On the Mechanism of Fluid Transport Across the Grinding Zone

1996 ◽  
Vol 118 (3) ◽  
pp. 332-338 ◽  
Author(s):  
C. C. Chang ◽  
S. H. Wang ◽  
A. Z. Szeri
Keyword(s):  
Flow Rate ◽  
Fluid Transport ◽  
Tangential Velocity ◽  
Hydrodynamic Pressure ◽  
Pressure Effects ◽  
Depth Of Penetration ◽  
Continuity Equations ◽  
Creep Feed ◽  
Ram Pressure ◽  
Flow Through

By considering both hydrodynamic pressure and ram pressure effects on flow through a porous wheel, we construct here a predictive model for calculating the flow-rate of the cooling fluid through the grinding zone. The hydrodynamic pressure is computed by means of a modified Reynolds equation, with upstream boundary conditions supplied by the ram pressure. To find the tangential velocity, the radial velocity, the depth of penetration of the fluid into the wheel, and the flow rate through the grinding zone, we solve momentum and continuity equations for flow through porous media. An empirical correlation for permeability, containing two dimensionless parameters, is employed to provide correction for wheel surface roughness, yielding theoretical results that show good agreement with experimental data for both conventional and creep feed grinding.

Analysis of Fluid Flow through the Grinding Zone

1992 ◽  
Vol 114 (4) ◽  
pp. 427-434 ◽  
Author(s):  
C. Guo ◽  
S. Malkin
Keyword(s):  
Fluid Flow ◽  
Flow Rate ◽  
Tangential Velocity ◽  
Depth Of Penetration ◽  
Creep Feed ◽  
Useful Flow Rate ◽  
Useful Flow ◽  
Nozzle Position ◽  
Flow Through ◽  
Main Factors

A theoretical model of fluid flow in grinding has been developed by an analysis of fluid flow through a porous medium. Fluid tangential velocity, radial velocity, depth of penetration into the wheel, and the useful flow rate through the grinding zone are predicted by using this model. The analysis indicates that the nozzle position, nozzle velocity (or flow rate), and the effective wheel porosity are the three main factors which most significantly influence the useful flow rate through the grinding zone. A dimensionless effective wheel porosity parameter is introduced which is the ratio of the effective wheel porosity to its bulk porosity. By fitting the theoretical analysis to available experimental results, creep feed wheels were found to have much bigger dimensionless effective porosities than conventional wheels, which enhances their ability to more effectively pump fluid through the grinding zone.

Stabilization of the Speed of the Hydraulic Motor Through Throttle Compensation for Volume Losses

2020 ◽  
Vol 26 (3) ◽  
pp. 126-130
Author(s):  
Krasimir Kalev
Keyword(s):  
Flow Rate ◽  
Hydraulic Drive ◽  
Pressure Change ◽  
Operating Conditions ◽  
Drive System ◽  
Inlet Pressure ◽  
Schematic Diagram ◽  
Hydraulic Characteristics ◽  
Hydraulic Motor ◽  
Flow Through

AbstractA schematic diagram of a hydraulic drive system is provided to stabilize the speed of the working body by compensating for volumetric losses in the hydraulic motor. The diagram shows the inclusion of an originally developed self-adjusting choke whose flow rate in the inlet pressure change range tends to reverse - with increasing pressure the flow through it decreases. Dependent on the hydraulic characteristics of the hydraulic motor and the specific operating conditions.

Study of fluid flow through a channel deformed by piezoelement

2018 ◽  
Vol 13 (3) ◽  
pp. 1-10 ◽  
Author(s):  
I.Sh. Nasibullayev ◽  
E.Sh Nasibullaeva ◽  
O.V. Darintsev
Keyword(s):  
Fluid Flow ◽  
Pressure Drop ◽  
Boundary Conditions ◽  
Flow Rate ◽  
Contact Surface ◽  
Piezoelectric Element ◽  
Neumann Boundary ◽  
Differential Pressure ◽  
Physical Parameters ◽  
Flow Through

The flow of a liquid through a tube deformed by a piezoelectric cell under a harmonic law is studied in this paper. Linear deformations are compared for the Dirichlet and Neumann boundary conditions on the contact surface of the tube and piezoelectric element. The flow of fluid through a deformed channel for two flow regimes is investigated: in a tube with one closed end due to deformation of the tube; for a tube with two open ends due to deformation of the tube and the differential pressure applied to the channel. The flow rate of the liquid is calculated as a function of the frequency of the deformations, the pressure drop and the physical parameters of the liquid.

