scholarly journals Cavitation Erosion in Nonaqueous Liquids

1970 ◽  
Vol 92 (4) ◽  
pp. 807-813 ◽  
Author(s):  
M. S. Plesset
Keyword(s):  
Cavitation Erosion ◽  
Organic Liquid ◽  
Pure Water ◽  
Short Exposure ◽  
Organic Liquids ◽  
Cavitation Damage ◽  
Molecular Ratio ◽  
Erosion Rates ◽  
Damage Rate ◽  
Water Glycerol

Cavitation erosion rates in the organic liquids formamide, ethanol, acetone, and glycerol are compared with the rate in distilled water. As is to be expected, these non-ionizing liquids, which are chemically less reactive with metals than water, show lower damage rates. The cavitation damage rates have also been measured for solutions of these organic liquids in water and all these solutions show a monotonic decrease in going from pure water to the pure organic liquid except glycerol. The water-glycerol solutions go through a minimum damage rate for a solution with molecular ratio of glycerol to water of approximately 1 to 1. Solutions of ethanol in glycerol show a maximum in damage rate for a solution with molecular ratio, glycerol/ethanol, of about 2 to 1. Qualitative differences in the cavitation bubble cloud in the various liquids studied are indicated by short-exposure photographs.

scholarly journals The morphology of cavitation damage of heat-treated medium carbon steel

2006 ◽  
Vol 71 (8-9) ◽  
pp. 977-984 ◽  
Author(s):  
Marina Dojcinovic ◽  
Srdjan Markovic
Keyword(s):  
Carbon Steel ◽  
Cavitation Erosion ◽  
Medium Carbon Steel ◽  
Cavitation Damage ◽  
Medium Carbon ◽  
Erosion Rates ◽  
Hydraulic Machinery ◽  
Heat Treated ◽  
Set Up ◽  
Microscopy Techniques

In this paper the morphology of the cavitation damage to heat-treated medium carbon steel was analyzed. The experiments were conducted using a modified vibratory cavitation test set up. The erosion rates were measured by an analytical method. The morphology of the cavitation damage was studied by the scanning electron microscopy and optical microscopy techniques. The present work was aimed at understanding the cavitation erosion behavior of heat-treated medium carbon steel under laboratory conditions. The results indicate that the heat-treated medium carbon steel is not to be recommended for the production of hydraulic machinery parts exposed to high hydrodynamic intensity.

Synthesis of aligned carbon nanotubes in organic liquids

2002 ◽  
Vol 17 (9) ◽  
pp. 2457-2464 ◽  
Author(s):  
Yafei Zhang ◽  
Mikka N.-Gamo ◽  
Kiyoharu Nakagawa ◽  
Toshihiro Ando
Keyword(s):  
Carbon Nanotubes ◽  
Organic Liquid ◽  
Film Surface ◽  
Normal Pressure ◽  
Organic Liquids ◽  
X Ray Diffraction ◽  
Multiwalled Carbon ◽  
Aligned Carbon Nanotubes ◽  
Novel Method ◽  
The Right

A simple and novel method was developed for efficient synthesis of aligned multiwalled carbon nanotubes (CNTs) in methanol and ethanol under normal pressure. The CNTs' alignment and structures were investigated using Raman scattering and x-ray diffraction spectroscopy. A unique kind of coupled CNT was synthesized in which one rotated to the left and one rotated to the right. Chains periodically bridged the coupled CNTs. The growth mechanism of the CNTs within organic liquid is proposed to be a catalytic process at the Fe film surface in a dynamic and thermal nonequilibrium condition in organic liquids.

Coatings from Liquid and Supercritical Carbon Dioxide

2004 ◽  
Author(s):  
Yury Chernyak ◽  
Florence Henon
Keyword(s):  
Carbon Dioxide ◽  
Supercritical Carbon Dioxide ◽  
Physical Properties ◽  
Organic Liquid ◽  
Spray Coating ◽  
Organic Liquids ◽  
Liquid Density ◽  
Operating Pressure ◽  
Interfacial Tensions ◽  
Supercritical Carbon

