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1

Effect of suction on the mechanical behaviour of unsaturated compacted clay-sand mixtures

Bouchemella Salima, Taibi Said

Studia Geotechnica et Mechanica

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2022

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Vol. 44, nr 3

175--189

EN

In this work, a series of unconfined compression tests at different water contents were performed to investigate the mechanical behaviour of clay–sand mixtures compacted in standard Proctor conditions. For studying the effect of water content and suction on unconfined compressive strength (UCS) and on strain secant modulus (E50 modulus) of these mixtures, drying–wetting paths were defined by measuring the soil–water characteristic curves (SWCCs) using osmotic and salt solution techniques and filter paper method. The results highlighted that an increase in sand content of the mixture leads to an increase in the maximum dry densities and a decrease in the optimum water content of the materials. However, at the given state, when clay is mixed with 25% of sand, the UCS and E50 modulus increase to 37% and 70%, respectively, compared to those of clayey samples. But when clay is mixed with 50% of sand, the UCS and E50 modulus decrease to 38% and 46%, respectively, compared to those of clayey samples. The results also indicate that the UCS and E50 increase with a decrease in the water content and an increase in suction, irrespective of the sand content.

2

Heat transfer in oscillating flow through porous medium with dissipative heat

Guria M.

International Journal of Applied Mechanics and Engineering

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2022

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Vol. 27, no. 2

77--86

EN

In this paper, heat transfer in flow between two horizontal parallel porous plates through a porous medium when the upper plate oscillates in its own plane has been analyzed taking into account the effect of viscous dissipation. An increment in the Prandtl number or Reynolds number results in an increment of the temperature profile. With an increase in viscous dissipative heat the temperature distribution decreases.

3

Unsteady MHD plane Couette-Poiseuille flow of fourthgrade fluid with thermal radiation, chemical reaction and suction effects

Joseph K. M., Ayankop-Andi E., Mohammed S. U.

International Journal of Applied Mechanics and Engineering

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2021

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Vol. 26, no. 4

77--98

EN

This study investigates the unsteady MHD flow of a fourth-grade fluid in a horizontal parallel plates channel. The upper plate is oscillating and moving while the bottom plate is stationary. Solutions for momentum, energy and concentration equations are obtained by the He-Laplace scheme. This method was also used by Idowu and Sani [12] and there is agreement with our results. The effect of various flow parameters controlling the physical situation is discussed with the aid of graphs. Significant results from this study show that velocity and temperature fields increase with the increase in the thermal radiation parameter, while velocity and concentric fields decrease with an increase in the chemical reaction parameter. Furthermore, velocity, temperature and concentric fields decrease with an increase in the suction parameter. It is also interesting to note that when 4S0=, our results will be in complete agreement with Idowu and Sani [12] results. The results of this work are applicable to industrial processes such as polymer extrusion of dye, draining of plastic films etc.

4

A numerical approach to slip flow of a micropolar fluid above a flat permeable contracting surface

Parthiban R., Palani G., Tinker Seema, Sharma R. P.

International Journal of Applied Mechanics and Engineering

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2021

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Vol. 26, no. 2

173--185

EN

A plain linear penetrable contracting sheet with slip over a micro-polar liquid with a stagnation-point flow is analyzed. Through similarity mapping, the mathematical modeling statements are transformed as ODE’s and numerical results are found by shooting techniques. The varying impacts of physical quantities on the momentum, micro-rotation, and temperature were demonstrated through graphs. The computed measures including shear and couple stress with distinct measures of factors involved in this proposed problem are presented through a table.

5

Volumetric behavior of natural swelling soil on drying-wetting paths. Application to the Boumagueur marl -Algeria-

Mebarki Mehdi, Kareche Toufik, Benyahia Sabah, Derfouf Feth-Ellah Mounir, Abou-Bekr Nabil, Taibi Said

