Journal articles: 'Fluid film development'

1

Hashimoto, H. "Viscoelastic Squeeze Film Characteristics With Inertia Effects Between Two Parallel Circular Plates Under Sinusoidal Motion." Journal of Tribology 116, no. 1 (January 1, 1994): 161–66. http://dx.doi.org/10.1115/1.2927034.

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In this paper, viscoelastic squeeze film characteristics subjected to fluid inertia effects are investigated theoretically in the case of parallel circular type squeeze films. In the development of modified lubrication equations, the nonlinear Maxwell model combining the Rabinowitsch model and Maxwell model is used as a constitutive equation for the viscoelastic fluids, and the inertia term in the momentum equation is approximated by the mean value averaged over the film thickness. Applying the modified lubrication equation to parallel circular type squeeze films under sinusoidal motion, the variation of the pressure distribution with time is calculated numerically for various types of fluids such as Newtonian, pseudo-plastic, linear Maxwell and nonlinear Maxwell fluids. Some numerical results are presented in graphic form, and the effects of inertia forces on the viscoelastic squeeze film characteristics are discussed.

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Lin, Jaw-Ren, Tzu-Chen Hung, and Shu-Ting Hu. "Effects of fluid inertia forces in ferrofluid lubricated circular stepped squeeze films – Shliomis model." Industrial Lubrication and Tribology 68, no. 6 (September 12, 2016): 712–17. http://dx.doi.org/10.1108/ilt-09-2015-0122.

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Purpose This paper aims to study the inertia squeeze film characteristics between ferrofluid-lubricated circular stepped disks. Owing to the development of modern machine systems, the application of ferrofluids has received great attention. Because the circular disks are a special situation of circular stepped squeeze films, a further study of fluid inertia force effects on the ferrofluid-lubricated circular stepped squeezing mechanism is motivated. Design/methodology/approach On the basis of the ferrohydrodynamic flow model of Shliomis incorporating the momentum integral method, the effects of fluid inertia forces in ferrofluid-lubricated circular stepped squeeze films in the presence of external magnetic fields are investigated in this study. Analytical solutions of squeeze film performances are derived. Findings The fluid inertia force effects provide an increased load capacity and a longer squeeze film time for the ferrofluid-lubricated circular stepped squeeze film, especially for a larger value of the inertia parameter, the Langevin parameter and the volume concentration and a smaller value of the radius ratio and the step height ratio. Originality/value For engineering applications, numerical tables for squeeze film loads of circular stepped disks are also provided in this paper.

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ROY, R. VALÉRY, A. J. ROBERTS, and M. E. SIMPSON. "A lubrication model of coating flows over a curved substrate in space." Journal of Fluid Mechanics 454 (March 10, 2002): 235–61. http://dx.doi.org/10.1017/s0022112001007133.

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Consider the three-dimensional flow of a viscous Newtonian fluid upon an arbitrarily curved substrate when the fluid film is thin as occurs in many draining, coating and biological flows. We drive the lubrication model of the dynamics of the film expressed in terms of the film thickness. The comprehensive model accurately includes the effects of the curvature of the substrate, via a physical multiple-scale approach, and gravity and inertia, via more rigorous centre manifold techniques. This new approach theoretically supports the use of the model over a wide range of parameters and provides a sound basis for further development of lubrication models. Numerical simulations exhibit some generic features of the dynamics of such thin fluid films on substrates with complex curvature: we here simulate a film thinning at a corner, the flow around a torus, and draining of a film down a cylinder. The last is more accurate than other lubrication models. The model derived here describes well thin-film dynamics over a wide range of parameter regimes.

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Morita, Masafumi, Kazuhiro Doi, Masahito Miki, Hideyuki Ozawa, and Yoshiyuki Ishimaru. "Development of an artificial joint with excellent fluid film lubrication performance." Iryou kikigaku (The Japanese journal of medical instrumentation) 84, no. 5 (2014): 557–65. http://dx.doi.org/10.4286/jjmi.84.557.

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Morita, Masafumi, Kazuhiro Doi, Masahito Miki, Hideyuki Ozawa, and Yoshiyuki Ishimaru. "Development of an artificial joint with excellent fluid film lubrication performance." Iryou kikigaku (The Japanese journal of medical instrumentation) 84, no. 5 (2014): 566–74. http://dx.doi.org/10.4286/jjmi.84.566.

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Morita, Masafumi, Akihiro Kagami, Kazuhiro Doi, and Masahito Miki. "Development of an artificial joint with excellent fluid film lubrication performance." Iryou kikigaku (The Japanese journal of medical instrumentation) 85, no. 1 (2015): 2–9. http://dx.doi.org/10.4286/jjmi.85.2.

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MAKHOVA, N. N., and A. Yu BABIN. "DEVELOPMENT OF ANN-BASED PID CONTROLLER FOR ACTIVE FLUID-FILM BEARING CONTROL." Fundamental and Applied Problems of Engineering and Technology 6 (2020): 94–100. http://dx.doi.org/10.33979/2073-7408-2020-344-6-94-100.

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The article proposes a method for controlling an active fluid-film bearing, based on the use of a classical PID controller in conjunction with an artificial neural network. The regulator coefficients are not constant numbers, but are chosen by the network depending on the state of the controlled system. To implement such a control scheme, the coefficients are selected using a particle swarm optimization algorithm, which constitutes the training dataset, and an ANN is trained using the dataset. The controlled object is represented with a model operating in the Simulink environment.

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Peng, Tiefeng, Xuechao Gao, Qibin Li, Siyuan Yang, and Qizhong Tang. "Modelling of disjoining pressure for Lennard-Jones free thin films." Modern Physics Letters B 30, no. 10 (April 20, 2016): 1650169. http://dx.doi.org/10.1142/s0217984916501694.

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Development of disjoining pressure was performed to study the symmetric, Lennard-Jones (LJ) free thin films using molecular modelling. A methodology rooted from film thermodynamics was established to derive the disjoining pressure isotherm [Formula: see text], which is based on the surface tension at varied film thicknesses and can be viewed as a post-processing technique. The results showed that the disjoining pressure of LJ fluid is purely attractive. Compared with the complicated method reported previously, this methodology is demonstrated to be more convenient and readily applicable for other liquid films (e.g. water, aqueous thin films containing electrolyte or surfactants), meanwhile it can be applied at both low and high temperatures.

