Papers by Arvind Kumar Rajput
International Journal of Computer Applications, 2014
In the recent years the NFC with the combination of smart devices has widened the utilization ran... more In the recent years the NFC with the combination of smart devices has widened the utilization range of NFC. It is said it will replace the credit card in electronic payment so security is one of the area that is to be checked. Currently the NFC security requires user's public key with the fixed value which contain the message. The attacker can create a new profile of the user by using their public key and thus the privacy of the user is compromised. In this work, network environment can be generated using 50 nodes. User can select source and destination node and then simulation can be done on the basis of proposed algorithm. The conditional privacy protection based on multiple pseudonyms is used to solve the issues generated in NFC environment. This work is to optimize the above environment by using optimization algorithm. Genetic algorithm which is artificial intelligence based algorithm is used in this to reduce the storage requirement, average delay, packet drop ratio and improve the network's throughput.
A novel technique to compute static and dynamic performance characteristics of aerostatic thrust bearing
Industrial Lubrication and Tribology, 2018
Purpose This study aims to analyze the dynamic performance of aerostatic thrust bearing for diffe... more Purpose This study aims to analyze the dynamic performance of aerostatic thrust bearing for different geometries of recess. Different geometries of recess of equal recess area, i.e. circular, elliptical, rectangular and annular, have been considered in analysis. The work also analyzes the influence of tilt angle on the performance of thrust bearing. To compute the unknown pressure field, the Reynolds equation governing the flow of compressible lubricant (air) has been solved using finite element formulation. Further, separate finite element formulations have been carried out to compute fluid film stiffness and damping coefficients directly. This method provides quick computation of stiffness and damping coefficients of aerostatic thrust bearing than the usual approach. Design/methodology/approach As the Reynolds equation governing the flow of compressible lubricant is nonlinear partial differential equation, the computation of the stiffness and damping coefficient follows an iterati...
Proceedings of the Institution of Mechanical Engineers, Part J: Journal of Engineering Tribology, 2017
Gas bearings are extensively used in several industrial applications to support the rotating load... more Gas bearings are extensively used in several industrial applications to support the rotating load at high speed due to its favorable characteristics. The numerical computation of the gas film damping and stiffness coefficients is a difficult task due to nonlinearity in the Reynolds equation for compressible lubricant. In the present work, a numerical method based on the finite element method is developed for the direct computation of gas film damping and stiffness coefficients. In this method, a double partial differential equation approach has been used to compute the dynamic characteristics. Further, the numerical results presented shows that the bearing ellipticity ratio significantly affects the nonlinear trajectory of the journal.
Analysis of externally pressurized multirecess conical hybrid journal bearing system using micropolar lubricant
Proceedings of the Institution of Mechanical Engineers, Part J: Journal of Engineering Tribology, 2013
This article describes an analytical study to demonstrate the influence of micropolar lubricant o... more This article describes an analytical study to demonstrate the influence of micropolar lubricant on a four-pocket conical hybrid journal bearing system compensated with membrane restrictor. The modified Reynolds equation has been derived using Eringen’s theory of micropolar fluids with usual assumptions in cylindrical coordinates. The finite element modeling of the modified Reynolds equation has been made using Galerkin’s technique. The variation of bearing characteristics parameters for both Newtonian and micropolar lubricated bearings have been plotted with respect to radial load parameter for the chosen values of semi-cone angles, coupling number, characteristic length, and membrane compliance. The numerically simulated results indicate that micropolar lubricated bearing provides enhanced performance vis-à-vis Newtonian lubricated bearing.
Tribology International, 2013
The present paper theoretically describes the effect of geometric imperfections of journal on the... more The present paper theoretically describes the effect of geometric imperfections of journal on the performance of micropolar lubricated 4-pocket hybrid journal bearing. The numerically simulated results are presented for different forms of geometric irregularities of journal such as barrel shape, bellmouth shape, circumferential undulations along with the ideal shape for both the Newtonian and micropolar lubricant. The numerically simulated results clearly indicate that the geometric irregularities of journal significantly affect the performance of the bearing system. The deterioration in bearing performance due to geometric irregularities can be compensated partially by proper choice of lubricant (Newtonian/micropolar) and type of compensating device.
A study of capillary-compensated geometrically imperfect six-pocket hybrid journal bearing of various geometric shapes of recess
Proceedings of the Institution of Mechanical Engineers, Part J: Journal of Engineering Tribology, 2013
The present paper deals with the theoretical study of geometric imperfections of journal and its ... more The present paper deals with the theoretical study of geometric imperfections of journal and its influence on the performance of capillary-compensated six-pocket hybrid journal bearing configurations with different geometric shapes of recess. The analysis includes the geometric imperfections of journal such as barrel shape, bellmouth shape, and circumferential undulations and various geometric shapes of recess (square, circular, elliptical, triangular) of same pocket area. The governing Reynolds equation is solved using Galerkin’s technique. The numerically simulated results indicate that the selection of suitable geometric shape of recess is important to have the least influence of different geometric imperfections of journal on the bearing performance.
Stability of a constant flow valve compensated multi-recess conical hybrid journal bearing operating with micropolar lubricant
Lubrication Science, 2014
The present paper investigates the influence of micropolar lubrication on the stability of a cons... more The present paper investigates the influence of micropolar lubrication on the stability of a constant flow valve compensated multi‐recess conical hybrid journal bearing system. Eringen's micropolar fluid theory has been used to model the micropolar lubrication in a fluid‐film bearing system. The modified Reynolds equation of the micropolar lubricated bearing system has been solved using finite element method. Performance characteristics parameters of four pocket hybrid journal bearing system have been computed for the values of semi‐cone angle 10°, 20° and for the judiciously selected micropolar parameters. Numerically simulated results indicate that the value of stability threshold speed margin gets increased substantially with the use of micropolar lubricant vis‐à‐vis Newtonian lubricant. Copyright © 2014 John Wiley & Sons, Ltd.
Advances in Tribology, 2012
The present paper deals with a theoretical analysis of 4-pocket capillary compensated conical hyb... more The present paper deals with a theoretical analysis of 4-pocket capillary compensated conical hybrid journal bearing system operating with micropolar lubricant. The modified Reynolds equation for a conical journal bearing system operating with micropolar lubricant has been derived. In the present study, Eringen's micropolar theory has been used to model micropolar lubrication in cylindrical coordinate system. The study has been carried out for the different values of micropolar parameters, that is, characteristic length (l) and coupling number (N). The conical bearing configurations having semicone angle 10 • , 20 • , 30 • , and 40 • have been studied. The study suggests that micropolar lubricant offers better performance vis-á-vis Newtonian lubricant for bearing configurations having values of semicone angle 10 • and 20 • .
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Papers by Arvind Kumar Rajput