scholarly journals Experimental Correlation for Splashing Condition of Droplets on Solid Substrates

Fluids ◽  
2022 ◽  
Vol 7 (1) ◽  
pp. 38
Author(s):  
Yukihiro Yonemoto ◽  
Kanta Tashiro ◽  
Minori Yamashita ◽  
Tomoaki Kunugi

Droplet splashing behaviors of water-ethanol binary mixture liquids on roughened solid surfaces were experimentally observed in order to investigate the effects of surface tension, viscosity, and wettability/surface roughness on the splashing occurrence. The range of the droplet volumes was from 1.7 μL to 32.6 μL. The ranges of the surface tension and the viscosity were from 21.1 mN/m to 71.9 mN/m, and from 1 mPas to 2.91 mPas, respectively. The surface roughness range was from 0.03 μm to 1.25 μm for Ra. The present experimental data were evaluated on the basis of the existing models. Resulting from these experiments, a simple model using the Ohnesorge number evaluated by the capillary length was proposed and the accuracy of the predicted critical values such as the critical Weber and Reynolds numbers were discussed. The result indicated that the liquid properties and the quantification of the surface condition such as surface roughness are important factors for the prediction of the splashing behavior.

Author(s):  
John Davenport

Post-larval specimens of Hirundichthys affinis are capable of jumping out of water, but the pectoral and pelvic fins are not extended when in air. Penetration through the air/ water interface demands a force to overcome surface tension which is similar in magnitude to the force required for the jump itself. However, post-larvae do not produce the single propulsive tail flick which powers the jump until most of the animal has passed through the interface. The post-larva emerges at an angle close to 45°, thus maximising the horizontal distance travelled before re-entry.Whether swimming slowly (4 body lengths s-1), or at maximum speed (36 body lengths s-1), post-larvae swim with the pectoral and pelvic fins extended. Calculations show that fast swimming post-larvae operate at Reynolds’ numbers of about 4×103, where surface roughness and projections decrease rather than increase drag.


2004 ◽  
Vol 127 (2) ◽  
pp. 388-392 ◽  
Author(s):  
Ho-Yun Nam ◽  
Jong-Man Kim ◽  
Kyung-Won Seo ◽  
Seok-Ki Choi

An experimental study has been carried out to measure the pressure loss at the side orifice of a liquid metal reactor fuel assembly. The characteristics of the pressure loss at the side orifice are investigated using the experimental data measured from 17 different types of side orifices that have different geometric shapes, dimensions, and arrangements of nozzles, and a correlation that covers the whole flow range by one equation is developed. The error range of the correlation is within ±10%, and most of the errors occurred in a region where the Reynolds number is small. The range of Reynolds numbers based on the hydraulic diameter of the orifice is 2000–350,000. It is found that the geometric factor is the most important parameter for the pressure loss when the Reynolds number is >30,000. As the Reynolds number becomes smaller, its effect becomes larger, and when the Reynolds number is small, it is the most important parameter for the pressure loss at the side orifices. The measured data shows a trend that the pressure loss coefficient increases as the number of orifices increases, and the effect of the longitudinal arrangement is small.


2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Takao Kameda ◽  
Daiki Shikano ◽  
Yasuhiro Harada ◽  
Satoshi Yanagi ◽  
Kimiteru Sado

AbstractCurling is a sport in which players deliver a cylindrical granite stone on an ice sheet in a curling hall toward a circular target located 28.35 m away. The stone gradually moves laterally, or curls, as it slides on ice. Although several papers have been published to propose a mechanism of the curling phenomenon for the last 100 years, no established theory exists on the subject, because detailed measurements on a pebbled ice surface and a curling stone sliding on ice and detailed theoretical model calculations have yet to be available. Here we show using our precise experimental data that the curl distance is primarily determined by the surface roughness and the surface area of the running band on the bottom of a stone and that the ice surface condition has smaller effects on the curl distance. We also propose a possible mechanism affecting the curling phenomena of a curing stone based on our results. We expect that our findings will form the basis of future curling theories and model calculations regarding the curling phenomenon of curling stones. Using the relation between the curl distance and the surface roughness of the running band in this study, the curl distance of a stone sliding on ice in every curling hall can be adjusted to an appropriate value by changing the surface roughness of the running band on the bottom of a stone.


