General Correlations and Selection Procedures for Flow in Polyethylene Tubes With Uniformly Spaced Wall Orifices

1991 ◽  
Vol 113 (1) ◽  
pp. 98-103 ◽  
Author(s):  
E. Brundrett
Keyword(s):  
Data Base ◽  
Numerical Procedure ◽  
Experimental Results ◽  
Selection Procedures ◽  
Supply Pressure ◽  
Swirl Angle ◽  
Thin Walled ◽  
Predicted Values ◽  
Good Agreement ◽  
Economical Performance

A previously described experimentally based numerical procedure is used to characterize the flow in thin walled polyethylene tubes with uniformly spaced wall orifices (polytubes). The procedure evaluates the required supply pressure for specified geometry, supply flow, and supply swirl angle; and then predicts the pressure and discharge profiles along the polytube. The predicted values are in good agreement with reported experimental results and are used to develop a data base of the most significant ranges of polytube and supply parameters. Then, explicit design correlations and recommendations are obtained for satisfactory and economical performance.

A Method for Measurement of Axisymmetric Axial Residual Stresses in Circumferentially Welded Thin-Walled Cylinders

1985 ◽  
Vol 107 (3) ◽  
pp. 181-185 ◽  
Author(s):  
Weili Cheng ◽  
Iain Finnie
Keyword(s):  
Residual Stress ◽  
Stress Field ◽  
Axial Component ◽  
Residual Stress Field ◽  
Strain Measurements ◽  
Thin Walled ◽  
Predicted Values ◽  
Inside Wall ◽  
Good Agreement

A new method is proposed for measuring the axial component of an axisymmetric residual stress field in thin-walled cylinders. The specific application considered is determination of the stress at the centerline of a circumferential weld. The method involves strain measurements at the outside wall while a complete circumferential slit is cut to increasing depths from the inside wall. The technique is applied to the simple case of a single pass weld. Experimental results are in good agreement with predicted values.

Force Coefficients for a Centrally Grooved Short Squeeze Film Damper

1996 ◽  
Vol 118 (3) ◽  
pp. 608-616 ◽  
Author(s):  
J. X. Zhang ◽  
J. B. Roberts
Keyword(s):  
Hydrodynamic Force ◽  
Theoretical Work ◽  
Experimental Results ◽  
Squeeze Film ◽  
Static Force ◽  
Squeeze Film Damper ◽  
Force Coefficients ◽  
Supply Pressure ◽  
Supply Mechanism ◽  
Good Agreement

A centrally grooved short squeeze film damper (SFD), together with its lubricant supply mechanism (LSM), is analyzed, using an integrated theoretical model. It is shown that the traditional analysis for such a damper, where the effects of the central groove and the LSM are ignored, can lead to a seven-fold underestimation of the magnitude of the hydrodynamic force coefficients. The new theory gives predictions for the damping coefficients which are in good agreement with corresponding experimental results. Moreover, a five-fold improvement is obtained for both the temporal and convective inertia coefficients, at low values of eccentricity. The new model leads to the prediction of a nonzero fluid static force which, in conformity with experimental results, is linearly related to the supply pressure. The existence of this static force has not been explained by previous theoretical work on SFDs.

Separation of CO2 by Using Aqueous Mixtures of AMP and [B3MPYR][BF4] at High Pressure

2014 ◽  
Vol 67 (4) ◽  
Author(s):  
Syamila Nordin ◽  
Ruzitah Mohd Salleh ◽  
Norhuda Ismail
Keyword(s):  
Absorption Capacity ◽  
Experimental Results ◽  
Co2 Absorption ◽  
Loading Capacity ◽  
Aqueous Mixtures ◽  
Simple Correlation ◽  
Separation Of Co2 ◽  
Predicted Values ◽  
Experimental Values ◽  
Good Agreement

In this study, CO2 absorption capacity in aqueous mixtures of 2-amino-2-methyl-1-propanol, (AMP) and N-butyl-3-methylpyridinium tetrafluoroborate, [B3MPYR][BF4] was measured at pressures from 200 kPa up to 5000 kPa and temperatures of 303.15 K - 333.15 K. The AMP concentration was maintained at 1 M while the [B3MPYR][BF4] concentration ranges from 0.05 M to 0.3 M. It was observed that CO2 loading capacity increases when the pressure increased. However, increasing of temperature will decrease the CO2 loading. From the experimental results, a simple correlation, as suggested by Jou and Mather was used to predict the CO2 loading in the aqueous AMP-[B3MPYR][BF4] mixtures. The model were found to be in a good agreement with the experimental results where only 1.66% of the predicted values deviate more than 20% compared to the experimental values.

