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1
Claramunt, Sara, Florian Völker, Uta Gerhards, Manfred Kraut, and Roland Dittmeyer. "Membranes for the Gas/Liquid Phase Separation at Elevated Temperatures: Characterization of the Liquid Entry Pressure." Membranes 11, no. 12 (November 23, 2021): 907. http://dx.doi.org/10.3390/membranes11120907.
Повний текст джерелаАнотація:
Hydrophobic membranes were characterized at elevated temperatures. Pressure was applied at the feed and permeate side to ensure liquid phase conditions. Within this scope, the applicability of different polymeric and ceramic membranes in terms of liquid entry pressure was studied using water. The Visual Method and the Pressure Step Method were applied for the experimental investigation. The results show the Pressure Step Method to be an early detection method. The tests at higher pressure and temperature conditions using the Pressure Step Method revealed the temperature as being the main factor affecting the liquid entry pressure. Novel LEP data up to 120 °C and 2.5 bar were obtained, which broadens the application range of hydrophobic membranes.
2
Yazgan-Birgi, Pelin, Mohamed I. Hassan Ali, and Hassan A. Arafat. "Estimation of liquid entry pressure in hydrophobic membranes using CFD tools." Journal of Membrane Science 552 (April 2018): 68–76. http://dx.doi.org/10.1016/j.memsci.2018.01.061.
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3
Matsumura, Kunihito, and Fumito Kaminaga. "Experimental Investigation of Rising Gas Bubble Characteristics from a Vertical Tube under CCFL Condition." Science and Technology of Nuclear Installations 2012 (2012): 1–15. http://dx.doi.org/10.1155/2012/785157.
Повний текст джерелаАнотація:
This paper describes an experimental study of gas/liquid countercurrent flow in a vertical circular tube. CCFL experiments were carried out with three different water levels in the upper plenum, two different tube diameters. Measurements were made for liquid and gas flow rates, time variations of pressure at locations of the upper entry of the tube and lower plenum. Visual observations were also conducted to investigate the relationship between rising gas bubble characteristics and time variation of gas pressure at the upper entry of the tube. The results indicate that one bubble formation cycle (e.g., bubble growth, expansion, and detachment into the water pool) corresponds to one pressure fluctuation cycle. For the 20 mm diameter tube, it was confirmed that there was a characteristic waiting time between bubble cycles in which no bubble was formed at the upper entry of the tube. The waiting time is a favorable time for a liquid introduction into the tube from the upper plenum. The bubble volumes are compared with existing bubble formation correlations.
4
Park, Chansoo, Dongsoo Shin, Chang-Kyu Lee, Yong-Soo Lee, and Jong-Oh Kim. "Theoretical and experimental approaches of liquid entry pressure determination in membrane distillation processes." DESALINATION AND WATER TREATMENT 99 (2017): 172–76. http://dx.doi.org/10.5004/dwt.2017.21653.
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5
Rácz, Gábor, Steffen Kerker, Zoltán Kovács, Gyula Vatai, Mehrdad Ebrahimi, and Peter Czermak. "Theoretical and Experimental Approaches of Liquid Entry Pressure Determination in Membrane Distillation Processes." Periodica Polytechnica Chemical Engineering 58, no. 2 (2014): 81–91. http://dx.doi.org/10.3311/ppch.2179.
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6
Chamani, Hooman, Pelin Yazgan-Birgi, Takeshi Matsuura, Dipak Rana, Mohamed I. Hassan Ali, Hassan A. Arafat, and Christopher Q. Lan. "CFD-based genetic programming model for liquid entry pressure estimation of hydrophobic membranes." Desalination 476 (February 2020): 114231. http://dx.doi.org/10.1016/j.desal.2019.114231.
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7
FALTINSEN, ODD M., and YURIY A. SEMENOV. "Nonlinear problem of flat-plate entry into an incompressible liquid." Journal of Fluid Mechanics 611 (September 25, 2008): 151–73. http://dx.doi.org/10.1017/s0022112008002735.
Повний текст джерелаАнотація:
The self-similar flow and free-surface shape induced by a flat plate entering an inviscid and incompressible liquid are investigated for arbitrary initial conditions. An analytical solution, which is based on two governing expressions, namely the complex velocity and the derivative of the complex potential, is obtained. These expressions are derived in an auxiliary parameter plane using integral formulae proposed for the determination of an analytical function from its modulus and argument given on the boundary of the parameter region. We derive a system of an integral and an integro-differential equation in terms of the velocity modulus and the velocity angle at the free surface, which are determined by the dynamic and kinematic boundary conditions. A numerical procedure for solving these equations is carefully validated by comparisons with results available in the literature. The results are presented in terms of the free surface shape, the angles at the tip of the splash jet, the contact angles at the intersection with the plate surface, pressure distribution and force coefficients. New features caused by the flow unsteadiness are found and discussed.
8
Wang, Yajun, Jun Yang, Manchao He, Xichun Tian, Jianning Liu, Haojie Xue, and Ruifeng Huang. "Test of a liquid directional roof-cutting technology for pressure-relief entry retaining mining." Journal of Geophysics and Engineering 16, no. 3 (June 1, 2019): 620–38. http://dx.doi.org/10.1093/jge/gxz041.
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9
Racz, Gabor, Steffen Kerker, Oliver Schmitz, Benjamin Schnabel, Zoltan Kovacs, Gyula Vatai, Mehrdad Ebrahimi, and Peter Czermak. "Experimental determination of liquid entry pressure (LEP) in vacuum membrane distillation for oily wastewaters." Membrane Water Treatment 6, no. 3 (May 25, 2015): 237–49. http://dx.doi.org/10.12989/mwt.2015.6.3.237.
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10
García-Payo, M. C., M. A. Izquierdo-Gil, and C. Fernández-Pineda. "Wetting Study of Hydrophobic Membranes via Liquid Entry Pressure Measurements with Aqueous Alcohol Solutions." Journal of Colloid and Interface Science 230, no. 2 (October 2000): 420–31. http://dx.doi.org/10.1006/jcis.2000.7106.
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11
Marston, J. O., T. T. Truscott, N. B. Speirs, M. M. Mansoor, and S. T. Thoroddsen. "Crown sealing and buckling instability during water entry of spheres." Journal of Fluid Mechanics 794 (April 5, 2016): 506–29. http://dx.doi.org/10.1017/jfm.2016.165.
Повний текст джерелаАнотація:
We present new observations from an experimental investigation of the classical problem of the crown splash and sealing phenomena observed during the impact of spheres onto quiescent liquid pools. In the experiments, a 6 m tall vacuum chamber was used to provide the required ambient conditions from atmospheric pressure down to $1/16\text{th}$ of an atmosphere, whilst high-speed videography was exploited to focus primarily on the above-surface crown formation and ensuing dynamics, paying particular attention to the moments just prior to the surface seal. In doing so, we have observed a buckling-type azimuthal instability of the crown. This instability is characterised by vertical striations along the crown, between which thin films form that are more susceptible to the air flow and thus are drawn into the closing cavity, where they atomize to form a fine spray within the cavity. To elucidate to the primary mechanisms and forces at play, we varied the sphere diameter, liquid properties and ambient pressure. Furthermore, a comparison between the entry of room-temperature spheres, where the contact line pins around the equator, and Leidenfrost spheres (i.e. an immersed superheated sphere encompassed by a vapour layer), where there is no contact line, indicates that the buckling instability appears in all crown sealing events, but is intensified by the presence of a pinned contact line.
12
Needham, D., та R. M. Hochmuth. "Rapid Flow of Passive Neutrophils Into a 4 μm Pipet and Measurement of Cytoplasmic Viscosity". Journal of Biomechanical Engineering 112, № 3 (1 серпня 1990): 269–76. http://dx.doi.org/10.1115/1.2891184.