Studia Geotechnica et Mechanica

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2020

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Vol. 42, nr 3

248--262

EN

This article presents the results of experimental work carried out both in situ (coring; pressuremeter test) and in the laboratory (drying-wetting and oedometric tests) to describe the volumetric behavior on drying-wetting path of a swelling clayey soil of eastern Algeria. In order to perform drying-wetting tests the osmotic technique and saturated salts solutions were used. These suction-imposed methods have gained widespread acceptance as reliable methods for imposing suction on soil specimens. They allowed to sweep a wide range of suctions between 0 and 500 MPa. The ability to impose suction on soil specimens allows for drying and wetting stress paths to be applied to evaluate resulting changes in state parameters (void ratio, degree of saturation and water content). These paths were carried out on specimens with different initial states. Slurries of soil were used to characterize the reference behavior, while the undisturbed soil samples allow to describe the behavior of material under in situ conditions. In the last part of this article and to specify the behavior observed in the saturated domain, a comparison between the resulting deformations of the drying-wetting test and those resulting from the oedometric test was made.

6

Transient heat and mass transfer of hydromagnetic effects on the flow past a porous medium with movable vertical permeablesheet

Okedoye A. M., Salawu S. O.

International Journal of Applied Mechanics and Engineering

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2020

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Vol. 25, no. 4

175--190

EN

An unsteady flow of heat and species transport through a porous medium in an infinite movable vertical permeable flat surface is considered. The hydromagnetic chemical reactive fluid flow is stimulated by the thermal and solutant convection, and propelled by the movement of the surface. The formulated nonlinear flow equations in time space are solved analytically by asymptotic expansions to obtain solutions for the flow momentum, energy and chemical concentration for various thermo-physical parameters. The existence of flow characteristic is defined with the assistance of the flow parameters. In the study, the impact of some pertinent flow terms is reported and discussed. The study revealed that the species boundary layer increases with a generative chemical reaction and decreases with a destructive chemical reaction. Also, arise in the generative species reaction term reduces the flow momentum for the cooling surface. The impact of other flow governing parameters is displayed graphically as well as the fluid wall friction, wall energy and species gradients. The results of this study are important in chemical thermal engineering for monitoring processes to avoid solution blow up.

7

Mechanism of biochar soil pore-gas-water interaction: gas properties of biochar-amended sandy soil at diferent degrees of compaction using KNN modeling

Garg Ankit, Huang He, Kushvaha Vinod, Madhushri Priyanka, Kamchoom Viroon, Wani Insha, Koshy Nevin, Zhu Hong-Hu

Acta Geophysica

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2020

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Vol. 68, no. 1

207--217

EN

Soil compaction has contrasting efect on soil strength (i.e., positive) and vegetation growth (i.e., negative), respectively. Biochar has been utilized mostly in combination with soils in both agricultural felds (i.e., loose soils) and geo-structures (i.e., dense soil slopes, landfll cover) for improving water retention due to its microporous structure. Biochar is also found to be useful to reduce gas permeability in compacted soil recently. However, the efciency of biochar in reducing gas permeability in loose and dense soils is rarely understood. The objective of this study is to analyze efects of compaction on gas permeability in soil at diferent degrees of compaction (i.e., 65%, 80% and 95%) and also diferent biochar amendment contents (0%, 5% and 10%). Another aim is to identify relative signifcance of parameters (soil suction, water content, biochar content and compaction) in afecting gas permeability. Experiments were conducted before applying k-nearest neighbor (KNN) modeling technique for identifying relative signifcance of parameters. Biochar was synthesized from a coastal invasive species (water hyacinth), which has relatively no infuence on food chain (as unlike in biochar produced from biomass such as rice husk, straw, peanut shell). Based on measurements and KNN modeling, it was found that gas permeability of biochar-amended soil is relatively lower than that of soil without amendment. It was found from KNN model that for denser soils, higher amount of soil suction is mobilized for a signifcant increase in gas permeability as compared to loose soils. Among all parameters, soil suction is found to be most infuential in afecting gas permeability followed by water content and compaction.

8

Radiation absorption and chemical reaction effects on Rivlin-Ericksen flow past a vertical moving porous plate

Sravanthi C. S., Gorla R. S. R.

