scholarly journals Peristaltic transport of a two-layered fluid in a catheterized tube

2012 ◽  
Vol 39 (4) ◽  
pp. 291-311
Author(s):  
Amit Medhavi ◽  
U.K. Singh
Keyword(s):  
Pressure Drop ◽  
Linear Relationship ◽  
Layer Thickness ◽  
Friction Force ◽  
Flow Rate ◽  
Tube Wall ◽  
Flow Characteristics ◽  
Tube Size ◽  
Friction Forces ◽  
Catheter Size

The flow of a two-layered Newtonian fluid induced by peristaltic waves in a catheterized tube has been investigated. The expressions for the flow characteristics- the flow rate, the pressure drop and the friction forces at the tube and catheter wall are derived. It is found that the pressure drop increases with the flow rate but decreases with the increasing peripheral layer thickness and a linear relationship between pressure and flow exists. The pressure drop increases with the catheter size (radius) and assumes a high asymptotic magnitude at the catheter size more that the fifty percent of the tube size. The friction forces at the tube and catheter wall posses characteristics similar to that of the pressure drop with respect to any parameter. However, friction force at catheter wall assumes much smaller magnitude than the corresponding value at the tube wall.

Experimental Investigation of Effect of Tip Coolant Ejection on Internal Flow Characteristics Within a Realistic Blade Coolant Channel

2013 ◽  
Author(s):  
Jian Pu ◽  
Zhaoqing Ke ◽  
Jianhua Wang ◽  
Lei Wang ◽  
Hongde You
Keyword(s):  
Experimental Investigation ◽  
Reynolds Number ◽  
Pressure Drop ◽  
Turbine Blade ◽  
Flow Rate ◽  
Flow Characteristics ◽  
Reynolds Numbers ◽  
Flow Ratio ◽  
Lp Turbine ◽  
Mass Flow Ratio

This paper presents an experimental investigation on the characteristics of the fluid flow within an entire coolant channel of a low pressure (LP) turbine blade. The serpentine channel, which keeps realistic blade geometry, consists of three passes connected by a 180° sharp bend and a semi-round bend, 2 tip exits and 25 trailing edge exits. The mean velocity fields within several typical cross sections were captured using a particle image velocimetry (PIV) system. Pressure and flow rate at each exit were determined through the measurements of local static pressure and volume flow rate. To optimize the design of LP turbine blade coolant channels, the effect of tip ejection ratio (ER) from 180° sharp bend on the flow characteristics in the coolant channel were experimentally investigated at a series of inlet Reynolds numbers from 25,000 to 50,000. A complex flow pattern, which is different from the previous investigations conducted by a simplified square or rectangular two-pass U-channel, is exhibited from the PIV results. This experimental investigation indicated that: a) in the main flow direction, the regions of separation bubble and flow impingement increase in size with a decrease of the ER; b) the shape, intensity and position of the secondary vortices are changed by the ER; c) the mass flow ratio of each exit to inlet is not sensitive to the inlet Reynolds number; d) the increase of the ER reduces the mass flow ratio through each trailing edge exit to the extent of about 23–28% of the ER = 0 reference under the condition that the tip exit located at 180° bend is full open; e) the pressure drop through the entire coolant channel decreases with an increase in the ER and inlet Reynolds number, and a reduction about 35–40% of the non-dimensional pressure drop is observed at different inlet Reynolds numbers, under the condition that the tip exit located at 180° bend is full open.

THE EFFECT OF DIFFERENT LOCATIONS OF TRACHEAL STENOSIS TO THE FLOW CHARACTERISTICS USING RECONSTRUCTED CT-SCANNED IMAGE

2012 ◽  
Vol 12 (04) ◽  
pp. 1250066 ◽  
Author(s):  
NASRUL HADI JOHARI ◽  
KAHAR OSMAN ◽  
ZULIAZURA MOHD SALLEH ◽  
JUHARA HARON ◽  
MOHAMMED RAFIQ ABDUL KADIR
Keyword(s):  
Pressure Drop ◽  
Flow Rate ◽  
Tracheal Stenosis ◽  
Flow Behavior ◽  
Flow Characteristics ◽  
Flow Conditions ◽  
Inlet Flow Rate ◽  
Exhaled Air ◽  
Scanned Image ◽  
The Right

The presence of tracheal stenosis would alter the flow path of the inhaled and exhaled air and subsequently changed the flow behavior inside the trachea and main bronchi. Therefore, it was our aim to investigate and predict the changes of flow behavior along with the pressure distribution with respect to the presence of stenosis on the tracheal lumen. In this study, actual CT scan images were extracted for flow modeling purposes. The images were then reconstructed to mimic the effect of different stenosis locations. This method overcomes the problem of the absence of actual images for different tracheal stenosis locations. The flow was subjected to different breathing situations corresponding to low, moderate and rigorous activities. The results showed that for flow over the stenosis farthest from the bifurcation, the pressure drop was insignificant for all breathing situations. At the same time, the inlet flow rate at the bifurcation showed less air flows into the right lung as compared to healthy flow conditions. On the other hand, for the flow over stenosis closest to the bifurcation, the pressure drop near the bifurcation area was very significant at high flow rate.