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Kim, Joon Hyun, and Joo-Hyun Kim. "Thermohydrodynamic Analysis of Surface Roughness in the Flow Field." Journal of Tribology 127, no. 2 (April 1, 2005): 293–301. http://dx.doi.org/10.1115/1.1828072.

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The study deals with the development of a thermohydrodynamic (THD) computational procedure for evaluating the pressure, temperature, and velocity distributions in fluid films with a very rough geometry. A parametric investigation is performed to predict the bearing behaviors in the lubricating film with the absorbed layers and their interfaces as determined by rough surfaces with Gaussian distribution. The layers are expressed as functions of the standard deviations of each surface to characterize flow patterns between both rough surfaces. Velocity variations and heat generation are assumed to occur in the central (shear) zone with the same bearing length and width. The coupled effect of the surface roughness and shear zone dependency on the hydrodynamic pressure and temperature has been found in the noncontact mode. The procedure confirms the numerically determined relationship between the pressure and film gap, provided that its roughness magnitude is smaller than the fluid film thickness.

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Senthilkumar, K., and C. Vijaya. "Formulation Development of Mouth Dissolving Film of Etoricoxib for Pain Management." Advances in Pharmaceutics 2015 (January 26, 2015): 1–11. http://dx.doi.org/10.1155/2015/702963.

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Etoricoxib is a potent, orally active, and highly selective COX-2 inhibitor that exhibits anti-inflammatory, analgesic, and antipyretic activities. The present research was undertaken to develop mouth dissolving films of etoricoxib to have rapid onset of action. Mouth dissolving film (MDF) is a better alternate to oral disintegrating tablets due to its novelty, ease of use, and the consequent patient compliance. Solubility enhancement and taste masking of etoricoxib were the two challenges solved by formulating drug-inclusion complex with beta-cyclodextrin (BCD). MDF prepared by solvent casting etoricoxib-BCD complex along with HPMC as film forming polymer was found to possess desirable physicomechanical properties. In vitro release of etoricoxib from MDF in simulated salivary fluid and 0.1 N HCl was more than 95% within 2 minutes. Taste masking and in vivo disintegration were in acceptable range as assessed by human volunteers. Etoricoxib MDF was further characterized by differential scanning calorimetry, powder X-ray diffraction, and scanning electron microscopy. The index of analgesia shown by etoricoxib MDF was comparable to that of immediate release tablets (100% activity within 40 minutes) in animal studies. Conclusively, the present study documents the development of a commercially viable formula for an MDF of etoricoxib with rapidity in pain management.

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Simon, Amélie, Jean-Marc Dorey, and Michel Lance. "Development of a model for thin films and numerical sensitivity tests." Proceedings of the Institution of Mechanical Engineers, Part A: Journal of Power and Energy 232, no. 5 (March 1, 2018): 525–35. http://dx.doi.org/10.1177/0957650918759860.

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Because the unsteady behavior of liquid films in steam turbines is a key point for additional friction losses and atomization process (that leads to coarse water generation), the development of a dedicated model has been found necessary. A two-dimensional computational fluid dynamics code for unstructured mesh is being developed using the finite volume method to simulate this thin liquid film. The aim is to predict the formation of the waves in the film since it is suspected to be a key parameter for friction and atomization. Applied as a first step to a plane plate, the code has been verified in a one-dimensional version with analytical solutions and is tested in low-pressure turbine steam conditions. Falling films computations (without gas shear stress) show that the model is capable to reproduce the waves’ shape of experiments from the literature. With steam under low-pressure turbine conditions, and compared to experimental data from the University of Michigan, the model including shear stress and surface tension provides good results for heights. Sensitivity calculations have been undergone showing the crucial influence of the surface tension and the generation of solitary waves for high velocities is captured by the code. The effect of gravity is also quantified.

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Ardekani, M. A., V. Dashtizad, and B. Akbari. "Development of cylindrical hot-film sensors for measuring instant velocity of fluid flow." Measurement 44, no. 4 (May 2011): 778–83. http://dx.doi.org/10.1016/j.measurement.2011.01.015.

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Hu, Youlin. "Development of Film Forming Agent HN-1 and Its Application in Drilling Fluid." Geomaterials 03, no. 04 (2013): 121–25. http://dx.doi.org/10.4236/gm.2013.34015.

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14

Poll, G., and A. Gabelli. "Formation of Lubricant Film in Rotary Sealing Contacts: Part II—A New Measuring Principle for Lubricant Film Thickness." Journal of Tribology 114, no. 2 (April 1, 1992): 290–96. http://dx.doi.org/10.1115/1.2920886.

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The development of models for the elastohydrodynamic lubrication of rotary lip seals requires the measurement of the film thickness under a real seal. A new method has been developed for this purpose which is based on the use of lubricant oils in which magnetite particles are suspended (so-called magnetic fluids). A change in the fluid film thickness will create a change in the impedance of the coil of the measuring circuit, the magnetic flux of which is directed through the oil film of the contact area. The advantage of this technique is that minimal modifications have to be applied to the tribological system under examination. Initial measurements carried out with a model rubber lip seal provided new insight into the build-up of a lubricant film as a function of the rotary speed and allowed comparison with the results of a theoretical model for the analysis of lip seal lubrication developed in parallel.

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Ferfecki, Petr, Jaroslav Zapoměl, Marek Gebauer, Václav Polreich, and Jiří Křenek. "A computational fluid dynamics investigation of the segmented integral squeeze film damper." MATEC Web of Conferences 254 (2019): 08005. http://dx.doi.org/10.1051/matecconf/201925408005.