Повний текст джерелаАнотація:
Neutrophils from five different individuals are isolated with a density separation technique. A total of 151 unactivated (passive) cells are rapidly aspirated at constant suction pressure and at room temperature into a pipet with a diameter of 4 μm. The suction pressures in excess of an initial yield threshold are 0.5, 1 and 2 kPa and are comparable to those encountered in the microcirculation. These pressures are well in excess of the small suction pressure of ~ 20 Pa that is required to form a static hemispherical bump on the cell. At a given aspiration pressure, the leading edge of an individual cell is “tracked” as it flows into the pipet. A theory based on the flow of a Newtonian liquid from either a hemisphere or a spherical segment into a cylinder is used to model the entry process. Both theory and experiment show that during most of the entry process the leading edge of the cell moves at a nearly constant velocity with a rapid acceleration at the end. For cells from five different individuals at the three different excess aspiration pressures, Newtonian theory gives a cytoplasmic viscosity of 135 ± 54 Pa·s and overall entry times of 3.3s (0.5 kPa), 1.6s (1 kPa) and 0.82s (2 kPa). These results and those of Evans and Yeung at lower aspiration pressures indicate that the complex cytoplasm inside unactivated neutrophils behaves as a nearly Newtonian fluid with a viscosity on the order of 102 Pa·s over almost a two order of magnitude range in aspiration pressure and, thus, rate of deformation.
13
Xie, Shengrong, Yiyi Wu, Fangfang Guo, Hang Zou, Dongdong Chen, Xiao Zhang, Xiang Ma, Ruipeng Liu, and Chaowen Wu. "Application of Pre-Splitting and Roof-Cutting Control Technology in Coal Mining: A Review of Technology." Energies 15, no. 17 (September 5, 2022): 6489. http://dx.doi.org/10.3390/en15176489.
Повний текст джерелаАнотація:
According to the development requirements of green mining of coal resources, it is imperative to improve the extraction rate of coal and the application of safe and efficient mining technology. Pre-splitting and roof cutting technology is widely used in reducing residual coal pillars and safe pressure relief mining, which has become the crucial technology for pillar-free mining methods. Therefore, it is essential to review and discuss the research hotspots, cutting-edge methods, principles of action, and application areas of the development of this technology. Above all, the research data on pre-splitting and roof-cutting development in the past ten years are summarized and outlined. The research’s hot spots are pressure relief technology and gob-side entry retaining technology. Then, the functional forms of pre-splitting and roof cutting technology are discussed and compared, including explosive blasting (directional energy gathering blasting, liquid explosive blasting, and composite blasting), hydraulic fracturing, liquid CO2 gas fracturing, and mechanized roof cutting (chain arm saw machine and directional cutting roof rig). Through the analysis of field application cases, the application field is divided into three major areas: non-coal pillar mining (gob-side entry driving with narrow coal pillar, gob-side entry retaining with the filling body, completely gob-side entry retaining, and “N00” construction method), pressure relief at working face (thick and hard main roof cracking and end area hard roof cracking), and pressure relief at roadway (gob-side roadway pressure relief and blasting pressure relief technology for roadways). By detailing the process of each application technology one by one, the principle and mode of pre-splitting in each technology are expounded. Finally, the development prospects of pre-splitting and roof cutting in new technical methods, deep pressure relief mining, intelligent unmanned mining, and green and efficient mining are prospected, providing references for similar projects.
14
Moore, M. R., S. D. Howison, J. R. Ockendon, and J. M. Oliver. "Three-dimensional oblique water-entry problems at small deadrise angles." Journal of Fluid Mechanics 711 (September 19, 2012): 259–80. http://dx.doi.org/10.1017/jfm.2012.391.
Повний текст джерелаАнотація:
AbstractThis paper extends Wagner theory for the ideal, incompressible normal impact of rigid bodies that are nearly parallel to the surface of a liquid half-space. The impactors considered are three-dimensional and have an oblique impact velocity. A formulation in terms of the displacement potential is used to reveal the relationship between the oblique and corresponding normal impact solutions. In the case of axisymmetric impactors, several geometries are considered in which singularities develop in the boundary of the effective wetted region. We present the corresponding pressure profiles and models for the splash sheets.
15
Silva, Regilene de Sousa, Heloisa Ramlow, Bianca de Castro Santos, Heloísa Bremm Madalosso, Ricardo Antonio Francisco Machado, and Cintia Marangoni. "Membrane Distillation: Experimental evaluation of Liquid Entry Pressure in commercial membranes with textile dye solutions." Journal of Water Process Engineering 44 (December 2021): 102339. http://dx.doi.org/10.1016/j.jwpe.2021.102339.
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16
Tipnis, Neelesh A., Jianmin Liu, James L. Puckett, and Ravinder K. Mittal. "Common cavity pressure during gastroesophageal reflux: reassessment using simultaneous pressure, impedance, and ultrasound imaging." American Journal of Physiology-Gastrointestinal and Liver Physiology 290, no. 6 (June 2006): G1149—G1156. http://dx.doi.org/10.1152/ajpgi.00361.2005.
Повний текст джерелаАнотація:
An increase in intraesophageal pressure during transient lower esophageal sphincter (LES) relaxation [referred to as common cavity (CC) pressure] is thought to be a marker of gastroesophageal reflux (GER). Multiluminal impedance (MII) measurement is a sensitive marker of reflux entry into the esophagus during GER. We recorded GER using esophageal pressure, pH, impedance, and intraluminal ultrasound (US) images to understand the genesis of the esophageal CC pressure. Nine normal subjects underwent simultaneous MII/pH/pressure and US image recording of the esophagus for 2 h following a standardized meal. MII and pressure transducers were located at 5 and 15 cm above the LES. The US transducer and pH sensors were also placed at 5 cm above the LES. Refluxate entry into the esophagus by MII criteria was determined relative to the onset of CC pressure wave. Esophageal lumen cross-sectional area (CSA) and muscle CSA during GER were determined from the US images. Eighty liquid GER episodes identified using MII criteria, of which 55 were clearly associated with CC pressure waves, were analyzed. The GER reached 15 cm above LES in 49 of 55 (89%) by MII criteria, but the CC pressure wave was observed at 5 and 15 cm during all episodes. The propagation of the CC pressure wave was simultaneous between 5 and 15 cm during 49 of 55 (89%) of the GER episodes, but reflux entry by MII criteria was retrograde during 53 of 55 (96%) of these episodes. During 5 air-reflux episodes, MII showed a simultaneous reflux entry between the 5- and 15-cm site, however, the CC pressure preceded reflux entry during all of these episodes. There was poor correlation between the luminal CSA and the magnitude of CC pressure ( R2 = 0.144). US images revealed a close temporal correlation between CC pressure and the increase in esophageal muscle thickness and muscle CSA (markers of longitudinal muscle contraction). Disassociation between CC pressure and MII-detected reflux suggests that the onset of CC pressure is not due to GER. We speculate that longitudinal muscle contraction plays an important role in the genesis of CC pressure.
17
Mu, Qing, Yipin Lv, Kangjian Wang, Tianhong Xiong, and Wenjun Yi. "Numerical Simulation on the Cavitation Flow of High Speed Oblique Water Entry of Revolution Body." Mathematical Problems in Engineering 2019 (January 17, 2019): 1–10. http://dx.doi.org/10.1155/2019/8034619.
Повний текст джерелаАнотація:
To explore the effects of water entry angle on the cavitation flow field of high-speed revolution body, based on the finite volume method, VOF (Volume of Fluid) multiphase model, Schnerr-Sauer cavity model, SST k-ω turbulence model, and dynamic mesh method, numerical simulation for modeling the oblique water entry of revolution body at high speed is performed. The evolution laws of cavity shape, motion characteristics, and hydrodynamic characteristics of revolution body at different water entry angles are analyzed. The results show that the numerical calculation method can effectively simulate the change of cavity shape during the water entry of the revolution body. With the increase of water entry angle, the uplift of liquid level decreases in the positive direction of the open cavity and increases in the negative direction. The angle of water entry has little effect on the velocity of the revolution body. The larger the angle of water entry, the greater the peak pressure and the faster the pressure decay at the moment of water entry.
18
Hurd, Randy C., Jesse Belden, Michael A. Jandron, D. Tate Fanning, Allan F. Bower, and Tadd T. Truscott. "Water entry of deformable spheres." Journal of Fluid Mechanics 824 (July 14, 2017): 912–30. http://dx.doi.org/10.1017/jfm.2017.365.
