scholarly journals Droplet breakup in the square microchannel with a short square constriction to generate slug flow

2022 ◽  
Author(s):  
Xiaoda Wang ◽  
Yuanyuan Liu ◽  
Dayu Liu ◽  
Xuehui Ge ◽  
Ling Li ◽  
...  
Keyword(s):  
Droplet Size ◽  
Slug Flow ◽  
Empirical Equation ◽  
Industrial Applications ◽  
Droplet Breakup ◽  
Mechanism Analysis ◽  
Operation Conditions ◽  
Comparison Results ◽  
Daughter Droplets ◽  
Square Microchannel

Droplet breakup in micro-constrictions is an important phenomenon in industrial applications. This work aimed to investigate the droplet breakup in the square microchannel with a short square constriction to generate the slug flow, which drew little attention before. Mechanism analysis indicated that this breakup process included the shear-force-dominated, squeezing-force-dominated, and pinch-off stages. Non-uniform daughter droplets were generated in the constriction with their interface restricted in the horizontal and perpendicular directions by the microchannel walls. The average relative deviation of the daughter droplet size was < 30%, much lower than that for the breakup with the daughter droplet restricted only in one direction. An empirical equation with a deviation of < 20% was provided to show the dependence of the daughter droplet size on the operation conditions. The comparison results suggested that the different restriction effects of microchannel wall on daughter droplets led to the different breakup mechanisms in different constrictions.

scholarly journals Gradual Wear Diagnosis of Outer-Race Rolling Bearing Faults through Artificial Intelligence Methods and Stray Flux Signals

Electronics ◽  
2021 ◽  
Vol 10 (12) ◽  
pp. 1486
Author(s):  
Israel Zamudio-Ramirez ◽  
Roque A. Osornio-Rios ◽  
Jose A. Antonino-Daviu ◽  
Jonathan Cureño-Osornio ◽  
Juan-Jose Saucedo-Dorantes
Keyword(s):  
Kinematic Chain ◽  
Industrial Applications ◽  
Electric Motors ◽  
Feed Forward Neural Network ◽  
Mechatronic Systems ◽  
Linear Discriminant ◽  
Bearing Faults ◽  
Outer Race ◽  
Non Invasive ◽  
Operation Conditions

Electric motors have been widely used as fundamental elements for driving kinematic chains on mechatronic systems, which are very important components for the proper operation of several industrial applications. Although electric motors are very robust and efficient machines, they are prone to suffer from different faults. One of the most frequent causes of failure is due to a degradation on the bearings. This fault has commonly been diagnosed at advanced stages by means of vibration and current signals. Since low-amplitude fault-related signals are typically obtained, the diagnosis of faults at incipient stages turns out to be a challenging task. In this context, it is desired to develop non-invasive techniques able to diagnose bearing faults at early stages, enabling to achieve adequate maintenance actions. This paper presents a non-invasive gradual wear diagnosis method for bearing outer-race faults. The proposal relies on the application of a linear discriminant analysis (LDA) to statistical and Katz’s fractal dimension features obtained from stray flux signals, and then an automatic classification is performed by means of a feed-forward neural network (FFNN). The results obtained demonstrates the effectiveness of the proposed method, which is validated on a kinematic chain (composed by a 0.746 KW induction motor, a belt and pulleys transmission system and an alternator as a load) under several operation conditions: healthy condition, 1 mm, 2 mm, 3 mm, 4 mm, and 5 mm hole diameter on the bearing outer race, and 60 Hz, 50 Hz, 15 Hz and 5 Hz power supply frequencies

Stability characteristics of lubricating film in mill oil-film bearings

2018 ◽  
Vol 70 (1) ◽  
pp. 201-211 ◽  
Author(s):  
Jianmei Wang ◽  
Zhixiong Li ◽  
Sadoughi Mohammadkazem ◽  
Min Cai ◽  
Jianfeng Kang ◽  
...  
Keyword(s):  
Influential Factors ◽  
Film Stability ◽  
High Rotational Speed ◽  
Content Type ◽  
Oil Film ◽  
Practical Applications ◽  
Lubricating Film ◽  
Operation Conditions ◽  
Comparison Results ◽  
The Stability