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Rotor vibration attenuation is achieved with damping devices which work on different, often mutually coupled, physical principles. Squeeze film dampers are damping devices that have been widely used in rotordynamic applications. A new concept of a 5-segmented integral squeeze film damper, in which a flexure pivot tilting pad journal bearing is integrated, was investigated. The damper is studied for the eccentric position between the outer and inner ring of the squeeze film land. The ANSYS CFX software was used for solving the pressure and velocity distribution. The development of the complex three-dimensional computational fluid dynamics model of the squeeze film damper, learning more about the effect of the forces in the damper, and the knowledge about the behaviour of the flow are the principal contributions of this article.

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Shapiro, Wilbur. "Impact on Reynolds Theory on Bearing and Seal Design." Journal of Tribology 109, no. 1 (January 1, 1987): 42–49. http://dx.doi.org/10.1115/1.3261325.

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The governing equation of lubrication theory was developed by Osborne Reynolds in 1886. Two-dimensional solutions to this equation were not obtained until many years afterwards, first by electric analog techniques and then by digital computer. Solving the equation has produced tremendous advances in bearing design and development and insight into the mechanisms of lubricating film behavior. This paper concentrates on some of the developments for solving the Reynolds’ equation and some applications that have followed a better understanding of fluid-film phenomena.

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17

Wang, Nen-Zi, and Ali A. Seireg. "Thermohydrodynamic Lubrication Analysis Incorporating Thermal Expansion Across the Film." Journal of Tribology 116, no. 4 (October 1, 1994): 681–88. http://dx.doi.org/10.1115/1.2927316.

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The study reported in this paper deals with the development of a thermohydrodynamic computational procedure for evaluating the pressure, temperature and velocity distributions in fluid films with fixed geometry between the stationary and moving bearing surfaces. The velocity variations and the heat generation are assumed to occur in a central zone with the same length and width as the bearing but with a significantly smaller thickness than the fluid film thickness. The thickness of the heat generation (shear) zone is developed empirically for the best fit with experimentally determined peak pressures for a journal bearing with a fixed film geometry operating in the laminar regime. A transient thermohydrodynamic computational model with a transformed rectangular computational domain is utilized. The analysis can be readily applied to any given film geometry. The computed distribution of the pressure in the film is in excellent agreement with the experimental findings for different oils and speeds. The developed procedure gives an analytical basis for explaining the “Fogy effect” where significant pressures can be generated in slider bearings with parallel surfaces as a result of the thermal expansion of the film in the direction of the thickness. The procedure confirms the experimentally determined square root relationship between the pressure and the sliding velocity reported in references [1–4]. The normalized pressure profiles computed for the different conditions of the journal bearings are identical to those obtained by isoviscous theory.

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18

Kercher, D. M. "A Film-Cooling CFD Bibliography: 1971–1996." International Journal of Rotating Machinery 4, no. 1 (1998): 61–72. http://dx.doi.org/10.1155/s1023621x98000062.

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After more than 25 years of three-dimensional film cooling experimental investigations, analytical correlations and modeling, film cooling utilizing computational fluid dynamics has emerged from a similar development-applications growth process into a near-attainable heat transfer engineering tool. Analytical applications include high temperature subsonic to hypersonic flow with complex wall-geometry coolant injection film performance analysis techniques spanning usage from gas turbines to rocket engines to scramjets. In recent years there has been significant development in increased computer power and modeling capacity, increasingly more complex and successful Navier-Stokes turbulence modeling techniques, innovative labor-saving meshing techniques, and more successful validation of experimental results. These combined innovations have continued to transition computational film cooling technology from the academic, government and commercial research and development environment to the industrial design-analysis environment. This bibliography is an openliterature reference resource whose papers collectively describe the continual emerging of numerical film cooling as a viable design tool for high temperature components.

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19

Zhang, Rui, Xing Ai, Yi Wan, Zhanqiang Liu, Dong Zhang, and Sheng Feng. "Surface Corrosion Resistance in Turning of Titanium Alloy." International Journal of Corrosion 2015 (2015): 1–8. http://dx.doi.org/10.1155/2015/823172.

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This work addresses the issues associated with implant surface modification. We propose a method to form the oxide film on implant surfaces by dry turning to generate heat and injecting oxygen-rich gas at the turning-tool flank. The morphology, roughness, composition, and thickness of the oxide films in an oxygen-rich atmosphere were characterized using scanning electron microscopy, optical profiling, and Auger electron spectroscopy. Electrochemical methods were used to study the corrosion resistance of the modified surfaces. The corrosion resistance trends, analyzed relative to the oxide film thickness, indicate that the oxide film thickness is the major factor affecting the corrosion resistance of titanium alloys in a simulated body fluid (SBF). Turning in an oxygen-rich atmosphere can form a thick oxide film on the implant surface. The thickness of surface oxide films processed at an oxygen concentration of 80% was improved to 4.6 times that of films processed at an oxygen concentration of 21%; the free corrosion potential shifted positively by 0.357 V, which significantly improved the corrosion resistance of titanium alloys in the SBF. Therefore, the proposed method may (partially) replace the subsequent surface oxidation. This method is significant for biomedical development because it shortens the process flow, improves the efficiency, and lowers the cost.

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Morshed, Md Masud, Jewel Mallick, Fahamida Islam, Md Kamrul Islam, Md Didaruzzaman Sohel, and Md Hassan Kawsar. "Formulation Development and Characterization of Levosalbutamol Sulphate Oral Thin Film using Propylene glycol as a Plasticizer." Bangladesh Pharmaceutical Journal 20, no. 1 (April 5, 2017): 64–70. http://dx.doi.org/10.3329/bpj.v20i1.32095.