This chapter describes several aspects of the use of carbon dioxide as a solvent or cosolvent in coating applications. The primary impetus for using carbon dioxide for this purpose has been the alleviation of volatile emissions and liquid solvent wastes. However, the special physical properties of liquid and supercritical carbon dioxide may offer some processing advantages over conventional organic or aqueous solvents. Liquid carbon dioxide is quite compressible, and a reduction in temperature results not only in a reduction in the operating pressure, but also in a significant increase in the liquid density to values of approximately 0.9 g/cm3. At these high liquid densities, carbon dioxide exhibits improved solvent performance, but with much lower viscosities and interfacial tensions than aqueous or organic liquid solvents. Under supercritical conditions, carbon dioxide also exhibits high densities, low viscosities, and improved solvent power. Low viscosities and interfacial tensions tend to facilitate the transport of the solvents into any crevices or imperfections on the surface to be covered, and this might prove advantageous in the coating of patterned or etched surfaces. Since carbon dioxide dissolves and diffuses easily into many different polymers and organic liquids, it can also be used to reduce the viscosity of coating solutions. Whether in the liquid or the supercritical state, the temperature and pressure of the mixture can be used to control its physical properties in ways that are impossible to achieve with traditional solvents. These distinguishing features have raised the level of industrial interest in carbon dioxide as a solvent for coating applications, beyond those based solely on environmental concerns. In this chapter, we will discuss current applications and research on the use of CO2 as a solvent for coatings. The first section deals with spray coating from supercritical CO2. Subsequent sections deal with the use of liquid coatings, such as spin and free meniscus coatings, and impregnation coatings. Since the start of the 20th century (ca. 1907), atomization has been the basis for conventional spray coating applications (Muirhead, 1974). Typically, atomization is caused by high shear of the coating fluid in air, leading to droplet or particle formation.

A dual underliquid superlyophobic surface in organic media for on-demand separation of immiscible organic liquid mixtures

2019 ◽  
Vol 55 (92) ◽  
pp. 13876-13879 ◽  
Author(s):  
Yihan Sun ◽  
Jinxia Huang ◽  
Zhiguang Guo
Keyword(s):  
Organic Liquid ◽  
Liquid Mixtures ◽  
Organic Liquids ◽  
Organic Media ◽  
On Demand

A facile protocol was developed for preparing a dual underliquid superlyophobic surface for the on-demand separation of immiscible organic liquids.

A discussion on deformation of solids by the impact of liquids, and its relation to rain damage in aircraft and missiles, to blade erosion in steam turbines, and to cavitation erosion - The collapse of cavitation bubbles and the pressures thereby produced against solid boundaries

1966 ◽  
Vol 260 (1110) ◽  
pp. 221-240 ◽  
Keyword(s):  
Cavitation Erosion ◽  
Experimental Information ◽  
Liquid Jets ◽  
Steam Turbines ◽  
Jet Formation ◽  
Cavitation Damage ◽  
Cavity Collapse ◽  
New Ideas ◽  
The Impact ◽  
Shape Changes

Our object is to present a broad review of this subject as a branch of hydrodynamics, referring both to the well known ‘implosion’ mechanism first analysed by Lord Rayleigh and, more particularly, to the recently perceived possibility that effects of equally great violence, such as to damage solid boundaries, may arise through the impact of liquid jets formed by collapsing cavities. In §2 a few practical facts about cavitation damage are recalled by way of background, and then in §3 the significance of available theoretical and experimental information about cavity collapse is discussed. The main exposition of new ideas is in §4, which is a review of the factors contributing to shape changes and eventual jet formation by collapsing cavities. Finally, in §5, some new experimental observations on the unsymmetrical collapse of vapour-filled cavities are presented.

scholarly journals Mitigating cavitation erosion using biomimetic gas-entrapping microtextured surfaces (GEMS)

2020 ◽  
Vol 6 (13) ◽  
pp. eaax6192 ◽  
Author(s):  
Silvestre Roberto Gonzalez-Avila ◽  
Dang Minh Nguyen ◽  
Sankara Arunachalam ◽  
Eddy M. Domingues ◽  
Himanshu Mishra ◽  
...  
Keyword(s):  
Solid Surface ◽  
Surface Hardening ◽  
High Speed ◽  
Cavitation Erosion ◽  
Flow Problem ◽  
Vapor Bubbles ◽  
Cavitation Damage ◽  
Cavitation Bubbles ◽  
Microtextured Surfaces ◽  
High Speed Flows

Cavitation refers to the formation and collapse of vapor bubbles near solid boundaries in high-speed flows, such as ship propellers and pumps. During this process, cavitation bubbles focus fluid energy on the solid surface by forming high-speed jets, leading to damage and downtime of machinery. In response, numerous surface treatments to counteract this effect have been explored, including perfluorinated coatings and surface hardening, but they all succumb to cavitation erosion eventually. Here, we report on biomimetic gas-entrapping microtextured surfaces (GEMS) that robustly entrap air when immersed in water regardless of the wetting nature of the substrate. Crucially, the entrapment of air inside the cavities repels cavitation bubbles away from the surface, thereby preventing cavitation damage. We provide mechanistic insights by treating the system as a potential flow problem of a multi-bubble system. Our findings present a possible avenue for mitigating cavitation erosion through the application of inexpensive and environmentally friendly materials.

