Stress Analysis of Pseudo-Plastic Flow Between Rotating Cylinders

2011 ◽  
Author(s):  
Nariman Ashrafi ◽  
Habib Karimi Haghighi
Keyword(s):  
Dynamical System ◽  
Stress Analysis ◽  
Plastic Flow ◽  
Galerkin Projection ◽  
Narrow Gap ◽  
Rotating Cylinders ◽  
Flow Parameters ◽  
Wide Range ◽  
Stress Components ◽  
Mathematica Software

Stress analysis of Pseudo-Plastic flow between rotating cylinders is studied in the narrow gap limit. The Galerkin projection method is used to derive dynamical system from the conservation of mass and momentum equations. Flow parameters were obtained using IMSL and also verified by Mathematica Software. Stresses are computed in a wide range of the Pseudo-Plastic effects. Azimuthal stress was found to be far greater than other stress components. All stress components increased as Pseudo-Plasticity decreased. Furthermore, complete stress and viscosity maps are presented for different scenarios in the flow regime.

Rubber Plastometer with Uniform Rate of Shear—Shearing-Cone Plastometer

1946 ◽  
Vol 19 (3) ◽  
pp. 822-831 ◽  
Author(s):  
G. H. Piper ◽  
J. R. Scott
Keyword(s):  
Plastic Flow ◽  
Mechanical Design ◽  
Plastic Material ◽  
Edge Zone ◽  
Uniform Rate ◽  
Wide Range

Abstract A new shearing-cone plastometer, suitable for investigating the plastic-flow relations of highly viscous materials over a wide range of stress, is described. A mushroom-shaped rotor, having upper and lower surfaces of conical type, is rotated in the plastic material contained in a cylindrical mould. With this type of shearing surface the rate of shear is uniform throughout the material, except for a small edge zone, thus overcoming some disadvantages of previous plastometers. The mechanical design is based on the Mooney shearing-disk plastometer except that provision is made for a wide range of speeds of rotation.

Management of Complex Loading Histories for Use in Probabilistic Creep-Fatigue Damage Assessments

2018 ◽  
Author(s):  
N. A. Zentuti ◽  
J. D. Booker ◽  
R. A. W. Bradford ◽  
C. E. Truman
Keyword(s):  
Fatigue Damage ◽  
Input Parameter ◽  
Three Dimensional ◽  
Complex Loading ◽  
Fe Model ◽  
Plant Component ◽  
Fatigue Lifetime ◽  
Wide Range ◽  
Stress Components ◽  
Creep Fatigue

An approach is outlined for the treatment of stresses in complex three-dimensional components for the purpose of conducting probabilistic creep-fatigue lifetime assessments. For conventional deterministic assessments, the stress state in a plant component is found using thermal and mechanical (elastic) finite element (FE) models. Key inputs are typically steam temperatures and pressures, with the three principal stress components (PSCs) at the assessment location(s) being the outputs. This paper presents an approach which was developed based on application experience with a tube-plate ligament (TPL) component, for which historical data was available. Though both transient as well as steady-state conditions can have large contributions towards the creep-fatigue damage, this work is mainly concerned with the latter. In a probabilistic assessment, the aim of this approach is to replace time intensive FE runs with a predictive model to approximate stresses at various assessment locations. This is achieved by firstly modelling a wide range of typical loading conditions using FE models to obtain the desire stresses. Based on the results from these FE runs, a probability map is produced and input(s)-output(s) functions are fitted (either using a Response Surface Method or Linear Regression). These models are thereafter used to predict stresses as functions of the input parameter(s) directly. This mitigates running an FE model for every probabilistic trial (of which there typically may be more than 104), an approach which would be computationally prohibitive.

scholarly journals Impacts of Heat and Mass Transfer on Magneto Hydrodynamic Peristaltic Flow Having Temperature-dependent Properties in an Inclined Channel Through Porous Media