International Journal of Applied Mechanics and Engineering

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2019

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Vol. 24, no. 3

675--689

EN

An analysis has been carried out to study the combined effects of radiation absorption and chemical reaction on an incompressible, electrically conducting and radiating flow of a Rivlin-Ericksen fluid along a semi-infinite vertical permeable moving plate in the presence of a transverse applied magnetic field. It is assumed that the suction velocity, the temperature and the concentration at the wall are exponentially varying with time. The dimensionless governing equations for this investigation are solved analytically using two-term harmonic and non-harmonic functions. A comparison is made with the available results in the literature for a special case and our results are in very good agreement with the known results. A parametric study of the physical parameters is made and results are presented through graphs and tables. The results indicate that the fluid velocity and temperature could be controlled by varying the radiation absorption.

9

O potrzebie uwzględniania zasysania w praktycznych zagadnieniach filtracji wody podziemnej

Hauryłkiewicz J.

Przegląd Geologiczny

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2018

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Vol. 66, nr 8

481--482

EN

Seven examples of issues have been pointed out, when one should take into account the suction exerting on groundwater by capillary attraction from fine sands or similar other fine soils.

10

Problematyka systemów zbierania i załadunku zanieczyszczeń w aspekcie zamiatarek podciśnieniowych

Stawowiak M.

Magazyn Autostrady

|

2018

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Nr 4

66--70

PL

W artykule przedstawiono systemy podciśnieniowego zbierania i załadunku w samobieżnych zamiatarkach podciśnieniowych, metodologię doboru wymiarów ssawy zasysającej zanieczyszczenia w zamiatarkach podciśnieniowych, a także schematy działania ssawy bosej oraz ssawy kołnierzowej. Artykuł zakończony jest podsumowaniem, traktującym w sposób ogólny problematykę samobieżnych zamiatarek podciśnieniowych.

EN

The article presents systems for vacuum collection and loading in self-propelled vacuum sweepers. In addition, the author of this article presented a methodology for the selection of suction dimensions sucking in pollution in vacuum sweepers. The diagrams of barefoot suction and flanged suction are also presented. The article ends with a summary that deals in general with the problem of self-propelled vacuum sweepers.

11

Bidirectionally stretched flow of Jeffrey liquid with nanoparticles, Rosseland radiation and variable thermal conductivity

Archana M., Gireesha B. J., Rashidi M. M., Prasannakumara B. C., Gorla R. S. R.

Archives of Thermodynamics

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2018

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Vol. 39, no 4

33–-57

EN

Heat and mass transfer stretched flow of an incompressible, electrically conducting Jeffrey fluid has been studied numerically. Nanoparticles are suspended in the base fluid and it has many applications such as cooling of engines, thermal absorption systems, lubricants fuel cell, nanodrug delivery system and so on. Temperature dependent variable thermal conductivity with Rosseland approximation is taken into account and suction effect is employed in the boundary conditions. The governing partial differential equations are first transformed into set of ordinary differential equations using selected similarity transformations, which are then solved numerically using Runge-Kutta-Felhberg fourth-fifth order method along with shooting technique. The flow, heat and mass transfer characteristics with local Nusselt number for various physical parameters are presented graphically and a detailed discussion regarding the effect of flow parameters on velocity and temperature profiles are provided. It is found that, increase of variable thermal conductivity, radiation, Brownian motion and thermophoresis parameter increases the rate of heat transfer. Local Nusselt number has been computed for various parameters and it is observed that, in the presence of variable thermal conductivity and Rosseland approximation, heat transfer characteristics are higher as compared to the constant thermal conductivity and linear thermal radiation.

12

Problems of dust removal from multi-cyclones of engine air cleaners in cross-country motor vehicles

Dziubak T.

Archiwum Motoryzacji

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2017

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Vol. 76, nr 2

37--62

EN

The organization of the process of extracting dust (by suction) from inertial intake air cleaners of internal combustion (IC) engines of motor vehicles has been discussed. The ejector configurations used in the dust removal systems have been demonstrated. Examples of contaminant extraction systems based on the ejection effect have been presented. The notion of dust suction ratio has been defined. The impact of this ratio on the filter restriction and air filtration efficiency characteristics of individual cyclones has been analysed. The impact of the dust extraction from the dust settling chamber of an inertial air cleaner (multi-cyclone) on the filtration efficiency has been explained. The impact of the dust extraction from the dust settling chamber on the unevenness of dust suction from individual cyclones of a multi-cyclone has been analysed and the reasons for the unevenness have been shown. The analysis results visualizing the impact of the unevenness of suction on the filtration efficiency of a multi-cyclone combined with a nonwoven fabric filter element have been quoted. The methods aimed at the obtaining of relatively even flow rates of the streams sucked off from individual cyclones have been analysed. It has been shown that even flow rates of the suction streams flowing out from individual cyclones can be obtained by appropriately modifying the structure of the multi-cyclone’s dust settling chamber.

