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1 |
Performance analysis of tilting pad journal bearing using COMSOL Multiphysics and Neural Networks
تجزیه و تحلیل عملکرد تحمل ژورنال پد کج با استفاده از چند رسانه ای و شبکه های عصبی COMSOL-2020 The objective of this paper is to study the effect of geometrical parameters on the performance
of tilting pad journal bearing. COMSOL Multiphysics software is used to simulate the tilting
pad journal bearing at different eccentricity ratios and pad clearances. The effect of changing pad
numbers (from 3 to 6 pads) and the pads clearance angles (from 2 to 6) on the performance
parameters such as the load carrying capacity, frictional torque and attitude angle was analyzed.
It was found that as the number of pads increases the load carrying capacity and the friction coefficient
increase, while the attitude angle decreases. Decreasing the clearance between pads leads to
an increase in the load carrying capacity of the bearing while it has minor effect on the other performance
parameters. The characteristic data obtained from COMSOL program is used to train
three suggested neural networks. The first is a feed-forward Neural Network which consists of three
layers with {80 sigmoid, 5 sigmoid and 1 linear} neurons. The second is a radial bases Neural Network
and the third is a generalized regression Neural Network. Applying the three trained Neural
Networks (Feed forward, Radial basis, and Generalized regression) to predict the performance of
tilting pad bearing at values not used in the training process. The results show a high accuracy to
predict the attitude angle, the coefficient of friction and the load carrying capacity. The percentage
relative errors between the predicted values and that obtained by COMSOL are between (0 and
0.98) %. The neural networks model show high capacity in predicting the output variables correctly
for both the training data and that which was not included. KEYWORDS : Lubrication | Tilting pad journal bearings | Artificial neural networks | Artificial intelligence | COMSOL Multiphysics |
مقاله انگلیسی |
2 |
Investigating the migration law of aggregates during concrete flowing in pipe
بررسی قانون مهاجرت مصالح هنگام جریان بتن در لوله-2020 During pumping fresh concrete pipes, aggregate migration is occurred under the action of various forces.
In order to study the migration characteristic of aggregates during concrete flowing in pipes, in this paper,
we built the test system based on particle tracking technology. Transparent concrete was prepared. The
particle capture function of high-speed camera was used to track particle motion. Results showed that
the radial displacement of particles depended on the initial location and aggregate size. Small aggregates
near pipe wall or center axis had fewer motion. For the particles with larger diameter, the migration
direction almost pointed to the axis of pipe. The migration displacement of nature aggregates was smaller
than that of ground grinding ball. The migration displacement firstly increased and then decreased with
increasing the diameter of particle. Moreover, the effect of particle shape on migration was explored.
Finally, the wall effect, gravity induced particle migration and shear induced particle migration were
compared based on the phenomenon of flow induced particle migration, results showed that the phenomenon
of shear induced particle migration played the main role in the formation of lubrication layer.