2011 ◽  
Vol 486 ◽  
pp. 262-265
Author(s):  
Amit Kohli ◽  
Mudit Sood ◽  
Anhad Singh Chawla

The objective of the present work is to simulate surface roughness in Computer Numerical Controlled (CNC) machine by Fuzzy Modeling of AISI 1045 Steel. To develop the fuzzy model; cutting depth, feed rate and speed are taken as input process parameters. The predicted results are compared with reliable set of experimental data for the validation of fuzzy model. Based upon reliable set of experimental data by Response Surface Methodology twenty fuzzy controlled rules using triangular membership function are constructed. By intelligent model based design and control of CNC process parameters, we can enhance the product quality, decrease the product cost and maintain the competitive position of steel.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Ilyas Al-Kindi ◽  
Tayfun Babadagli

AbstractThe thermodynamics of fluids in confined (capillary) media is different from the bulk conditions due to the effects of the surface tension, wettability, and pore radius as described by the classical Kelvin equation. This study provides experimental data showing the deviation of propane vapour pressures in capillary media from the bulk conditions. Comparisons were also made with the vapour pressures calculated by the Peng–Robinson equation-of-state (PR-EOS). While the propane vapour pressures measured using synthetic capillary medium models (Hele–Shaw cells and microfluidic chips) were comparable with those measured at bulk conditions, the measured vapour pressures in the rock samples (sandstone, limestone, tight sandstone, and shale) were 15% (on average) less than those modelled by PR-EOS.


Author(s):  
Chao Ma ◽  
Jingzhou Zhao ◽  
Chezheng Cao ◽  
Ting-Chiang Lin ◽  
Xiaochun Li

It is of great scientific and technical interests to conduct fundamental studies on the laser interactions with nanoparticles-reinforced metals. This part of the study presents the effects of nanoparticles on surface tension and viscosity, thus the heat transfer and fluid flow, and eventually the laser melting process. In order to determine the surface tension and viscosity of nanoparticles-reinforced metals, an innovative measurement system was developed based on the characteristics of oscillating metal melt drops after laser melting. The surface tensions of Ni/Al2O3 (4.4 vol. %) and Ni/SiC (3.6 vol. %) at ∼1500 °C were 1.39 ± 0.03 N/m and 1.57 ± 0.06 N/m, respectively, slightly lower than that of pure Ni, 1.68 ± 0.04 N/m. The viscosities of these Ni/Al2O3 and Ni/SiC MMNCs at ∼1500 °C were 13.3 ± 0.8 mPa·s and 17.3 ± 3.1 mPa·s, respectively, significantly higher than that of pure Ni, 4.8 ± 0.3 mPa·s. To understand the influences of the nanoparticles-modified thermophysical properties on laser melting, an analytical model was used to theoretically predict the melt pool flows using the newly measured material properties from both Part I and Part II. The theoretical analysis indicated that the thermocapillary flows were tremendously suppressed due to the significantly increased viscosity after the addition of nanoparticles. To test the hypothesis that laser polishing could significantly benefit from this new phenomenon, systematic laser polishing experiments at various laser pulse energies were conducted on Ni/Al2O3 (4.4 vol. %) and pure Ni for comparison. The surface roughness of the Ni/Al2O3 was reduced from 323 nm to 72 nm with optimized laser polishing parameters while that of pure Ni only from 254 nm to 107 nm. The normalized surface roughness reduced by nearly a factor of two with the help of nanoparticles, validating the feasibility to tune thermophysical properties and thus control laser-processing outcomes by nanoparticles. It is expected that the nanoparticle approach can be applied to many laser manufacturing technologies to improve the process capability and broaden the application space.