Повний текст джерелаАнотація:
When a rigid body collides with a liquid surface with sufficient velocity, it creates a splash curtain above the surface and entrains air behind the sphere, creating a cavity below the surface. While cavity dynamics has been studied for over a century, this work focuses on the water entry characteristics of deformable elastomeric spheres, which has not been studied. Upon free surface impact, an elastomeric sphere deforms significantly, giving rise to large-scale material oscillations within the sphere resulting in unique nested cavities. We study these phenomena experimentally with high-speed imaging and image processing techniques. The water entry behaviour of deformable spheres differs from rigid spheres because of the pronounced deformation caused at impact as well as the subsequent material vibration. Our results show that this deformation and vibration can be predicted from material properties and impact conditions. Additionally, by accounting for the sphere deformation in an effective diameter term, we recover previously reported characteristics for time to cavity pinch off and hydrodynamic force coefficients for rigid spheres. Our results also show that velocity change over the first oscillation period scales with the dimensionless ratio of material shear modulus to impact hydrodynamic pressure. Therefore, we are able to describe the water entry characteristics of deformable spheres in terms of material properties and impact conditions.
19
Min, Ji Hee, Min Soo Park, and Jinho Kim. "Measurement of Liquid Entry Pressure of PE and PVDF Hollow Fiber Membranes in Membrane Distillation Process." Membrane Journal 25, no. 3 (June 30, 2015): 216–22. http://dx.doi.org/10.14579/membrane_journal.2015.25.3.216.
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20
Wang, Ke, Hailiang Hou, Dian Li, and Yongqing Li. "Study on the Penetration Characteristics of Water Entry Rod Projectile into Liquid Cabin at an Attack Angle." Applied Sciences 12, no. 20 (October 11, 2022): 10213. http://dx.doi.org/10.3390/app122010213.
Повний текст джерелаАнотація:
The penetration of a projectile into a warship broadside liquid cabin is usually a non-ideal penetration process. To explore the protective effects of the broadside liquid cabin of a large warship against the non-ideal penetration of rod projectiles and to provide reference for the design of new liquid cabin structures, ballistic impact tests of rod projectiles penetrating the liquid cabin at different attack angles were carried out. Combined with numerical calculation, the impact of the attack angle on the water entry and penetration characteristics of the projectile into the liquid cabin as well as their failure modes were studied. The overturning and yawing of the projectile in water were analyzed. The pressure load characteristics in the liquid cabin and the deformation/failure modes of the projectile and the liquid cabin were identified. The results showed that: multiple overturning and yawing occur in the projectile with an initial attack angle during penetration into liquid; the yaw direction is mainly affected by the initial attack angle and projectile attitude; the projectile mainly undergoes four basic failure modes, namely, asymmetric mushrooming at the projectile nose, side erosion, overall plastic bending and fracture; the actual failure of the projectile is a combination of the basic failure modes; the overall plastic bending and fracture are mainly related to the length to diameter ratio, initial attack angle and initial projectile velocity; the front plate of the liquid cabin may undergo tearing along the central plastic hinge line of the plate: at a small attack angle, the tear is “I” shaped, and at a large attack angle, it is “X”-shaped.
21
Jäger, Tobias, Athanasios Mokos, Nikolaos I. Prasianakis, and Stephan Leyer. "Pore-Level Multiphase Simulations of Realistic Distillation Membranes for Water Desalination." Membranes 12, no. 11 (November 8, 2022): 1112. http://dx.doi.org/10.3390/membranes12111112.
Повний текст джерелаАнотація:
Membrane distillation (MD) is a thermally driven separation process that is operated below boiling point. Since the performance of MD modules is still comparatively low, current research aims to improve the understanding of the membrane structure and its underlying mechanisms at the pore level. Based on existing realistic 3D membrane geometries (up to 0.5 billion voxels with 39nm resolution) obtained from ptychographic X-ray computed tomography, the D3Q27 lattice Boltzmann (LB) method was used to investigate the interaction of the liquid and gaseous phase with the porous membrane material. In particular, the Shan and Chen multi-phase model was used to simulate multi-phase flow at the pore level. We investigated the liquid entry pressure of different membrane samples and analysed the influence of different micropillar structures on the Wenzel and Cassie–Baxter state of water droplets on rough hydrophobic surfaces. Moreover, we calculated the liquid entry pressure required for entering the membrane pores and extracted realistic water contact surfaces for different membrane samples. The influence of the micropillars and flow on the water-membrane contact surface was investigated. Finally, we determined the air–water interface within a partially saturated membrane, finding that the droplet size and distribution correlated with the porosity of the membrane.
22
Puig Montellà, Eduard, Chao Yuan, Bruno Chareyre, and Antonio Gens. "Modeling multiphase flow with a hybrid model based on the Pore-network and the lattice Boltzmann method." E3S Web of Conferences 195 (2020): 02009. http://dx.doi.org/10.1051/e3sconf/202019502009.
Повний текст джерелаАнотація:
Lattice Boltzmann method (LBM) simulations provide an excellent description of two-phase flow through porous media. However, such simulations require a significant computation time. In order to optimize the computation resources, we propose a hybrid model that combines the efficiency of the pore-network approach and the accuracy of the lattice Boltzmann method at the pore scale. The hybrid model is based on the decomposition of the granular assembly into small subsets, in which LBM simulations are performed to determine the main hydrostatic properties (entry capillary pressure, capillary pressure - liquid content relationship and liquid morphology for each pore throat). A primary drainage of a random packing of spheres is presented and contrasted to the results of the same problem fully resolved by the LBM. Liquid morphology and invasion paths are correctly reproduced by the hybrid method.
23
OLIVER, J. M. "Second-order Wagner theory for two-dimensional water-entry problems at small deadrise angles." Journal of Fluid Mechanics 572 (January 23, 2007): 59–85. http://dx.doi.org/10.1017/s002211200600276x.
Повний текст джерелаАнотація:
The theory of Wagner from 1932 for the normal symmetric impact of a two-dimensional body of small deadrise angle on a half-space of ideal and incompressible liquid is extended to derive the second-order corrections for the locations of the higher-pressure jet-root regions and for the upward force on the impactor using a systematic matched-asymptotic analysis. The second-order predictions for the upward force on an entering wedge and parabola are compared with numerical and experimental data, respectively, and it is concluded that a significant improvement in the predictive capability of Wagner's theory is afforded by proceeding to second order.
24
Yeszhanov, A. B. "HYDROPHOBIZATION OF PET TRACK-ETCHED MEMBRANES FOR DIRECT CONTACT MEMBRANE DISTILLATION OF LIQUID RADIOACTIVE WASTES." Eurasian Physical Technical Journal 17, no. 2 (December 24, 2020): 45–54. http://dx.doi.org/10.31489/2020no2/45-54.
Повний текст джерелаАнотація:
This article provides the results of liquid low-level radioactive wastes treatment by direct contact membrane distillation using polyethylene terephthalate hydrophobic track-etched membranes. The hydrophobization of track-etched membranes was carried out by UV-induced graft polymerization of triethoxyvinylsilane with styrene and coating with fluorine-containing silanes. Hydrophobic membranes were investigated by scanning electron microscope, Fourier-transform infrared spectroscopy, contact anglemeasurements, and liquid entry pressure analysis. Prepared membranes were tested in treatment of liquid low-level radioactive wastes by membrane distillation. The influence of pore sizes on water flux and rejection degree was studied. Rejection degree was evaluated by conductometry and atomic emission method. Decontamination factors evaluated by gamma-ray spectroscopy for 60Co, 137Cs, and 241Am are 85.4, 1900 and 5.4 for membranes modified with polystyrene and triethoxyvinylsilanewith pore diameters of 142 nm; 85.0, 1462 and 4 for membranes modified with perfluorododecyltrichlorosilanewith pore diameters of 150 nm respectively.
25
Ahmadpour, M. R., and A. Mansourizadeh. "Hydrophobic Modification of Polyetherimide Hollow Fiber Membrane Contactor by 2-(Perfluoroalkyl) Ethanol Coating for Carbon Dioxide Absorption." Journal of Applied Membrane Science & Technology 26, no. 3 (November 20, 2022): 65–76. http://dx.doi.org/10.11113/amst.v26n3.254.