scholarly journals Research on a Piezoelectric Pump with Flexible Valves

2021 ◽  
Vol 11 (7) ◽  
pp. 2909
Author(s):  
Weiqing Huang ◽  
Liyi Lai ◽  
Zhenlin Chen ◽  
Xiaosheng Chen ◽  
Zhi Huang ◽  
...  
Keyword(s):  
Flow Rate ◽  
Fluid Transport ◽  
Smooth Transition ◽  
Driving Voltage ◽  
Piezoelectric Pump ◽  
Venous Valve ◽  
Output Pressure ◽  
Small Flow ◽  
Working Principle ◽  
Opening And Closing

Imitating the structure of the venous valve and its characteristics of passive opening and closing with changes in heart pressure, a piezoelectric pump with flexible valves (PPFV) was designed. Firstly, the structure and the working principle of the PPFV were introduced. Then, the flexible valve, the main functional component of the pump, was analyzed theoretically. Finally, an experimental prototype was manufactured and its performance was tested. The research proves that the PPFV can achieve a smooth transition between valved and valveless by only changing the driving signal of the piezoelectric (PZT) vibrator. The results demonstrate that when the driving voltage is 100 V and the frequency is 25 Hz, the experimental flow rate of the PPFV is about 119.61 mL/min, and the output pressure is about 6.16 kPa. This kind of pump can realize the reciprocal conversion of a large flow rate, high output pressure, and a small flow rate, low output pressure under the electronic control signal. Therefore, it can be utilized for fluid transport and pressure transmission at both the macro-level and the micro-level, which belongs to the macro–micro combined component.

scholarly journals Computational Fluid Dynamic Accuracy in Mimicking Changes in Blood Hemodynamics in Patients with Acute Type IIIb Aortic Dissection Treated with TEVAR

2018 ◽  
Vol 8 (8) ◽  
pp. 1309 ◽  
Author(s):  
Andrzej Polanczyk ◽  
Aleksandra Piechota-Polanczyk ◽  
Christoph Domenig ◽  
Josif Nanobachvili ◽  
Ihor Huk ◽  
...  
Keyword(s):  
Blood Flow ◽  
Aortic Dissection ◽  
Flow Rate ◽  
Fluid Dynamic ◽  
3D Models ◽  
Renal Arteries ◽  
Acute Type ◽  
Type Iiib ◽  
Doppler Data ◽  
Flow Through

Background: We aimed to verify the accuracy of the Computational Fluid Dynamics (CFD) algorithm for blood flow reconstruction for type IIIb aortic dissection (TBAD) before and after thoracic endovascular aortic repair (TEVAR). Methods: We made 3D models of the aorta and its branches using pre- and post-operative CT data from five patients treated for TBAD. The CFD technique was used to quantify the displacement forces acting on the aortic wall in the areas of endograft, mass flow rate/velocity and wall shear stress (WSS). Calculated results were verified with ultrasonography (USG-Doppler) data. Results: CFD results indicated that the TEVAR procedure caused a 7-fold improvement in overall blood flow through the aorta (p = 0.0001), which is in line with USG-Doppler data. A comparison of CFD results and USG-Doppler data indicated no significant change in blood flow through the analysed arteries. CFD also showed a significant increase in flow rate for thoracic trunk and renal arteries, which was in accordance with USG-Doppler data (accuracy 90% and 99.9%). Moreover, we observed a significant decrease in WSS values within the whole aorta after TEVAR compared to pre-TEVAR (1.34 ± 0.20 Pa vs. 3.80 ± 0.59 Pa, respectively, p = 0.0001). This decrease was shown by a significant reduction in WSS and WSS contours in the thoracic aorta (from 3.10 ± 0.27 Pa to 1.34 ± 0.11Pa, p = 0.043) and renal arteries (from 4.40 ± 0.25 Pa to 1.50 ± 0.22 Pa p = 0.043). Conclusions: Post-operative remodelling of the aorta after TEVAR for TBAD improved hemodynamic patterns reflected by flow, velocity and WSS with an accuracy of 99%.

