scholarly journals Vibroextrusion flow of concrete mixtures in a right four-corner pyramidal channel

2021 ◽  
pp. 9-15
Author(s):  
Igor Andreiev ◽  
Andrey Pinchuk ◽  
Oleksandra Kramar
Keyword(s):  
Cross Section ◽  
Newtonian Fluid ◽  
Flow Rate ◽  
Rectangular Cross Section ◽  
Rectangular Channel ◽  
Maximum Flow ◽  
Fiber Reinforced Concrete ◽  
Concrete Mixture ◽  
Parallel Plates ◽  
Concrete Mixtures

The purpose of the research was to obtain calculation formulas for describing the flow of concrete mixtures and determining their viscosity directly in the process of vibroextrusion in regular quadrangular pyramidal channels. In solving the flow problems, it was taken into account that concrete mixtures are non-Newtonian systems in the conditions of a vibration field, and hydrodynamic theories were used to calculate the processes and rheological characteristics. Since the calculation formulas for describing the flow of fluids in a regular quadrangular pyramidal channel are absent and the channel has a square cross section, an analytical dependence was used to characterize the process, which describes the flow of a Newtonian fluid in a rectangular channel of constant cross section. The authors proposed for use simplified formulas for determining the maximum flow rate and flow rate of a Newtonian fluid in a channel of rectangular cross-section. The degree of decrease in the flow velocity and the flow rates of a Newtonian fluid in a channel of rectangular cross-section in comparison with the flow between flat parallel plates are analyzed. To describe the flow of concrete mixtures in regular quadrangular pyramidal channels, the proposed coefficients for reducing the speed and flow rate, as well as the existing formulas for the flow between flat symmetric stationary walls, which converge, were used. The possibility of using the obtained formula for the flow rate in a regular quadrangular pyramidal channel for calculating the viscosity of a concrete mixture during vibration extrusion is shown. To simplify the experimental procedure, a new formula for calculating the viscosity based on the expiration time for a certain amount of concrete mixture has been proposed. The formulas obtained are convenient for further mathematical processing and have no restrictions in their application. The proposed method for determining the viscosity expands the possibilities of studying the rheological properties of concrete mixtures in the vibroextrusion of fiber-reinforced concrete mixtures.

scholarly journals Finite Element Simulation of Newtonian and Non-Newtonian Fluid through the Parallel Plates Affixed with Single Screen

2020 ◽  
Vol 13 (1) ◽  
pp. 69-83
Author(s):  
Abid Ali Memon ◽  
Muhammad Asif Memon ◽  
Kaleemullah Bhatti ◽  
Gul Muhammad Shaikh
Keyword(s):  
Reynolds Number ◽  
Finite Element ◽  
Newtonian Fluid ◽  
Flow Rate ◽  
Rectangular Channel ◽  
Maximum Flow ◽  
Least Square ◽  
Maximum Flow Rate ◽  
Parallel Plates ◽  
The Impact

In the contemporary research article we have performed a numerical investigation of the non-Newtonian fluid flow through a rectangular channel with a fixed solid screen devoted at the angles 100 to 450 degrees. We have employed the power-law model for shear thickening and shear thinning fluids with the high Reynolds number between 1000 and 10,000. The obstacle has been solved by putting in the Galerkin’s least square strategy of the finite element method and the procedure has been carried out utilizing the commercial software COMSOL Multiphysics. Various flow properties such as 'maximum flow rate' and 'pressure' have been discussed in the terms of the Reynolds number and also using the linear and quadratic regressions in order to establish the relationship between them for the future analysis. Moreover the impact of turning screen in the shape of increment in the maximum flow rate and pressure is checked in terms of Reynolds number and  Satisfactory results are gained in comparison with the results available in the literature.

scholarly journals Finite Element Simulation of Newtonian and Non-Newtonian Fluid through the Parallel Plates Affixed with Single Screen

2020 ◽  
Vol 13 (1) ◽  
pp. 69-83
Author(s):  
Abid Ali Memon ◽  
Muhammad Asif Memon ◽  
Kaleemullah Bhatti ◽  
Gul Muhammad Shaikh
Keyword(s):  
Reynolds Number ◽  
Finite Element ◽  
Newtonian Fluid ◽  
Flow Rate ◽  
Rectangular Channel ◽  
Maximum Flow ◽  
Least Square ◽  
Maximum Flow Rate ◽  
Parallel Plates ◽  
The Impact

