Effect of Dilute Polymer Additives on the Acoustic Cavitation Threshold of Water

1984 ◽  
Vol 106 (1) ◽  
pp. 99-104 ◽  
Author(s):  
L. A. Crum ◽  
J. E. Brosey
Keyword(s):  
Theoretical Model ◽  
Solid Particle ◽  
Polyethylene Oxide ◽  
Guar Gum ◽  
Acoustic Cavitation ◽  
Polymer Additives ◽  
Gas Bubble ◽  
Index Reduction ◽  
Cavitation Threshold ◽  
Good Agreement

Measurements are presented of the variation of the acoustic cavitation threshold of water with concentration of the polymer additives polyethylene oxide and guar gum. It was found that small amounts of these additives could significantly increase the cavitation threshold. A theoretical model, based upon nucleation of a gas bubble from a Harvey-type crevice in a mote or solid particle, is developed that gives good agreement with the measurements. The applicability of this approach to an explanation of cavitation index reduction in flow-generated or confined jet cavitation, when polymer additives are introduced, is discussed.

Effects of Various Polymer Additives on Cavitation Damage

1986 ◽  
Vol 200 (4) ◽  
pp. 231-235 ◽  
Author(s):  
T Tsujino ◽  
A Shima ◽  
H Nanjo
Keyword(s):  
Weight Loss ◽  
Polyethylene Oxide ◽  
Guar Gum ◽  
Polymer Solutions ◽  
The Other ◽  
Polymer Additives ◽  
Cavitation Damage ◽  
Polyacrylamide Solution ◽  
Weight Losses

Cavitation damage tests in various polymer solutions have been carried out using a vibratory damage apparatus. The relation of weight loss-time, the damage patterns, the cavitation clouds and the damaged area in a polyacrylamide solution, a sodium carboxy-methylcellulose solution, a hydroxyethylcellulose solution, a guar gum solution and a polyethylene oxide solution are compared and are discussed. It is found that the weight losses in the PAM solution and the Polyox solution, which are more elastic, are smaller than the cases of the other polymer solutions and water after sixty minutes exposure to cavitation.

scholarly journals An Analysis of Acoustic Cavitation Thresholds of Water Based on the Incubation Time Criterion Approach

Fluids ◽  
2021 ◽  
Vol 6 (4) ◽  
pp. 134
Author(s):  
Ivan Smirnov ◽  
Natalia Mikhailova
Keyword(s):  
Incubation Time ◽  
Dynamic Strength ◽  
Acoustic Cavitation ◽  
Nucleation Theory ◽  
Classical Nucleation Theory ◽  
Accurate Estimation ◽  
Ultrasound Frequency ◽  
Time Criterion ◽  
Good Potential ◽  
Cavitation Threshold

Researchers are still working on the development of models that facilitate the accurate estimation of acoustic cavitation threshold. In this paper, we have analyzed the possibility of using the incubation time criterion to calculate the threshold of the onset of acoustic cavitation depending on the ultrasound frequency, hydrostatic pressure, and temperature of a liquid. This criterion has been successfully used by earlier studies to calculate the dynamic strength of solids and has recently been proposed in an adapted version for calculating the cavitation threshold. The analysis is carried out for various experimental data for water presented in the literature. Although the criterion assumes the use of macroparameters of a liquid, we also considered the possibility of taking into account the size of cavitation nuclei and its influence on the calculation result. We compared the results of cavitation threshold calculations done using the incubation time criterion of cavitation and the classical nucleation theory. Our results showed that the incubation time criterion more qualitatively models the results of experiments using only three parameters of the liquid. We then discussed a possible relationship between the parameters of the two approaches. The results of our study showed that the criterion under consideration has a good potential and can be conveniently used for applications where there are special requirements for ultrasound parameters, maximum negative pressure, and liquid temperature.