2017 ◽  
Vol 261 ◽  
pp. 267-274
Author(s):  
Pantelis N. Botsaris ◽  
Chaido Kyritsi ◽  
Dimitris Iliadis

In this paper, there is an attempt to monitor and evaluate machining parameters when turning 34CrNiMo6 material under different cooling and lubrication conditions. The machining parameters concerned are temperature of the cutting tool and the workpiece, level of vibrations of the cutting tool, surface roughness of the workpiece, noise levels of the turning process and current drawn by the main spindle motor. Four different experimental machining scenarios were completed, specifically: conventional wet turning process, dry cutting and two additional modes employing cooling by cold air. Experimental data were acquired and recorded by an optimally designed network of sensors. Experimental data were statistically analyzed in order to reach conclusions. According to the research that has been done, although, overall, minimum cutting tool and workpiece temperatures were observed under wet machining, cold air cooling is capable of achieving comparable cooling results to wet machining. The lowest values of surface roughness were achieved by wet machining, whereas the lowest level of cutting tool vibrations were observed under cold air cooling.


1995 ◽  
Vol 10 (8) ◽  
pp. 1984-1992 ◽  
Author(s):  
X.B. Zhou ◽  
J.Th.M. De Hosson

A this paper the influence of surface roughness on contact angles in the system of liquid Al wetting solid surfaces of Al2O3 has been studied. It was observed that contact angles of liquid Al vary significantly on different rough surfaces of Al2O3. A model is proposed to correlate contact angles with conventional roughness measurements and wavelengths by assuming a cosine profile of rough grooves with a Gaussian distribution of amplitudes. In comparison with the experimental results, the model provides a good estimate for describing the influence of surface roughness on contact angles of liquid Al on Al2O3.


1997 ◽  
Vol 119 (1) ◽  
pp. 20-25 ◽  
Author(s):  
H. Yuan ◽  
C. Sarica ◽  
S. Miska ◽  
J. P. Brill

A new test facility was designed and constructed to simulate flow in a horizontal well with a single perforation. A total of 635 tests were conducted with Reynolds numbers ranging from 5000 to 60,000 with influx to main rate ratios ranging from 1/5 to 1/100, and also for the no-influx case. The flow behavior in a single-perforation new friction expression for a single-perforation horizontal well was developed. A new simple correlation for the horizontal well friction factor was developed by applying experimental data to the general friction factor expression. The new friction factor correlation and experimental data were compared with the Asheim et al. (1992) data and model, and showed that the new correlation performed better than the Asheim et al. (1992) model.


2021 ◽  
Vol 1022 ◽  
pp. 194-202
Author(s):  
R.Kh. Dadashev ◽  
R.A. Kutuev

The experimental study results of the melts concentration dependence of the surface tension of the four-component indium-tin-lead-bismuth system and its constituent binary systems of indium-tin, indium-lead, indium-bismuth, tin-lead, tin-bismuth, lead-bismuth are presented in the paper. It is shown that the concentration dependence of the melts surface tension of the In-Sn-Pb-Bi four-component system can be predicted from the data on ST (surface tension) values of lateral binary systems. Features in the ST isotherms in the form of a minimum are observed only in the indium-tin lateral system from all lateral binaries. A distinctive feature of the detected minimum is that the minimum depth slightly exceeds the experimental error. Therefore, in addition to the fact that the area of average compositions was studied more thoroughly, we carried out the surface tension measurements by two independent methods. The experimental data obtained by both methods coincide within the experimental error and indicate the extremum availability on ST isotherms. Thus, ST experimental studies by two independent methods confirmed the presence of a flat minimum on ST isotherms of the indium-tin binary system increasing the reliability of the obtained data. The obtained outcomes and their comparison with experimental data have shown that the considered models for predicting surface properties based on data due to similar properties of lateral binary systems adequately reflect the experimental dependences. However, the prediction model based on Kohler's method of excess values describes the experimental curves more accurately.


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