Height Of Capillary Rise Research Articles

Relationship Between Capillary Water Absorption Value, Capillary Water Absorption Speed, and Capillary Rise Height in Pyroclastic Rocks

The existence of water is one of the most effective factors in deterioration of natural building stones. In the process of deterioration, capillary water absorption is the most significant procedure of water penetration into the building stones. Pyroclastic rocks have been widely utilized as building stone especially in historical buildings and monuments since ancient times in the Central Anatolia in Turkey. Nowadays, this type of rocks is used in the restoration of historical buildings as well as in the construction of modern buildings. Pyroclastic rocks are highly susceptible to deterioration process. Capillary rise has a significant influence on water penetration into building stones. Therefore, it is quite important to identify the factors affecting the values of capillarity, capillary rising speed, and capillary rise that define capillary water absorption in these rocks. To this end, pyroclastic rock samples in different textures were compiled from the Cappadocia region, in Central Anatolia. First, petrographic, mineralogical, geochemical, physical, and pore diameter distribution properties of the samples were determined in the laboratory. Then, capillarity values with capillary rise and capillary rise speeds dependent on time were established. Based on the data obtained, correlation coefficients between matrix percentage and capillary water absorption rate and capillary rise values of pyroclastic rocks were calculated and found to be as 0.850 and 0.891, respectively. Thus, the article proposes a new empirical equation to practically calculate the capillary rise value depending on the matrix percentage (MP) and median pore diameter (MPD) values.

Changes of meniscus shapes and capillary rise heights under hypergravity

We investigate meniscus shapes and capillary rise heights in glass capillaries with rectangular cross sections (4 × 0.2 mm), which we modified with established coatings to generate a range of surfaces that interact differently with water. Meniscus positions and shapes are imaged while the capillaries are rotated horizontally about their longitudinal axis in order to generate centrifugal forces opposing the capillary driven fluid propagation, i.e. volumetric forces. Changing the rotational speed allows us to balance both forces thereby bringing capillary rise to a stop. In brief, we find very good agreement of the different meniscus shapes we observe over a wide range of centrifugal accelerations (up to 191 g) with two independent simulations of the scenario. In addition, we are able to precisely measure capillary rise heights in differently modified capillaries over a range of centrifugal accelerations and correlate these values. Lastly, we mention how this system will prove useful to investigate wetting phenomena on swellable surfaces, i.e. surfaces whose properties dynamically change upon fluid contact, by providing precise control over the propagation speed of the three phase contact line.

Effect on Silt Capillary Water Absorption upon Addition of Sodium Methyl Silicate (SMS) and Microscopic Mechanism Analysis

Silt has the characteristics of developed capillary pores and strong water sensitivity, and capillary water is an important factor inducing the erosion and slumping of silt sites. Therefore, in order to suppress the effect of capillary water, this article discusses the improvement effect of sodium methyl silicate (SMS) on silt. The effect was investigated by capillary water rise testing and contact angle measurement, and the inhibition mechanism is discussed from the microscopic view by X-ray diffraction (XRD) testing, X-ray fluorescence (XRF) testing, scanning electron microscope (SEM) testing and mercury intrusion porosimetry (MIP) testing. The results show that SMS can effectively inhibit the rise of capillary water in silt, the maximum height of capillary rise can be reduced to 0 cm when the ratio of SMS (g) to silt (g) increases to 0.5%, and its contact angle is 120.2°. In addition, considering also the XRD, XRF, SEM and MIP test results, it is considered that SMS forms a water-repellent membrane by reacting with water and carbon dioxide, which evenly distribute on the surface of silt particles. The membrane reduces the surface energy and enhances the water repellence of silt, and combines with small particles in the soil, reduces the number of 2.5 μm pores and inhibits the rise of capillary water.