Повний текст джерелаАнотація:
Highly porous polyether imide (PEI) hollow fiber membranes were fabricated through a phase-inversion process. Surface modification of the membranes was performed by coating an ultra-thin layer of 2-(perfluoroalkyl) ethanol (ZONYL). The properties of the prepared membranes were evaluated through field emission scanning electronic microscopy (FESEM), water contact angle, N2 permeation, overall porosity, critical water entry pressure (CEPw) and collapsing pressure experiments. From FESEM, the PEI membrane showed an open structure with large finger-likes cavities. By coating the ZONYL layer, the modified membrane presented improved outer surface water contact angle (105 °), CEPw (450 kPa), and collapsing pressure (750 kPa). The improved PEI-ZONYL membrane presented an almost stable CO2 absorption flux (6.8×10-4 mol/m2 s) during 72 h of the gas-liquid membrane contactor operation while a significant flux reduction was observed for the plain PEI membrane. Therefore, the improved membrane with high surface hydrophobicity and porosity can be a promising candidate for high performance gas-liquid membrane contactors.
26
McNeil, D. A. "Two-phase momentum flux in pipes and its application to incompressible flow in nozzles." Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 212, no. 7 (July 1, 1998): 631–40. http://dx.doi.org/10.1243/0954406981521592.
Повний текст джерелаАнотація:
The pressure drop produced when a single-phase gas or liquid flows through a nozzle can be reasonably well estimated from inviscid flow theory. A similarly based model, taking the slip with entrained liquid fraction approach, has been developed for two-phase gas—liquid flows. Fundamental to the model is the constraint that the nozzle flow depends on the entry conditions, particularly the momentum flux. At low qualities the tendency was for fractions of the liquid flow to be accelerated with the gas phase to maintain uniform momentum flux across the nozzle flow area. At higher qualities the gas core of the annular flow, along with its associated droplets, was found to contract with negligible interaction with the surrounding liquid film. The model has been compared with data sources and other models available in the literature and shown to perform well.
27
Park, Seung-Min, and Sangho Lee. "Influence of Hydraulic Pressure on Performance Deterioration of Direct Contact Membrane Distillation (DCMD) Process." Membranes 9, no. 3 (March 6, 2019): 37. http://dx.doi.org/10.3390/membranes9030037.
Повний текст джерелаАнотація:
Direct contact membrane distillation (DCMD) is a membrane distillation (MD) configuration where feed and distillate directly contact with a hydrophobic membrane. Depending on its operating conditions, the hydraulic pressures of the feed and distillate may be different, leading to adverse effects on the performance of the DCMD process. Nevertheless, little information is available on how hydraulic pressure affects the efficiency of DCMD. Accordingly, this paper investigates the effect of external hydraulic pressure on the process efficiency of DCMD. Gas permeabilities of MD membranes were measured to analyze the effect of membrane compaction by external pressure. Mass transfer coefficients were calculated using experimental data to quantitatively explain the pressure effect. Experiments were also carried out using a laboratory-scale DCMD set-up. After applying the pressure, the cross-sections and surfaces of the membranes were examined using a scanning electron microscope (SEM). Results showed that the membrane structural parameters such as porosity and thickness were changed under relatively high pressure conditions (>30 kPa), leading to reduction in flux. The mass transfer coefficients were also significantly influenced by the hydraulic pressure. Moreover, local wetting of the membranes were observed even below the liquid entry pressure (LEP), which decreased the rejection of salts. These results suggest that the control of hydraulic pressure is important for efficient operation of DCMD process.
28
Iafrati, A. "Experimental investigation of the water entry of a rectangular plate at high horizontal velocity." Journal of Fluid Mechanics 799 (June 28, 2016): 637–72. http://dx.doi.org/10.1017/jfm.2016.374.
Повний текст джерелаАнотація:
The water entry of a rectangular plate with a high horizontal velocity component is investigated experimentally. The test conditions are representative of those encountered by aircraft during emergency landing on water and are given in terms of three main parameters: horizontal velocity, approach angle, i.e. vertical to horizontal velocity ratio, and pitch angle. Experimental data are presented in terms of pressure, spray root shape, pressure peak propagation velocity and total loads acting on the plate. A theoretical solution of the plate entry problem based on two-dimensional and potential flow assumptions is derived and is used to support the interpretation of the experimental measurements. The results indicate that, as the plate penetrates and the ratio between the plate breadth and the wetted length measured on the longitudinal plane diminishes, the role of the third dimension becomes dominant. The increased possibility for the liquid to escape from the lateral sides yields a reduction of the pressure peak propagation velocity and, consequently, of the corresponding pressure peak intensity. In particular, it is shown that, at the beginning of the entry process, the pressure peak moves much faster than the geometric intersection between the body and the free surface, but at a later stage the two points move along the body at the same speed. Furthermore, it is shown that the spray root develops a curved shape which is almost independent of the specific test conditions, even though the initial growth rate of the curvature is higher for larger pitch angles. The loads follow a linear increase versus time, as predicted by the theoretical model, only in a short initial stage. Next, for all test conditions examined here, they approach a square-root dependence on time. It is seen that, if the loads are scaled by the square of the velocity component normal to the plate, the data are almost independent of the test conditions.
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Francis, Lijo, and Nidal Hilal. "Electrosprayed CNTs on Electrospun PVDF-Co-HFP Membrane for Robust Membrane Distillation." Nanomaterials 12, no. 23 (December 6, 2022): 4331. http://dx.doi.org/10.3390/nano12234331.
Повний текст джерелаАнотація:
In this investigation, the electrospraying of CNTs on an electrospun PVDF-Co-HFP membrane was carried out to fabricate robust membranes for the membrane distillation (MD) process. A CNT-modified PVDF-Co-HFP membrane was heat pressed and characterized for water contact angle, liquid entry pressure (LEP), pore size distribution, tensile strength, and surface morphology. A higher water contact angle, higher liquid entry pressure (LEP), and higher tensile strength were observed in the electrosprayed CNT-coated PVDF-Co-HFP membrane than in the pristine membrane. The MD process test was conducted at varying feed temperatures using a 3.5 wt. % simulated seawater feed solution. The CNT-modified membrane showed an enhancement in the temperature polarization coefficient (TPC) and water permeation flux up to 16% and 24.6%, respectively. Field-effect scanning electron microscopy (FESEM) images of the PVDF-Co-HFP and CNT-modified membranes were observed before and after the MD process. Energy dispersive spectroscopy (EDS) confirmed the presence of inorganic salt ions deposited on the membrane surface after the DCMD process. Permeate water quality and rejection of inorganic salt ions were quantitatively analyzed using ion chromatography (IC) and inductively coupled plasma-mass spectrometry (ICP-MS). The water permeation flux during the 24-h continuous DCMD operation remained constant with a >99.8% inorganic salt rejection.
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Mitani, Yuya, Takahiro Yano, Takuyoh Hagi, Keiko Watanabe, and Koji Fukudome. "High-Speed impact experiment for evaluation of magnetorheological fluid’s shock-absorption performance." EPJ Web of Conferences 183 (2018): 04008. http://dx.doi.org/10.1051/epjconf/201818304008.
Повний текст джерелаАнотація:
Magnetorheological (MR) fluids are categorized as smart fluids, which are made of small iron particles suspended in carrier fluids such as silicone oil. The presence of a magnetic field will instantaneously increase the viscosity of the MR fluid, also known as the MR effect. The application of the MR fluid as viscous dampers to automobiles and buildings has shown excellent performance in shock absorption. To expand the practical application of the MR fluid, various evaluations of shock-absorption performance under high-loading conditions are needed. Therefore, we decided to investigate its performance in high-speed impact conditions. Impact experiments were conducted in different liquids—tap water, two types of silicone oils with different kinematic viscosities, and an MR fluid—and it was investigated how the properties of each liquid affect the shock-absorption performance. Accordingly, it was found that kinematic viscosity and compressibility affect shock-absorption performance. The kinematic viscosity did not affect the speed attenuation of the projectile. Furthermore, it was found that the compressibility affected the pressure wave generated by the entry of a projectile into the liquid.