2020 ◽  
pp. 854-869
Author(s):  
Rabiha S. Kareem ◽  
Ahmed M. Abdulhadi
Keyword(s):  
Mass Transfer ◽  
Heat And Mass Transfer ◽  
Variable Viscosity ◽  
Peristaltic Flow ◽  
Long Wavelength ◽  
Inclined Channel ◽  
Flow Parameters ◽  
Temperature Dependent Properties ◽  
Mathematica Software ◽  
Velocity Pressure

In this paper, we study the impacts of variable viscosity , heat and mass transfer on magneto hydrodynamic (MHD) peristaltic flow in a asymmetric tapered inclined channel with porous medium . The viscosity is considered as a function of temperature. The slip conditions at the walls were taken into consideration. SmallReynolds number and the long wavelength approximations were used to simplify the governing equations. A comparison between the two velocities in cases of slip and no-slip was plotted. It was observed that the behavior of the velocity differed in the two applied models for some parameters. Mathematica software was used to estimate the exact solutions of temperature and concentration profiles. The resolution of the equations to the momentum was based on the perturbation method to find the axial velocity, pressure gradient and trapping phenomenon. The influences of the various flow parameters of the problem on these distributions were debated and proved graphically by figures.

High Resolution Measurements of Local Effectiveness by Discrete Hole Film Cooling

1999 ◽  
Author(s):  
S. Baldauf ◽  
A. Schulz ◽  
S. Wittig
Keyword(s):  
Surface Temperature ◽  
Film Cooling ◽  
Density Ratio ◽  
Geometrical Parameters ◽  
Element Analysis ◽  
Cooling Effectiveness ◽  
Film Cooling Effectiveness ◽  
Flow Parameters ◽  
Wide Range ◽  
Local Measurements

Local adiabatic film cooling effectiveness on a flat plate surface downstream a row of cylindrical holes was investigated. Geometrical parameters like blowing angle and hole pitch as well as the flow parameters blowing rate and density ratio were varied in a wide range emphasizing on engine relevant conditions. An IR-thermography technique was used to perform local measurements of the surface temperature field. A spatial resolution of up to 7 data points per hole diameter extending up to 80 hole diameters downstream of the ejection location was achieved. Since all technical surface materials have a finite thermoconductivity, no ideal adiabatic conditions could be established. Therefore, a procedure for correcting the measured surface temperature data based on a Finite Element analysis was developed. Heat loss over the backside of the testplate and remnant heat flux within the testplate in lateral and streamwise direction were taken into account. The local effectiveness patterns obtained are systematically analyzed to quantify the influence of the various parameters. As a result, a detailed description of the characteristics of local adiabatic film cooling effectiveness is given. Furthermore, the locally resolved experimental results can serve as a data base for the validation of CFD-codes predicting discrete hole film cooling.

Predictions of Momentum Transfer Between Rotating Cylinders: The Narrow Gap Problem

1972 ◽  
Vol 39 (1) ◽  
pp. 33-35 ◽  
Author(s):  
I. Catton ◽  
P. Ayyaswamy
Keyword(s):  
Momentum Transfer ◽  
Taylor Number ◽  
Rotating Cylinders ◽  
Comparison With Experiment ◽  
Number Comparison ◽  
Wide Range ◽  
Secondary Motion ◽  
Marginal State ◽  
Range Of Values ◽  
Molecular Viscosity

The contributions to momentum transfer by secondary motion, which arises beyond the marginal state of stability in a layer of fluid confined between rotating cylinders is calculated by an integral method. The procedure invokes the “shape assumption” due to Stuart. Results are presented in terms of an effective viscosity to molecular viscosity ratio that is a function of Taylor number. Comparison with experiment is found to be excellent over a wide range of values of the Taylor number (up to 1000 times the critical value).

