scholarly journals The relationship between the surface tension and the saturated vapor pressure of model nanofluids

2019 ◽  
Vol 55 (1) ◽  
pp. 40-46
Author(s):  
O. Ya. Khliyeva ◽  
D. A. Ivchenko ◽  
K. Yu. Khanchych ◽  
I. V. Motovoy ◽  
V. P. Zhelezny
Keyword(s):  
Surface Tension ◽  
Surface Layer ◽  
Vapor Pressure ◽  
Saturated Vapor Pressure ◽  
Saturated Vapor ◽  
Practical Interest ◽  
Al2o3 Nanoparticles ◽  
Temperature Range ◽  
Specific Intermolecular Interaction ◽  
The Relationship

Information on surface tension is necessary for modeling boiling processes in nanofluids. It was shown that the problem of predicting the surface tension of complex thermodynamic systems, such as nanofluids, remains outstanding. It should be noted that the surface tension of liquids and the saturated vapor pressure are due to a specific intermolecular interaction in the region of spatial heterogeneity of the substance (surface layer). Moreover, the compositions of the surface layer of nanofluid and its liquid phase are not equal. The presence of nanoparticles in the base fluid affects the composition of the surface layer of liquids. However, there are no methods for determining the composition of the surface layer of nanofluids and this fact complicates establishing the dependence of the surface tension on the state parameters of nanofluids. It should be mentioned that the number of possible methodological errors in measurements of the saturated vapor pressure of nanofluids is significantly lower than for the surface tension measurements. Therefore, in the development of models for predicting the surface tension, scientific and practical interest has establishing the relationship between the surface tension and the saturated vapor pressure of nanofluids. In the presented work, we consider the nanofluids of isopropanol/Al2O3 nanoparticles and o-xylene/fullerenes C60. Saturated vapor pressure and surface tension of nanofluids of isopropanol/Al2O3 nanoparticles have been studied in the temperature range 293 – 363 K and concentrations of Al2O3 nanoparticles 0-8.71 g/kg. Measurement of saturated vapor pressure and surface tension of nanofluids of o-xylene/fullerenes C60 have been performed in the temperature range 283 – 348 K and the concentration of C60 0-7.5 g/kg. It is shown that additives of Al2O3  nanoparticles and fullerenes C60 lead to a decrease in the surface tension and increase in the saturated vapor pressure. It is shown that there is a universal dependence between the reduced surface tension and saturated vapor pressure for the researched nanofluids.

Influence of Nano-Refrigeration-Oil on Saturated Vapor Pressure of R22

2011 ◽  
Vol 694 ◽  
pp. 309-314 ◽  
Author(s):  
Jiang Feng Lou ◽  
Rui Xiang Wang ◽  
Min Zhang
Keyword(s):  
Experimental Data ◽  
Vapor Pressure ◽  
Mass Fraction ◽  
Saturated Vapor Pressure ◽  
Saturated Vapor ◽  
Experimental Results ◽  
Vapor Pressures ◽  
Temperature Range ◽  
Mass Fractions

The saturated vapor pressures of R22 uniformly mixed with refrigeration oil and nano- refrigeration-oil were measured experimentally at a temperature range from 263 to 333K and mass fractions from 1 to 5%. The experimental results showed that the saturated vapor pressure of R22/KT56 mixture was lower than that of pure R22; the pressure deviation between them increased with a raising mass fraction of refrigeration oil and temperature. After adding nano-NiFe2O4 and nano-fullerene into KT56, the pressure deviation increased at the same mass fraction and temperature. A saturated vapor pressure correlation for R22 and refrigeration oil/nano-refrigeration-oil mixture was proposed, and the calculated values agreed with the experimental data within the deviation of ± 0.77%.

Surface Tension and Bubbles

2011 ◽  
Vol 354-355 ◽  
pp. 37-40
Author(s):  
Cai Xia Xu ◽  
Hai Rong Tang
Keyword(s):  
Phase Transition ◽  
Surface Tension ◽  
Liquid Phase ◽  
Vapor Pressure ◽  
Saturated Vapor Pressure ◽  
Saturated Vapor ◽  
Surfactant Solution ◽  
Liquid Phase Transition ◽  
Almost All

From a molecular perspective, we described the origin of surface tension. Surface tension is exceptionally good at rounding things out, such as bubbles can produce in surfactant solution , also in liquid or vapor-liquid phase transition. Through the experiment of determination of saturated vapor pressure of pure liquids, maybe we can conclude that almost all the bubbles were generated as result of the breakup of the gas-liquid interface.

scholarly journals Glycerin-containing Working Fluids for Hydraulic Drives for Special Purposes

2020 ◽  
pp. 1-16
Author(s):  
K. D. Efremova ◽  
V. N. Pilgunov
Keyword(s):  
Vapor Pressure ◽  
Saturated Vapor Pressure ◽  
Saturated Vapor ◽  
Experimental Studies ◽  
Practical Interest ◽  
Hydrodynamic Cavitation ◽  
Absolute Pressure ◽  
Flow Section ◽  
Hydraulic Machines ◽  
The Absolute