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Scolan, Y. M., and A. A. Korobkin. "Water entry of a body which moves in more than six degrees of freedom." Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences 471, no. 2177 (May 2015): 20150058. http://dx.doi.org/10.1098/rspa.2015.0058.
Повний текст джерелаАнотація:
The water entry of a three-dimensional smooth body into initially calm water is examined. The body can move freely in its 6 d.f. and may also change its shape over time. During the early stage of penetration, the shape of the body is approximated by a surface of double curvature and the radii of curvature may vary over time. Hydrodynamic loads are calculated by the Wagner theory. It is shown that the water entry problem with arbitrary kinematics of the body motion, can be reduced to the vertical entry problem with a modified vertical displacement of the body and an elliptic region of contact between the liquid and the body surface. Low pressure occurrence is determined; this occurrence can precede the appearance of cavitation effects. Hydrodynamic forces are analysed for a rigid ellipsoid entering the water with 3 d.f. Experimental results with an oblique impact of elliptic paraboloid confirm the theoretical findings. The theoretical developments are detailed in this paper, while an application of the model is described in electronic supplementary materials.
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Cherniuk, Volodymyr, Roman Hnativ, Oleksandr Kravchuk, Vadym Orel, Iryna Bihun, and Matvii Cherniuk. "The problem of hydraulic calculation of pressure distribution pipelines." Eastern-European Journal of Enterprise Technologies 6, no. 7 (114) (December 21, 2021): 93–103. http://dx.doi.org/10.15587/1729-4061.2021.246852.
Повний текст джерелаАнотація:
Most production technologies require a uniform flow path of liquid from pressure distribution pipelines. To achieve this goal, it is proposed to introduce polymer additives into the liquid flow or to use converging distribution pipelines with a continuous longitudinal slot in the wall. To reduce the uneven operation of the distribution pipeline during discrete liquid dispensing, it is proposed to use cylindrical output rotary nozzles with a lateral orthogonal entry of the jet into the nozzle. The problem is the lack of methods for accurate hydraulic calculation of the operation of distribution pipelines. Adequate calculation methods are based on differential equations. Finding the exact solution of the differential equation of fluid motion with variable path flow rate for perforated distribution pipelines is urgent, because it still does not exist. The available calculation methods take into account only the right angles of separation of the jets from the flow in the distribution pipeline. These methods are based on the assumption that the coefficient of hydraulic friction and the coefficient of resistance of the outlets are constant along the flow. A calculation method is proposed that takes into account the change in the values of these resistance coefficients along the distribution pipeline. The kinematic and physical characteristics of the flow outside the distribution pipeline are also taken into account. The accuracy of calculating the value of the flow rate of water distributed from the distribution pipeline has been experimentally verified. The error in calculating the water consumption by the method assuming that the values of the resistance coefficients are unchanged along the distribution pipeline reaches 18.75 %. According to the proposed calculation method, this error does not exceed 6.25 %. However, both methods are suitable for the design of pressure distribution pipelines, provided that the jet separation angles are straight. Taking into account the change from 90° to 360° of the angle of separation of the jets from the flow in the distribution pipeline will expand the scope and accuracy of calculation methods.
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Gervasoni, Jacopo, Andrea Cocci, Cecilia Zuppi, and Silvia Persichilli. "Total 25-Hydroxyvitamin D Determination by an Entry Level Triple Quadrupole Instrument: Comparison between Two Commercial Kits." BioMed Research International 2013 (2013): 1–5. http://dx.doi.org/10.1155/2013/270426.
Повний текст джерелаАнотація:
Objective. 25-hydroxyvitamin D2/D3(25-OHD2/D3) determination is a reliable biomarker for vitamin D status. Liquid chromatography-tandem mass spectrometry was recently proposed as a reference method for vitamin D status evaluation. The aim of this work is to compare two commercial kits (Chromsystems and PerkinElmer) for 25-OHD2/D3determination by our entry level LC-MS/MS.Design and Methods. Chromsystems kit adds an online trap column to an HPLC column and provides atmospheric pressure chemical ionization, isotopically labeled internal standard, and 4 calibrator points. PerkinElmer kit uses a solvent extraction and protein precipitation method. This kit can be used with or without derivatization with, respectively, electrospray and atmospheric pressure chemical ionization. For each analyte, there are isotopically labeled internal standards and 7 deuterated calibrator points.Results. Performance characteristics are acceptable for both methods. Mean bias between methods calculated on 70 samples was 1.9 ng/mL. Linear regression analysis gave anR2of 0.94. 25-OHD2is detectable only with PerkinElmer kit in derivatized assay option.Conclusion. Both methods are suitable for routine. Chromsystems kit minimizes manual sample preparation, requiring only protein precipitation, but, with our system, 25-OHD2is not detectable. PerkinElmer kit without derivatization does not guarantee acceptable performance with our LC-MS/MS system, as sample is not purified online. Derivatization provides sufficient sensitivity for 25-OHD2detection.
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Prvulović, Slavica, Jasna Tolmac, Eleonora Desnica, Milica Josimović, and Ivana Bicok. "The station for dosing the substratum into existing digesters: PreMix." Scientific Technical Review 71, no. 1 (2021): 15–18. http://dx.doi.org/10.5937/str2101015p.
Повний текст джерелаАнотація:
In this paper the analysis and description of the operation of the Premix station for dosing the substrate into existing digesters whose location is in the system of the device for processing of liquid waste are described. Apart from the capacity and other entry parameters, the necessary diameter of the pipeline with the length of the section for supplying the devices of the PreMix system is calculated, as it is given in the appropriate tables, the connection of the existing equipment and digesters is presented. The appropriate dependence of the volume flow, the velocity of circulation and power at constant pressure as well as the dependence of the volume flow, pressure and power at constant velocity of circulation are presented by diagrams.
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Salem, Mohamed Sameh Abdalghany, Ahmed H. El-Shazly, Mohamed R. El-Marghany, Mohamed Nabil Sabry, and Norhan Nady. "Effect of Adding Functionalized Graphene on the Performance of PVDF Membrane in Direct Contact Membrane Distillation." Key Engineering Materials 801 (May 2019): 337–42. http://dx.doi.org/10.4028/www.scientific.net/kem.801.337.
Повний текст джерелаАнотація:
In this paper, the effect of adding modified graphene nanoplatelets (MGNPs) as a filler on the characteristics and performance of Polyvinylidene fluoride (PVDF) membrane in a direct contact membrane distillation (DCMD) configuration was investigated. Both pure PVDF and PVDF/MGNPs composite (2%) membranes were fabricated by using electrospinning technique. The fabricated membranes were characterized using different analyses techniques such as SEM imaging, XRD analysis, static water contact angle as well as membrane porosity and liquid enter pressure measurements. Also, the average fiber diameter and the average membrane pore diameter were estimated using ImageJ software. The prepared PVDF/MGNPs composite membrane exhibited lower fiber diameter by about 5.7%, whereas the contact angle increased by 10 and liquid entry pressure increased by 11.7%. The membrane also showed an enhanced flux that reached about 19.8 kg/m2∙h at feed inlet temperature of 65°C, feed flow rate of 30 l/h. and feed inlet concentration of 10000 ppm. This represents about 13.46% improvement over the pure PVDF membrane at the same conditions. The produced membrane presents a viable alternative to commercial MD membranes.
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Ramakrishnan, T. S., P. Wu, H. Zhang, and D. T. Wasan. "Dynamics in closed and open capillaries." Journal of Fluid Mechanics 872 (June 7, 2019): 5–38. http://dx.doi.org/10.1017/jfm.2019.328.
Повний текст джерелаАнотація:
Capillary rise of a liquid displacing gas is analysed for both open and closed capillaries. We include menisci mass and hysteresis, and show that oscillations due to inertia are muted by friction at the advancing meniscus. From single-phase numerical computations in a no-slip/slip capillary, we quantify losses due to entry, flow development, meniscus slip, exit and acceleration of fluid within the reservoir. For closed capillaries, determining viscous drag due to gas requires inclusion of compressibility, and solving a moving boundary problem. This solution is derived through perturbation expansion with respect to two different small parameters for obtaining pressure above the liquid meniscus. Our rise predictions spanning a large range of experimental conditions and fluids for both open and closed capillaries match the data. The experimental data confirm the adequacy of the theoretically constructed dimensionless groups for predicting oscillatory behaviour.