The structure of the Cincinnati arch as determined by short period Rayleigh waves

1969 ◽  
Vol 59 (1) ◽  
pp. 399-407
Author(s):  
Robert B. Herrmann
Keyword(s):  
Experimental Data ◽  
Theoretical Model ◽  
Layer Thickness ◽  
Rayleigh Waves ◽  
Layer Model ◽  
Depth Data ◽  
Short Period ◽  
Best Fitting ◽  
Good Agreement

Abstract The propagation of Rayleigh waves with periods of 0.4 to 2.0 seconds across the Cincinnati arch is investigated. The region of investigation includes southern Indiana and Ohio and northern Kentucky. The experimental data for all paths are fitted by a three-layer model of varying layer thickness but of fixed velocity in each layer. The resulting inferred structural picture is in good agreement with the known basement trends of the region. The velocities of the best fitting theoretical model agree well with velocity-depth data from a well in southern Indiana.

Analytical approach for transient photoconductivity in undoped a-Si:H

1995 ◽  
Vol 377 ◽  
Author(s):  
M. Goerlitzer ◽  
P. Pipoz ◽  
H. Beck ◽  
N. Wyrsch ◽  
A. V. Shah
Keyword(s):  
Steady State ◽  
Theoretical Model ◽  
Analytical Approach ◽  
Room Temperature ◽  
Free Electrons ◽  
Recombination Time ◽  
Sample Quality ◽  
Transient Photoconductivity ◽  
Light Intensities ◽  
Good Agreement

ABSTRACTTransient photoconductive response of undoped a-Si:H has been studied; the changes were analysed between two slightly different steady-state illumination conditions, at room temperature. A theoretical model is developed to describe transient photoconductivity; it yields good agreement with the measured curves for a whole range of light intensities. Numerical evaluations allows one to extract the recombination time of electrons. Comparison with steady-state photoconductivity yields a band mobility of free electrons between 0.1 and 6 cm2V−1s−1, depending upon sample quality.

Thermocouple Response Characteristics in Deflagrating Low-Conductivity Materials

1971 ◽  
Vol 93 (1) ◽  
pp. 77-84 ◽  
Author(s):  
Nam P. Suh ◽  
C. L. Tsai
Keyword(s):  
Theoretical Model ◽  
Gas Phase ◽  
Wire Diameter ◽  
Solid Propellants ◽  
Optimum Ratio ◽  
Response Characteristics ◽  
Bead Diameter ◽  
Double Base ◽  
Theoretical Results ◽  
Good Agreement

The transient thermocouple response characteristics in deflagrating low-conductivity materials with high temperature gradients were investigated theoretically and experimentally. The theoretical model considers the thermocouple bead and lead wires separately, and the two resulting partial differential equations are solved simultaneously by a finite difference technique. The experimental results are obtained by embedding various size thermocouple wires in double-base solid propellants and consequently measuring the temperature profiles and the surface temperatures. The theoretical model is used to predict the experimentally measured temperatures. There is good agreement. The experimentally measured values are smaller than the correct surface temperature, corresponding to the model prediction for zero wire diameter, by at least 20 percent even when 1/2-mil thermocouple wire is used. Both the experimental and theoretical results show a plateau when the thermocouple bead emerges from the solid into the gas phase. The theoretical results also show that there is an optimum ratio of. the thermocouple bead diameter to the wire diameter, which is found to be close to three

Theoretical Model of the Spanwise Mixing Caused by Periodic Incoming Wakes

1994 ◽  
Author(s):  
K. Imanari
Keyword(s):  
Experimental Data ◽  
Theoretical Model ◽  
Turbulent Diffusion ◽  
Axial Flow ◽  
Single Stage ◽  
Mixing Coefficients ◽  
Predicted Values ◽  
Good Agreement ◽  
Axial Flow Compressors

A theoretical model is proposed for the spanwise mixing caused by periodic incoming wakes in the context of turbulent diffusion in axial-flow compressors prior to repeating-stage conditions. The model was used to predict the spanwise mixing coefficients across a stator of a single-stage compressor without IGVs. The correctness of the theory was demonstrated by the results that the predicted values were in good agreement with the associated experimental data.