PL

Omówiono organizację procesu odsysania pyłu z bezwładnościowych filtrów powietrza wlotowego silników spalinowych pojazdów mechanicznych. Przedstawiono stosowane konfiguracje ejektorów w układach odsysania pyłu. Omówiono przykłady układów ejekcyjnego odsysania zanieczyszczeń. Zdefiniowano stopień odsysania pyłu. Przeanalizowano jego wpływ na charakterystykę przepływową i skuteczności filtracji powietrza pojedynczych cyklonów. Wyjaśniono zjawisko wpływu odsysania pyłu z osadnika filtru bezwładnościowego (multicyklonu) na skuteczność filtracji. Przeanalizowano wpływ odsysania pyłu z osadnika na nierównomierność odsysania z pojedynczych cyklonów multicyklonu oraz pokazano przyczyny nierównomierności. Przytoczono wyniki obrazujące wpływ nierównomierności odsysania na skuteczność filtracji multicyklonu i wkładu włókninowego. Przeanalizowano metody prowadzące do uzyskania względnej równomierności strumieni odsysanych z pojedynczych cyklonów. Wykazano, że równomierne wartości strumieni odsysania z pojedynczych cyklonów można uzyskać poprzez odpowiednią zmianę struktury osadnika pyłu multicyklonu.

13

Wpływ odsysania mieszaniny parowo-powietrznej na efektywność procesu chłodzenia strumieniem kropel

Sobczak M., Zapałowicz Z.

Zeszyty Naukowe Politechniki Rzeszowskiej. Mechanika

|

2016

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z. 88 [293], nr 1

55--64

PL

W pracy przedstawiono budowę stanowiska badawczego, metodykę pomiarów i obliczeń oraz wstępne wyniki badań doświadczalnych procesu chłodzenia podgrzewanej powierzchni strumieniem kropel wody, gdy powstająca mieszanina parowo-powietrzna jest odsysana z zamkniętej przestrzeni otaczającej grzejnik. Badania przeprowadzono dla trzech wariantów procesu chłodzenia grzejnika tj. przy zastosowaniu bocznego odsysania powstającej mieszaniny przestrzeni nad ogrzewaną powierzchnią, przy odsysaniu tej mieszaniny z wnętrza tej przestrzeni oraz w warunkach, gdy mieszanina powietrzno-parowa nie jest odsysana. Celem pracy jest analiza wpływu miejsca odsysania mieszaniny parowo-powietrznej oraz czasu na intensywność procesu odparowania filmu wodnego. Eksperyment przeprowadzono dla temperatury podgrzewanej powierzchni wynoszącej 90°C. Na podstawie analizy wstępnych wyników badań doświadczalnych oszacowano, że odsysanie mieszaniny parowo-powietrznej z wnętrza przestrzeni zwiększa intensywność odparowania chłodziwa (wody) o około 5÷30%, gdy czas chłodzenia wzrasta trzykrotnie. Zmiana miejsca odsysania mieszaniny parowo-powietrznej nie zmienia istotnie intensywności odparowania filmu wodnego.

EN

The paper presents test stand, research methodology and preliminary results of an experimental cooling of hot surface by stream of water droplets when the resulting steam-air mixture is sucked - off from the confined space surrounding the heater. Experiments were carried out for three cases of cooling process. In the first case steam-air mixture was sucked off from the confined space over heated surface through the outlet at the lateral surface of glass cover, in the second case mixture was sucked off from the center of the confined space over the hot surface and in the third case mixture in question was not sucked off. The vacuum pump was used for suction of steam-air mixture. The paper is aimed at analysis of effect location of steam-air suction point and time on intensity of water film evaporation. The temperature of the heating plate surface during experiments of 90°C. Based on preliminary analysis of the experimental results it was estimated that suction of vapor – air mixture from the interior of the confined space increases the intensity of cooling fluid (water) evaporation of approximately 5-30%, when the cooling time is increased threefold. Change in location of vapor-air suction mixture point enables to increase the intensity of water film evaporation is too high.