Hierarchically 3D-textured copper surfaces with enhanced wicking properties for high-power cooling

Phase change heat transfer devices (PCHTDs) have been considered as an ideal choice for the application of high-power cooling. Wick, as the core of PCHTD, has received extensive attention. In this study, hierarchically 3D-textured copper surfaces (TSs) were fabricated as the potential wicks to meet the needs of high-power cooling in PCHTDs. Laser machining, as an efficient special processing means, was employed to complete the fabrication of TSs with different structural parameters. The capillary performance of the TSs, including capillary rise height and velocity, was evaluated by the infrared thermal imaging method with ethanol as working fluid. In particular, the maximum volumetric flow rate of the textured surfaces due to the capillary wicking was found to dominate the two-phase heat transfer capacity through saturated pool boiling tests. The best two-phase heat transfer performance was achieved by TS75 with the critical heat flux of 173.9 W/cm2 and the maximum heat transfer coefficient of 34.6 W/cm2K, which are 1.54 and 5.71 times higher than those of the plain surface. Comparative studies with other capillary structures indicated that TSs have comparable or even better enhanced heat transfer performance, making it a promising wick for the application of high-power cooling devices.

Biporous nanocarbon foams and the effect of the structure on the capillary performance

Biporous nanocarbon foams (NC foams) which have both nano-pores and micro-pores, were fabricated and used to explore the liquid transportation in the porous structures formed by nanomaterials. Scanning electron microscopy was utilized to observe the structure of the NC foams. Capillary rise tests using acetone as the working fluid were conducted by the IR thermal imaging method. The results show that the capillary rise height of the NC foam with 65 μm micro-pore size was 47% higher than that with 9 μm micro-pore size in 50 s. The capillary performance of the NC foams was reduced when its density was higher than 60 mg/cm3. A model is built to illustrate the effect of both nano-structure and micro-structure on the transportation of working fluid in the biporous foam. The data indicates that the nano-structure generated high capillary pressure while the micro-structure provided low resistant pathways for fast liquid transportation. The size of micro-pores and the ratio of micro-pores to nano-pores were two important factors. It is demonstrated that the NC foams had large sorption capacity up to 878 mg/cm3 and their capillary performance was further enhanced when using a substrate.

Calculation of the Height of Capillary Rise of Water in Soils

Rain and melt water will form temporary accumulations of surface water on the surface. When they seep into the ground, temporary streams of leaky filter water are formed. If a limited section of water-resistant soil layer or the roof of an underground structure is encountered in the path of these waters, a temporary aquifer-the upper layer of ground water-may form above them. In temporary and permanent aquifers, the soil pores are completely filled with gravitational water, the degree of water saturation is equal to one, and there is pressure under the surface of underground water. Above this surface is a zone of capillary moisture, while the level of capillary rise is determined by the granulometric composition of the soil and ranges from tens of centimeters in sand to several meters in dusty and clay soils. Capillary water rises in the ground on free canals formed by mutually communicating pores, or is kept in them in limbo.The lifting of the liquid in the capillary continues until the gravity acting on the column of the liquid in the capillary becomes equal to the resulting force. Capillary water penetrates from the ground into the walls and rises to a height of up to 2 meters. The normal moisture content of the brick walls is 0.02...0,03, and in the case of unprotected contact with moist soil is increased to 0.15...0.25. On the inside of the walls there is a damp, mildew. Evaporating water increases humidity in the room, and the salts released when it evaporates from salt solutions lead to peeling paint, destruction of plaster and wall material.

Modelling of horizontal pipe drainage for Sultansandjar dam

The article discusses research work results for new type horizontal pipe drainage in earth fill dams, obtained from a physical model for Sultansandjar dam, made of natural sand with scale of 1:75. The main goal of the work is to determine the location and discharge from new drainage, as well as to determine the location of the phreatic surface in the dam body. The task was accomplished with the account of main factors, such as freezing depth, capillary rise height of water and the scope of work.

Capillary Nylon 6 polymer material produced by femtosecond laser processing.

A wicking Nylon 6 polymer material was produced through surface structuring by a direct femtosecond laser nano/microstructuring approach. The produced wicking structure is an array of parallel microgrooves, the surface of which is textured with irregular nanostructures and fine microstructures. High-speed imaging of water spreading vertically uphill against the gravity discloses a series of capillary flow regimes with h ∝ t, h ∝ t1/2, and h ∝ t1/3 scaling laws, where h is the height of capillary rise and t is the time. In the initial stage, the capillary flow occurs with a single front, from which at a certain time a precursor front forms and advances ahead of the main one. Our study shows that the onset of the precursor front occurs in h ∝ t flow regime. The created material exhibits excellent wicking properties and may find applications in various technologically important areas.

