scholarly journals Evaluation of static and dynamic characteristics of hydrodynamic spiral-grooved journal bearings using the CFD

2019 ◽  
Vol 39 (2) ◽  
pp. 197-204
Author(s):  
Janardhan Chander Matlapudi ◽  
Prudhvi Kanth Gunti ◽  
Datta Sriram Sigatapu ◽  
Niranjana Behera
Keyword(s):  
Cross Sections ◽  
Carrying Capacity ◽  
Journal Bearing ◽  
Journal Bearings ◽  
Load Carrying Capacity ◽  
Load Carrying ◽  
Rotor Surface ◽  
Computational Fluid Dynamics Cfd ◽  
Predicted Values ◽  
Stiffness And Damping

Performance of plain journal bearings can be different by inserting inserting grooves of different cross-sections either on the journal or a bearing surface. This paper presents the prediction of load carrying capacity, stiffness, and damping coefficients of spiral-grooved bearing using the Computational Fluid dynamics (CFD) technique. The spiral grooves have been provided on the rotor surface. The error between the predicted values of these parameters using the CFD and the experimental value is low. A comparative analysis of performance has also been carried out between a grooved journal bearing and a plain journal bearing. The load carrying capacity of plain journal bearing is high when compared to spiral grooved journal bearing. At higher eccentrcity ratios, stability of a spiral-grooved journal bearing is comparatively better than a plain bearing.

Load-Carrying Capacity Analysis for Sinusoidal Surfaces Hydrodynamic Bearing

2011 ◽  
Vol 295-297 ◽  
pp. 1244-1250
Author(s):  
Jian Xi Yang ◽  
Fa Yu Zhang ◽  
Jian Ting Liu ◽  
Jian Fang Zhou
Keyword(s):  
Carrying Capacity ◽  
Journal Bearing ◽  
Mathematic Model ◽  
Journal Bearings ◽  
Capacity Analysis ◽  
Load Carrying Capacity ◽  
Hydrodynamic Bearing ◽  
Load Carrying ◽  
Hydrodynamic Journal Bearing ◽  
Sinusoidal Surface

To obtain a new method to improve hydrodynamic bearing carrying capacity, hydrodynamic journal bearing’s characteristics as well as the current study direction are analyzed. According to the calculation of general cylindrical hydrodynamic journal bearing, the mathematic model for sinusoidal surface hydrodynamic bearing’s carrying capacity is established. It is used to calculate, analyze and compare these two bearings’ carrying capacity with example. The bearing, which has the characteristic of sinusoidal surface, has stronger carrying capacity than general cylindrical hydrodynamic bearing. What’s more, the improvement is more obvious when the number of waves is 3, also it has wider carrying area. Compared with other journal bearings, the journal bearing with sinusoidal surfaces has stronger carrying capacity, smaller friction moment and longer life-span. Therefore, it has extensive prospect.

Computational investigation on the performance of hydrodynamic micro-textured journal bearing lubricated with micropolar fluid using mass-conserving numerical approach

2019 ◽  
Vol 234 (8) ◽  
pp. 1310-1331
Author(s):  
Belkacem Manser ◽  
Idir Belaidi ◽  
Sofiane Khelladi ◽  
Mohamed A Ait Chikh ◽  
Michael Deligant ◽  
...  
Keyword(s):  
Carrying Capacity ◽  
Micropolar Fluid ◽  
Journal Bearing ◽  
Load Capacity ◽  
Journal Bearings ◽  
Combined Effects ◽  
Load Carrying Capacity ◽  
Material Characteristic ◽  
Micropolar Fluids ◽  
Load Carrying

