Hydrodynamic journal bearing lubricated with a ferrofluid

2017 ◽  
Vol 69 (5) ◽  
pp. 754-760 ◽  
Author(s):  
Nimeshchandra S. Patel ◽  
Dipak Vakharia ◽  
Gunamani Deheri
Keyword(s):  
Design Methodology ◽  
Journal Bearing ◽  
Magnetic Bearing ◽  
Point Of View ◽  
Content Type ◽  
Test Conditions ◽  
Hydrodynamic Journal Bearing ◽  
Bearing Design ◽  
Set Up ◽  
Bearing System

Purpose This paper aims to investigate the performance of a ferrofluid-based hydrodynamic journal bearing system. Design/methodology/approach This paper presents a new design of ferrofluid-based hydrodynamic journal bearing. An experimental set-up consisting of a magnetic shaft along with a brass bearing was modified and developed. A permanent magnet was used to make the selected shaft material magnetic. The load and speed were varied to conduct the analyses for different test conditions. Findings The paper provides information about a design of ferrofluid-based journal bearing and its improved performances. For moderate to higher loads at different shaft speeds, it was found that because of the magnetization effect, the maximum film pressure in case of a ferrofluid lubricant increased up to approximately 60 per cent, compared with that of the conventional lubricant-based journal bearing system. Besides, the temperature rise was found smaller for ferrofluid lubricants, thus making the system cooler while running. Originality/value This paper offers a new design of magnetic bearing system for the experimental analysis by utilizing a magnetic shaft with a non-magnetic bearing. The present ferrofluid-based bearing design is less complicated from manufacturing point of view.

Behaviour of two-lobe hole-entry hybrid journal bearing system under the combined influence of textured surface and micropolar lubricant

2017 ◽  
Vol 69 (6) ◽  
pp. 844-862 ◽  
Author(s):  
Chandra B. Khatri ◽  
Satish C. Sharma
Keyword(s):  
Design Methodology ◽  
Reynolds Equation ◽  
Journal Bearing ◽  
Numerical Technique ◽  
Surface Texturing ◽  
Textured Surface ◽  
Performance Parameters ◽  
Content Type ◽  
Fluid Theory ◽  
Bearing System

Purpose The aim of the present paper is to study the combined influence of textured surface and micropolar lubricant behaviour on the performance of two-lobe hole-entry hybrid journal bearing system. The bearing performance parameters of the textured circular/two-lobe hole-entry hybrid journal bearing system have been computed against the constant vertical external load supported by the bearing. Design/methodology/approach In this work, Eringen’s micropolar fluid theory has been used to derive the governing Reynolds equation. The consequent solution of the governing Reynolds equation has been obtained by using finite element method (FEM) numerical technique. Findings The present study indicates that the use of the textured surface, two-lobe profile of bearing and micropolar lubricant, significantly enhances the bearing performance as compared to non-textured circular journal bearing. Originality/value The present study concerning the influence of surface texturing on the behaviour of the two-lobe hole-entry hybrid journal bearing lubricated with micropolar lubricant is original. The theoretically simulated results of the present study will be useful to design an efficient journal bearing system.

Analysis of wind turbine modelling using TSMC techniques

2018 ◽  
Vol 37 (6) ◽  
pp. 1981-1992
Author(s):  
Yuvaraja T. ◽  
K. Ramya
Keyword(s):  
Design Methodology ◽  
Induction Generator ◽  
Doubly Fed Induction Generator ◽  
Two Stage ◽  
Content Type ◽  
After Effects ◽  
Displacement Factor ◽  
Set Up ◽  
Doubly Fed ◽  
Bearing System