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The present study was concerned with the preparation and evaluation of oral thin films of levosalbutamol sulphate (LS) is to avoid presystemic elimination by gastrointestinal degradation and first pass hepatic metabolism. The films were prepared using four different water soluble polymers in various proportions and combinations using propylene glycol as plasticizers. Total five formulations were developed and evaluated for the various physicochemical characteristics namely mass uniformity, thickness, folding endurance, density, surface pH, swelling index, disintegration time, content uniformity, in vitro release profile, percent moisture absorption and loss and ex vivo mucoadhesion time. Data of every parameter were taken in triplicate. Results of film thickness, mass, density and swelling index of medicated films of LS were found with relatively low standard deviation along with high folding endurance (>300). The surface pH of all films approached to the salivary fluid pH range (6.1~7.0). Disintegration time and content uniformity complied with standard for all formulations. Among the total five formulations, F-2 and F-5 followed first order release and F-1 and F-4 followed Higuchi release and F-5 followed zero order and hixon-crowell release. The residence time for mucoadhesion of the tested films ranged between 1 to 5 minutes. Percent moisture absorption and loss study revealed the excellent stability of the films in dried conditions and relatively low standard deviation indicated the stability also in humid conditions.Bangladesh Pharmaceutical Journal 20(1): 64-70, 2017

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Lund, J. W. "Review of the Concept of Dynamic Coefficients for Fluid Film Journal Bearings." Journal of Tribology 109, no. 1 (January 1, 1987): 37–41. http://dx.doi.org/10.1115/1.3261324.

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The development of the concept of spring and damping coefficients for journal bearings is briefly reviewed. Methods for computing the coefficients are described, and their use in rotor dynamics calculations (unbalance response, stability) is discussed. The limitations imposed by nonlinearities on the application of the coefficients is illustrated by examples.

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Bohan, M. F. J., I. J. Fox, T. C. Claypole, and D. T. Gethin. "Influence of non-Newtonian fluids on the performance of a soft elastohydrodynamic lubrication contact with surface roughness." Proceedings of the Institution of Mechanical Engineers, Part J: Journal of Engineering Tribology 217, no. 6 (June 1, 2003): 447–59. http://dx.doi.org/10.1243/135065003322620273.

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The paper focuses on the development and results of a numerical model to evaluate the fluid transfer behaviour for non-Newtonian fluids in a rough soft elastohydrodynamic nip contact. The solution required coupling of the fluid and elastomer regimes, with a multi-gridding technique to facilitate the high mesh densities required to capture the rough surface representation. The non-Newtonian fluid behaviour was modelled using a power-law model. The study evaluated circumferential and longitudinal roughness forms. The introduction of longitudinal roughness introduced significant shear in the nip with the resultant large change to the viscosity profile. This also removed the stagnation point in the centre of the nip. The longitudinal roughness had a large impact on the film thickness and flow through the nip while the circumferential affected the local performance of the nip but not its overall pumping capacity.

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Grab, Sheila, Yvonne Cosgrove Sweeney, Dorothy L. Patton, and Lisa C. Rohan. "2519." Journal of Clinical and Translational Science 1, S1 (September 2017): 67. http://dx.doi.org/10.1017/cts.2017.238.

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OBJECTIVES/SPECIFIC AIMS: To establish an in vitro quantitative method for the evaluation of polymeric film disintegration that can be applied to predict in vivo behavior. METHODS/STUDY POPULATION: Two clinically advanced vaginal microbicide film products containing tenofovir and dapivirine were used as model films throughout this work. Films were made using the solvent cast manufacturing method in which polymers, excipients, plasticizer, and APIs were either dissolved or dispersed in water, mixed, and cast on a heated substrate. The novel, quantitative method was developed using a TA.XT Plus Texture Analyzer® (Texture Technologies) in combination with a TA-108S5 fixture and the TA-8A: 1/8″ diameter rounded end ball probe. Exponent® was used as the data analysis software. In this method, the film was placed and secured in the fixture, the probe applied a constant force to the film product, and a biologically relevant amount of fluid was applied to the film. The probe was able to penetrate the film upon disintegration resulting in an applied force of zero at that point. A curve of force Versus time was plotted, and disintegration time was defined as the time between fluid addition until the probe force reached zero. Test parameters were optimized in order to reduce error. Visual observation of film disintegration was conducted in the in vivo macaque model using films that included a water-soluble blue dye for film visualization. Colpophotography was also used to confirm film disintegration. In vitro results were compared with in vivo findings. RESULTS/ANTICIPATED RESULTS: The Texture Analyzer disintegration method developed provided quantitative disintegration times and did not rely on user defined endpoints which is common in many visual disintegration tests. The disintegration method was able to distinguish differences between the 2 clinical film products and produced reproducible disintegration times for the tenofovir and dapivirine films. The tenofovir film had a shorter disintegration time (41.28±2.85 s) compared with that of the dapivirine film (88.3 6±9.82 s). This method was also able to distinguish changes made to these 2 clinical film products in terms of volume and formulation alterations. In vitro and in vivo disintegration times differed by orders of magnitude, with in vitro time being measured in seconds and in vivo time being measured in days, for a variety of factors, mainly the application of constant force to the film product. Regardless of these differences, the rank order of film disintegration remained constant for in vitro and in vivo disintegration and an In Vitro In Vivo Correlation (IVIVC) trend could be seen. DISCUSSION/SIGNIFICANCE OF IMPACT: Standardization of preclinical in vitro assessments which minimize user bias are crucial to the field of pharmaceutical film development. As this field continues to develop and more products advance for pharmaceutical application, this method has the potential to become a standard assessment of film functionality. This study represents a first step in the process of developing an IVIVC. More films will need to be tested using both in vitro and visual methods in order to establish and accurate factor to predict in vivo behavior.

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Zhao, Jin Sheng, Ying Jun Ju, Mei Rong Tang, and Rong Huan Chen. "Experimental Study on the Corrosion Behavior of Produced Fluid on J55 Steel during CO₂ Flooding." Key Engineering Materials 773 (July 2018): 179–83. http://dx.doi.org/10.4028/www.scientific.net/kem.773.179.

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CO2 flooding has been widely used in oil field development, but the produced fluid is easy to cause corrosion of tubing and casing. In order to determine the corrosion behavior of produced fluid on J55 steel during CO2 flooding, we use the simulated oil well produced fluid as corrosive medium and conduct the corrosion simulation experiment at high temperature and high pressure. The experimental results showed that the crystalline grain size of corrosion film surface is different for the different CO2 partial pressure. When CO2 partial pressure is greater than the critical pressure, the crystalline grain is not oblique six-party crystal structure, and the grains become small and compact, so the corrosion product film should have a good corrosion inhibition. Both static and dynamic corrosion of samples are serious. The research has a theoretical guiding significance on corrosion protection during CO2 flooding.

