied Mechanics and Materials 493 (January 2014): 93–98. http://dx.doi.org/10.4028/www.scientific.net/amm.493.93.

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There are two ejector configurations described in the present study: ejector refrigeration cycle and the ejector as an expansion device. The use of waste heat from the car engine and industry as a heat-driven energy for air conditioning system in automobile and building can save energy. Although the ejector refrigeration cycle has a low COP, the use of waste heat as a heat-driven energy incurs a lower operational cost compared with vapor compression refrigeration system. In addition, an ejector as an expansion device can be applied in the vapor compression refrigeration cycle to improve the performance system.

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