MSWI Bottom Ash Application to Resist Sulfate Attack on Concrete

This research provides a strategy for partially replacing cement with municipal solid waste incineration (MSWI) bottom ash (BA) to improve the performance of concrete against sulphate attack. Mortar strength tests were performed firstly to evaluate the hydration activity of the ground BA. Concrete specimens were cured in standard conditions and immersed in a solution that contained 10% sodium sulfate. Then, the compressive strength of these specimens was measured to investigate the mechanical properties and durability of the concrete. Next, the capillary porosity of the concrete was determined from the volume fractions of water lost in specimens. Finally, the transport of the sulphate solution in concrete was analyzed using capillary rise, crystallization rate, and solution absorption tests. The results indicated that BA had a certain hydration activity. The equivalent replacement of cement by BA decreased the compressive strength of the specimens but increased the durability of the concrete. There was an excellent correlation between capillary rise height, sulfate solution absorption amount, crystallization rate, and coarse capillary porosity. The addition of BA can decrease the coarse capillary porosity and further slow the capillary transport and crystallization of sulfate solution in concrete. Overall, the replacement of cement with BA can improve the durability of concrete and actualize the utilization of MSWI residues as a resource.

Reduction thermal resistance methods in the thermal stabilizer

The thermal resistance of the composite thermal stabilizer and methods for its reduction are investigated. The thermal resistance of thermal stabilizer decreases due to the heat exchange intensification in evaporator by a layer of aluminum oxide nanoparticles. A method of producing aluminum oxide nanoparticles has been developed. The liquid capillary rise height is measured in the layer of nanoparticles. Estimate of the properties stability is obtained in the coating from aluminum oxide nanoparticles. The thermal resistance dependences are obtained on the transferred heat flux for models of thermal stabilizers from steel and aluminum

Experimental study on the capillary performance of aluminum micro-grooved wicks with reentrant cavity array

In order to enhance the capillary performance for two-phase heat transfer apparatus, the aluminum micro-grooved wick with reentrant cavity array (MGRA) was developed by using orthogonal Ploughing-Extrusion (P-E) method. Different MGRAs with variation in the P-E pitch and depth were designed to study the effect of the fabrication parameters on the capillary performance and obtain the optimal wick structures. The IR-thermal imaging method and forced liquid flow approach were used in the capillary rise and permeability tests, respectively. It was found that the reentrant cavities became more visible and bigger with a larger pitch or smaller depth. The results manifested that the capillary rise height decreased with the increasing longitudinal P-E pitch and depth. Besides, the permeability increased with increase of pitch but decreased with increases of depth. The capillary parameter K·ΔPcap was taken as a comprehensive index to evaluate the wicks. The sample with the largest pitch and smallest depth in the tests obtained the maximal value of K·ΔPcap due to the good balance between the permeability and capillary pressure. Therefore, this sample may be the optimum structural design in this study for the application as enhanced wick for two-phase heat transfer apparatus.

Onset of thin film meniscus along a fibre

The dynamics of spreading of a macroscopic liquid droplet over a wetting surface is often described by a power-law relaxation, namely, the droplet radius increases as $t^{m}$ for time $t$, which is known as Tanner’s law. Here we show, by both experiments and theory, that when the liquid spreading takes place between a thin soap film and a glass fibre penetrating the film, the spreading is significantly slowed down. When the film thickness $\ell$ becomes smaller than the fibre diameter $d$, the strong hydrodynamic confinement effect of the soap film gives rise to a logarithmic relaxation with fibre creeping time $t$. Such a slow dynamics of spreading is observed for hours both in the measured time-dependent height of capillary rise $h(t)$ on the fibre surface and viscous friction coefficient $\unicode[STIX]{x1D709}_{s}(t)$ felt by the glass fibre in contact with the soap film. A new theoretical approach based on the Onsager variational principle is developed to describe the dynamics of thin film spreading along a fibre. The newly derived equations of motion provide the analytical solutions of $h(t)$ and contact angle $\unicode[STIX]{x1D703}(t)$, which are found to be in good agreement with the experimental results. Our work thus provides a common framework for understanding the confinement effect of thin soap films on the dynamics of spreading along a fibre.