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Wang, Zhuangzhuang, and Zhaomin Li. "Roles of Flue Gas in Promoting Steam Flow and Heat Transfer in Multithermal Fluid Flooding." Mathematical Problems in Engineering 2019 (February 21, 2019): 1–8. http://dx.doi.org/10.1155/2019/4989375.

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Multithermal fluid technology is becoming an important method in the field of heavy oil development. However, because of insufficient investigation on the heat transfer for the multithermal fluid, some development phenomena and characteristics still cannot be well explained. In order to determine the effect of flue gas on the thermal swept scope, multithermal fluid flooding experiments were carried out through 1D sandpack. The temperatures along the sandpack were measured. On this basis, steam heat transfer simulation experiments were conducted and the heat transfer coefficients were calculated. The mechanism of flue gas on steam heat transfer was analyzed. The results show that at the same heat injection conditions, the thermal swept scope for the multithermal fluid flooding was larger than that for the steam flooding. With the increase of flue gas proportion in the multithermal fluid, the heat transfer coefficient decreased and the condensation pattern was transformed from drop condensation to film condensation gradually. The flue gas can form gas film on the surface of the cold body and inhibit the heat transfer between steam and the cold body. Because of the inhibiting effect of flue gas on steam heat transfer, flue gas can reduce the heat transferred to the rock matrix in flooding and thus promote steam to carry more heat further. Meanwhile, flue gas can accelerate the flow of steam in porous media, which also leads to the expansion of the thermal swept scope for the multithermal fluid flooding.

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Chun, Ji-Han, Won-Jae Lee, and Un-Chul Lee. "Development of the film-splitting look-up table applicable to mechanistic annular film dryout model in annulus geometry." International Journal of Heat and Mass Transfer 49, no. 7-8 (April 2006): 1350–57. http://dx.doi.org/10.1016/j.ijheatmasstransfer.2005.10.005.

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Sha, W. T., and S. L. Soo. "Development of steady flow of liquid film over a domed cylinder." International Journal of Heat and Fluid Flow 14, no. 3 (September 1993): 254–59. http://dx.doi.org/10.1016/0142-727x(93)90056-s.

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Pavlenko, Ivan, Oleksandr Liaposhchenko, Marek Ochowiak, Radosław Olszewski, Maryna Demianenko, Oleksandr Starynskyi, Vitalii Ivanov, Vitalii Yanovych, Sylwia Włodarczak, and Michał Doligalski. "Three-Dimensional Mathematical Model of the Liquid Film Downflow on a Vertical Surface." Energies 13, no. 8 (April 15, 2020): 1938. http://dx.doi.org/10.3390/en13081938.

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Film downflow from captured liquid without wave formation and its destruction is one of the most important aspects in the development of separation equipment. Consequently, it is necessary to create well-organized liquid draining in areas of captured liquid. Thus, the proposed 3D mathematical model of film downflow allows for the determination of the hydrodynamic parameters of the liquid film flow and the interfacial surface. As a result, it was discovered that the interfacial surface depends on the proposed dimensionless criterion, which includes internal friction stress, channel length, and fluid density. Additionally, equations for determining the averaged film thickness, the averaged velocity vectors over the film thickness, the longitudinal and vertical velocity components, and the initial angle of streamline deviation from the vertical axis were analytically obtained.

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Singh, Shivashkar. "Nutritional factors in the development of fixed-film reactors for the treatment of metalworking fluid wastewaters." New Biotechnology 33 (July 2016): S55. http://dx.doi.org/10.1016/j.nbt.2016.06.915.

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Kostrzewsky, Gregory J., and Ronald D. Flack. "Accuracy Evaluation of Experimentally Derived Dynamic Coefficients of Fluid Film Bearings Part I: Development of Method." Tribology Transactions 33, no. 1 (January 1990): 105–14. http://dx.doi.org/10.1080/10402009008981936.

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Kanai, Toshitaka, and James L. White. "Dynamics, heat transfer and structure development in tubular film extrusion of polymer melts: a mathematical model and predictions." Journal of Polymer Engineering 5, no. 2 (April 1, 1985): 135–58. http://dx.doi.org/10.1515/polyeng-1985-0204.

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Abstract A theoretical model of the dynamics, heat transfer and crystallization processes in tubular film extrusion is presented. It is presumed that the polymer melts flow behavior is dominated by the temperature dependence of its rheological properties, as opposed to the specific rheological model used to represent it. Specifically we presume the melt is a Newtonian fluid with a temperature dependent viscosity, characterized by an activation energy of viscous flow E. The shape of the bubble and radius and film thickness profiles are primarily influenced by E. Crystallization makes a second order correction. Detailed comparisons are made to experimental investigations for low density polyethylene, linear low density polyethylene and high density polyethylene and generally good agreement is found.

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Phan, Chau-Minh, Manish Shukla, Hendrik Walther, Miriam Heynen, David Suh, and Lyndon Jones. "Development of an In Vitro Blink Model for Ophthalmic Drug Delivery." Pharmaceutics 13, no. 3 (February 25, 2021): 300. http://dx.doi.org/10.3390/pharmaceutics13030300.

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Purpose: The purpose of this study was to develop an advanced in vitro blink model that can be used to examine the release of a wide variety of components (for example, topical ophthalmic drugs, comfort-inducing agents) from soft contact lenses. Methods: The model was designed using computer-aided design software and printed using a stereolithography 3D printer. The eyelid and eyeball were synthesized from polyvinyl alcohol and silicone material, respectively. Simulated tear fluid was infused through tubing attached to the eyelid using a syringe pump. With each blink cycle, the eyelid slides and flexes across the eyeball to create an artificial tear film layer. The flow-through fluid was collected using a specialized trough. Two contact lenses, etafilcon A and senofilcon A, were incubated in 2 mL of a water-soluble red dye for 24 h and then placed on the eye model (n = 3). The release of the dye was measured over 24 h using a tear flow rate of 5 µL/min. Results: Approximately 25% of the fluid that flowed over the eye model was lost due to evaporation, nonspecific absorption, and residual dead volume. Senofilcon A absorbed more dye (47.6 ± 2.7 µL) than etafilcon A (22.3 ± 2.0 µL). For etafilcon A, the release of the dye followed a burst-plateau profile in the vial but was sustained in the eye model. For senofilcon A, the release of the dye was sustained in both the vial and the eye model, though more dye was released in the vial (p < 0.05). Overall, the release of the dye from the contact lenses was higher in the vial compared with the eye model (p < 0.05). Conclusion: The blink model developed in this study could be used to measure the release of topical ophthalmic drugs or comfort agents from contact lenses. Simulation of a blink mechanism, an artificial tear film, and nonspecific absorption in an eye model may provide better results than a simple, static vial incubation model.