The cavitation properties of a liquid must be taken into account in the engineering design of hydraulic machines and devices for hydraulic automation in cases when in their working process the absolute pressure in the liquid may drop below atmospheric, and the liquid is in a rarefied state for a certain time. Cold boiling, which occurs at a relatively low temperature and reduced absolute pressure inside or on the surface of the liquid, is considered as hydrostatic cavitation, if the liquid is stationary, or as hydrodynamic cavitation, if the liquid enters conditions under which the velocity head sharply increases in the flow section and the absolute pressure.In accordance with the theory of cavitation, the first phase of cavitation occurs when the absolute pressure in the degassed liquid drops to the value of the saturated vapor pressure and the air dissolved in the liquid, leaving the intermolecular space, turns into microbubbles of undissolved air and becomes a generator of cavitation "nuclei". Of practical interest is a quantitative assessment of the value of the minimum permissible absolute pressure in a real, partially or completely degassed liquid, at which hydrostatic cavitation occurs.Since the pressure of saturated vapor of a liquid is, to a certain extent, associated with the forces of intermolecular interaction, it is necessary to have information on the cavitation properties of technical solutions, including the solution of air in a liquid, since a solute can weaken intermolecular bonds and affect the value of the pressure of saturated vapors of the solvent. The article describes an experiment carried out by the authors to evacuate liquids. During the experiment, evacuation of various liquids was carried out using a developed hydraulic vacuum pump with a pneumatic drive.The article presents the technologies of hydrostatic and hydrodynamic degassing of liquids used in the experiment.As a result of experimental studies of the cavitation properties of pure glycerin and glycerin in the form of a 49/51% solution in water, mineral oil and aviation kerosene, quantitative estimates of the permissible absolute pressure in the considered technical fluids and solutions were obtained, its dependence on the saturated vapor pressure, the influence of the degree of hydrodynamic degassing the liquid, and the amount of dissolved substance in it on the strength of the liquid to rupture.In the process of studying the cavitation properties of solutions, it was found that the level of permissible absolute pressure in the solution is greater than that of the solvent. It has been suggested that dissolved solid, liquid or gaseous substances weaken the intermolecular bonds of the solvent and increase the pressure of its saturated vapor.On the basis of the experimental studies, a method for determining the highest rarefaction in solvents and in glycerol solutions has been developed. In addition, a comparative assessment of the cavitation properties of the considered technical fluids is given.

Pyrolytic properties of di-n-butyltin(IV) diacetate as a precursor for sprayed SnO2 thin films

1994 ◽  
Vol 9 (3) ◽  
pp. 663-668 ◽  
Author(s):  
Isao Yagi ◽  
Eiichiro Ikeda ◽  
Yasuo Kuniya
Keyword(s):  
Thin Films ◽  
Vapor Pressure ◽  
Spray Pyrolysis ◽  
Saturated Vapor Pressure ◽  
Saturated Vapor ◽  
Chemical Species ◽  
Crystal Phase ◽  
Temperature Range ◽  
Sno2 Thin Films ◽  
Two Stages

The saturated vapor pressure and pyrolytic properties of di-n-butyltin(IV) diacetate have been investigated with and without oxygen in order to understand the orientational growth of SnO2 thin films by spray pyrolysis. The dependence of the saturated vapor pressure on temperature was determined: log P(evap.)Torr = −2.827 × 103/T + 7.687. It has been found that the pyrolysis of this compound consisted of two stages: elimination of the n-butyl groups in a temperature range between about 280°and 310 °C, and of the acetoxy groups above 320 °C. Such decompositions were shifted toward lower temperatures under oxygen. It was also found that oxygen in air in addition to intramolecular oxygen contributed to the formation of SnO2 crystal phase. Moreover, it was suggested that pyrolized chemical species preserving the Sn-O bond probably related the orientational growth of the (200) plane of sprayed SnO2 thin films.

scholarly journals Effects of nanoparticles on hydraulic cavitation

2018 ◽  
Vol 240 ◽  
pp. 03004
Author(s):  
Min-rui Chen ◽  
Jin-yuan Qian ◽  
Zan Wu ◽  
Chen Yang ◽  
Zhi-jiang Jin ◽  
...  
Keyword(s):  
Vapor Pressure ◽  
Saturated Vapor Pressure ◽  
Saturated Vapor ◽  
Geometric Model ◽  
Pressure Ratio ◽  
Perforated Plate ◽  
Significant Parameter ◽  
Operation Conditions ◽  
Small Bubbles ◽  
Crucial Condition

When liquids flowing through a throttling element, such as a perforated plate, the velocity increases and the pressure decreases. If the pressure is below the saturated vapor pressure, the liquid will vaporize into small bubbles, which is called hydraulic cavitation. In fact, vaporization nucleus is another crucial condition for vaporizing. The nanoparticles contained in the nanofluids play a significant role in vaporization of liquids. In this paper, the effects of the nanoparticles on hydraulic cavitation are investigated. Firstly, a geometric model of a pipe channel equipped with a perforated plate is established. Then with different nanoparticle volume fractions and diameters, the nanofluids flowing through the channel is numerically simulated based on a validated numerical method. The operation conditions, such as the temperature and the pressure ratio of inlet to outlet, are the considered variables. As a significant parameter, cavitation numbers under different operation conditions are achieved to investigate the effects of nanoparticles on hydraulic cavitation. Meanwhile, the contours are extracted to research the distribution of bubbles for further investigation. This study is of interests for researchers working on hydraulic cavitation or nanofluids.

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