In the contemporary research article we have performed a numerical investigation of the non-Newtonian fluid flow through a rectangular channel with a fixed solid screen devoted at the angles 100 to 450 degrees. We have employed the power-law model for shear thickening and shear thinning fluids with the high Reynolds number between 1000 and 10,000. The obstacle has been solved by putting in the Galerkin’s least square strategy of the finite element method and the procedure has been carried out utilizing the commercial software COMSOL Multiphysics. Various flow properties such as 'maximum flow rate' and 'pressure' have been discussed in the terms of the Reynolds number and also using the linear and quadratic regressions in order to establish the relationship between them for the future analysis. Moreover the impact of turning screen in the shape of increment in the maximum flow rate and pressure is checked in terms of Reynolds number and  Satisfactory results are gained in comparison with the results available in the literature.

scholarly journals Experimental Investigation of a Rectangular Airlift Pump

2010 ◽  
Vol 2010 ◽  
pp. 1-5 ◽  
Author(s):  
I. I. Esen
Keyword(s):  
Experimental Investigation ◽  
Cross Section ◽  
Flow Rate ◽  
Liquid Flow ◽  
Liquid Flow Rate ◽  
Rectangular Cross Section ◽  
Hydraulic Performance ◽  
Experimental Program ◽  
Empirical Equations ◽  
Airlift Pump

Hydraulic performance of an airlift pump having a rectangular cross-section 20 mm × 80 mm was investigated through an experimental program. The pump was operated at six different submergence ratios and the liquid flow rate was measured at various flowrates of air injected. The effectiveness of the pump, defined as the ratio of the mass of liquid pumped to the mass of air injected, was determined as a function of the mass of air injected for different submergence ratios. Results obtained were compared with those for circular airlift pumps using an analytical model for circular pumps. Effectiveness of the rectangular airlift pump was observed to be comparable to that of the circular pumps. Hydraulic performance of the rectangular airlift pump investigated was then described by a set of semilogarithmic empirical equations.

DURABILITY PERFORMANCE AND DIMENSIONAL STABILITY OF POLYPROPYLENE FIBER REINFORCED CONCRETE

2018 ◽  
Vol 13 (2) ◽  
pp. 20-41 ◽  
Author(s):  
Ali Mardani-Aghabaglou ◽  
Süleyman Özen ◽  
Muhammet Gökhan Altun
Keyword(s):  
Reinforced Concrete ◽  
Dimensional Stability ◽  
Polypropylene Fiber ◽  
Pulse Velocity ◽  
Fiber Reinforced Concrete ◽  
Concrete Mixture ◽  
Fiber Reinforced ◽  
Concrete Mixtures ◽  
Durability Performance ◽  
Polypropylene Fiber Reinforced Concrete

In this study, the durability performance and dimensional stability of polypropylene fiber reinforced concrete mixture were investigated. For this purpose, two series of concrete mixtures, including a 0.45 water/cement ratio was prepared both in the absence and presence of fiber. A CEMI 42.5 R type portland cement and crushed limestone aggregate with a maximum particle size of 25 mm were used. In addition to the control mixture without fiber, three different concrete mixtures were prepared by adding polypropylene fiber as 0.4%, 0.8% and 1% of total volume into the mixture. The time-dependent fresh state properties, strength, ultrasonic pulse velocity, transport properties, drying shrinkage and freeze-thaw resistance of concrete mixtures, sodium sulfate attack and abrasion were investigated comparatively. Test results demonstrated that utilization of fiber affected the fresh properties of the concrete mixtures negatively. However, the 0.8% fiber-bearing mixture showed the highest performance in terms of durability and dimensional stability. Beyond this utilization ratio, the durability performance of the concrete mixture was negatively affected. The risk of nonhomogeneous dispersion of the fiber in the mixture was relatively high in the excess fiber-bearing mixture. Consequently, with the formation of flocculation in the mixture the void ratio of concrete mixture increased.