This study was of great significance to reveal the transport law of dense particle flow in the pipeline. Keywords: Concrete flow | Aggregate | Migration characteristic | Particle tracking |
مقاله انگلیسی |
3 |
Thermal management in conventional diesel engines
مدیریت حرارتی در موتورهای دیزلی معمولی-2020 In the era of high-powered automobiles, there occurs a potential for making faster advances in vehicle
speed, power, comfort and with improved mileage and efficiency. Increased power demand in India
due to the rapid industrialization necessitates the design of vehicles with low cost, reduced losses, less
emission and higher efficiency. Large numbers of automobile models step in every year. Hence it is necessary
to control the engine operation simultaneously for quicker and efficient operation. As the amount
of higher power fid engines increase rapidly so as the requirement of thermal management to withstand
the high power. This project focuses on two methods for efficient thermal management; they are conversion
of mechanical coolant pump to electric coolant pump and installation of a thermostat in the lubrication
system. Both methods have been proved to be efficient in thermal management. These are
practically tested and can be used in the near future so that our nation can meet Bharat Stage 6 emission
norms. Keywords: Electric coolant pump | Oil thermostat | Power fid engine | Controller | Thermal management |
مقاله انگلیسی |
4 |
Measurement and Analysis of Surface Roughness in WS2 Solid Lubricant Assisted Minimum Quantity Lubrication (MQL) Turning of Inconel 718
اندازه گیری و تجزیه و تحلیل ناهمواریهای سطحی در WS2 روان کننده جامد به کمک حداقل روانکاری تعداد (MQL) تبدیل اینکونل 718-2016 The current research work demonstrates through experiment, the effect of solid lubricant assisted minimum quantity lubrication (MQL) turning of Inconel 718 on the finish quality of machined surface. In MQL application, micron sized tungsten disulfide (WS2) solid lubricant powder particles were dispersed (0.5% wt.) in emulsifier oil based cutting fluid (20:1). To comprehend the finish quality of machined surface with the presence of WS2 solid lubricant, turning tests are conducted. The effect of cutting parameters on the finish quality of work surface is evaluated using statistical design approach. Multiple linear regression models are developed and validated to understand the correlations between cutting parameters. Results demonstrate that, surface quality of machined work material during WS2 solid lubricant assisted MQL machining showed a much improvement on the finish quality of work material by on average about 35% when compared to MQL machining alone.© 2016 The Authors. Published by Elsevier B.V.Peer-review under responsibility of the International Scientific Committee of the 13th Global Conference on Sustainable Manufacturing.© 2016 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).Peer-review under responsibility of the International Scientific Committee of the 13th Global Conference on Sustainable Manufacturing Keywords: Solid lubricant | Inconel | turning | MQL | dry machining | surface roughness |
مقاله انگلیسی |
5 |
Impregnated porous bearings textured with a pocket on sliding surfaces: comparison of h-boron nitride with graphite and molybdenum disulphide up to 150 C
یاتاقانهای متخلخل آغشته به بافت با جیب در سطوح کشویی: مقایسه نیترید ساعت بور با گرافیت و disulphide مولیبدن تا 150 سانتی گراد؟-2015 The iron bearings with porosities of 16 and
28 % were impregnated with mineral oil and the
surface was textured with a pocket and then filled by a
solid lubricant. The h-boron nitride, h-BN, as a pocket
lubricant was compared with graphite and MoS2 up to
150 C. Low friction at temperature80 C is a result
of weak van der Waals forces between layers and
allows for easy shearing of the layers. It was found that
the h-boron nitride solid lubricant particles provided a
much better lubrication at 150 C than did graphite
and MoS2. An increase in friction was due to oxidation
MoS2 and the formation of MoO3, and desorption of
water vapour of from graphite and progressive disappearance
of the lamellar structure at temperature up to
150 C.
Keywords Lamellar lubrication Textured porous
bearing Friction coefficient up to 150 C Boron
nitride h-BN Graphite Molybdenum disulphide |
مقاله انگلیسی |
6 |
Piston dynamic characteristics analyses based on FEM method Part I: Effected by piston skirt parameters
ویژگی های پویا پیستون تجزیه و تحلیل بر اساس روش FEM قسمت اول: تاثیر پارامترهای دامن پیستون-2014 The dynamic and lubrication characteristics are all very complex problem in piston-liner analysis, and
they have great effect on the power output, vibration, noise emission. In this paper, the numerical model
which concludes lubrication part and dynamic motion is established, the lubrication is solved by the
finite element method, and dynamic equation is solved by Runge–Kutta. The effect of piston skirt parameters
on dynamic characteristics are compared based on a typical inline six-cylinder engine, such as:
clearance, offset of piston pin, length of piston skirt, position of bump, curvature parameter and ellipticity
of the piston, all the result mainly focus on the slap noise of the engine. All the analyses are very useful to
design of piston-liner at the development of the engine, and it can provide the guidance for the design of
the low noise engine.
Keywords:
Piston-liner
Lubrication
Dynamic characteristics
FEM
Runge–Kutta
Slapping noise |
مقاله انگلیسی |