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Dowson, D. "Osborne Reynolds Centenary (1886–1986)." Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 201, no. 2 (March 1987): 75–96. http://dx.doi.org/10.1243/pime_proc_1987_201_091_02.

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Osborne Reynolds' concept of fluid-film lubrication revealed one hundred years ago played a major role in the design and development of machinery in our technological age. This year marks the centenary of the publication of the most significant paper ever written in the field of tribology.

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Benedicto, Elisabet, Eva María Rubio, Laurent Aubouy, and María Ana Sáenz-Nuño. "Formulation of Sustainable Water-Based Cutting Fluids with Polyol Esters for Machining Titanium Alloys." Metals 11, no. 5 (May 8, 2021): 773. http://dx.doi.org/10.3390/met11050773.

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The machinability of titanium alloys still represents a demanding challenge and the development of new clean technologies to lubricate and cool is greatly needed. As a sustainable alternative to mineral oil, esters have shown excellent performance during machining. Herein, the aim of this work is to investigate the influence of esters’ molecular structure in oil-in-water emulsions and their interaction with the surface to form a lubricating film, thus improving the efficiency of the cutting fluid. The lubricity performance and tool wear protection are studied through film formation analysis and the tapping process on Ti6Al4V. The results show that the lubricity performance is improved by increasing the formation of the organic film on the metal surface, which depends on the ester’s molecular structure and its ability to adsorb on the surface against other surface-active compounds. Among the cutting fluids, noteworthy results are obtained using trimethylolpropane trioleate, which increases the lubricating film formation (containing 62% ester), thus improving the lubricity by up to 12% and reducing the torque increase due to tool wear by 26.8%. This work could be very useful for fields where often use difficult-to-machine materials—such as Ti6Al4V or γ-TiAl—which require large amounts of cutting fluids, since the formulation developed will allow the processes to be more efficient and sustainable.

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Lee, I., and H. J. Sung. "Development of an array of pressure sensors with PVDF film." Experiments in Fluids 26, no. 1-2 (January 1, 1999): 27–35. http://dx.doi.org/10.1007/s003480050262.

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Acierno, D., L. Di Maio, and G. Cuccurullo. "Analysis of Temperature Fields in Film Casting." Journal of Polymer Engineering 19, no. 2 (March 1, 1999): 75–94. http://dx.doi.org/10.1515/polyeng-1999-0202.

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Abstract Film casting extrusions were performed on polyethylene terephthalate) (PET) and polypropylene (PP) in a laboratory plant to evaluate the development of temperature profiles in the region from die to chill roll. This was done under different conditions of mass rate, drawing, and cooling. Thermal exchange of the film was evaluated by making use of an infrared thermography apparatus, which provides a bidimentional map of temperature profile for each testing condition. The different melt viscosity of the various polymers lead to more developed or less developed edge-beads. Therefore, at fixed working conditions, the resulting shapes of the temperature profiles and border effects differ for PET and PP. In particular, the temperatures in the transverse direction changed significantly from the edge to the center of the film, as shown in the thermographs. The thermal-fluid-dynamics behavior of polymeric-cast film during processing is discussed.

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Liu, Yang, Yuichi Mitsutake, and Masanori Monde. "Development of fast response heat transfer measurement technique with thin-film thermocouples." International Journal of Heat and Mass Transfer 162 (December 2020): 120331. http://dx.doi.org/10.1016/j.ijheatmasstransfer.2020.120331.

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Yue, Y., J. Sun, K. L. Gunter, D. J. Michalek, and J. W. Sutherland. "Character and Behavior of Mist Generated by Application of Cutting Fluid to a Rotating Cylindrical Workpiece, Part 1: Model Development." Journal of Manufacturing Science and Engineering 126, no. 3 (August 1, 2004): 417–25. http://dx.doi.org/10.1115/1.1765150.

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Increasing attention is being devoted to the airborne emissions resulting from a variety of manufacturing processes because of health, safety, and environmental concerns. In this two-part paper, a model is presented for the amount of cutting fluid mist produced by the interaction of the fluid with the rotating cylindrical workpiece during a turning operation. This model is based on relationships that describe cutting fluid atomization, droplet settling, and droplet evaporation. Experiments are performed to validate the model. In Part 1 of the paper, the emphasis is on model development. In the model, thin film theory is used to determine the maximum fluid load that can be supported by a rotating cylindrical workpiece; rotating disk atomization theory is applied to the turning process to predict the mean size of the droplets generated by atomization; and expressions for both the evaporation and settling behavior are established. Droplet size distribution and mass concentration predictions are used to characterize the fluid mist. Model predictions indicate that the droplet mean diameter is affected by both fluid properties and operating conditions, with cutting speed having the most significant affect. Model predictions and experimental results show that the number distribution of droplets within the control volume is dominated by small droplets because of the settling and evaporation phenomena. In Part 2 of the paper, the cutting fluid mist behavior model is validated using the results obtained from a series of experiments.

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Assaad, M. C., B. Kimble, Y. M. Huang, R. Burgan, G. C. Fralick, J. D. Wrbanek, and J. M. Gonzalez. "Thin-Film Heat Flux Sensor for Measuring the Film Coefficient of Rubber Components of a Rolling Tire." Tire Science and Technology 36, no. 4 (December 1, 2008): 275–89. http://dx.doi.org/10.2346/1.2999702.

