THE FLOW OF FLUIDS THROUGH ACTIVATED CARBON RODS: III. THE FLOW OF ADSORBED FLUIDS

1952 ◽  
Vol 30 (5) ◽  
pp. 389-410 ◽  
Author(s):  
E. A. Flood ◽  
R. H. Tomlinson ◽  
A. E. Leger
Keyword(s):  
Empirical Equation ◽  
Flow Equation ◽  
Surface Forces ◽  
Physical Factors ◽  
Pressure Gradients ◽  
Total Flow ◽  
Flow Rates ◽  
Carbon Rods ◽  
Porous Adsorbent ◽  
Simple Flow

Total flow rates of gases through activated charcoal rods are regarded as consisting of the sums of comparatively independent flows through macropores and micropores. The flow rate through the macropore system is related to the relevant adsorption isotherm by means of an empirical equation having three arbitrary constants. The empirical equations can be fitted to all of our observed results within the experimental error. Assuming that the adsorbate behaves as a one-component fluid such as a gas in a gravitational field, it is shown that compressive surface forces give rise to large fluid pressures within micropores. A very simple flow equation is derived which is qualitatively in agreement with observed results and which indicates a mean micropore diameter, of the order of 10−7 cm. The derived equation illustrates the nature of the physical factors involved and shows that surface forces may increase flow rates of adsorbable gases by very large factors. The increased flow rates are due mainly to the greatly increased densities and to the increased pressure gradients resulting from the action of surface forces. A model porous adsorbent is presented which exhibits many properties of real adsorbent systems and illustrates especially the relations between adsorbate densities and the various tensions and pressures existing within micropore systems.

THE MICROPORE FLOW OF H2O AND D2O THROUGH ACTIVATED CARBON RODS

1956 ◽  
Vol 34 (9) ◽  
pp. 1288-1301 ◽  
Author(s):  
M. E. Huber ◽  
E. A. Flood ◽  
R. D. Heyding
Keyword(s):  
High Pressure ◽  
Flow Rate ◽  
Relative Viscosity ◽  
Adsorbed Water ◽  
Liquid Films ◽  
Surface Forces ◽  
Sudden Increase ◽  
Flow Data ◽  
Flow Rates ◽  
Carbon Rods

The flow rates of water adsorbed on activated charcoal have been measured at temperatures between −24 °C. and +35 °C. and compared with the flow rate of adsorbed D2O at 25 °C. In earlier papers a formula was presented which describes the micropore flow rate of adsorbed water as a laminar flow of liquid adsorbate under a high pressure gradient due to surface forces. Our results confirm this picture. From our flow data the relative viscosity of adsorbates can be calculated. Above 0 °C. the viscosity of the adsorbate shows nearly the same temperature dependence as liquid water; below 0 °C. the viscosity increases much more rapidly, but there is no sudden increase which could be ascribed to freezing of an appreciable fraction of the adsorbate at any particular temperature. The greater temperature coefficient of the adsorbate viscosity is consistent with a viscous flow of liquid films over a solid surface which exerts attractive forces on the liquid.

THE FLOW OF FLUIDS THROUGH ACTIVATED CARBON RODS: II. THE PORE STRUCTURE OF ACTIVATED CARBON

1952 ◽  
Vol 30 (4) ◽  
pp. 372-385 ◽  
Author(s):  
E. A. Flood ◽  
R. H. Tomlinson ◽  
A. E. Leger
Keyword(s):  
Activated Carbon ◽  
Zinc Chloride ◽  
Activated Carbons ◽  
Surface Forces ◽  
Flow Measurements ◽  
Flow Rates ◽  
Frequency Distributions ◽  
Carbon Rods ◽  
Ordinary Type ◽  
Flow Through

The flow rates of adsorbable gases through zinc chloride activated carbon rods are considerably greater than might be expected from classical considerations. From data independent of flow measurements, the pore-size frequency distributions of the activated carbon are deduced and a model macropore system presented. It is shown that flow rates of nonadsorbable gases are consistent with a mean macropore diameter of about 3 × 10−5 cm., as well as being consistent with what can be inferred concerning such structures. The macropore system is regarded as an interstitial structure and is described as a random assembly of "bottle necks" joining relatively large void spaces. The assembly is described by means of two constant parameters and one stochastic variable. The mean micro-pore diameter of zinc chloride activated carbons is generally regarded as being of the order of 2 × 10−7 cm. or less. It is shown that no ordinary type of effusive or diffusive flow through pores of the order of 2 × 10−7 cm. can be appreciable compared with the flow through the macropore system, unless surface forces increase flow rates by large factors. In the case of strongly adsorbed gases the anomalous flow rates are ascribed to a flow through the micropore system and hence it is inferred that surface forces introduce large factors tending to increase flow rates in these very small pores.