14

Sprężysto-plastyczny model gruntu nienawodnionego

Fedczuk P.

Inżynieria i Budownictwo

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2016

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R. 72, nr 11

595--597

PL

Przedstawiono koncepcję sprężysto-plastycznego modelu częściowo nawodnionego gruntu. Model jest oparty na zmodyfikowanym równaniu powierzchni plastyczności Wheelera i Shivakumara. W przypadku zmiennej wartości ssania uogólnione prawo wzmocnienia wiąże przyrost plastycznej części wskaźnika porowatości z poziomem efektywnego naprężenia i ssania.

EN

The paper presents the concept of elasto-plastic model for partially saturated soil. The model operates equation of Wheeler and Shivakumar’s plastic surface. Generalized hardening rule, for changing value of suction, connects the increment of plastic part of void ratio with stress and suction levels.

15

Three dimensional flow and mass transfer analysis of a second grade fluid in a porous channel with a lower stretching wall

Khan N. A., Naz F.

International Journal of Applied Mechanics and Engineering

|

2016

|

Vol. 21, no. 2

359--376

EN

This investigation analyses a three dimensional flow and mass transfer of a second grade fluid over a porous stretching wall in the presence of suction or injection. The equations governing the flow are attained in terms of partial differential equations. A similarity transformation has been utilized for the transformation of partial differential equations into the ordinary differential equations. The solutions of the nonlinear systems are given by the homotopy analysis method (HAM). A comparative study with the previous results of a viscous fluid has been made. The convergence of the series solution has also been considered explicitly. The influence of admissible parameters on the flows is delineated through graphs and appropriate results are presented. In addition, it is found that instantaneous suction and injection reduce viscous drag on the stretching sheet. It is also shown that suction or injection of a fluid through the surface is an example of mass transfer and it can change the flow field.

16

Effect of slip condition on vertical channel flow in the presence of radiation

Guria M.

International Journal of Applied Mechanics and Engineering

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2016

|

Vol. 21, no. 2

341--358

EN

An analysis is made on the three dimensional flow of a viscous incompressible fluid through a vertical channel in the presence of radiation in slip flow regime. The right plate is subjected to an uniform injection and the left plate to a periodic suction velocity distribution. The velocity and temperature fields have been derived using the perturbation technique. It is found that the velocity decreases with the increase of the slip parameter. It is also found that the velocity decreases with the increase of the radiation parameter but near the right plate it increases. For cooling of the plate, the velocity increases with the increase of the Grashoff number and decreases near the right plate but the reverse effect is observed for heating the plate.

17

On unsaturated soil mechanics – personal views on current research

Pande G. N., Pietruszczak S.

Studia Geotechnica et Mechanica

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2015

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Vol. 37, nr 3

73--84

EN

This paper presents the authors’ personal views on current research being conducted by various research groups around the world in the broad area of mechanics of unsaturated geomaterials in general and soils in particular. The topic is of interest to a wide spectrum of scientists and engineers working in diverse areas such as geology and geophysics, powder technology, agricultural, petroleum, chemical, geotechnical, civil, environmental and nuclear engineering. Even if we restrict ourselves to civil, geotechnical and environmental engineering, it is noted that a plethora of hypotheses as well as a number of empirical and semiempirical relations have been introduced for describing the mechanics of unsaturated porous media. However, many of these proposed advances as well as methods of testing may lack sound theoretical basis.

18

Evaluation of expansivity of Neogene clays and glacial tills from central Poland on the basis of suction tests

Izdebska-Mucha D., Wójcik E.