JUSTIFICATION THE HOPPER OUTLET FORM, WHICH PROVIDES CONSTANT DISCHARGE OF THE GRAIN

10.12737/3813 ◽  
2014 ◽  
Vol 9 (1) ◽  
pp. 79-83
Author(s):  
Савенков ◽  
Dmitriy Savenkov
Keyword(s):  
Friction Force ◽  
Experimental Research ◽  
Flow Rate ◽  
Industrial Development ◽  
Air Flow ◽  
External Friction ◽  
Constant Flow ◽  
Friction Forces ◽  
Frictional Forces ◽  
Side Walls

The uniformity of air flow in the aspirating channels largely depends on constant supply of grain across the channel. However, most of the feeding aspirators do not provide a constant flow of particulate mater. That’s why one of the areas of industrial development of new technological operations is their preliminary theoretical and experimental research. The uniformity expiration of grain from the hopper to the outlet side occurs through the action of frictional forces. The friction forces are divided into internal and external friction, opposing the grain movement. External friction force, provided by the walls of the hopper, reduce the exhaust velocity of bulk near the walls. Thus, the extensional discharge of the bulk is more in the central parts of the outlet, than in its outer parts. Reducing the extensional discharge in the extreme zones is associated with a decrease in the flow rate of these zones. So that to ensure a constant grain unloading from the hopper, it is proposed to change the outlet profile, enhancing the area of outlet in the areas of its contact with the edges of the side walls. It is shown, that the area of the secondary part depends on the angle of the bottom hopper and the height of the outlet. The results of the data can be used to optimize the geometry of the hopper.

Peristaltic Transport of a Power-Law Fluid With Variable Consistency

1982 ◽  
Vol 104 (3) ◽  
pp. 182-186 ◽  
Author(s):  
J. B. Shukla ◽  
S. P. Gupta
Keyword(s):  
Pressure Drop ◽  
Friction Force ◽  
Power Law ◽  
Flow Rate ◽  
Peristaltic Transport ◽  
Peristaltic Wave ◽  
Power Law Fluid ◽  
Peripheral Layer

Effects of the consistency variation on the peristaltic transport of a non-Newtonian power-law fluid fluid through a tube have been investigated by taking into account the existence of a peripheral layer. It is shown that the flow rate flux, for zero pressure drop, increases as the amplitude of the peristaltic wave increases but it decreases due to the pseudoplastic nature of the fluid. It is also noted that, for zero pressure drop, the flux does not depend on the consistency of peripheral layer while the friction decreases as this consistency decreases. However, for nonzero pressure drop, the flux increases and the friction force decreases as the consistency of peripheral layer fluid decreases.

Motion of a deformable capsule through a hyperbolic constriction

1994 ◽  
Vol 279 ◽  
pp. 135-163 ◽  
Author(s):  
Anne Leyrat-Maurin ◽  
Dominique Barthes-Biesel
Keyword(s):  
Pressure Drop ◽  
Flow Rate ◽  
Stokes Equations ◽  
Flow Characteristics ◽  
Quantitative Information ◽  
Maximum Energy ◽  
Centre Of Mass ◽  
Intrinsic Properties ◽  
Constant Flow Rate ◽  
Reynolds Number Flow

A model for the low-Reynolds-number flow of a capsule through a constriction is developed for either constant-flow-rate or constant-pressure-drop conditions. Such a model is necessary to infer quantitative information on the intrinsic properties of capsules from filtration experiments conducted on a dilute suspension of such particles. A spherical capsule, surrounded by an infinitely thin Mooney-Rivlin membrane, is suspended on the axis of a hyperbolic constriction. This configuration is fully axisymmetric and allows the entry and exit phenomena through the pore to be modelled. An integral formulation of the Stokes equations describing the flow in the internal and external domains is developed. It provides a representation of the velocity at any location in the flow as a function of the unknown forces exerted by the boundaries on the fluids. The problem is solved by a collocation technique in the case where the internal and external viscosities are equal. Microscopic quantities (instantaneous geometry, centre of mass velocity, elastic tensions in the membrane) as well as macroscopic quantities (entry time, additional pressure drop or flow rate reduction) are predicted as a function of the capsule intrinsic properties and flow characteristics. The results obtained for a capsule whose initial diameter is larger than that of the constriction throat show that the maximum energy expenditure occurs when the particle centre of mass is still upstream of the throat (typically 1 diameter away), and is thus due to the entry process. For large enough or rigid enough capsules, the model predicts entrance or exit plugging, in agreement with experimental observations. It is then possible to correlate the variation of the pore hydraulic resistance to the flow capillary number (ratio of viscous to elastic forces) and to the size ratio between the pore and the capsule.