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Suga, Yuki, Ryousuke Takagi, and Hideto Matsuyama. "Effect of the Characteristic Properties of Membrane on Long-Term Stability in the Vacuum Membrane Distillation Process." Membranes 11, no. 4 (March 31, 2021): 252. http://dx.doi.org/10.3390/membranes11040252.
Повний текст джерелаАнотація:
Membrane distillation (MD) is a technology that can treat feed solutions with higher osmotic pressure, as well as produce high-purity water. However, the water production cost of the MD process is expensive. In this study, to decrease the water production cost, we attempted to evaluate the effect of membrane characteristics on the long-term stability of a vacuum MD (VMD) system. We fabricated four different types of polyvinylidene difluoride hollow fiber membranes, and operated a VMD system with 3.5 wt% NaCl aqueous solution at 65 °C as a feed under 11 kPa of air gap pressure. Consequently, in the proposed VMD system, it is found that the liquid entry pressure (LEP) is the most important factor. When LEP was higher than 0.37 MPa, the pilot-scale module was very stable for long-term operations, and the vapor flux was approximately 19.3 kg/m2·h with a total salt retention factor of over 99.9% during the 300-h operation.
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Usai, Vittorio, Carla Cordalonga, and Silvia Marelli. "Experimental evaluation of isentropic efficiency in turbocharger twin-entry turbines." Journal of Physics: Conference Series 2385, no. 1 (December 1, 2022): 012135. http://dx.doi.org/10.1088/1742-6596/2385/1/012135.
Повний текст джерелаАнотація:
Abstract Turbocharging plays a fundamental role not only in improving the performance of automotive engines, but also in reducing the fuel consumption and exhaust emissions of spark-ignited biofuel, diesel, liquid, and gaseous engines. Dedicated experimental investigations on turbochargers are therefore needed to evaluate a better understanding of its performance. The availability of experimental information on the steady flow performance of the turbocharger is an essential requirement to optimize the matching calculation. It is interesting to know the isentropic efficiency of the turbine in order to improve the coupling with the engine, in particular it is difficult to identify the definition of the turbine efficiency through a direct evaluation. In a radial turbine, the isentropic efficiency, evaluated directly starting from the measurement of the thermodynamic quantities at the inlet and outlet sections, can be affected by significant errors. This inaccuracy is mainly related to the incorrect evaluation of the turbine outlet temperature, due to the non-uniform distribution of the flow field in the measurement section. For this purpose, a flow conditioner was installed downstream the turbine. Tests were performed at different values of the rotational speed, and in quasi-adiabatic conditions. The flow field downstream the de-coupler was analysed through a hand-made three-hole probe with an exposed junction thermocouple inserted in the pipe with different protrusions. Thanks to this experimental campaign, it was possible to measure pressure, velocity, mass flow and temperature profiles necessary to examine the homogeneity of the flow field. As the turbocharger is fitted with a twin entry turbine, the thermodynamic quantities have been properly taken into account referring to each sector.
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Pal, Shweta, Arun Kumar Wamankar, and Sailendra Dwivedi. "Review on Condenser Heat Transfer of Computational FluidDynamic System Using ANSYS." International Journal of Recent Development in Engineering and Technology 10, no. 2 (June 24, 2021): 63–68. http://dx.doi.org/10.54380/ijrdetv10i109.
Повний текст джерелаАнотація:
Condenser is a high pressure side heat exchanger in which heated vapor enters and gets converted into liquid form by condensation process. In the condenser coil, gaseous substance is condensed into liquid by transferring latent heat content present in it to the surrounding. In the whole process, mode of heat transfer is conduction in condenser coil and forced convection between refrigerant and condenser. Any refrigeration system's backbone is comprised of condensers. It aids in the transfer of heat from the refrigerant to the universal sink, which is the atmosphere. The latent heat of the refrigerant is lost in the condenser. At the entry of the condenser, vapours from the compressor enter, and during the length of the condenser, the vapours are converted to liquid form, resulting in refrigerant in the form of saturated or even sub-cooled liquid form at the condenser's exit. In several sectors of chemical and petroleum engineering, computational fluid dynamics (CFD) is a common tool for simulating flow systems. As a branch of fluid mechanics, computational fluid dynamics (CFD) is an appropriate tool for investigating and modelling the ANSYS Program. The applicability of CFD studies for simulating the ANSYS Program was reviewed in this work. Ansys CFD is one of the industry's most powerful simulation packages
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Hwang, J. J., and B. Y. Chang. "Effect of Outflow Orientation on Heat Transfer and Pressure Drop in a Triangular Duct With an Array of Tangential Jets." Journal of Heat Transfer 122, no. 4 (May 5, 2000): 669–78. http://dx.doi.org/10.1115/1.1318216.
Повний текст джерелаАнотація:
Experiments are conducted to study the heat transfer and pressure drop characteristics in a triangular duct cooled by an array of tangential jets, simulating the leading-edge cooling circuit of a turbine blade. Coolant ejected from a high-pressure plenum through an array of orifices is aimed at the leading-edge apex and exits from the radial outlets. Three different outflow orientations, namely coincident with the entry flow, opposed to the entry flow, and both, are tested for various Reynolds numbers 12600⩽Re⩽42000. A transient liquid crystal technique is used to measure the detailed heat transfer coefficients on two walls forming the leading-edge apex. Flow rate across each jet hole and the crossflow development, which are closely related to the local heat transfer characteristics, are also measured. Results show that increasing Re increases the heat transfer on both walls. The outflow orientation affects significantly the local heat transfer characteristics through influencing the jet flow together with the crossflow in the triangular duct. The triangular duct with two openings is recommended since it has the highest wall-averaged heat transfer and the moderate loss coefficient among the three outflow orientations investigated. Correlations for wall-averaged Nusselt number and loss coefficient in the triangular duct have been developed by considering the Reynolds number for three different outflow orientations. [S0022-1481(00)01204-4]
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Yu, Hao, and Minjun Peng. "Assessment of Severe Accident Management for Small IPWR under an ESBO Scenario." Science and Technology of Nuclear Installations 2019 (August 25, 2019): 1–10. http://dx.doi.org/10.1155/2019/1510967.
Повний текст джерелаАнотація:
Interest in evaluation of severe accidents induced by extended station blackout (ESBO) has significantly increased after Fukushima. In this paper, the severe accident process under the high and low pressure induced by an ESBO for a small integrated pressurized water reactor (IPWR)-IP200 is simulated with the SCDAP/RELAP5 code. For both types of selected scenarios, the IP200 thermal hydraulic behavior and core meltdown are analyzed without operator actions. Core degradation studies firstly focus on the changes in the core water level and temperature. Then, the inhibition of natural circulation in the reactor pressure vessel (RPV) on core temperature rise is studied. In addition, the phenomena of core oxidation and hydrogen generation and the reaction mechanism of zirconium with the water and steam during core degradation are analyzed. The temperature distribution and time point of the core melting process are obtained. And the IP200 severe accident management guideline (SAMG) entry condition is determined. Finally, it is compared with other core degradation studies of large distributed reactors to discuss the influence of the inherent design characteristics of IP200. Furthermore, through the comparison of four sets of scenarios, the effects of the passive safety system (PSS) on the mitigation of severe accidents are evaluated. Detailed results show that, for the quantitative conclusions, the low coolant storage of IP200 makes the core degradation very fast. The duration from core oxidation to corium relocation in the lower-pressure scenario is 53% faster than that of in the high-pressure scenario. The maximum temperature of liquid corium in the lower-pressure scenario is 134 K higher than that of the high-pressure scenario. Besides, the core forms a molten pool 2.8 h earlier in the lower-pressure scenario. The hydrogen generated in the high-pressure scenario is higher when compared to the low-pressure scenario due to the slower degradation of the core. After the reactor reaches the SAMG entry conditions, the PSS input can effectively alleviate the accident and prevent the core from being damaged and melted. There is more time to alleviate the accident. This study is aimed at providing a reference to improve the existing IPWR SAMGs.