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Abstract Heat flux is one of a number of parameters, together with pressure, temperature, flow, etc., of interest to tire engineers, engine designers and fluid dynamicists. The ability to measure heat flux magnitude and direction was incorporated into a resistance bridge design fabricated using thin-film techniques to allow fast response. The result is a sensor that does not need the large area and stiff packaging required for the thermopile design, nor does it have a low output, but has nearly as fast response. The development of this sensor offers a new laboratory procedure to establish heat transfer coefficients for different regions of a tire. Testing generated heat transfer coefficients that were within the range reported in the literature, and the numerically predicted temperatures from this data agree well with the experimentally generated values.

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Maslen, E. H., P. E. Allaire, M. D. Noh, and C. K. Sortore. "Magnetic Bearing Design for Reduced Power Consumption." Journal of Tribology 118, no. 4 (October 1, 1996): 839–46. http://dx.doi.org/10.1115/1.2831617.

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Magnetic bearings have relatively low power consumption compared to fluid film and rolling element bearings. They are now candidates for supporting gas turbines and aeropropulsion engines. This paper describes the design and construction of permanent magnet biased, actively controlled magnetic bearings for a flexible rotor. The rotor was originally supported in fluid film bearings consuming as much as 3000 watts of power. For the magnetic bearing, both permanent magnets and electromagnets are used in a configuration which effectively provides the necessary fluxes in the appropriate air gaps to support the rotor. The theoretical development related to the bearing design is presented along with some experimental performance results. The results include measurements of power consumption, load capacity, bearing linearized coefficients, and the dynamic response of the rotor. The measured total power consumption, excluding shaft losses, was 210 watts in the permanent magnet biased bearing.

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Jinga, Sorin-Ion, Michael Skokin, Bogdan-Stefan Vasile, Izabela Constantinoiu, Dana Miu, Mihaela Bacalum, and Cristina Busuioc. "Development of Vitroceramic Coatings and Analysis of Their Suitability for Biomedical Applications." Coatings 9, no. 10 (October 16, 2019): 671. http://dx.doi.org/10.3390/coatings9100671.

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Within the field of tissue engineering, thin films have been studied to improve implant fixation of metallic or ceramic materials in bone, connective tissue, oral mucosa or skin. In this context, to enhance their suitability as implantable devices, titanium-based substrates received a superficial vitroceramic coating by means of laser ablation. Further, this study describes the details of fabrication and corresponding tests in order to demonstrate the bioactivity and biocompatibility of the newly engineered surfaces. Thus, the metallic supports were covered with a complex material composed of SiO2, P2O5, CaO, MgO, ZnO and CaF2, in the form of thin layers via a physical deposition techniques, namely pulsed laser deposition. The resulting products were characterized by X-ray diffraction, Fourier-transform infrared spectroscopy, scanning and transmission electron microscopy coupled with energy dispersive X-ray spectroscopy, selected area electron diffraction, and electron energy loss spectroscopy. It was found that a higher substrate temperature and a lower working pressure lead to the highest quality film. Finally, the samples biocompatibility was assessed and they were found to be bioactive after simulated body fluid soaking and biocompatible through the MTT cell viability test.

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Carpio, Ana, and Elena Cebrián. "Incorporating Cellular Stochasticity in Solid–Fluid Mixture Biofilm Models." Entropy 22, no. 2 (February 6, 2020): 188. http://dx.doi.org/10.3390/e22020188.

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The dynamics of cellular aggregates is driven by the interplay of mechanochemical processes and cellular activity. Although deterministic models may capture mechanical features, local chemical fluctuations trigger random cell responses, which determine the overall evolution. Incorporating stochastic cellular behavior in macroscopic models of biological media is a challenging task. Herein, we propose hybrid models for bacterial biofilm growth, which couple a two phase solid/fluid mixture description of mechanical and chemical fields with a dynamic energy budget-based cellular automata treatment of bacterial activity. Thin film and plate approximations for the relevant interfaces allow us to obtain numerical solutions exhibiting behaviors observed in experiments, such as accelerated spread due to water intake from the environment, wrinkle formation, undulated contour development, and the appearance of inhomogeneous distributions of differentiated bacteria performing varied tasks.

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Ji, Zhanling. "Research on thermal-fluid-structure coupling of valve plate pair in an axial piston pump with high pressure and high speed." Industrial Lubrication and Tribology 70, no. 6 (August 13, 2018): 1137–44. http://dx.doi.org/10.1108/ilt-04-2017-0102.

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Purpose High pressure and high speed of the axial piston pump can improve its power density, but they also deteriorate the thermal-fluid-structure coupling effect of the friction pairs. This paper aims to reveal the coupling mechanism of the pump, for example, valve plate pair, by carrying out research on multi-physics field coupling. Design/methodology/approach Considering the influences of temperature on material properties and thermal fluid on structure, the thermal-fluid elastic mechanics model is established. A complete set of fast and effective thermal-fluid-structure coupling method is presented, by which the numerical analysis is conducted for the valve plate pair. Findings According to calculations, it is revealed that the temperature and pressure evolution laws of oil film with time, the pressure distribution law of the fluid, stress and displacement distribution laws of the solid in the valve plate pair. In addition, the forming history of the wedge-shaped oil film and mating clearance change law with rotational speed and outlet pressure in the valve plate pair are presented. Originality/value For an axial piston pump operating under high speed, high pressure and wide temperature range, the multi-physics field coupling analysis is an indispensable means and method. This paper provides theoretical evidence for the development of the pump and lays a solid foundation for the research of the same kind of problem.

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Pagano, Cinzia, Debora Puglia, Francesca Luzi, Alessandro Di Michele, Stefania Scuota, Sara Primavilla, Maria Rachele Ceccarini, et al. "Development and Characterization of Xanthan Gum and Alginate Based Bioadhesive Film for Pycnogenol Topical Use in Wound Treatment." Pharmaceutics 13, no. 3 (March 3, 2021): 324. http://dx.doi.org/10.3390/pharmaceutics13030324.