Aerothermochemistry of Metal Erosion by Hot Reactive Gases

1978 ◽  
Vol 100 (3) ◽  
pp. 531-536 ◽  
Author(s):  
A. Gany ◽  
L. H. Caveny ◽  
M. Summerfield
Keyword(s):  
Surface Reactions ◽  
Experimental Studies ◽  
Heating Surface ◽  
Melting Rate ◽  
Short Exposure ◽  
Convective Heating ◽  
Erosion Rates ◽  
Diffusion Limited ◽  
O2 Concentration ◽  
Reactive Gases

Analytical studies were conducted to investigate the mechanisms of metal erosion produced by short exposures (< 2 ms) to flowing high pressure (∼ 350 MPa), high temperature (∼ 3000 K) reactive gases. Previous experimental studies established that the intense heating during the short exposure produced melting and, when reactive gases were used, oxidation of the surface and enhanced erosion. The reactions were modeled as diffusion-limited, heterogeneous surface reactions which achieved equilibrium at the gas/metal interface. Calculated results for the sequential events of initial heating, surface reactions, and melting explained and correlated the experimental trends for Fe, Al, Ti, and Mo. Rapidly increasing erosion rates with increasing O2 concentration are the result of the surface reactions between the metal and O2. As O2 concentration increases, the heating produced by the surface reaction exceeds the forced convective heating which, in turn, greatly enhances the melting rate.

Numerical Prediction of Cavitation Erosion on a Francis Turbine Runner

2013 ◽  
Vol 655-657 ◽  
pp. 449-456
Author(s):  
Hong Ming Zhang ◽  
Li Xiang Zhang
Keyword(s):  
Cavitation Erosion ◽  
Stokes Equations ◽  
Volume Fraction ◽  
Three Dimensional ◽  
Numerical Prediction ◽  
Francis Turbine ◽  
Navier Stokes ◽  
Transfer Model ◽  
Cavitation Damage ◽  
Turbine Runner

The paper presents numerical prediction of cavitation erosion on a Francis turbine runner using CFD code. The SST turbulence model is employed in the Reynolds averaged Navier–Stokes equations in this study. A mixture assumption and a finite rate mass transfer model were introduced. The computing domain is discretized with a full three-dimensional mesh system of unstructured tetrahedral shapes. The finite volume method is used to solve the governing equations of the mixture model and the pressure-velocity coupling is handled via a Pressure Implicit with Splitting of Operators(PISO) procedure. Comparison the numerical prediction results with a real runner with cavitation damage, the region of higher volume fraction by simulation with the region of runner cavitation damage is consistent.

A discussion on deformation of solids by the impact of liquids, and its relation to rain damage in aircraft and missiles, to blade erosion in steam turbines, and to cavitation erosion - Damage to solids caused by cavitation

1966 ◽  
Vol 260 (1110) ◽  
pp. 245-255 ◽  
Keyword(s):  
Mechanical Properties ◽  
Cavitation Erosion ◽  
Cavitation Resistance ◽  
Steam Turbines ◽  
Single Event ◽  
Cavitation Damage ◽  
Erosion Damage ◽  
Highly Sensitive ◽  
Wide Range ◽  
The Impact

This paper describes the early stages of cavitation damage observed in cavitating venturi tunnels. The cavitating fluids were water and mercury, and a wide range of specimen materials were used. The damage was found to consist of single-event symmetical craters and irregular fatigue-type failures. The degree of damage was highly sensitive to minor flow perturbations, and this is discussed. The effect of stress level in the specimen before testing, and relations between cavitation resistance and the mechanical properties of the materials are considered.

The Electrochemical Approach To Cavitation Damage and Its Prevention

CORROSION ◽  
1961 ◽  
Vol 17 (11) ◽  
pp. 535t-549t ◽  
Author(s):  
H. S. PREISER ◽  
B. H. TYTELL
Keyword(s):  
Fatigue Damage ◽  
Cathodic Protection ◽  
Cavitation Erosion ◽  
Unified Theory ◽  
Protection Measures ◽  
Cavitation Damage ◽  
Electrochemical Approach ◽  
Mechanical Factors ◽  
Extensive Bibliography

Abstract This paper presents a unified theory on the interrelationship between electrochemical and mechanical factors causing damage to materials subjected to cavitating environments. The ambiguous term “cavitation erosion” is rejected in favor of three modes ot damage which depend on the severity of cavitation collapse forces: Cavitation Deformation or Fracture; Cavitation Fatigue; and Cavitation Corrosion. The authors describe some model propeller experiments which demonstrate Cavitation Fatigue damage and how specific cathodic protection measures reduce the damage. An extensive bibliography is appended. 3.5.3

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