Flow Characteristics of Aluminium Oxide Nanofluids

2009 ◽  
Author(s):  
Vanessa M. Egan ◽  
Patrick A. Walsh ◽  
Edmond J. Walsh
Keyword(s):  
Pressure Drop ◽  
Flow Rate ◽  
Volume Fraction ◽  
Relative Viscosity ◽  
Flow Characteristics ◽  
Aluminium Oxide ◽  
Nanoparticle Size ◽  
Rotational Viscometer ◽  
Volume Fractions ◽  
Viscosity Measurements

The current study is an investigation in the flow characteristics of aluminium oxide nanofluids. Relative viscosity measurements are obtained for varying volume fractions using both a rotational viscometer and an experimental setup designed for pressure drop measurements in tubes. The effect of nanoparticle size and preparation method is also investigated as predispersed nanofluids of nominal particle size 10nm and 50nm are compared with each other and with a fluid mixed from Al2O3 nanopowder. Volume fractions of between 1% and 7% were tested. The first method employed to obtain viscosities is based on the Hagen-Poiseuille equation for laminar pipe flow, where pressure drop measurement and flow rate measurements are used to determine relative viscosities of various nanofluids samples. Viscosity measurements were also obtained for a number of solutions on a rotational viscometer and compared to the latter and existing models available in the literature. Overall, it was found during experimentation that the relationship between pressure and flow rate for the various nanofluids was linear indicating that the fluids were Newtonian in nature. An increase in viscosity was recorded for increasing volume fraction; however this was seen to be negligible for volume fractions lower than 1%. Overall it was also seen that both methods of determining relative viscosity were in good agreement. There was not a clear indication of the effect of nanoparticle size on the relative viscosity however the nanofluids formulated from purchased Al2O3 powder resulted in a considerably lower relative viscosity when compared to both nanofluids purchased pre-dispersed from suppliers.

An Experimental Investigation of the Shell-Side Pressure Drop of Enlarged-Hole Whole-Rounded Baffle Heat Exchanger

2010 ◽  
Vol 160-162 ◽  
pp. 1622-1627 ◽  
Author(s):  
Hai Yang Sun ◽  
Cai Fu Qian
Keyword(s):  
Experimental Investigation ◽  
Heat Exchanger ◽  
Pressure Drop ◽  
Flow Rate ◽  
Heat Exchangers ◽  
Flow Characteristics ◽  
Shell Side ◽  
Pressure Drops ◽  
Side Pressure

In this paper, the flow characteristics of the whole-rounded enlarged-hole baffle heat exchangers are experimentally studied with the stress on the shell-side pressure drops. It is found that the shell-side pressure drops for the whole-rounded baffles with the enlarged holes are greatly decreased. Compared with the square layout, the enlarged-hole whole-rounded baffles in the case of triangle layout is even more effective in decreasing the pressure drop. The shell-side pressure drops for the heat exchangers with the enlarged-hole whole-rounded baffles are proportional to the square of the flow rate.

scholarly journals Differential equations for calculating gas exchange in an internal combustion engine

2021 ◽  
Vol 264 ◽  
pp. 01003
Author(s):  
Zakirjon Musabekov ◽  
Jamshid Khakimov ◽  
Ergashev Botir
Keyword(s):  
Pressure Drop ◽  
Gas Exchange ◽  
Internal Combustion Engine ◽  
Flow Rate ◽  
Combustion Engine ◽  
Flow Characteristics ◽  
Maximum Flow ◽  
Internal Combustion ◽  
Dimensional Model ◽  
Short Period

Considering the unsteadiness of the flow in the valve channels and windows of the internal combustion engine in combination with limiting the maximum flow rate allows you to take into account the flow characteristics in the exhaust systems of forced engines. Thus, the calculation according to the above method allows us to obtain by calculation, observed in experiments, the reverse pressure drop in the short period of the end of the free release, the validity of using a modified 0-dimensional model of gas exchange, even for engines with long manifolds, where the Strophe number is less than 8.

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.

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