Purpose The stability characteristics of an oil film directly influence the safety and service life of mill oil-film bearings. However, very limited work has been done to address the stability characteristics of mill oil-film bearings. To this end, this paper aims to investigate the stability characteristics of mill oil-film bearings through theoretical and experimental analysis. Design/methodology/approach For the first time, a special designed experiment platform was developed to investigate the stability characteristics of mill oil-film bearings. In addition, a theoretical model of lubricating film of the tested bearings was established to analyze the oil-film stability. The theoretical results were compared with the experimental results. Findings The comparison results demonstrate that the critical influential factors on the bearing stability were the eccentricity ratio and the ratio of bearing length to diameter. The mill bearing was likely to be unstable under a small load and at a high rotational speed. Practical implications The paper includes implications for suitable operation conditions in practical use of mill oil-film bearings. Originality/value This paper fulfills an identified need to investigate oil-film stability of mill bearings for practical applications.

scholarly journals Collisions of Two-Phase Liquid Droplets in a Heated Gas Medium

Entropy ◽  
2021 ◽  
Vol 23 (11) ◽  
pp. 1476
Author(s):  
Pavel Tkachenko ◽  
Nikita Shlegel ◽  
Pavel Strizhak
Keyword(s):  
Volume Fraction ◽  
Industrial Applications ◽  
Droplet Breakup ◽  
Liquid Volume ◽  
Liquid Droplets ◽  
Vapor Bubbles ◽  
Two Phase ◽  
Relative Volume Fraction ◽  
Phase Liquid ◽  
Gas Medium

The paper presents the experimental research findings for the integral characteristics of processes developing when two-phase liquid droplets collide in a heated gas medium. The experiments were conducted in a closed heat exchange chamber space filled with air. The gas medium was heated to 400–500 °C by an induction system. In the experiments, the size of initial droplets, their velocities and impact angles were varied in the ranges typical of industrial applications. The main varied parameter was the percentage of vapor (volume of bubbles) in the droplet (up to 90% of the liquid volume). The droplet collision regimes (coalescence, bounce, breakup, disruption), size and number of secondary fragments, as well as the relative volume fraction of vapor bubbles in them were recorded. Differences in the collision regimes and in the distribution of secondary fragments by size were identified. The areas of liquid surface before and after the initial droplet breakup were determined. Conditions were outlined in which vapor bubbles had a significant and, on the contrary, fairly weak effect on the interaction regimes of two-phase droplets.

scholarly journals Transfer Learning based Impedance Identification of Voltage Source Converters

2021 ◽  
Author(s):  
Mengfan Zhang ◽  
xiongfei wang ◽  
Qianwen Xu
Keyword(s):  
Transfer Learning ◽  
Internal Control ◽  
Industrial Applications ◽  
Black Box ◽  
System Stability ◽  
Voltage Source ◽  
Voltage Source Converters ◽  
Impedance Model ◽  
Comparison Results ◽  
Stability Method

The black-box impedance of the voltage source converters (VSCs) can be directly identified at the converter terminal without access to its internal control details, which greatly facilitates the converter-grid interactions. However, since the limited impedance data amount in practical industrial applications, the existing impedance identification methods cannot accurately capture characteristics of the impedance model at various operating scenarios, which is the indicators of the VSCs system stability at the changing profiles of renewables and loads. In this paper, a transfer learning based impedance identification is proposed to fill this research gap. This method can significantly reduce the required data amount used in impedance identification so that the black-box impedance-based stability method could be applied for the practical industrial application. The comparison results confirm the accuracy of the impedance model obtained by this transfer learning based impedance identification method.

scholarly journals Water Droplets Translocation and Fission in a 3D Bi-Planar Multifurcated T-Junction Microchannels

Processes ◽  
2020 ◽  
Vol 8 (5) ◽  
pp. 510
Author(s):  
Inn-Leon Lu ◽  
Voon-Loong Wong ◽  
Jit-Kai Chin ◽  
Kuzilati Kushaari
Keyword(s):  
Droplet Size ◽  
Flow Behavior ◽  
Phase 1 ◽  
Maximum Velocity ◽  
Droplet Size Distribution ◽  
Continuous Phase ◽  
Fission Process ◽  
Model Studies ◽  
Daughter Droplets ◽  
Droplet Fission