Purpose According to bidirectional ability, wind application are having variable acceleration which connected large quantity of wind ability bearing system with doubly-fed induction generator (DFIG) fed by the two-stage cast converter (TSMC) system, the accentuation action for TSMC and arithmetic standard for DFIG are all deduced. The purpose of this study is for, stator accelerated action in Doubly fed induction generator and controlled by the Two Stage Cast Converter for better control. Design/methodology/approach The purpose of this study is for, stator accelerated action in Doubly fed induction generator and controlled by the Two Stage Cast Converter for better control. Findings Then, the beginning ancestor was set up to verify this system; the allotment of the filigree beginning after-effects are offered beneath no-load and the three plan states. Originality/value These after-effects apparent by the fact that the arrangement fed by TSMC-DFIG could apprehend the safe ability bearing accumulated to the filigree in the sub-synchronous, synchronisation and super-synchronous state; meanwhile generated sinusoidal describes the displacement factor.

scholarly journals Geometrical transformations and equivalent materials in computational electromagnetism

2008 ◽  
Vol 27 (4) ◽  
pp. 806-819 ◽  
Author(s):  
A. Nicolet ◽  
F. Zolla ◽  
Y. Ould Agha ◽  
S. Guenneau
Keyword(s):  
Material Properties ◽  
Design Methodology ◽  
Point Of View ◽  
The Finite Element Method ◽  
Open Problems ◽  
Content Type ◽  
Geometrical Transformation ◽  
Computational Electromagnetism ◽  
Set Up ◽  
Invisibility Cloaks

PurposeThis paper aims to review various techniques used in computational electromagnetism such as the treatment of open problems, helicoidal geometries and the design of arbitrarily shaped invisibility cloaks. This seemingly heterogeneous list is unified by the concept of geometrical transformation that leads to equivalent materials. The practical set‐up is conveniently effected via the finite element method.Design/methodology/approachThe change of coordinates is completely encapsulated in the material properties.FindingsThe most significant examples are the simple 2D treatment of helicoidal geometries and the design of arbitrarily shaped invisibility cloaks.Originality/valueThe paper provides a unifying point of view, bridging several techniques in electromagnetism.

Effect of recess configuration on the performances of high-speed hybrid journal bearing

2016 ◽  
Vol 68 (3) ◽  
pp. 301-307 ◽  
Author(s):  
Qiyin Lin ◽  
Zhengying Wei ◽  
Ning Wang ◽  
Yubin Zhang
Keyword(s):  
Temperature Rise ◽  
High Speed ◽  
Design Methodology ◽  
High Stability ◽  
Journal Bearing ◽  
Content Type ◽  
Structure Interaction ◽  
Bearing Design ◽  
Effects Of Temperature ◽  
Interaction Approach

Purpose The purpose of this paper is to study the influences of recess configurations on the performances of high-speed hybrid journal bearing. Hybrid journal bearing earns increasing attention in high-speed machine tool spindle owing to its intrinsic outstanding performances of low temperature rise and high stability. Design/methodology/approach To investigate the coupled effects of temperature, turbulence and the interaction between lubricant and journal/bearing bush, a thermal fluid-structure interaction approach is presented and validated by the experimental results. Findings Ladder-type recess has excellent tribological characteristics in decreasing temperature rise, improving stability and inhibiting cavitation, which are all beneficial to improve the performances of high-speed spindle system. Originality/value This work can be a valuable guide for the future high-speed hybrid journal bearing design.

Comparison of the reluctance laminated and solid rotor synchronous machine operating at high temperatures

2019 ◽  
Vol 38 (4) ◽  
pp. 1111-1119 ◽  
Author(s):  
Marcin Lefik ◽  
Krzysztof Komeza ◽  
Ewa Napieralska-Juszczak ◽  
Daniel Roger ◽  
Piotr Andrzej Napieralski
Keyword(s):  
High Speed ◽  
Design Methodology ◽  
Three Dimensional ◽  
Synchronous Machine ◽  
Point Of View ◽  
Heat Sources ◽  
Model Calculations ◽  
Content Type ◽  
Thermal Phenomenon ◽  
Practical Implications