Infrared Thermography technique (IRT) for the evaluation of the hydric behavior of building stones

The water distribution into stone specimens in laboratory conditions is evaluated through the infrared thermography method (IRT). Porous building stones samples (calcarenite and sandstone) are examined under stable laboratory conditions (controlled temperature and relative humidity) in order to simulate the same hydric behavior in real scale of material systems <em>in situ.</em> Hydric tests monitored through IRT are performed in order to analyze the capillary water absorption and evaporation transport phenomena into stone samples. IRT technique allows to record thermal images at different intervals of time highlighting the internal capillary and evaporation rise heights, responsible for the majority of decay processes occurring in masonries. The geometric shape of the damped area and the time of spreading are directly related to the open porosity of the investigated stone materials. Hydric tests are repeated for each splitting plane of the specimens (faces), in order to obtain useful results that could be applied for real masonries. Results demonstrate the usefulness of IRT as a non-destructive and portable technique in the field of new construction and for restoration purposes, as well as its importance in characterizing the physical stone features and the effectiveness of applied conservation treatments.

Drainage, rebound and oscillation of a meniscus in a tube

In this paper, the drainage and subsequent rebound of a liquid column in a cylindrical tube is examined experimentally and theoretically. When liquid is drawn up into a capillary and then released under gravity, inertia allows the meniscus to overshoot the equilibrium capillary rise height. The meniscus then rebounds up the tube, again overshooting the equilibrium height and undergoes oscillation. By varying both the immersion depth and radius of the tube, one can observe rich dynamical behavior, with the most dramatic being the formation of a fast liquid jet, barely visible to the naked eye but easily captured with high-speed video. In addition to the flow separation caused by the sudden expansion at the end of the tube, this jet serves as a mechanism of energy dissipation. Some qualitative differences between the works of Quere et al. [“Rebounds in a capillary tube,” Langmuir 15, 3679–3682 (1999)] and Lorenceau et al. [“Gravitational oscillations of a liquid column in a pipe,” Phys. Fluids 14(6), 1985–1992 (2002)] and the present experiment are observed and discussed. A critical condition for oscillatory behavior is derived theoretically and matches well with the experimental observation. Once in the oscillatory regime, both the maximum depth below and the maximum rebound height above the equilibrium level are investigated by performing a systematic sweep through the relevant parameter space, incorporating the initial meniscus height, immersion depth, tube radius, and fluid properties. Lastly, the characteristic period of oscillation, tp, is assessed and found to be largely independent of fluid viscosity, and could be reasonably well-collapsed by a single curve whereby tp∼hi, where hi is the tube immersion depth.

Fractal imbibition in Koch's curve-like capillar tubes

Fractal geometry eects in capillary imbibition process are studied. Capillary rise analysis in Koch's curve-like tubes were be carried out with iterations i = 0; 1; 2; 3; 4; 5. The behaviour was characterized in function of time, fractal geometry and height of capillary rise. An geometrical relationship for fractal dimension of ow tortuosity (dr) in porous media is obtained. The analytical model of Lucas-Washburn-Cai to describe the capillary rise by spontaneus imbibition in tubes with deterministic fractal geometry is adjusted. The equilibrium height time as function of fractal dimension of ow tortuosity in capillary tubes with tortuous path is also derived.

Estimation of bare soil evaporation for different depths of water table in the wind-blown sand area of the Ordos Basin, China

