The movement of three-phase contact line which formed in the oil-water-solid three-phase area is of great importance in a number of applications, such as oil recovery, groundwater remediation, decontamination and dein...
The movement of three-phase contact line which formed in the oil-water-solid three-phase area is of great importance in a number of applications, such as oil recovery, groundwater remediation, decontamination and deinking The process of oil droplets/film migration and detachment, which are controlled by the moving contact line, has shown its great significance in oil *** are various factors which can drive the contact line to move, such as pressure and electrical driving ***, which will generate a velocity gradient for the flow near the *** this paper, we dedicate to investigate the moving rule of contact line under a velocity gradient from molecular dynamics (MD) insights.
A lab experiment was carried out to study the effects of pipe flow rate, particle concentration and pipe inner diameter ratio on proppant erosion of the reducing wall in hydraulic fracturing. The results show that the...
A lab experiment was carried out to study the effects of pipe flow rate, particle concentration and pipe inner diameter ratio on proppant erosion of the reducing wall in hydraulic fracturing. The results show that the erosion rate and erosion distribution are different not only in radial direction but also in circumferential direction of the sample. The upper part of sample always has a minimum erosion rate and erosion area. Besides, the erosion rate of reducing wall is most affected by fluid flow velocity, and the erosion area is most sensitive to the change in the diameter ratio. Meanwhile, the erosion rate of reducing wall in crosslinked fracturing fluid is mainly determined by the fluid flowing state due to the high viscosity of the liquid. In general, the increase in flow velocity and diameter ratio not only cause the expansion of erosion-affected flow region in sudden contraction section, but also lead to more particles impact the wall.
In this study, the mechanisms that cause heat split, a specific phenomenon in dual-cooled annular fuel elements, were investigated. On the basis of thermal resistance analysis, the developing process of heat split phe...
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In this study, the mechanisms that cause heat split, a specific phenomenon in dual-cooled annular fuel elements, were investigated. On the basis of thermal resistance analysis, the developing process of heat split phenomenon was summarized. It was found that thermal expansion, fuel densification, swelling, creep, relocation and fission gas release are the original parameters driving the development of heat split. Due to these factors, thermal resistances for heat flux to internal and external channels change with the operating time, which results in heat split. Furthermore, the theoretical simulation on heat split was performed by FROBA-ANNULAR, which is a coupled thermal–mechanical analysis code for dual-cooled annular fuel elements. key parameters at different burnup stages, including gap size, gap conductance, temperature profile, coolant flux and heat flux were obtained. The calculation result shows that the fraction of heat flux to the internal cooling channel experiences complicated variation at the range of 32.9–39.7%. In addition, it was found that heat split does not match with the coolant split, especially at the lower burnup stage. Asymmetric heat transfer occurred because of the imbalance between heat split and coolant split, resulting in a substantial asymmetric temperature profile. Furthermore, heat split exerts an influence on DBNRs of inner and outer channels, although the computational values were still within the allowable limits.
The wettability of solid surfaces is very important to fundamental research and practical application. Inspired from species in nature a variety of bionic surfaces with super wettability have been fabricated by lithog...
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The wettability of solid surfaces is very important to fundamental research and practical application. Inspired from species in nature a variety of bionic surfaces with super wettability have been fabricated by lithography, templating, plasma treatment and laser methods. Recent years, metal bionic materials used in heat transfer and their enhancement mechanism have been promising topics, for example superhydrophilic surface was used in boiling enhancement [1]dropwise condensation [2]and heat exchangers[3]and so on. But most metal superwettability surfaces used in heat transfer field were uniform while hybrid wetting substrates always were non-metal like silicon wafer. In this paper, the porous metal that involved in the hot applications was chosen as substrate. Superhydrophilic copper mesh(~0 o) and superhydrophobic copper mesh(~150 o) were fabricated by directly oxidation method and functionalization by trichloro(1 H, 1 H, 2 H, 2 H-perfluorooctyl) silane respectively, whose wettability can be interconverted by simple operation. After oxidation a layer of knife-like-flower oxide at thickness of 2μm covered the mesh lines. Closed to the substrate several knife sheets interdigitate together and disperse on the top, the gap between the knife sheets on the top of flowers is 100-200 nm. With functionalization by silane, mesh wettability converted from superhydrophilic into superhydrophobic, while, the knife-like flower layer has littler change but blunt edges. Then, a hybrid wettability mesh with inspired from Stenocara Beetle was prepared, which has circle superhydrophilic spots surrounded by hydrophobic background. The hybrid wettability mesh could be widely used in boiling enhancement, water harvesting, biological medicine and other practical applications.