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Ilisca, Ernest. "Hydrogen Storage in Cryogenic, Cybernetic, and Catalytic Vessels for Transport Vehicles." Journal of Energy and Power Technology 03, no. 04 (June 18, 2021): 1. http://dx.doi.org/10.21926/jept.2104045.
Повний текст джерелаАнотація:
Most of the hydrogen storage vessels meant for vehicles to run the electric motor via a fuel cell during transport are designed for drives of only a few tenths of kilometers per day. The present report, however, describes a vessel model that is conceived to hold the hydrogen energy only for short periods during transport, such as a few hours. This would include transport via a light-duty vehicle, a taxi, or a bus, which would load liquid hydrogen at a station every morning for the day. This is a simple model based on the novel concept of Double Open Vessel (DOV), in which the liquid H2 is loaded inside an open container inserted inside another open container. The walls of this DOV are constituted of simplified linings that allow the entry of thermal heat nearly a hundred times greater than that allowed by the cryo-compressed vessels with higher insulation. After loading, the liquid evaporates, while the gas flows around its initial container into which it was loaded, passes through a few porous plugs, and is gradually released towards the Fuel Cell (or toward an ignition motor). Such a counter-flow of the gas creates a retroaction effect that insulates the inner container, thereby delaying the increases in temperature and pressure. The successive porous plugs installed in the space between the two containers form a system of barrages that regulate the gas flow through successive expansions of decreasing pressures. In addition, these catalytic plugs convert a portion of the loaded hydrogen into its ortho variety, acting as a heat pump, while temporarily storing the other portion. Collectively, these effects maintain the internal pressures below 150 bar. The proposed design for the DOV models is convenient to manufacture and has a lighter weight, and consequently, a low cost.
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Maryin, S. B., and Phyo Wai Aung. "Working Body for Deformation of Thin-Walled Pipe Billets." Materials Science Forum 945 (February 2019): 628–33. http://dx.doi.org/10.4028/www.scientific.net/msf.945.628.
Повний текст джерелаАнотація:
In this paper we consider different types of working bodies and fillers used in the manufacture of hydro-gas systems of aircraft from thin-walled pipe billets, and also explored the advantages and disadvantages of liquid, fusible, solid, elastic, loose and combined fillers in the deformation of pipe segments by means of distribution, crimping, forming and flexible. As a result of the research, a device for distributing pipe billets along a rigid matrix and a working body made of granular polyurethane and ice, the main advantages of which are: good rheological properties (fast flow); high ductility and viscosity; high ability to transfer pressure throughout the metal zone; ability to withstand high compression load; ease of entry into the workpiece and removal from the finished part; low production costs.
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Miranda, Fabrício A., Abelardo B. Barreto, and Alvaro M. Peres. "A Novel Uniform-Flux Solution Based on the Green's Function Method for Modeling the Pressure-Transient Behavior of a Restricted-Entry Well in Anisotropic Gas Reservoirs." SPE Journal 21, no. 05 (April 25, 2016): 1870–82. http://dx.doi.org/10.2118/180919-pa.
Повний текст джерелаАнотація:
Summary Applied gas-well-testing data analysis considers that the nonlinear diffusivity equation becomes linearized by the pseudopressure function and by assuming the gas viscosity-compressibility product constant throughout the test history. This approach is justified for small pressure drawdowns only. This condition is seldom met in low-permeability gas reservoirs, whether the wellbore is fully perforated or not. This paper considers a restricted-entry vertical well in a homogeneous anisotropic infinite reservoir producing at constant-gas-flow rate, which, surprisingly, has not been the object of much research, either by numerical simulation or by analytical means. In this work, the Green's function (GF) method is used to rewrite the usual partial-differential formulation as a multidimensional integro-differential equation for the pseudopressure function that rigorously accounts the gas viscosity-compressibility product change. From there, an approximate explicit solution for a uniform-flux boundary condition is derived, which shows that the pseudopressure solution is given by the correspondent restricted-entry well slightly compressible (i.e., liquid) solution, plus a corrective term that handles the gas viscosity-compressibility product variation with pressure. Comparison with a commercial numerical simulator shows that the uniform-flux approximate solution is very accurate. Results are presented for a few perforation lengths and positions, with and without vertical anisotropy. It is shown that during the perforation-radial (early-time) and final-radial (late-time) flow regimes, the corrective term becomes constant. Their magnitudes, however, are quite different; during the perforation-radial flow regime, the corrective term is quite large compared with the one seen at long times. Thus, the pseudopressure derivative with respect to the natural log of time exhibits the same restricted-entry behavior observed in oil reservoirs. By averaging the uniform-flux solution over the open interval, an infinite-conductivity approximate solution for the wellbore pseudopressure is presented, which shows a very-good agreement with results obtained from a finite-difference simulator.
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Kuzina, Yu, and A. Sorokin. "FUNDAMENTAL INVESTIGATONS IN THE FIELD OF NUCLEAR POWER FACILITIES THERMOPHYSICS: ACHIEVED RESULTS AND PROBLEMS FOR FURTHER INVESTIGATON." PROBLEMS OF ATOMIC SCIENCE AND TECHNOLOGY. SERIES: NUCLEAR AND REACTOR CONSTANTS 2020, no. 1 (March 26, 2020): 177–204. http://dx.doi.org/10.55176/2414-1038-2020-1-177-204.
Повний текст джерелаАнотація:
The results of experimental and theoretical calculations of fundamental research in the field of hydrodynamics, heat transfer, physical chemistry and nuclear power technology cooled by water and liquid metal coolants are analyzed, problems and tasks of further research are formulated. The effects and physical phenomena, laws and characteristics for a wide range of processes occurring in the first and second circuits of reactor facilities, including the flow part, the core, the heating equipment, the means of monitoring and cleaning coolants from impurities as applied to watercooled thermal neutron reactors, fast liquid metal reactors, fusion plants, etc. Particular attention in the field of hydrodynamics and heat transfer is given to studies of the heat transfer crisis in watercooled reactors, hydrodynamics of collector systems, stratification and mixing of jets, vibroacoustics, turbulent transfer in complex channels, heat transfer in the channels and assemblies of fast reactor fuel elements, contact thermal resistance, boiling in large volume and bundles of fuel rods, condensation of liquid metals. In the field of physical chemistry and the technology of liquid metal coolants, the types of impurities and the sources of their entry into the coolants for various nuclear power plants, the characteristics of the mass and heat transfer processes in the circuits and equipment of reactor facilities with liquid metal coolants (sodium, potassium, lithium, lead, bismuth lead), the efficiency of using various purification devices (cold and hot traps) and monitoring the state of impurities in coolants are analyzed.Problem questions and suggestions for further research are formulated. Information is given on the key thermophysical problems of basic research in relation to the development of innovative nuclear energy technologies: water-cooled reactors with supercritical water pressure, high-temperature fast reactors with sodium coolant for hydrogen production, thermonuclear installations, nuclear power plants with liquid-metal space coolants.
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Ozkan, E., and R. Raghavan. "A Computationally Efficient, Transient-Pressure Solution for Inclined Wells." SPE Reservoir Evaluation & Engineering 3, no. 05 (October 1, 2000): 414–25. http://dx.doi.org/10.2118/66206-pa.