Effect of the Leakage Flows and the Upstream Platform Geometry on the Endwall Flows of a Turbine Cascade

2006 ◽  
Author(s):  
E. de la Rosa Blanco ◽  
H. P. Hodson ◽  
R. Vazquez
Keyword(s):  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Separation Bubble ◽  
Tangential Velocity ◽  
Low Pressure ◽  
Leakage Flow ◽  
Backward Facing Step ◽  
Surface Separation ◽  
Pressure Surface

This work describes the effect that the injection of leakage flow from a cavity into the mainstream has on the endwall flows and their interaction with a large pressure surface separation bubble in a low-pressure turbine. The effect of a step in hub diameter ahead of the blade row is also simulated. The blade profile under consideration is a typical design of modern low-pressure turbines. The tests are conducted in a low speed linear cascade. These are complemented by numerical simulations. Two different step geometries are investigated, i.e., a backward-facing step and a forward-facing step. The leakage tangential velocity and the leakage mass flow rate are also modified. It was found that the injection of leakage mass flow gives rise to a strengthening of the endwall flows independently of the leakage mass flow rate and the leakage tangential velocity. The experimental results have shown that below a critical value of the leakage tangential velocity, the net mixed-out endwall losses are not significantly altered by a change in the leakage tangential velocity. For these cases, the effect of the leakage mass flow is confined to the wall, as the inlet endwall boundary layer is pushed further away from the wall by the leakage flow. However, for values of the leakage tangential velocity around 100% of the wheelspeed, there is a large increase in losses due to a stronger interaction between the endwall flows and the leakage mass flow. This gives rise to a change in the endwall flows structure. In all cases, the presence of a forward-facing step produces a strengthening of the endwall flows and an increase of the net mixed-out endwall losses when compared with a backward-facing step. This is because of a strong interaction with the pressure surface separation bubble.

scholarly journals Taking into Account Outer Hydrodynamic Pressure in Differential Equation of Variable Flow Rate Fluid Flow for Distributive Pressure Pipelines

2012 ◽  
Vol 7 (1) ◽  
pp. 13-22
Author(s):  
Volodymyr V. Cherniuk
Keyword(s):  
Differential Equation ◽  
Fluid Flow ◽  
Flow Rate ◽  
Hydrodynamic Pressure ◽  
Variable Flow

Abstract In the differential equation of variable flow rate fluid flow a component which takes into account outer hydrodynamic pressure is introduced. The variables of the equation are expressed in terms of full operating head and in terms of independent distance along the axis of the stream, i. e. this equation is reduced to a singlevariable equation.

Experimental, Numerical, and Statistical Investigation of Two Phase Flow in a Cylindrical Perforation Tunnel

2021 ◽  
Author(s):  
Ekhwaiter Abobaker ◽  
Abadelhalim Elsanoose ◽  
Mohammad Azizur Rahman ◽  
Faisal Khan ◽  
Amer Aborig ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Steady State ◽  
Statistical Analysis ◽  
Flow Rate ◽  
Gas Flow ◽  
Two Phase Flow ◽  
Phase Flow ◽  
Gas Flow Rate ◽  
Two Phase ◽  
Flow Through

Abstract Perforation is the final stage in well completion that helps to connect reservoir formations to wellbores during hydrocarbon production. The drilling perforation technique maximizes the reservoir productivity index by minimizing damage. This can be best accomplished by attaining a better understanding of fluid flows that occur in the near-wellbore region during oil and gas operations. The present work aims to enhance oil recovery by modelling a two-phase flow through the near-wellbore region, thereby expanding industry knowledge about well performance. An experimental procedure was conducted to investigate the behavior of two-phase flow through a cylindrical perforation tunnel. Statistical analysis was coupled with numerical simulation to expand the investigation of fluid flow in the near-wellbore region that cannot be obtained experimentally. The statistical analysis investigated the effect of several parameters, including the liquid and gas flow rate, liquid viscosity, permeability, and porosity, on the injection build-up pressure and the time needed to reach a steady-state flow condition. Design-Expert® Design of Experiments (DoE) software was used to determine the numerical simulation runs using the ANOVA analysis with a Box-Behnken Design (BBD) model and ANSYS-FLUENT was used to analyses the numerical simulation of the porous media tunnel by applying the volume of fluid method (VOF). The experimental data were validated to the numerical results, and the comparison of results was in good agreement. The numerical and statistical analysis demonstrated each investigated parameter’s effect. The permeability, flow rate, and viscosity of the liquid significantly affect the injection pressure build-up profile, and porosity and gas flow rate substantially affect the time required to attain steady-state conditions. In addition, two correlations obtained from the statistical analysis can be used to predict the injection build-up pressure and the required time to reach steady state for different scenarios. This work will contribute to the clarification and understanding of the behavior of multiphase flow in the near-wellbore region.