scholarly journals Brazier Effect of Thin Angle-Section Beams under Bending

2018 ◽  
Vol 10 (9) ◽  
pp. 3047
Author(s):  
Zhiguang Zhou ◽  
Liuyun Xu ◽  
Chaoxin Sun ◽  
Songtao Xue
Keyword(s):  
Nonlinear Response ◽  
Beam Theory ◽  
Bending Moment ◽  
Numerical Results ◽  
Experimental Results ◽  
Angle Section ◽  
Thin Walled ◽  
The Moment ◽  
Good Agreement ◽  
Brazier Effect

Thin-walled section beams have Brazier effect to exhibit a nonlinear response to bending moments, which is a geometric nonlinearity problem and different from eigenvalue problem. This paper is aimed at investigating the Brazier effect in thin-walled angle-section beams subjected to pure bending about its weak axis. The derivation using energy method is presented to predict the maximum bending moment and section deformation. Both numerical analyses and experimental results were used to show the validity of the proposed formula. Numerical results show that the boundary condition can influence the results due to the end effect, and that the influence tends to be negligible when the length of angle beam goes up to 30 times as the length of beam side. When the collapse in experiments is governed by Brazier flattening, the moment vs. curvature curve deviates significantly from the linear beam theory, but coincides well with the proposed formula in consideration of the restraint due to limited span of experimental setup. It can be concluded that the proposed formula shows good agreement with numerical results and experimental results.

Optimization of Morphology and Particle Size of Modified Sol Gel Synthesized YSZ Nanopowder Using Taguchi Method

2012 ◽  
Vol 21 ◽  
pp. 65-70 ◽  
Author(s):  
Morteza Hajizadeh Oghaz ◽  
Reza Shoja Razavi ◽  
Mohammad Reza Loghman-Estark ◽  
Reza Ghasemi
Keyword(s):  
Particle Size ◽  
Design Method ◽  
Sol Gel ◽  
Chelating Agent ◽  
Experimental Results ◽  
Experimental Conditions ◽  
Influence Of Process Parameters ◽  
Predicted Values ◽  
Good Agreement ◽  
Significant Factors

The morphology and particle size of yttria stabilized zirconia (YSZ) nanopowders synthesized by Pechini's method are very much dependent on the type of chelating agent, pH of solution, calcinations temperature, calcinations time, etc. In the present study, the influence of process parameters like the type of zirconium salt, pH of solution, calcinations temperature and time on the morphology and particle size of a YSZ nanopowder was analyzed by the Taguchi Design method and analysis of variance (ANOVA). According to the experimental results and ANOVA, the pH of solution and calcinations temperature are the most significant factors influencing the morphology and particle size of YSZ nanopowder; pH of solution is the most significant factor influencing the morphology; and calcinations temperature is the most significant factor affecting the particle size. Models were developed for predicting the morphology and particle size of the YSZ nanopowder. They were found to be in good agreement with the experimental results. The models were tested for experimental conditions and were found to be close to predicted values. Both morphology and particle size of YSZ nanopowders were mainly dependent on the pH of solution.

Inducing Frictional Force to Enhance the Transient Response in Beams

2019 ◽  
Vol 22 (2) ◽  
pp. 88-93
Author(s):  
Hamed Khanger Mina ◽  
Waleed K. Al-Ashtrai
Keyword(s):  
Numerical Analysis ◽  
Transient Response ◽  
Frictional Force ◽  
Damping Ratio ◽  
Experimental Results ◽  
Damping Capacity ◽  
Tightening Force ◽  
Contact Areas ◽  
Good Agreement ◽  
Ansys Workbench

This paper studies the effect of contact areas on the transient response of mechanical structures. Precisely, it investigates replacing the ordinary beam of a structure by two beams of half the thickness, which are joined by bolts. The response of these beams is controlled by adjusting the tightening of the connecting bolts and hence changing the magnitude of the induced frictional force between the two beams which affect the beams damping capacity. A cantilever of two beams joined together by bolts has been investigated numerically and experimentally. The numerical analysis was performed using ANSYS-Workbench version 17.2. A good agreement between the numerical and experimental results has been obtained. In general, results showed that the two beams vibrate independently when the bolts were loosed and the structure stiffness is about 20 N/m and the damping ratio is about 0.008. With increasing the bolts tightening, the stiffness and the damping ratio of the structure were also increased till they reach their maximum values when the tightening force equals to 8330 N, where the structure now has stiffness equals to 88 N/m and the damping ratio is about 0.062. Beyond this force value, increasing the bolts tightening has no effect on stiffness of the structure while the damping ratio is decreased until it returned to 0.008 when the bolts tightening becomes immense and the beams behave as one beam of double thickness.