Soil surface evaporation is a significant component of the hydrological cycle, occurring at the interface between the atmosphere and vadose zone, but it is affected by factors such as groundwater level, soil properties, solar radiation and others. In order to understand the soil evaporation characteristics in arid regions, a field experiment was conducted in the Ordos Basin, central China, and high accuracy sensors of soil moisture, moisture potential and temperature were installed in three field soil profiles with water-table depths (WTDs) of about 0.4, 1.4 and 2.2 m. Soil-surface-evaporation values were estimated by observed data combined with Darcy’s law. Results showed that: (1) soil-surface-evaporation rate is linked to moisture content and it is also affected by air temperature. When there is sufficient moisture in the soil profile, soil evaporation increases with rising air temperature. For a WTD larger than the height of capillary rise, the soil evaporation is related to soil moisture content, and when air temperature is above 25 °C, the soil moisture content reduces quickly and the evaporation rate lowers; (2) phreatic water contributes to soil surface evaporation under conditions in which the WTD is within the capillary fringe. This indicates that phreatic water would not participate in soil evaporation for a WTD larger than the height of capillary rise. This finding developed further the understanding of phreatic evaporation, and this study provides valuable information on recognized soil evaporation processes in the arid environment.

Multipurpose nonwoven viscose/polypropylene fabrics: Effect of fabric characteristics on sorption and dielectric properties

ABSTRACTIn this work, sorption and dielectric properties of viscose/polypropylene multipurpose nonwoven fabrics were examined. The analysis of sorption behavior showed that the changes of the water absorptive capacity, the height of capillary rise and water retention value are in a function of viscose fiber content, total porosity, the pore size and used web bonding process. It is observed that dielectric properties at frequencies from 30 Hz to 140 kHz, for samples exposed to different relative air humidity and wet samples, are dependent on viscose fiber content, web bonding process, frequency of electric field and bulk free water content. The effective dielectric permeability of wet samples rapidly decreases with an increase in frequency up to 3 kHz while spectra of the AC specific electrical conductivity showed a plateau above 13 kHz. It is also observed that the dielectric properties of wet samples increase by several orders of magnitude compared to dry samples. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2018, 56, 947–957

Wettability of Reservoir Rocks Having Different Polarity by a Model Nonionic Surfactant: Fluid Imbibition Study into Crushed Rock Packs

The imbibition of solutions of a model nonionic surfactant into packed beds of crushed reservoir rocks was studied using the Washburn technique. A linear dependence between the equivalent height of capillary rise and the square root of imbibition time was observed at different stages of imbibition experiments. It has been shown that, under the conditions when surfactants did not alter the polarity of rocks, the imbibition rate of surfactant solutions correlated well with the nondispersion (polar) component of the surface free energy of the rocks. It was possible to compare data obtained for different rocks by normalizing the slopes of imbibition curves over the corresponding slopes determined for a completely wetting fluid, hexamethyldisiloxane (HMDS). Such a normalization allowed one to account for substantial differences in the morphology of crushed rock powders. Overall, the observed trends in the imbibition behavior were qualitatively similar to the trends reported previously for the rise of surfactan...

Calculation of Capillary Rise Height of Soils by SWCC Model

The maximum capillary rise height of soil is a complex system which is mainly determined by the distribution characteristics of soil pores. The tests of the rising height of capillary water on 8 kinds of soils by the method of vertical tube are widely conducted to measure the maximum capillary rise height. Based on the BCC model and principles of thermodynamics, the soil‐water characteristic curve test is designed for the purpose of calculating the pore distribution of soil samples. A new method for calculating the maximum capillary rise height of soil is proposed by the author by using the distribution function of the soil pore. The coefficient β which reflects the relationship between the maximum capillary rise and the average pore radius of soils is utilized during the calculation process, and then the reference range of β for different soils is obtained according to series of experiments corresponding. The proposed calculation method offers an effective way to calculate the maximum capillary rise height, which can be applied to analyze the capillary effect area of relevant engineering problems.

Evaluation of the Influence of Jiangxiang Reservoir Immersion on Corp and Residential Areas

Reservoir immersion is an environmental geological issue. Jiangxiang reservoir was taken as an example, where both analytical and numerical methods were employed to calculate the banked-up water level after reservoir impoundment, based on the hydrological, meteorological, geological, and hydrogeological conditions. The capillary rise height of soils in the reservoir area was determined through in situ measurement and laboratory analysis. The depth of foundation and crop roots in residential areas can be obtained by field investigation. The critical depth to groundwater was calculated according to the height of capillary rise and land elevation. Furthermore, the influence of reservoir immersion was evaluated, which provides a scientific basis for the relocation of people in reservoir areas, planting of crops, and project investment.