Geological Quarterly

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2015

|

Vol. 59, No. 3

593--602

EN

This paper presents the characteristics of the expansivity and quantitative prediction of heave of clay soils from Poland based on suction testing. 11 Neogene clays and 6 glacial tills, differing in genesis and plasticity, were analyzed to identify the expansive potential using eight empirical methods. The laboratory studies included measurements of soil-water characteristic curves and soil index properties. Data from water content, volume and suction measurements served to determine the suction compression index Ch and the suction-water content index Dh/Dw of the soils examined. The values of these indices are clearly dependent of the clay fraction content in tested soils. Compared with glacial tills, Neogene clays are expected to exhibit larger changes in volume due to changes in soil suction. Comparative results of the evaluation of expansivity suggest that the chosen classification methodologies provided consistent expansion ratings for glacial tills, while values for Neogene clays vary from low to very high. The lowest expansivity classes have been obtained from evaluation based on soil suction. The McKeen (1992) method has been adopted for calculations of the potential field heave of Neogene clays and glacial tills. In order to provide a rational estimation of expansive soil behavior, specialists should take into consideration the specific site and design features.

19

Badania wstępne wpływu odsysania mieszaniny parowo-powietrznej na efektywność wymiany ciepła między chłodziwem a podgrzewaną powierzchnią

Sobczak M., Zapałowicz Z.

Zeszyty Naukowe Politechniki Rzeszowskiej. Mechanika

|

2014

|

z. 86 [290], nr 2

249--256

PL

W pracy przedstawiono budowę stanowiska badawczego, metodykę pomiarów i obliczeń oraz wstępne wyniki badań doświadczalnych chłodzenia podgrzewanej powierzchni strugami wody. Celem pracy jest wstępna analiza wpływu procesu odsysania mieszaniny parowo-powietrznej na intensywność procesu odparowania filmu wodnego. Nagrzana powierzchnia chłodzona jest trzema strugami wody wytwarzanymi w zakraplaczach zamontowanych w płytce i ustawionych w wierzchołkach trójkąta równobocznego. Natężenie przepływu wody jest ustalone. W środku tego trójkąta umieszczono sondę połączoną z pompą próżniową, zadaniem której jest usunięcie powstałej nad powierzchnią filmu pary wodnej i otaczającego układ powietrza atmosferycznego. Strugi wody chłodzą powierzchnię roboczą grzejnika wykonanego z bloku miedzianego o wymiarach 0,04×0,04×0,02 m. Eksperyment przeprowadzono dla temperatury podgrzewanej powierzchni zmieniającej się w zakresie od 50÷100°C. Na podstawie analizy uzyskanych wstępnych wyników badań oszacowano, że odsysanie mieszaniny parowo-powietrznej z nad warstwy filmu cieczowego zwiększa się intensywność odparowania chłodziwa (wody) o około 25÷50%.

EN

The paper presents test stand structure, measurement and calculation methodology and initial results of investigation of preheated surface cooling by water stream The aim of this article is preliminary analysis of influence of steam-air mixture evacuation on the intensity of water film evaporation. The hot surface is cooling by three streams of water. Streams are produced in droppers mounted in plate and located in the vertices of a equilateral triangle. The water flow rate is stationary. In the center of triangle is mounted the probe connected to a vacuum pump that is used for evacuation of steam-air mixture from above the hot surface and atmospheric air surrounding the system. Streams of water cooling the heater surface made of cooper block with the dimensions: 0.04×0.04×0.02 m). The surface temperature of block is changed in the range from 50°C to 100°C. Based on the results of preliminary investigations itwas stated that the suction of steam-air mixture from above the liquid film layer enhancement the water film evaporation about 25÷50%.

20

A three-scale cracking criterion for drying soils

Hueckel T., Mielniczuk B., El Youssoufi M. S., Hy L. B., Laloui L.

Acta Geophysica

|

2014

|

Vol. 62, no. 5

1049--1059

EN

Cracking is a most unwanted development in soil structures under-going periodic drying and wetting. Desiccation cracks arise in an apparent absence of external forces. Hence, either an internal, self-equilibrated stress pattern resulting from kinematic incompatibilities, or a stress resulting from reaction forces at the constraints appear as a cracking cause, when reaching tensile strength. At a mesoscale, tubular drying pores are considered in the vicinity of a random imperfection, inducing a stress concentration in the presence of significant pore suction. This approach allows one to use the effective stress analysis, which otherwise, away from the stress concentration, usually yields compressive effective stress and hence a physically incompatible criterion for a tensile crack. Recent experiments on idealized configurations of clusters of grains provide geometrical data suggesting that an imperfection as a result of air entry deep into the granular medium penetrates over 4 to 8 internal radii of a typical pore could yield a tensile effective stress sufficient for crack propagation