THE FLOW OF FLUIDS THROUGH ACTIVATED CARBON RODS.

1952 ◽  
Vol 30 (4) ◽  
pp. 348-371 ◽  
Author(s):  
E. A. Flood ◽  
R. H. Tomlinson ◽  
A. E. Leger
Keyword(s):  
Activated Carbon ◽  
Relative Pressure ◽  
End Effects ◽  
Flow Rates ◽  
Frequency Distributions ◽  
Literal Sense ◽  
Fine Grained ◽  
Porous Bodies ◽  
Carbon Rods ◽  
Flow Through

The flow rates of the vapors of benzene, ethyl chloride, diethyl ether, methanol, and water through activated carbon rods have been found to exceed, considerably, flow rates calculated by classical equations. The excess flow rates show maxima in widely different relative pressure regions and are ascribed to flow of adsorbed material. An empirical equation is presented which correlates the observed flow rates with relevant adsorption isotherms. Classical equations of flow through elliptical and rectangular pipes are discussed with reference to flow through fine-grained porous materials. It is shown that equations of the Adzumi type are roughly valid as applied to fine-grained porous bodies, but that without a knowledge of the frequency distributions of pore sizes and shapes, flow data cannot be related to pore dimensions in any literal sense. End effects are discussed.

scholarly journals The creeping motion of liquid drops through a circular tube of comparable diameter

1975 ◽  
Vol 71 (2) ◽  
pp. 361-383 ◽  
Author(s):  
B. P. Ho ◽  
L. G. Leal
Keyword(s):  
Pressure Drop ◽  
Circular Tube ◽  
Total Flow ◽  
Flow Rates ◽  
Liquid Drops ◽  
Neutrally Buoyant ◽  
Creeping Motion

The creeping motion through a circular tube of neutrally buoyant Newtonian drops which have an undeformed radius comparable to that of the tube was studied experimentally. Both a Newtonian and a viscoelastic suspending fluid were used in order to determine the influence of viscoelasticity. The extra pressure drop owing to the presence of the suspended drops, the shape and velocity of the drops, and the streamlines of the flow are reported for various viscosity ratios, total flow rates and drop sizes.

Effect of reaction-rate on leaching of phosphate through sandy soils of Western-Australia

Soil Research ◽  
1995 ◽  
Vol 33 (1) ◽  
pp. 211 ◽  
Author(s):  
RG Gerritse
Keyword(s):  
Computer Simulation ◽  
Reaction Rate ◽  
Empirical Equation ◽  
Sandy Soils ◽  
Breakthrough Curves ◽  
Computer Simulation Model ◽  
Input Concentration ◽  
Flow Rates ◽  
Field Situation ◽  
Leaching Experiments

The effect of reaction rate on the mobility of phosphate in soils was measured from breakthrough curves in the leachate from small columns of soil, following step increases in the input concentration of phosphate. Average mobilities of phosphate in columns of soil, following a step increase in the input concentration, decrease with decreasing rate of flow and with increasing distance travelled and appear to be linearly correlated on a log-log scale with both flow rate and distance travelled. An empirical equation, describing these relationships, fits data from leaching experiments at flow rates between 30 and 600 cm/day in columns of soil ~10-30 cm in length. Two coefficients are required and are obtained by curve fitting breakthrough curves, calculated with a numerical computer simulation model, to experimental breakthrough curves. The fitted equation enables extrapolation to flow rates and distances travelled that are more relevant to a field situation.

Possible Reason of the Dependence of an Apparent Permeability on the Pressure Gradient at low Flow Rates in Laboratory Study

2021 ◽  
Author(s):  
Nikolay Baryshnikov ◽  
Evgeniy Zenchenko ◽  
Sergey Turuntaev
Keyword(s):  
Pressure Gradient ◽  
Pore Pressure ◽  
Pore Space ◽  
Low Flow ◽  
Pressure Gradients ◽  
Apparent Permeability ◽  
Flow Rates ◽  
Rock Samples ◽  
Pore Pressure Gradient ◽  
Filtration Properties