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Pycnogenol (PYC) is a concentrate of phenolic compounds derived from French maritime pine; its biological activity as antioxidant, anti-inflammatory and antibacterial suggests its use in the treatment of open wounds. A bioadhesive film, loaded with PYC, was prepared by casting, starting with a combination of two biopolymer acqueous solutions: xanthan gum (1% wt/wt) and sodium alginate (1.5% wt/wt), in a 2.5/7.5 (wt/wt) ratio. In both solutions, glycerol (10% wt/wt) was added as plasticizing agent. The film resulted in an adhesive capable to absorb a simulated wound fluid (~ 65% wt/wt within 1 h), therefore suitable for exuding wounds. The mechanical characterization showed that the film is deformable (elastic modulus E = 3.070 ± 0.044 MPa), suggesting adaptability to any type of surface and resistance to mechanical solicitations. PYC is released within 24 h by a sustained mechanism, achieving a maximum concentration of ~ 0.2 mg/mL, that is safe for keratinocytes, as shown by cytotoxicity studies. A concentration of 0.015 mg/mL is reached in the first 5 min after application, at which point PYC stimulates keratinocyte growth. These preliminary results suggest the use of PYC in formulations designed for topical use.

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Edwards, Gareth, Doris Schedlitzki, Jenna Ward, and Martin Wood. "Exploring Critical Perspectives of Toxic and Bad Leadership Through Film." Advances in Developing Human Resources 17, no. 3 (May 26, 2015): 363–75. http://dx.doi.org/10.1177/1523422315587903.

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The Problem This article considers concepts of toxic and bad leadership from a critical, post-structuralist perspective and illustrates how this can be conveyed to management students through the use of film analysis. In response to the paucity of critical approaches within toxic and bad leadership studies, we suggest that film is a useful way of developing in-depth discussion in student and management groups to uncover underlying subtleties and complexity in leadership theory and practice. The Solution We connect to film clips from Batman: The Dark Knight, and explain how this film is used with students and managers to illustrate the ambiguous nature of “good” and “bad” leadership and explore the fluid, shifting, and relational nature of these two concepts. We conclude that students and managers can recognize this more readily through viewing, discussing, and analyzing film clips such as the ones discussed herein. The Stakeholders University lecturers and students, executive educators and managers, general human resource development (HRD) professionals

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Cann, P. M. "In-Contact Molecular Spectroscopy of Liquid Lubricant Films." MRS Bulletin 33, no. 12 (December 2008): 1151–58. http://dx.doi.org/10.1557/mrs2008.245.

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AbstractThe primary role of a lubricant is to control the friction and wear of rubbing surfaces to optimize the operation of a component by forming an interfacial film separating the surfaces. Lubrication research seeks to develop new lubricant formulations and to optimize component life and performance. To do this, we must understand the mechanisms of film formation and film properties and the way these relate to operating conditions. In many engineering components, the lubricant film is subjected to severe mechanical and thermal stresses as it passes through the loaded zone. These severe conditions can result in molecular alignment or conformational change and the formation of new chemical species, which will impact the lubrication performance of the fluid. The lubricant response within the contact is often transient and thus has proved difficult to study by conventional surface analytical methods. One alternative is to replace one of the surfaces by a transparent window and use molecular microspectroscopy (infrared or Raman) to analyze the film within the contact zone formed during rubbing. This article reviews the development and application of in-contact molecular spectroscopy for the study of lubricant properties within the rubbing interface for both conventional and biolubrication systems. This technique has been used to study molecular conformation, chemical composition, and pressure distribution in the high-pressure region of the contact zone. However, challenges remain, including detecting very thin films, obtaining depth profile information, and applying these methods more generally to biotribology.

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Kawata, K., N. Nakamua, H. Yoshimura, T. Hasebe, and S. Suda. "537 Development of Ecological-Friendly Machining System for Magnesium Alloy with Oil Film on Water Fog Cutting Fluid." Proceedings of International Conference on Leading Edge Manufacturing in 21st century : LEM21 2003 (2003): 1053–57. http://dx.doi.org/10.1299/jsmelem.2003.1053.

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Novikov, Dmitrii K., and Dmitrii S. Diligenskii. "The Development of A Squeeze Film Damper Parametric Model in the Context of a Fluid-structural Interaction Task." IOP Conference Series: Materials Science and Engineering 302 (January 2018): 012008. http://dx.doi.org/10.1088/1757-899x/302/1/012008.

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Tee, Kian Sek, Muhammad Sharil Saripan, Hiung Yin Yap, and Chin Fhong Soon. "Development of a Mechatronic Syringe Pump to Control Fluid Flow in a Microfluidic Device Based on Polyimide Film." IOP Conference Series: Materials Science and Engineering 226 (August 2017): 012031. http://dx.doi.org/10.1088/1757-899x/226/1/012031.

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Piqué, Teresa María, Luis Fernandez Luco, and Analía Vázquez. "Fluid Transport Mechanisms in Portland Cement Mortar Modified with PVA and Nano Montmorillonite." Advanced Materials Research 687 (April 2013): 311–15. http://dx.doi.org/10.4028/www.scientific.net/amr.687.311.

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The development of new materials for specific applications is an increasing field in the construction industry, so is the employment of nanotechnology for this goal. When poly(vinyl alcohol) (PVA) is added to a Portland cement mortar, a film is formed in between the hydration products. This film has low elasticity modulus and high tensile strength and it enhances the mortar’s mechanical properties in the fresh and hardened states. The addition of nano montmorillonites (MMT) gives the polymer a better compatibility with the cement matrix. In this work, the changes in the microstructure of Portland cement mortars modified with PVA and PVA with MMT are assessed by means of transport of fluids capacity as an indicator. The reference is a standard mortar according to EN 196-1. The parameters measured are: weight loss under drying and air permeability. Complementary measures, such as compressive and flexural strengths and drying shrinkage have also been performed. From the obtained results, it can be concluded that the inclusion PVA + MMT to Portland cement mortar doesn’t affect the microstructure, when compared with Portland cement mortar with PVA, and even increase its tensile strength.

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Journal articles on the topic 'Fluid film development'

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