A Limiting Defect Study of an Elbow

2011 ◽  
Author(s):  
Jinhua Shi ◽  
David Blythe
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
Hoop Stress ◽  
Defect Size ◽  
Welding Residual Stress ◽  
Central Section ◽  
Butt Welding ◽  
Wide Range ◽  
Stress Components ◽  
Hoop Stresses

In order to ensure the integrity of a seamless butt-welding elbow, both the central section and ends of the elbow need to be assessed, as the maximum stress is normally located at the central section of the elbow but there are no welding residual stresses. Furthermore, at the ends (welds) of the elbow, very high welding residual stresses exist if the welds have not been post weld heat treated but the primary stresses induced by the internal pressure and system moments are lower. For a 90 degree elbow welded to seamless straight pipe, both maximum axial and hoop stress components in the elbow can be calculated using ASME III NB-3685. At the ends of the elbow, axial and hoop stress components can be obtained using the stress equations presented in the paper of PVP2010-25055. In this paper, a series of limiting defect assessments have been carried out on an elbow assuming a postulated axial external defect as follows: • A number of assessments have been conducted directly using the axial and hoop stresses calculated based on ASME III NB-3685 for different system moments. • A series of assessments have been carried out using the axial and hoop stresses calculated using the stress equations presented in the paper of PVP2010-25055, a wide range of welding residual stresses and different system moments. A comparison of the assessment results in the elbow and at the ends of the elbow shows that when system moments are relatively low and the welding residual stress is high, the limiting defect size is located at the ends of the elbow; when the system moments are high and the welding residual stress is low the limiting defect size is located at the central section of the elbow. Therefore, it can be concluded that when assessing an elbow, the assessments should be carried out at both the central section and the ends of the elbow, in order to ensure the integrity of the elbow.

scholarly journals Effect of endoscope on the peristaltic transport of a couple stress fluid with heat transfer: Application to biomedicine

2019 ◽  
Vol 8 (1) ◽  
pp. 619-629 ◽  
Author(s):  
K. Ramesh ◽  
M. Devakar
Keyword(s):  
Heat Transfer ◽  
Couple Stress ◽  
Medical Engineering ◽  
Horizontal Tube ◽  
Vertical Tube ◽  
Long Wavelength ◽  
Flow Parameters ◽  
Wide Range ◽  
Cylindrical Coordinate ◽  
Frictional Forces

Abstract In this investigation, we have studied the problem of peristaltic flow with heat transfer through the gap between coaxial inclined tubes where the inner tube is rigid and the outer tube has sinusoidal wave travelling down its wall. The problem has been formulated in cylindrical coordinate system. The equations governing the flow have been simplified under the long wavelength and low Reynolds number assumptions. The exact solution is obtained for the temperature profile. The perturbation solutions for the velocity and pressure gradient are obtained for small couple stress parameter. Pressure difference per wavelength and frictional forces on the tube walls have been computed numerically. Results are demonstrated for various flow parameters. The better pumping results occur in vertical tube, while less pumping is seen in horizontal tube. The size of trapped bolus is small in triangular wave as compared to other waves. The present study has a wide range of applications in bio-medical engineering like the transport phenomenon in peristaltic micro pumps.

Instability of the flow between rotating cylinders: the wide-gap problem

1964 ◽  
Vol 20 (1) ◽  
pp. 35-46 ◽  
Author(s):  
E. M. Sparrow ◽  
W. D. Munro ◽  
V. K. Jonsson
Keyword(s):  
Viscous Fluid ◽  
Closed Form ◽  
Solution Method ◽  
Analytical Investigation ◽  
Radius Ratio ◽  
Narrow Gap ◽  
Rotating Cylinders ◽  
Coaxial Cylinders ◽  
Wave Numbers ◽  
Wide Gap

An analytical investigation is carried out to determine the conditions for instability in a viscous fluid contained between rotating coaxial cylinders of arbitrary radius ratio. A solution method is outlined and then applied to cylinders having radius ratios ranging from 0·95 to 0·1. Consideration is given to both cases wherein the cylinders are rotating in the same direction and in opposite directions. Results are reported for the Taylor numbers and wave-numbers which mark the onset of instability. The present results are also employed to delineate the range of applicability of the closed-form instability predictions of Taylor and of Meksyn, which were derived for narrow-gap conditions.

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