<p>Currently, a number of studies showing that the injection of fluid into the formation can cause induced seismicity. Usually, it is associated with a change in the stress-strain state of the reservoir during the pore pressure front propagation. Modeling this process requires knowledge of the features of the filtration properties of reservoir rocks. Many researchers note the fact that the measured permeability of rock samples decreases at low pressure gradients. Among other things, this may be due to the formation of boundary adhesion layers with altered properties at the interfaces between the liquid and solid phases. The characteristic thickness of such layer can be fractions of a micron, and the effect becomes significant when filtering the fluid in rocks with a comparable characteristic pore size. The purpose of this work was to study the filtration properties of rock samples with low permeability at low flow rates. Laboratory modeling of such processes is associated with significant technical difficulties, primarily with the accuracy limit of measuring instruments when approaching zero speed values. The technique used by us to conduct the experiment and data processing allows us to study the dependence of the apparent permeability on the pore pressure gradient in the range of 0.01 MPa/m, which is comparable to the characteristic pressure gradients during the development of oil fields. In the course of the study, we carried out laboratory experiments on limestone core samples, during which the dependencies of their apparent permeability on the pore pressure gradient were obtained. We observed a significant decrease in their permeability at low flow rates. In the course of analyzing the experimental results, we proposed that a decrease in apparent permeability may occur due to the effect of even a small amount of residual gas in the pore space of the samples. This has been confirmed by additional experiments. The possibility of clogging of core sample pore space must be considered when conducting when conducting laboratory studies of the core apparent permeability.</p>

Effect of CS2 Flow Rate on the Formation of Aligned Carbon Microcoils

2019 ◽  
Vol 947 ◽  
pp. 40-46
Author(s):  
Hyun Ji Kim ◽  
Sung Hoon Kim
Keyword(s):  
Flow Rate ◽  
Vapor Deposition ◽  
Rate Ratio ◽  
Chemical Vapor ◽  
Regular Structure ◽  
Flow Rate Ratio ◽  
Total Flow ◽  
Total Flow Rate ◽  
Flow Rates ◽  
Thermal Chemical Vapor Deposition

The formation of aligned carbon microcoils could be achieved using C2H2 as a source gas and CS2 as an incorporated additive gas under thermal chemical vapor deposition system. To elucidate the ratio of C2H2/CS2 for the formation of the aligned carbon microcoils, the CS2 flow rate was first manipulated under the identical C2H2 flow rate (500sccm) condition. The formation and the alignment of carbon microcoils could be only achieved under the ratio of C2H2/CS2 = 33.3 condition, namely the flow rates of CS2 = 15sccm and C2H2= 500sccm. The total flow rate of the used gases was varied under the identical C2H2/CS2 flow rate ratio (33.3) condition. The C2H2 flow rate was manipulated under the identical CS2 flow rate (15sccm) condition. It was found that the formation and the alignment of carbon microcoils could be only achieved under the condition of 15sccm of CS2 flow rate in the range of 200 ~ 500sccm of C2H2 flow rate, regardless of the flow rate ratio of C2H2/CS2 and the total flow rate. The crystal structure of the well-aligned CMCs reveals the increase in the (002) peak in XRD spectrum for the aligned carbon microcoils, indicating the existence of the more regular structure in the aligned carbon microcoils. Based on these results, the cause for the formation of the aligned carbon microcoils only in the case of the CS2 flow rate = 15sccm with the imaginary pictures for the flow rate ratio of C2H2/CS2 just above the substrate were proposed.

Total Flow Rates in an Isotope Separation System

1964 ◽  
Vol 3 (1) ◽  
pp. 83-85 ◽  
Author(s):  
Alexander Apelblat ◽  
Gideon Pery
Keyword(s):  
Isotope Separation ◽  
Separation System ◽  
Total Flow ◽  
Flow Rates

Improved hydrodynamics of a new aortic cannula with a novel tip design

Perfusion ◽  
2004 ◽  
Vol 19 (3) ◽  
pp. 193-197 ◽  
Author(s):  
Michael Scharfschwerdt ◽  
Axel Richter ◽  
Kurt Boehmer ◽  
Detlef Repenning ◽  
Hans-H. Sievers
Keyword(s):  
Flow Visualization ◽  
Pressure Profile ◽  
Back Pressure ◽  
Low Back ◽  
Pressure Gradients ◽  
Flow Area ◽  
Flow Rates ◽  
Background Reduction ◽  
Mock Circulation ◽  
Aortic Cannula

Background: Reduction of atheroembolic complications during cardiopulmonary bypass remains a major challenge in cardiac surgery. New cannula tip designs may help to attenuate this problem by improved hydrodynamics. Methods: Pressure gradients and back pressures of a new aortic cannula tip design were measured and compared with the Medos X-Flow, Sarns Soft-Flow and Argyle THI cannulae at various flow rates in a mock circulation followed by flow visualization. Results: Pressure gradients were the lowest for the new cannula. Back pressures of the new cannula were up to 84% lower than for the Argyle cannula. The back pressure profile and flow visualization of the new cannula showed broad centric flow dispersion with a transcannula increase of flow area from 38 mm2 to 139 mm2. Conclusions: The new design of an aortic cannula tip provides improved hydrodynamics, with low pressure gradients, low back pressures and a uniform central dispersion of flow, reducing the sandblasting effect.

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