USE OF SPATIOTEMPORAL DIAGRAMS TO CHARACTERIZE A SILO DISCHARGING PROCESS

2013 ◽  
Vol 37 (1) ◽  
pp. 53-70
Author(s):  
Blaise Nsom ◽  
Noureddine Latrache
Keyword(s):  
Cross Section ◽  
Flow Rate ◽  
Mechanical Characterization ◽  
Direct Method ◽  
Rectangular Cross Section ◽  
Small Scale ◽  
Flat Bottom ◽  
Shear Box ◽  
A Direct Method

To get a better knowledge of discharging flows of ensiled granular materials, a small scale silo was designed and built. It is equipped with a flat bottom and it has a rectangular cross section. Moreover, it is entirely transparent for image processing purpose. First of all, a physical and mechanical characterization of wood granules (inert materials) was performed using a shear box testing. Then, silo emptying flows were generated. Flow regimes and flow rate were determined using spatiotemporal diagrams extracted from images of the free surface of the ensiled material. The same method was then used to measure the flow rate of discharging flows of soya, colza and rye seeds which were characterized in a previous study. For each material studied, the flow rate measured with this non intrusive method was successfully compared with a direct method consisting in weighing a volume of grains discharged during a unit time and with Berveloo’s formula.

FLOW MODIFICATION INDUCED BY QUINCKE ROTATION IN A CAPILLARY

2002 ◽  
Vol 16 (17n18) ◽  
pp. 2603-2609 ◽  
Author(s):  
A. CEBERS ◽  
E. LEMAIRE ◽  
L. LOBRY
Keyword(s):  
Cross Section ◽  
Flow Rate ◽  
Effective Viscosity ◽  
Rectangular Cross Section ◽  
Colloidal Suspension ◽  
Direct Determination ◽  
Flow Modification ◽  
Insulating Liquid ◽  
Quincke Rotation

When particles immersed in a semi-insulating liquid are submitted to a sufficiently high DC field, they can rotate spontaneously around any axis perpendicular to the field (Quincke rotation). Recently we have shown that due to Quincke effect the effective viscosity of a colloidal suspension could be reduced. When the suspension is submitted to a shear, the particles rotation is amplified by the electric torque and drives the suspending liquid. For a flow in a capillary, this effect manifests itself by an increase of the flow rate. We present the results of our experiments carried out with a rectangular cross section capillary. These results are compared with the direct determination of the apparent viscosity in a Couette flow rheometer.

Comparison of Countercurrent Flow Limitation Experiments Performed in Two Different Models of the Hot Leg of a Pressurized Water Reactor With Rectangular Cross Section

2010 ◽  
Vol 133 (5) ◽  
Author(s):  
Christophe Vallée ◽  
Tobias Seidel ◽  
Dirk Lucas ◽  
Akio Tomiyama ◽  
Michio Murase
Keyword(s):  
Cross Section ◽  
Flow Rate ◽  
Cross Sections ◽  
Characteristic Length ◽  
Rectangular Cross Section ◽  
Channel Height ◽  
Countercurrent Flow ◽  
Flow Limitation ◽  
Pressurized Water Reactor ◽  
Pressurized Water

In order to investigate the two-phase flow behavior during countercurrent flow limitation in the hot leg of a pressurized water reactor, two test models were built: one at the Kobe University and the other at the TOPFLOW test facility of Forschungszentrum Dresden-Rossendorf (FZD). Both test facilities are devoted to optical measurement techniques; therefore, a flat hot leg test section design was chosen. Countercurrent flow limitation (CCFL) experiments were performed, simulating the reflux condenser cooling mode appearing in some accident scenarios. The fluids used were air and water, both at room temperature. The pressure conditions were varied from atmospheric at Kobe to 3.0 bars absolute at TOPFLOW. According to the presented review of literature, very few data are available on flooding in channels with a rectangular cross section, and no experiments were performed in the past in such flat models of a hot leg. Commonly, the macroscopic effects of CCFL are represented in a flooding diagram, where the gas flow rate is plotted versus the discharge water flow rate, using the nondimensional superficial velocity (also known as Wallis parameter) as coordinates. However, the classical definition of the Wallis parameter contains the pipe diameter as characteristic length. In order to be able to perform comparisons with pipe experiments and to extrapolate to the power plant scale, the appropriate characteristic length should be determined. A detailed comparison of the test facilities operated at the Kobe University and at FZD is presented. With respect to the CCFL behavior, it is shown that the essential parts of the two hot leg test sections are very similar. This geometrical analogy allows us to perform meaningful comparisons. However, clear differences in the dimensions of the cross section (H×W=150×10 mm2 in Kobe, 250×50 mm2 at FZD) make it possible to point out the right characteristic length for hot leg models with rectangular cross sections. The hydraulic diameter, the channel height, and the Laplace critical wavelength (leading to the Kutateladze number) were tested. A comparison of our own results with similar experimental data and empirical correlations for pipes available in literature shows that the channel height is the characteristic length to be used in the Wallis parameter for channels with rectangular cross sections. However, some limitations were noticed for narrow channels, where CCFL is reached at lower gas fluxes, as already observed in small scale hot legs with pipe cross sections.

