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In view of the limitation that the existing theoretical methods cannot reflect the influence of fiber wettability on permeability, the analytical expression of capillary pressure and the calculation formula of lateral dynamic permeability of fiber tow impregnation process were derived. The numerical simulation of the process of resin impregnated fiber tows was carried out by using a phase field method. The simulation results indicated that the numerical solution of the capillary pressure obtained by the phase field method was consistent with the analytical solution obtained from this paper. This proved the reliability of the developed method. The effects of fiber volume fraction and contact angle on the dynamic permeability were studied. The results indicated that this method could better characterize the effect of fiber wettability on the permeability and realize the dynamic prediction of the permeability at different impregnation radii. Compared to the existing permeability calculation methods, the developed method is more applicable and the calculation results are more accurate. [ABSTRACT FROM AUTHOR]

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Based on the lattice Boltzmann method, the numerical simulation of droplet impacting on orifice plates with different wettabilities was carried out. The effects of the Weber number (We), the wettability of the orifice surface and the orifice size on different states of droplets passing through orifice plates during impacts were studied. The numerical simulation results show that, different phenomena will occur in the processes of droplets impacting on the orifice plates. If the orifice plate is hydrophilic, the droplet will not detach from the orifice plate surface, but adhere to the lower surface of the orifice plate for a relatively low We number, and then the droplet will rise for a certain distance in the orifice channel under the action of capillarity, forming the liquid plugging phenomenon. For relatively high We numbers, droplets will pass through the orifice plates and rupture will occur. If the orifice plate is hydrophobic, the droplet will not pass through the orifice plate and migrate to the lower surface for a relatively low We number, and will finally stabilize in the orifice channel. For higher We numbers, droplets will pass through the orifice plates, and then break up, leaving droplet remains on the surfaces of the orifice plates. For various orifice sizes, the droplet will be more difficult to pass through the plate for a smaller orifice size or a lager orifice plate thickness. [ABSTRACT FROM AUTHOR]

Copyright of Natural Gas Industry is the property of Natural Gas Industry Journal Agency and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Soil salinization is a great challenge for Chinese agriculture, severely crippling the development of agricultural production. Soil salinization is often caused because strong evaporation and capillary transport salt ions to soil surface. Probably, the salt removal from soil surface by materials with strong capillary is a way to control salinization. In this study, we investigated the cause of saline-alkali formation of 5 types of soils in droughty areas, and proposed a protection blanket for soil salinization control based on the principle of soil capillary and tested its feasibility of control soil saline in 5 soils. The blanket was composed of sponge (stronger absorbent layer) and endothermic polyethylene weaved cloth (sforzato evaporation layer). The soil salt ions were absorbed by sponge into the outer cloth so that the salt could not accumulate on the surface of the soil. The blanket was used in 5 soils with different textures (gravel, silt/silt sand, silt/fine sand, silt, mild clay). The soils were collected from Fangcao Lake farmland, Hutubi county, Xinjiang (43°16'-45°20'N, 86°05'-87°07'26''E), and air-dried to mix with salt solution made of 36 g/L NaCl, 34 g/L KCl, and deionized water. The soils were filled into a box with area of 1 m2 (30 cm depth to simulate tillage layer). The initial soil moisture was 12% and soil compactness was 0.8. The salt content of soils at 5 cm was determined destructively at 4, 12 and 20 d. The salt accumulation on soil surface was photographed. Meanwhile, another soil samples with salt water were placed in columns in 40-cm length and 20-cm diameter and 30-cm depth with blanket covered for measurements of salt-absorption dynamics and depth of the blanket. The results showed that: 1) The salt distribution on soil surface varied with soil texture and the salt crystals were much more in the coarse-grained soil (gravel sand and sand) with about 3-4 mm depth in 3-4 days than the fine granular soil (clay and silt) with salt accumulation at a comparatively low rate so that crystal salt could not observed in 10-12 days; 2) The salt accumulation was obvious in early stage of experiment in the coarse soil particles but in the later stage of experiment in the fine soil particles; 3) The blanket could reduce salt content in 0-10 cm soil layer by more than 80% (P<0.05), and reduce in 10-20 cm by more than 50% (P<0.05) after 4 days under the condition with the outdoor temperature of 25℃ and dry ventilation allowed; Using the blanket, the salt content in 20-30 cm depth could be reduced by more than 50%, and more than 20%-30% (P<0.05) for sandy soils, clay and loam soil, respectively. For practical application, the salt content reduction of 30% can greatly improve soil fertility and cultivability, and effectively alleviate the impact of salinity on the growth of crops. The results above indicate that the protective blanket is an effective measure for saline-alkali land amelioration. Theoretically, its effect should be best when soil capillary is strongest. However, its feasibility still need to be validated in more studies and in fields. [ABSTRACT FROM AUTHOR]

The heat transfer and flow field characteristics of a periodical turbulent jet impinging on a flat plate are experimental studied and the results as well as the mechanism of heat transfer enhancement are discussed. The periodical jets are produced by a special mass flow rate controller. The results of two typical periodical jets (i.e., sinusoidal and rectangular jets) are presented and the signal frequency is performed as a parameter in the experiments. The experimental results show that the heat transfer performances of two periodical jets with same average flow rate are obviously different. The rectangular jet, which has a step change in signal function itself, is much more effective for heat transfer improvement than the sinusoidal impinging jet. A higher frequency is promising in heat transfer for both signals. Particle Image Velocimetry (PIV) is used to measure the phase-locked flow field of the periodically impinging jet. For the higher frequency case of a rectangular impinging jet which has a step change in signal itself, the plate surface is exposed to both a strong impinging jet and a strong vortex during a periodical cycle and thereby it improves the convection process. In the flow field of a sinusoidal impinging jet, the phase-averaged velocity is lower than the case in a rectangular jet. The entrainment to the ambient fluid and the impingement as well as the vortex spreading are not so strong as that of a rectangular jet, thus it leads to only a slight heat transfer augmentation even at a higher frequency. [ABSTRACT FROM AUTHOR]

Taking No. 3 coal in Qinshui Basin as research object, factors such as solid phase of drilling fluid, water sensitivity, stress sensitivity, scaling, capillarity and polymer plugging which maybe damage coal reservoir were researched during coalbed methane drilling. Sample results analyzed show that No. 3 coal reservoir has low porosity and low permeability, high content of clay mineral. Lab evaluation results show water sensitivity, scaling, solid phase invasion of drilling fluid and polymer plugging are factors which induce the coal reservoir damage. Drilling fluid which has suitable salinity, suitable density, anti-scaling, and removable drilling fluid agents can protect coal reservoir from damage during drilling for pinnate horizontal wells. [ABSTRACT FROM AUTHOR]