The tribological characteristic of journal bearing systems can be enhanced with the integrating of textures in the contact interfaces, or using the lubricating effect of non-Newtonian fluids. In this study, the combined effects of bearing surface texturing and non-Newtonian lubricants behavior, using micropolar fluid model, on static characteristics of hydrodynamic circular journal bearings of finite length are highlighted. The modified Reynolds equation of micropolar lubrication theory is solved using finite differences scheme and Elrod's mass conservation algorithm, taking into account the presence of the cylindrical texture shape on full and optimum bearing surfaces. The optimization textured area is carried out through particle swarm optimization algorithm, in order to increase the load lifting capacity. Preliminary results are in good agreement with the reference ones, and present an enhancement in the performances of micro-textured journal bearings (load carrying capacity and friction). The results suggest that texturing the bearing convergent zone significantly increases the load carrying capacity and reduce friction coefficient, while fully texturing causes bad performances. It is also shown that the micropolar fluids exhibit better performances for smooth journal bearings than a Newtonian fluid depending on the size of material characteristic length and the coupling number. The combined effects of fully surface textured with micropolar fluids reduce the performance of journal bearing, especially at lower eccentricity ratios. Considering the optimal arrangement of textures on the contact surface, a significant improvement in terms of load capacity and friction can be achieved, particularly at high eccentricity ratios, high material characteristic lengths and high values of the coupling numbers of micropolar fluids.

The Lubricant Flow Structure and Pressure Generation in a Journal Bearing With Diamond-Knurled Stator Surface

2007 ◽  
Author(s):  
Hongmin Li ◽  
Minel J. Braun
Keyword(s):  
Computational Models ◽  
Journal Bearing ◽  
Stokes Equations ◽  
Journal Bearings ◽  
Navier Stokes ◽  
Navier Stokes Equations ◽  
Load Carrying ◽  
Rotor Surface ◽  
Volume Algorithm ◽  
Stiffness And Damping

Journal bearings are popularly used in turbo machinery. The load carrying capacity and the dynamic behavior, stiffness and damping, of a journal bearing are determined by lubricant and bearing parameters: clearance, and shaft diameter and rotation speed, and surface morphology of the rotor and stator surfaces. It has been found that journal bearings with roughened stator surfaces have better performance. This paper presents a numerical investigation on the flow of lubricant in the knurls, in the fluid film between the rotor and the land of the stator, and the pressure generated on the rotor surface in a knurled journal bearing. Three computational models are developed and compared. The full Navier-Stokes equations are solved with a finite volume algorithm to simulate the fluid flow and the pressure generation. The total forces on the rotor surfaces are correlated to the bearing eccentricity and compared to the forces on the smooth bearing shaft of the same clearance. The effects of knurls on the bearing performance will be analyzed and guidance on further investigations on knurled journal bearing is presented.

scholarly journals Eigenproblem Versus the Load-Carrying Capacity of Hybrid Thin-Walled Columns with Open Cross-Sections in the Elastic Range

Materials ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3468
Author(s):  
Zbigniew Kolakowski ◽  
Andrzej Teter
Keyword(s):  
Cross Sections ◽  
Carrying Capacity ◽  
Ultimate Load ◽  
Equilibrium Path ◽  
Load Carrying Capacity ◽  
Nonlinear Buckling ◽  
Elastic Range ◽  
Load Carrying ◽  
Thin Walled ◽  
Ultimate Load Carrying Capacity

The phenomena that occur during compression of hybrid thin-walled columns with open cross-sections in the elastic range are discussed. Nonlinear buckling problems were solved within Koiter’s approximation theory. A multimodal approach was assumed to investigate an effect of symmetrical and anti-symmetrical buckling modes on the ultimate load-carrying capacity. Detailed simulations were carried out for freely supported columns with a C-section and a top-hat type section of medium lengths. The columns under analysis were made of two layers of isotropic materials characterized by various mechanical properties. The results attained were verified with the finite element method (FEM). The boundary conditions applied in the FEM allowed us to confirm the eigensolutions obtained within Koiter’s theory with very high accuracy. Nonlinear solutions comply within these two approaches for low and medium overloads. To trace the correctness of the solutions, the Riks algorithm, which allows for investigating unsteady paths, was used in the FEM. The results for the ultimate load-carrying capacity obtained within the FEM are higher than those attained with Koiter’s approximation method, but the leap takes place on the identical equilibrium path as the one determined from Koiter’s theory.