Droplet fission has gained notable interest in drug delivery applications due to its ability to perform parallel operations in single device. Hitherto, droplet flow behavior in a 3D constriction was scarcely investigated. This study aims to investigate droplets fission inside a 3D bi-planar multifurcated microfluidic device. The flow behavior and droplet size distribution were studied in trifurcated microchannels using distilled water as dispersed phase (1 mPa·s) and olive oil (68 mPa·s) as continuous phase. Various sizes of subordinate daughter droplets were manipulated passively through the modulation of flowrate ratio (Q) (0.15 < Q < 3.33). Overall, we found droplet size coefficient of variations (CV%) ranging from 0.72% to 69%. Highly monodispersed droplets were formed at the upstream T-junction (CV% < 2%) while the droplet fission process was unstable at higher flowrate ratio (Q > 0.4) as they travel downstream (1.5% < CV% < 69%) to splitting junctions. Complex responses to the non-monotonic behavior of mean droplet size was found at the downstream boundaries, which arose from the deformations under nonuniform flow condition. CFD was used as a tool to study the preliminary maximum velocity (Umax) profile for the symmetrical (0.01334 m/s < Umax < 0.0153 m/s) and asymmetrical branched channels (0.0223 m/s< Umax < 0.00438 m/s), thus complementing the experimental model studies.

scholarly journals A Comprehensive Approach from Interfacial to Bulk Properties of Legume Protein-Stabilized Emulsions

Fluids ◽  
2019 ◽  
Vol 4 (2) ◽  
pp. 65 ◽  
Author(s):  
Manuel Félix ◽  
Alberto Romero ◽  
Cecilio Carrera-Sanchez ◽  
Antonio Guerrero
Keyword(s):  
Rheological Properties ◽  
Size Distribution ◽  
Droplet Size ◽  
Electrostatic Interactions ◽  
Ph Value ◽  
Droplet Size Distribution ◽  
Interfacial Properties ◽  
Industrial Applications ◽  
Droplet Sizes ◽  
Legume Protein

The correlation between interfacial properties and emulsion microstructure is a topic of special interest that has many industrial applications. This study deals with the comparison between the rheological properties of oil-water interfaces with adsorbed proteins from legumes (chickpea or faba bean) and the properties of the emulsions using them as the only emulsifier, both at microscopic (droplet size distribution) and macroscopic level (linear viscoelasticity). Two different pH values (2.5 and 7.5) were studied as a function of storage time. Interfaces were characterized by means of dilatational and interfacial shear rheology measurements. Subsequently, the microstructure of the final emulsions obtained was evaluated thorough droplet size distribution (DSD), light scattering and rheological measurements. Results obtained evidenced that pH value has a strong influence on interfacial properties and emulsion microstructure. The best interfacial results were obtained for the lower pH value using chickpea protein, which also corresponded to smaller droplet sizes, higher viscoelastic moduli, and higher emulsion stability. Thus, results put forward the relevance of the interfacial tension values, the adsorption kinetics, the viscoelastic properties of the interfacial film, and the electrostatic interactions among droplets, which depend on pH and the type of protein, on the microstructure, rheological properties, and stability of legume protein-stabilized emulsions.

Gas-Newtonian and Gas-Non-Newtonian Slug Flow in Vertical Pipe, Part I: Gas Holdup Characteristics

2010 ◽  
Vol 8 (1) ◽  
Author(s):  
Subrata Kumar Majumder ◽  
Sandip Ghosh ◽  
Arun Kumar Mitra ◽  
Gautam Kundu
Keyword(s):  
Slug Flow ◽  
Oil And Gas ◽  
Experimental Studies ◽  
Industrial Applications ◽  
Transportation Systems ◽  
Gas Holdup ◽  
Newtonian Liquid ◽  
Biochemical Engineering ◽  
Two Phase ◽  
Liquid Systems

Studies on two-phase gas-liquid co-current flow with non-Newtonian liquid system has attracted the attention of researchers over the years due to its wide-spread applications and importance in various different processes in chemical and biochemical industries, such as the process of two-phase in oil and gas wells, transportation systems of crude and refined products, and food processing in biochemical engineering and bio-reactors. This article examines the sole objective of experimental studies on gas holdup in Newtonian and non-Newtonian liquid slug flow within a range of gas and liquid flowrate of 0.5×10-4 to 1.92×10-4 m3/s and 1.6×10-4 to 6.7×10-4 m3/s, respectively. The present data was analyzed with different models. To predict gas holdup, correlations have been developed for individual system with Newtonian and non-Newtonian liquid. A general correlation was also developed to predict the gas holdup combing both the Newtonian and non-Newtonian liquid systems. The study of the gas holdup characteristics in gas-Newtonian and non-Newtonian liquid systems may give insight into a further understanding and modeling of this slug flow characteristics in industrial applications.

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