Purpose The purpose of this paper is to present a comparison between reluctance synchronous machine-enabling work at high internal temperature (HT° machine) with laminated and solid rotor. Design/methodology/approach To obtain heat sources for the thermal model, calculations of the electromagnetic field were made using the Opera 3D program including effect of rotation and the resulting eddy current losses. To analyse the thermal phenomenon, the 3D coupled thermal-fluid (CFD) model is used. Findings The presented results show clearly that laminated construction is much better from a point of view of efficiency and temperature. However, solid construction can be interesting for high speed machines due to their mechanical robustness. Research limitations/implications The main problem, despite the use of parallel calculations, is the long calculation time. Practical implications The obtained simulation and experimental results show the possibility of building a machine operating at a much higher ambient temperature than it was previously produced for example in the vicinity of the aircraft turbines. Originality/value The paper presents the application of fully three-dimensional coupled electromagnetic and thermal analysis of new machine constructions designed for elevated temperature.

Investigation of sustainability of lubricated journal bearing under relevant design parameters

2018 ◽  
Vol 70 (4) ◽  
pp. 789-804 ◽  
Author(s):  
M.M. Shahin ◽  
Mohammad Asaduzzaman Chowdhury ◽  
Md. Arefin Kowser ◽  
Uttam Kumar Debnath ◽  
M.H. Monir
Keyword(s):  
Aspect Ratio ◽  
Elastic Strain ◽  
Journal Bearing ◽  
Design Parameters ◽  
Content Type ◽  
Computational Fluid Dynamics Cfd ◽  
Stress Formation ◽  
Bearing Design ◽  
The Stability ◽  
Bearing Friction

Purpose The purposes of the present study are to ensure higher sustainability of journal bearings under different applied loads and to observe bearing performances such as elastic strain, total deformation and stress formation. Design/methodology/approach A journal bearing test rig was used to determine the effect of the applied load on the bearing friction, film thickness, lubricant film pressure, etc. A steady-state analysis was performed to obtain the bearing performance. Findings An efficient aspect ratio (L/D) range was obtained to increase the durability or the stability of the bearing while the bearing is in the working condition by using SAE 5W-30 oil. The results from the study were compared with previous studies in which different types of oil and water, such as Newtonian fluid (NF), magnetorheological fluid (MRF) and nonmagnetorheological fluid (NMRF), were used as the lubricant. To ensure a preferable aspect ratio range (0.25-0.50), a computational fluid dynamics (CFD) analysis was conducted by ANSYS; the results show a lower elastic strain and deformation within the preferable aspect ratio (0.25-0.50) rather than a higher aspect ratio using the SAE 5W-30 oil. Originality/value It is expected that the findings of this study will contribute to the improvement of the bearing design and the bearing lubricating system.

Using transfer learning for diabetic retinopathy stage classification

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Enas M.F. El Houby
Keyword(s):  
Diabetic Retinopathy ◽  
Transfer Learning ◽  
Grade Level ◽  
Design Methodology ◽  
Content Type ◽  
Stage Classification ◽  
Set Up ◽  
Retinal Fundus ◽  
Automated Methods

PurposeDiabetic retinopathy (DR) is one of the dangerous complications of diabetes. Its grade level must be tracked to manage its progress and to start the appropriate decision for treatment in time. Effective automated methods for the detection of DR and the classification of its severity stage are necessary to reduce the burden on ophthalmologists and diagnostic contradictions among manual readers.Design/methodology/approachIn this research, convolutional neural network (CNN) was used based on colored retinal fundus images for the detection of DR and classification of its stages. CNN can recognize sophisticated features on the retina and provides an automatic diagnosis. The pre-trained VGG-16 CNN model was applied using a transfer learning (TL) approach to utilize the already learned parameters in the detection.FindingsBy conducting different experiments set up with different severity groupings, the achieved results are promising. The best-achieved accuracies for 2-class, 3-class, 4-class and 5-class classifications are 86.5, 80.5, 63.5 and 73.7, respectively.Originality/valueIn this research, VGG-16 was used to detect and classify DR stages using the TL approach. Different combinations of classes were used in the classification of DR severity stages to illustrate the ability of the model to differentiate between the classes and verify the effect of these changes on the performance of the model.