scholarly journals Flow in a pipe of rectangular cross-section

1928 ◽  
Vol 120 (786) ◽  
pp. 691-700 ◽  
Keyword(s):  
Laminar Flow ◽  
Turbulent Flow ◽  
Cross Section ◽  
Rectangular Cross Section ◽  
Stream Line ◽  
Parallel Plates ◽  
Rectangular Section ◽  
Circular Section ◽  
Line Flow ◽  
Minimum Ratio

The object of the research was to investigate the flow of water in a pipe of rectangular cross-section. Much work has been done on similar problems with pipes of circular section, and pipes of rectangular section have been investigated by Fromm and Davies and White. Fromm avoided with pipes in which the ratio of the sides was never less than 6 to 1; his report deals only with turbulent flow. In the case of Davies and White's research, the minimum ratio of the sides was 40 to 1, so that the laminar flow could be calculated from the formula for flow between infinitely wide parallel plates. The present writer used a pipe of section 1·178 cms. by 0·404 cms, (ratio of sides = 2·92); this presents a fresh problem were stream line flow is concerned, and shows interesting results in the region of the critical velocity.

The Influence of Slip Boundary Conditions on Peristaltic Pumping in a Rectangular Channel

2008 ◽  
Vol 130 (12) ◽  
Author(s):  
X. Mandviwalla ◽  
R. Archer
Keyword(s):  
Reynolds Number ◽  
Boundary Conditions ◽  
Cross Section ◽  
Rectangular Cross Section ◽  
Rectangular Channel ◽  
Slip Boundary Conditions ◽  
Long Wavelength ◽  
Slip Boundary ◽  
Peristaltic Pumping ◽  
Side Walls

The flow of an incompressible fluid is modeled in a channel of a rectangular cross section with two symmetric peristaltic waves propagating on the top and bottom. A low Reynolds number and a long wavelength are assumed. The effect on pumping of the inclusion of slip boundary conditions on the side walls is investigated.

scholarly journals INFLUENCE OF ROUGHTY OF A RECTANGULAR OPEN CHANNEL ON FLOW SPEEDS AND WATER FLOW

2021 ◽  
Vol 1 (24) ◽  
Author(s):  
Nedim Suljić
Keyword(s):  
Water Flow ◽  
Cross Section ◽  
Open Channel ◽  
Rectangular Cross Section ◽  
Rectangular Channel ◽  
Quadratic Function ◽  
Hydraulic Calculation ◽  
Roughness Coefficient ◽  
Maximum Throughput ◽  
Flow Speeds

This paper presents an analysis of water flow and flow velocity in an open channel of rectangular cross section as a function of channel roughness, ie Manning roughness coefficient. Three different cases of finishing the open channel of rectangular cross-section were analyzed, namely the concrete channel, the channel with smoothed cement mortar and the channel in very poor condition with shore erosion overgrown with sedges and large stones at the bottom of the channel. Analyzes were performed on a rectangular channel 3.0 m wide and with water depths in the channel from 0.5 m to 1.5 m with a step of 0.1 m, for steady flow. The longitudinal fall of the bottom of the rectangular channel in all analyzed cases was 1%.u urađene na pravougaonom kanalu širine 3,0 m i sa dubinama vode u kanalu od 0,5 m do 1,5 m sa korakom od 0,1 m, za ustaljeno tečenje. Podužni pad dna pravougaonog kanala u svim analiziranim slučajevima je iznosio 1%. The paper showed that higher Mannig roughness coefficients give lower water flow in the canal. The importance of the paper is reflected in the fact that for each of the three analyzed treatments of the rectangular channel, a quadratic function of water velocity and flow depending on the water depth in the channel was obtained. During the hydraulic calculation, the type of lining of the open rectangular channel should be taken into account in order for the dimensioned channel to be the most favorable in terms of maximum throughput.

Sign in / Sign up

Export Citation Format

Share Document