Analysis of Seismic Performance of RC Frames with Centrally Reinforced Columns

2013 ◽  
Vol 671-674 ◽  
pp. 1319-1323
Author(s):  
Zi Xue Lei ◽  
Yu Hang Han ◽  
San Sheng Dong ◽  
Jun Qing Guo
Keyword(s):  
Seismic Performance ◽  
Cross Sections ◽  
Carrying Capacity ◽  
Pushover Analysis ◽  
Seismic Load ◽  
Load Carrying Capacity ◽  
Rc Columns ◽  
Rc Column ◽  
Rc Frames ◽  
Load Carrying

A centrally reinforced column is a new type of RC columns, formed by providing a reinforcement skeleton at the central part of the cross section of an ordinary RC column. Tests have shown that as compared with an ordinary RC column, this type of columns has a higher load carrying capacity and ductility. From the pushover analysis of a frame composed of ordinary RC columns and one consisting of centrally reinforced columns, their seismic performance under seismic load of 9-degree intensity was studied according to Chinese code, including target displacements, story-level displacements, interstory drifts, appearance and development of plastic hinges. The results indicate that although the dimensions of cross sections of columns in the frame with centrally reinforced columns are smaller than those of the ordinary frame, the former still has a higher overall load carrying capacity and seismic performance than the latter.

scholarly journals Load carrying capacity of the eccentric joint in the truss made of open cross-sections

2018 ◽  
Vol 219 ◽  
pp. 02002
Author(s):  
Małgorzata Gordziej-Zagórowska ◽  
Elżbieta Urbańska-Galewska
Keyword(s):  
Numerical Analysis ◽  
Cross Section ◽  
Experimental Research ◽  
Cross Sections ◽  
Carrying Capacity ◽  
Load Carrying Capacity ◽  
Main Achievement ◽  
Joint Area ◽  
Load Carrying ◽  
Open Cross Section

The influence of eccentricity at intersections of truss members on the load carrying capacity of the truss joint is presented in the paper. The research truss elements were designed as cold-formed open cross section. Analytical calculations, numerical analysis and experimental research were conducted to reveal how the eccentricity affects the effort of material in the joint area. The results of analysis and investigations are compared and discussed. The main achievement of the tests carried out is statement that slender plane members of the compression chords are safe compared with the results of analytical calculations.

The Granular Lubricated Journal Bearing: Evidence of Lift Formation

2019 ◽  
Vol 141 (4) ◽  
Author(s):  
Venkata K. Jasti ◽  
Martin C. Marinack ◽  
Deepak Patil ◽  
C. Fred Higgs
Keyword(s):  
Carrying Capacity ◽  
Granular Flow ◽  
High Speed ◽  
Journal Bearing ◽  
Hydrodynamic Lubrication ◽  
Flow Behavior ◽  
Extreme Environments ◽  
Granular Flows ◽  
Load Carrying Capacity ◽  
Load Carrying

This work demonstrates that granular flows (i.e., macroscale, noncohesive spheres) entrained into an eccentrically converging gap can indeed actually exhibit lubrication behavior as prior models postulated. The physics of hydrodynamic lubrication is quite well understood and liquid lubricants perform well for conventional applications. Unfortunately, in certain cases such as high-speed and high-temperature environments, liquid lubricants break down making it impossible to establish a stable liquid film. Therefore, it has been previously proposed that granular media in sliding convergent interfaces can generate load carrying capacity, and thus, granular flow lubrication. It is a possible alternative lubrication mechanism that researchers have been exploring for extreme environments, or wheel-regolith traction, or for elucidating the spreadability of additive manufacturing materials. While the load carrying capacity of granular flows has been previously demonstrated, this work attempts to more directly uncover the hydrodynamic-like granular flow behavior in an experimental journal bearing configuration. An enlarged granular lubricated journal bearing (GLJB) setup has been developed and demonstrated. The setup was made transparent in order to visualize and video capture the granular collision activity at high resolution. In addition, a computational image processing program has been developed to process the resulting images and to noninvasively track the “lift” generated by granular flow during the journal bearing operation. The results of the lift caused by granular flow as a function of journal rotation rate are presented as well.

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