For centuries, water has been a limited resource especially in arid regions, and nature has adapted to provide survival methods for species inhabiting. Stenocara beetles can collect water from morning fog using its bu...
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For centuries, water has been a limited resource especially in arid regions, and nature has adapted to provide survival methods for species inhabiting. Stenocara beetles can collect water from morning fog using its bumpy shell, an array of hydrophilic bumps surrounded by hydrophobic background exactly. Dorrer et al, Lee et al and other researches studied kinds of patterned superhydrophobic and superhydrophilc surfaces to prove which bump surface has best water harvesting performance. Obviously, drainage, temperature difference, wind velocity, surface pattern et al are all key factors, but most samples in their studies are solid substrates with a layer microstructure. There are three common grounds:(1) with spraying of fluid almost condensate is blocked on the surface to form a film which weaken the effect of surface pattern to condensation process.(2) draining efficiency of condensate directly determines the performance of next generation, while, condensate mainly relies on gravity and flows away along the substrate surface at a low velocity,(3) more attention is focused on the microstructures on the surface with neglect of cooperation with macro scale of *** this paper, copper foam with the controllable pore structures is chosen to harvest water. After superhydrophilic and superhydrophobic treatments copper foam with hybrid wettability is fabricated with inspiring from the stenocara beetle. As previous reported porous metal with a superhydrophilic wettability could absorb a droplet away instantly, this can be used in the drainage system during water collection. Cooperating multi-layer cooper foams with different wettability and an independent drainage, a novel water collector is designed. When wind blows through the porous structure with less pressure decrease a droplet is generated on the surface of copper foam with certain temperature difference. Meantime, condensate is quickly sucked away by latter superhydrophilica foam then collected. At last, the eff
Rapid detection of coal and fly ash is significant to improve the efficiency of thermal power plants and reduce environmental pollution. Given its fast response, high sensitivity, real-time, and noncontact features, l...
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Rapid detection of coal and fly ash is significant to improve the efficiency of thermal power plants and reduce environmental pollution. Given its fast response, high sensitivity, real-time, and noncontact features, laser-induced breakdown spectroscopy (LIBS) has a great potential for online measurement in these applications. The direct measurement of particles and gases using LIBS has been studied, and the method has been shown to be effective for this application.
Coal-bed methane (CBM) reserves are rich in Sinkiang of China, and liquefaction is a critical step for the CBM exploration and utilization. Different from other CBM gas fields in China, CBM distribution in Sinkiang is...
Coal-bed methane (CBM) reserves are rich in Sinkiang of China, and liquefaction is a critical step for the CBM exploration and utilization. Different from other CBM gas fields in China, CBM distribution in Sinkiang is widespread but scattered, and the pressure, flow-rate and nitrogen content of CBM feed vary significantly. The skid-mounted liquefaction device is suggested as an efficient and economical way to recover methane. Turbo-expander is one of the most important parts which generates the cooling capacity for the cryogenic liquefaction system. Using turbo-expander, more cooling capacity and higher liquefied fraction can be achieved. In this study, skid-mounted CBM liquefaction processes based on Claude cycle are established. Cryogenic turbo-expander with high expansion ratio is employed to improve the efficiency of CBM liquefaction process. The unit power consumption per liquefaction mole flow-rate for CBM feed gas is used as the object function for process optimization, compressor discharge pressure, flow ratio of feed gas to turbo-expander and nitrogen friction are analyzed, and optimum operation range of the liquefaction processes are obtained.
Differential pressure fluctuation is an inherent physical phenomenon in gas-liquid two-phase flow, which can be used to measure the quality and the whole flowrate. In order to study the influence of differential press...
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Laser-induced breakdown spectroscopy(LIBS) is an analytical detection technique based on atomic emission spectroscopy to measure the elemental *** has been extensively studied and developed due to the non-contact,fast...
Laser-induced breakdown spectroscopy(LIBS) is an analytical detection technique based on atomic emission spectroscopy to measure the elemental *** has been extensively studied and developed due to the non-contact,fast response,high sensitivity,real-time and multi-elemental detection *** development and applications of LIBS technique in Asia are summarized and discussed in this review *** researchers in Asia work on different aspects of the LIBS study in fundamentals,data processing and modeling,applications and *** to the current research status,the challenges,opportunities and further development of LIBS technique in Asia are also evaluated to promote LIBS research and its applications.
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