Non-linear stability analysis of micropolar fluid lubricated journal bearings with turbulent effect

2019 ◽  
Vol 71 (1) ◽  
pp. 31-39
Author(s):  
Subrata Das ◽  
Sisir Kumar Guha
Keyword(s):  
Stability Analysis ◽  
Linear Stability ◽  
Micropolar Fluid ◽  
Journal Bearing ◽  
Journal Bearings ◽  
Turbulent Regime ◽  
Content Type ◽  
Non Linear ◽  
The Stability ◽  
Bearing System

Purpose The purpose of this paper is to investigate the effect of turbulence on the stability characteristics of finite hydrodynamic journal bearing lubricated with micropolar fluid. Design/methodology/approach The non-dimensional transient Reynolds equation has been solved to obtain the non-dimensional pressure field which in turn used to obtain the load carrying capacity of the bearing. The second-order equations of motion applicable for journal bearing system have been solved using fourth-order Runge–Kutta method to obtain the stability characteristics. Findings It has been observed that turbulence has adverse effect on stability and the whirl ratio at laminar flow condition has the lowest value. Practical implications The paper provides the stability characteristics of the finite journal bearing lubricated with micropolar fluid operating in turbulent regime which is very common in practical applications. Originality/value Non-linear stability analysis of micropolar fluid lubricated journal bearing operating in turbulent regime has not been reported in literatures so far. This paper is an effort to address the problem of non-linear stability of journal bearings under micropolar lubrication with turbulent effect. The results obtained provide useful information for designing the journal bearing system for high speed applications.

Data mining in anti-money laundering field

2017 ◽  
Vol 20 (3) ◽  
pp. 301-310 ◽  
Author(s):  
Noriaki Yasaka
Keyword(s):  
Data Mining ◽  
Knowledge Management ◽  
Money Laundering ◽  
Design Methodology ◽  
Point Of View ◽  
Important Task ◽  
Content Type ◽  
Suspicious Transaction ◽  
Mining Methods ◽  
The Creation

Purpose This report aims to focus on how suspicious transaction report is created with data mining methods and used from the point of view of knowledge management. Design/methodology/approach This paper considers data mining versus knowledge management in the anti-money laundering (AML) field. Findings In the AML field, the information and knowledge gained are not necessarily used for or shared with the related shareholders. Creating and co-evolving the network of “knowledge professionals” is the impending assignment in this industry. The first and most important task is knowledge management in the global AML field. Originality/value The report considers the creation with data mining methods and utilization from the point of view of knowledge management.

Excellence and gender

2015 ◽  
Vol 34 (1) ◽  
pp. 37-54 ◽  
Author(s):  
Farinaz Fassa
Keyword(s):  
Gender Equality ◽  
Common Good ◽  
Design Methodology ◽  
Local Level ◽  
National Level ◽  
Academic Careers ◽  
Content Type ◽  
And Gender ◽  
Set Up ◽  
Feminist Movements

Purpose – Discussing the Swiss case, the purpose of this paper is to examine how gender equality policies deal with the present requirements for scholars to be considered “excellent”. It aims to pinpoint the lines of tension or coherence between excellence, meritocracy and gender politics. Design/methodology/approach – In order to specify the norms of academic careers and their different renditions, the author draws on two studies (at local and national levels) to illustrate where the changes and resistances are taking place. Findings – The translations of a number of demands of feminist movements into the policies set up to favour equality between the sexes may combine to challenge the norms of academia as a gendered realm. Nevertheless, without strong pressure from feminists at local level and the conduct of research pursuing the enterprise of deconstructing norms, top-down policies may prove less “corrective” than affirmative action. This pressure is not only useful to build gender equality in science but also to broaden the spectrum of knowledge that can become a common good. Research limitations/implications – As neither the names nor the positions of the experts who select the candidates at national level are made public, we had to opt for other, less satisfactory means. Originality/value – The originality of the paper lies in the link made between the enhancements brought by Equalities policies and the changes they bring. It attempts to bring to light the extent to which gender equality policies conform to the neo-managerial order or challenge its norms to build a world that is more just.

Sign in / Sign up

Export Citation Format

Share Document