Theoretical Analysis of Porosity in an Ordered Porous Copper Fabricated by Continuous Unidirectional Solidification

2018 ◽  
Vol 933 ◽  
pp. 136-141
Author(s):  
Rong Cao ◽  
Qing Lin Jin
Keyword(s):  
High Pressure ◽  
Theoretical Model ◽  
Theoretical Analysis ◽  
Processing Parameters ◽  
Unidirectional Solidification ◽  
Hydrogen Gas ◽  
Porous Copper ◽  
Gas Atmosphere ◽  
Ordered Porous ◽  
Good Agreement

Ordered porous copper with elongated pores has been fabricated by a continuous unidirectional solidification method in a hydrogen gas atmosphere with high pressure. The porosity of the ordered porous copper is significantly affected by the pressure of hydrogen. A theoretical model is developed to get the relation between the porosity and the processing parameters. The calculated values are in good agreement with the experimental results. Key words: Unidirectional solidification; Ordered porous copper; Porosity; Modeling.

scholarly journals Numerical Simulation of 980 nm-LD-Pumped Yb3+-Er3+-Tm3+-Codoped Fiber Amplifier for 1500 nm and 1600 nm Bands

2009 ◽  
Vol 2009 ◽  
pp. 1-8
Author(s):  
Chun Jiang
Keyword(s):  
Numerical Simulation ◽  
Theoretical Model ◽  
Pump Power ◽  
Fiber Length ◽  
Fiber Amplifier ◽  
Numerical Results ◽  
Experimental Result ◽  
Signal Wavelength ◽  
Gain Spectra ◽  
Good Agreement

The theoretical model of Yb3+-Er3+-Tm3+-codoped fiber amplifier pumped by 980 nm laser is proposed, and the rate and power propagation equations are numerically solved to analyze the dependences of the gains at 1500 nm and 1600 nm bands on the activator concentrations, fiber length, pump power, and signal wavelength. The numerical results show that our model is in good agreement with experimental result, and with pump power of 200 mW and fiber length varying from 0.15 to 1.5 m, the gains at the two bands may reach 10.0–20.0 dB when the codoping concentrations of Yb3+, Er3+, and Tm3+ are in the ranges 1.0–3.0×1025, 1.0–3.0×1024, and 1.0–3.0×1024 ions/m3, respectively. The fiber parameters may be optimized to flatten the gain spectra.

scholarly journals Theoretical model of ice nucleation induced by inertial acoustic cavitation. Part 2: Number of ice nuclei generated by a single bubble

2016 ◽  
Vol 28 ◽  
pp. 185-191 ◽  
Author(s):  
C. Cogné ◽  
S. Labouret ◽  
R. Peczalski ◽  
O. Louisnard ◽  
F. Baillon ◽  
...  
Keyword(s):  
Theoretical Model ◽  
Acoustic Cavitation ◽  
Ice Nucleation ◽  
Single Bubble ◽  
Ice Nuclei

scholarly journals Modelling of a low-temperature differential Stirling engine

2007 ◽  
Vol 221 (8) ◽  
pp. 927-943 ◽  
Author(s):  
A Robson ◽  
T Grassie ◽  
J Kubie
Keyword(s):  
Experimental Data ◽  
Theoretical Model ◽  
Low Temperature ◽  
First Principles ◽  
Dynamic Behaviour ◽  
Stirling Engine ◽  
Current Paper ◽  
Temperature Differential ◽  
Good Agreement

A full theoretical model of a low-temperature differential Stirling engine is developed in the current paper. The model, which starts from the first principles, gives a full differential description of the major components of the engine: the behaviour of the gas in the expansion and the compression spaces; the behaviour of the gas in the regenerator; the dynamic behaviour of the displacer; and the power piston/flywheel assembly. A small fully instrumented engine is used to validate the model. The theoretical model is in good agreement with the experimental data, and describes well all features exhibited by the engine.

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