Повний текст джерелаАнотація:
Summary This work provides an efficient algorithm to compute transient pressure responses of inclined wells. The solution is derived in the Laplace domain and cast into computationally efficient forms for all inclination angles. The algorithm allows the computation of pressures and derivatives at the wellbore as well as at observation points. Short- and long-time approximations for the evaluation of pressure responses are also provided. The long-time approximation is used to derive a general pseudoskin expression that is applicable for all inclination angles. Example computations are presented in the forms of tables and figures to display the efficacy, accuracy, and the practical use of the algorithm. Introduction The central contribution of this work is to present a new solution to compute pressure distributions caused by directionally drilled (inclined or slanted) wells. This solution is presented in terms of the Laplace transformation. We present a computationally attractive scheme that may be used for inclinations from vertical to horizontal; this feature permits us to compute pressure distributions for partially penetrating or limited-entry and extended-reach wells. Thus, our contribution removes a restriction that is often noted in the literature regarding the Cinco et al.1 solution (see Ref. 2). Results from our solution are compared with available solutions for vertical, inclined, and horizontal wells. The mathematical model is identical to that considered by Cinco et al.1 except that we work in terms of the Laplace transformation. We, however, present results for conditions not considered in Ref. 1 (high-angle and limited-entry wells). The advantage of working in terms of the Laplace transformation is that the extensions to the variable rate and wellbore storage and skin problems, the naturally fractured-reservoir formulation, and commingled-reservoir behavior may be readily handled. The focus of this work is on computational issues. The specific contributions of this communication are as follows: We present a viable and tractable solution to compute pressure distributions. Alternate forms of the solution are presented to permit computations for all time ranges of interest. An expression for the pseudoskin function is derived. This expression is useful in obtaining long-time, fluid flow responses around an inclined well and should be suitable for calculating the productivity index and transmissibility modifiers in reservoir simulation models. We present results in tabular form so as to permit others to evaluate their own codes; we supplement the information documented by Cinco et al.1 by concentrating on high-angle and limited-entry cases. Mathematical Model We consider the classic problem of the unsteady flow of a slightly compressible liquid to an inclined well in a reservoir that is infinite in its lateral extent. The top and bottom boundaries are impermeable. The well is assumed to be a line source and production may or may not take place over its entire length; that is, we examine limited-entry or partially penetrating wells. Two-dimensional anisotropy is considered; kh and kz represent the permeabilities in the horizontal and vertical directions, respectively. The pressure is uniform initially throughout the reservoir and equal to pi. The inclination angle of the well, ?, is measured from the positive z axis in the clockwise direction. Fig. 1 presents a schematic of the system examined here. We use the following dimensionless variables: The dimensionless pressure is defined by p D = k h h 141.2 q B μ ( p i − p ) , ( 1 ) the dimensionless time by t D = 0.0002637 k h ϕ c t μ l 2 t , ( 2 ) the dimensionless distances by r D = r l , ( 3 ) z D = z l k h k z , ( 4 ) h D = h l k h k z , ( 5 ) and the dimensionless well length and transformed well inclination angle are defined, respectively, by h w D = h w l k h k z c o s 2 ψ + s i n 2 ψ , ( 6 ) ψ ′ = t a n − 1 ( k z k h t a n ψ ) . ( 7 ) The definitions of hwD and ?? given in Eqs. 6 and 7 are a result of the transformation of the original anisotropic system into one that is isotropic (the coordinate transformation does not only scale distances but also rotates angles). Thus, for example, the effect of anisotropy appears to be a simple scale contraction for the formation thickness (hD) whereas it is both a scale change (hwD) and rotation of the angle (??) for the inclined well. In Eqs. 2-7, l is some characteristic length of the system and for the numerical results presented in this paper, it is chosen to be the wellbore radius rw The midpoint of the well is denoted by zwD which is also defined as in Eq. 4.
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Wang, Yuan, Jie Ren, Shaobin Hu, and Di Feng. "Global Sensitivity Analysis to Assess Salt Precipitation for CO2 Geological Storage in Deep Saline Aquifers." Geofluids 2017 (2017): 1–16. http://dx.doi.org/10.1155/2017/5603923.
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Salt precipitation is generated near the injection well when dry supercritical carbon dioxide (scCO2) is injected into saline aquifers, and it can seriously impair the CO2 injectivity of the well. We used solid saturation (Ss) to map CO2 injectivity. Ss was used as the response variable for the sensitivity analysis, and the input variables included the CO2 injection rate (QCO2), salinity of the aquifer (XNaCl), empirical parameter m, air entry pressure (P0), maximum capillary pressure (Pmax), and liquid residual saturation (Splr and Sclr). Global sensitivity analysis methods, namely, the Morris method and Sobol method, were used. A significant increase in Ss was observed near the injection well, and the results of the two methods were similar: XNaCl had the greatest effect on Ss; the effect of P0 and Pmax on Ss was negligible. On the other hand, with these two methods, QCO2 had various effects on Ss: QCO2 had a large effect on Ss in the Morris method, but it had little effect on Ss in the Sobol method. We also found that a low QCO2 had a profound effect on Ss but that a high QCO2 had almost no effect on the Ss value.
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Fu, Kaiyun, Yunzhao Guo, Wenbo Qi, Xianfu Chen, Minghui Qiu, and Yiqun Fan. "Efficient Estimation of Permeate Flux of Asymmetric Ceramic Membranes for Vacuum Membrane Distillation." Molecules 27, no. 3 (February 4, 2022): 1057. http://dx.doi.org/10.3390/molecules27031057.
Повний текст джерелаАнотація:
Ceramic membranes have the advantages of high mechanical strength and thermal stability and are promising candidates for membrane distillation. Ceramic membranes are generally designed to have a multilayer structure with different pore sizes to create a high liquid entry pressure and obtain a high permeability. However, these structural characteristics pose significant difficulties in predicting permeate flux in a ceramic membrane contactor for vacuum membrane distillation (VMD). Here, a modeling approach was developed to simulate the VMD process and verified by comparing the simulated results with the experimental data. Furthermore, correlations are proposed to simplify the calculations of permeate flux for VMD using asymmetric ceramic membranes by assuming those multilayers to be an effectively quasi-symmetric layer and by introducing a correction factor. The simulation results indicated that this simplified correlation was effective and enabled a quick estimation of the effect of membrane parameters on permeate flux.
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Kundu, Neha, Hyung Keun Lee, and Bal Raj Deshwal. "Surface modification of polymeric flat sheet membranes by adding oligomeric fluoroalcohol." Journal of Polymer Engineering 39, no. 2 (February 25, 2019): 170–77. http://dx.doi.org/10.1515/polyeng-2018-0091.
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Abstract The present study attempted to modify the surface of polymeric membranes by mixing 2-(perfluoroalkyl)ethanol with polyethersulfone to improve the hydrophobicity of the membrane. The characteristics of the surface-modified membrane were examined by using the contact angle, liquid entry pressure (LEPw), X-ray photoelectron spectroscopy spectra, and scanning electron microscopy measurements. The modified membrane was tested for SO2 absorption. The surface contact angle and LEPw values increased by the addition of fluoroalcohol. The fluorine/carbon atomic ratio decreased with increasing evaporation period. The modified membrane was utilized for the absorption of SO2 from the simulated flue gas in alkaline medium (0.5 m NaOH solution). The SO2 removal efficiency slightly decreased probably due to the transformation of the finger-like structure into a sponge-like structure, and the increase in the membrane resistance. The SO2 absorption rate also increased as the gas flow rate increased.
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Saini, Makmur, Rusdi Nur, Sattar Sattar, and Ibrahim Ibrahim. "Rancang Bangun Alat Eliminasi Gas Buang Menggunakan Mekanisme Ejektor." INTEK: Jurnal Penelitian 4, no. 2 (November 4, 2017): 115. http://dx.doi.org/10.31963/intek.v4i2.154.
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Environmental pollution (pollutants) can be caused by natural events or human care through uncontrolled industrial and technological activities, this can be a threat to living things including humans in the future. This phenomenon is caused by the entry of particles or chemical substances that do not exist in the natural component so that it exceeds the amount that should be. Pollution is the inclusion of substances, energy and aliens into the environment so that the quality of the environment decreases and no longer suitable allocation. Efforts to reduce or control environmental pollution that some environmental scientists and practitioners have done in a better way by the structures produced by various industries and technologies that are seen as backbones. The research installation can provide detailed information about the shape and structure of the current in the pipe (analogized as the exhaust) in the direction and the vertical velocity to air will be inhaled by the fluid of the liquid (air) as motive fluid in the opposite direction. The suction strength of the liquid against the airflow is greatly determined by the vacuum pressure in the chamber because of the effect of the working ejector that is geometrically formed so that the image can be adjusted to that achievement. The parameters used to measure performance in the design of this air-contaminating air-conditioning installation plant are composed of several variables in the ratio of changes between air velocity and liquid flow in opposite directions, vacuum compressions are formed large enough, the fluid flow capacity of the ejector, revascular and the ability to transform gas pollutants into liquid pollutants.