Advances in Fisheries Bioengineering

2008 ◽  
Keyword(s):  
Common Carp ◽  
Striped Bass ◽  
Flow Rate ◽  
Lepomis Macrochirus ◽  
Osmerus Mordax ◽  
Rainbow Smelt ◽  
Test Species ◽  
Wide Range ◽  
Flow Through ◽  
Pair Wise Comparison

Abstract.—Aquatic Filter Barrier (AFB) is a permeable fabric material used to reduce the entrainment of ichthyoplankton at water intakes. To determine the potential for this material to protect a wide range of species, we evaluated the retention and survival of the early life stages of common carp <em>Cyprinus carpio</em>, rainbow smelt <em>Osmerus mordax</em>, white sucker <em>Catostomus commersonii</em>, striped bass <em>Morone saxatilis</em>, and bluegill <em>Lepomis macrochirus </em>exposed to AFB fabric in the laboratory. Twelve flow-through testing apparatuses were used in a closed-loop system to evaluate two flow rates (0.04 L/min/cm2) and 0.08 L/min/cm2) and three sizes of fabric perforation (0.5, 1.0, and 1.5 mm) with each species. The results indicate that, with one exception (pair-wise comparison of bluegill survival between 1.0-mm and 1.5- mm perforations; <em>p </em>= 0.0481), survival of organisms was not significantly correlated (<em>p </em>≤ 0.05) to either flow rate or perforation size. Retention of organisms decreased significantly with increasing flow rate for one species of fish (pair-wise comparison of rainbow smelt between 0.04 and 0.08 L/min/cm<sup>2</sup>; <em>p </em>= 0.0084). In addition, larger perforation sizes resulted in significant decreases in retention for three of the test species (common carp, rainbow smelt, and striped bass; <em>p </em>≤ 0.05). Consequently, the potential effectiveness AFB material is reduced by the use of larger perforation sizes. Provided that the material can be maintained and perforation sizes remain small (0.5 mm), AFB should prevent the entrainment of the majority of the organisms of the species tested in the laboratory.

scholarly journals Calibration of Stainless Steel-edged V-Notch Weir Stop Logs for Water Level Control Structures

2019 ◽  
Vol 35 (5) ◽  
pp. 745-749
Author(s):  
L. E. Christianson ◽  
R. D. Christianson ◽  
A. E. Lipka ◽  
S. Bailey ◽  
J. Chandrasoma ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Water Level ◽  
Flow Rate ◽  
Subsurface Drainage ◽  
Conservation Practices ◽  
Nutrient Loads ◽  
Level Control ◽  
Control Structures ◽  
Flow Monitoring ◽  
Flow Through

Abstract. Dependable flow rate measurements are necessary to calculate flow volumes and resulting nutrient loads from subsurface drainage systems and associated conservation practices. The objectives of this study were (1) to develop appropriate weir equations for a new stainless steel-edged 45° V-notch weir developed for AgriDrain inline water level control structures and (2) to determine if the equation was independent of flow depth in the structure. Weirs for 15 cm (6 in.) and 25 cm (10 in.) inline water level control structures were placed at three heights in each structure: at the base, 48 cm from the base, or 97 cm from the base, and the height of the nappe above the weir crest was recorded over a range of flow rates. The resulting data were fitted to equations of the form Q = aHb where Q is the flow rate, H is the height of the nappe above the weir crest, and a and b are fitted parameters. There were no significant differences in the fitted parameters across the two structure sizes or across the three weir placements. The fitted equation for these new stainless steel-edged V-notch weirs was Q = 0.011H2.28 with Q in liters per second and H in centimeters, and Q = 1.44H2.28, with Q in gallons per minute and H in inches. These equations can be used for measuring flow through AgriDrain in-line structures, although in-house weir calibration is highly recommended for specific applications, when possible. Keywords: Drainage, Flow monitoring, Subsurface drainage, V-notch weir, Weir calibration.

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