PHOTOINDUCED NONLINEAR OCTUPOLAR POLARIZATION: TRANSIENT AND PERMANENT REGIMES

1996 ◽  
Vol 05 (04) ◽  
pp. 653-670 ◽  
Author(s):  
CÉLINE FIORINI ◽  
JEAN-MICHEL NUNZI ◽  
FABRICE CHARRA ◽  
IFOR D.W. SAMUEL ◽  
JOSEPH ZYSS
Keyword(s):  
Theoretical Analysis ◽  
Second Harmonic ◽  
Experimental Results ◽  
Polar Field ◽  
Rotational Spectrum ◽  
Dual Frequency ◽  
One Dimensional ◽  
Ethyl Violet ◽  
Disperse Red 1 ◽  
Good Agreement

An original poling method using purely optical means and based on a dual-frequency interference process is presented. We show that the coherent superposition of two beams at fundamental and second-harmonic frequencies results in a polar field with an irreducible rotational spectrum containing both a vector and an octupolar component. This enables the method to be applied even to molecules without a permanent dipole such as octupolar molecules. After a theoretical analysis of the process, we describe different experiments aiming at light-induced noncentrosymmetry performed respectively on one-dimensional Disperse Red 1 and octupolar Ethyl Violet molecules. Macroscopic octupolar patterning of the induced order is demonstrated in both transient and permanent regimes. Experimental results show good agreement with theory.

scholarly journals Seasonal Estimates and Uncertainties of Snow Accumulation from CloudSat Precipitation Retrievals

Atmosphere ◽  
2021 ◽  
Vol 12 (3) ◽  
pp. 363
Author(s):  
George Duffy ◽  
Fraser King ◽  
Ralf Bennartz ◽  
Christopher G. Fletcher
Keyword(s):  
Time Scales ◽  
Snow Water Equivalent ◽  
Spatial Scales ◽  
Snow Accumulation ◽  
High Latitudes ◽  
Percentage Points ◽  
Snow Water ◽  
Time Periods ◽  
Predicted Values ◽  
Good Agreement

CloudSat is often the only measurement of snowfall rate available at high latitudes, making it a valuable tool for understanding snow climatology. The capability of CloudSat to provide information on seasonal and subseasonal time scales, however, has yet to be explored. In this study, we use subsampled reanalysis estimates to predict the uncertainties of CloudSat snow water equivalent (SWE) accumulation measurements at various space and time resolutions. An idealized/simulated subsampling model predicts that CloudSat may provide seasonal SWE estimates with median percent errors below 50% at spatial scales as small as 2° × 2°. By converting these predictions to percent differences, we can evaluate CloudSat snowfall accumulations against a blend of gridded SWE measurements during frozen time periods. Our predictions are in good agreement with results. The 25th, 50th, and 75th percentiles of the percent differences between the two measurements all match predicted values within eight percentage points. We interpret these results to suggest that CloudSat snowfall estimates are in sufficient agreement with other, thoroughly vetted, gridded SWE products. This implies that CloudSat may provide useful estimates of snow accumulation over remote regions within seasonal time scales.

scholarly journals Comparison of Experimental and Numerical Transient Drop Deformation during Transition through Orifices in High-Pressure Homogenizers

2021 ◽  
Vol 5 (3) ◽  
pp. 32
Author(s):  
Benedikt Mutsch ◽  
Peter Walzel ◽  
Christian J. Kähler
Keyword(s):  
High Pressure ◽  
Visual Analysis ◽  
Imaging Technique ◽  
Extensional Flow ◽  
Droplet Breakup ◽  
Experimental Results ◽  
Drop Deformation ◽  
Droplet Deformation ◽  
Shadow Imaging ◽  
Good Agreement

The droplet deformation in dispersing units of high-pressure homogenizers (HPH) is examined experimentally and numerically. Due to the small size of common homogenizer nozzles, the visual analysis of the transient droplet generation is usually not possible. Therefore, a scaled setup was used. The droplet deformation was determined quantitatively by using a shadow imaging technique. It is shown that the influence of transient stresses on the droplets caused by laminar extensional flow upstream the orifice is highly relevant for the droplet breakup behind the nozzle. Classical approaches based on an equilibrium assumption on the other side are not adequate to explain the observed droplet distributions. Based on the experimental results, a relationship from the literature with numerical simulations adopting different models are used to determine the transient droplet deformation during transition through orifices. It is shown that numerical and experimental results are in fairly good agreement at limited settings. It can be concluded that a scaled apparatus is well suited to estimate the transient droplet formation up to the outlet of the orifice.

Steady-State and Dynamic Properties of the Floating-Ring Journal Bearing

1968 ◽  
Vol 90 (1) ◽  
pp. 243-253 ◽  
Author(s):  
F. K. Orcutt ◽  
C. W. Ng
Keyword(s):  
Steady State ◽  
Journal Bearing ◽  
Dynamic Properties ◽  
Calculated Data ◽  
Experimental Results ◽  
Supply Pressure ◽  
Pressure Parameter

Calculated data on steady-state and dynamic properties of the plain cylindrical floating-ring bearing with pressurized lubricant supply are given. The data are for a bearing with L/D of 1, and values of the ratio of inner to outer film clearances of 0.7 and 1.3. One value of dimensionless supply pressure parameter is covered. Experimental results are presented which verify the calculated results and which supplement them, particularly with respect to stability characteristics of the bearing.

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