Development of a Test Rig for Multi-Axial Static and Dynamic Loading of Bearings

2011 ◽  
Author(s):  
William Jacobs ◽  
Marco Malago´ ◽  
Rene Boonen ◽  
Paul Sas ◽  
David Moens
Keyword(s):  
Condition Monitoring ◽  
Outer Diameter ◽  
Dynamic Force ◽  
Test Results ◽  
Test Rig ◽  
Major Research ◽  
Different Types ◽  
Inner Diameter ◽  
Static And Dynamic Loading ◽  
Real Machine

Condition monitoring of bearings has been a major research topic for more than five decades. To validate and improve the condition monitoring techniques, this paper focuses on the development of an innovative and versatile bearing test rig. The rig allows applying a fully controlled multi-axial static and dynamic load on different types and sizes of bearings. Easy adjustment to mount bearings with different inner diameter, outer diameter and width is possible, without compromising on performance. Furthermore, the behaviour of the bearing is monitored by accelerometers, proximity probes and thermocouples. During the design of the rig, several techniques were applied to ensure clean measurements, with maximum repeatability, and to reduce errors due to temperature variations. Finally, introducing an additional dynamic force on the bearing makes it possible to load the bearing as if it were built into a real machine, for example a gearbox. At the time this paper is written, results of the test rig were not yet available. However, the authors expect to be able to report on the first test results during the conference.

Experimental Evaluation of Evaporative Cooler Using Agro Materials

2015 ◽  
Vol 23 (04) ◽  
pp. 1550028 ◽  
Author(s):  
R. Ramkumar ◽  
M. Kesavan ◽  
A. Ragupathy
Keyword(s):  
Ambient Condition ◽  
Experimental Results ◽  
Test Results ◽  
Test Rig ◽  
Air Velocity ◽  
Different Types ◽  
Saturation Efficiency ◽  
Evaporative Cooler ◽  
Luffa Sponge ◽  
Efficiency Improve

The purpose of the study is to investigate the direct evaporate cooler in hot and humid regions with two different types of agro-based materials. In our experimental study, the locally available agro materials luffa (Sponge Gourd), zizanioides (Vetiver) were used with various thickness and the experimental results were compared with mathematical values. The operating parameters of pad thickness, air velocity, were changed and the performance of the cooler was analyzed. A test rig was designed and fabricated to collect experimental data. The performance of the evaporative cooler was evaluated based on the ambient condition. The analysis of the data indicated that cooling saturation efficiency improve with decrease of air velocity and higher pad thickness. It was shown that zizanioides-based pad with 160[Formula: see text]mm thickness has the higher performance (88%) at 4.5[Formula: see text]m/s air velocity in comparison with luffa pad materials. The experimental results of outlet air temperature and number of transfer units (NTU) were compared with mathematical model. The test results were within the limit of 15% and 10% to mathematical values.

A Water Lubricated Hybrid Thrust Bearing: Measurements and Predictions of Static Load Performance

2016 ◽  
Author(s):  
Luis San Andrés ◽  
Stephen Phillips ◽  
Dara Childs
Keyword(s):  
Flow Rate ◽  
Axial Load ◽  
Static Load ◽  
Outer Side ◽  
Outer Diameter ◽  
Test Rig ◽  
Predictive Tool ◽  
Thrust Bearings ◽  
Supply Pressure ◽  
Inner Diameter

Process fluid lubricated thrust bearings (TBs) in a turbomachine control rotor placement due to axial loads arising from pressure fields on the front shroud and back surface of impellers. To date, prediction of aerodynamic induced thrust loads is still largely empirical. Thus needs persist to design and operate proven thrust bearings and to validate predictions of performance derived from often too restrictive computational tools. This paper describes a test rig for measurement of the load performance of water lubricated hydrostatic/hydrodynamic thrust bearings operating under conditions typical of cryogenic turbo pumps. The test rig comprises of a rigid rotor composed of a thick shaft and two end collars. A pair of flexure-pivot hydrostatic journal bearings (38 mm in diameter) support the rotor and quill shaft connected to a drive motor. The test rig hosts two thrust bearings (8 pockets with inner diameter equal to 41 mm and outer diameter equal to 76 mm); one is a test bearing and the other is a slave bearing, both facing the outer side of the thrust collars on the rotor. The slave TB is affixed rigidly to a bearing support. A load system delivers an axial load to the test TB through a non-rotating shaft floating on two aerostatic radial bearings. The test TB displaces to impose a load on the rotor thrust collar and the slave TB reacts to the applied axial load. The paper presents measurements of the TB operating axial clearance, flow rate and pocket pressure for conditions of increasing static load (max. 3,600 N) and shaft speed to 17.5 krpm (tip speed 69.8 m/s) and for an increasing water supply pressure into the thrust bearings, max. 17.2 bar (250 psig). Predictions from a bulk flow model that accounts for both fluid inertia and turbulence flow effects agree well with recorded bearing flow rates (supply and exiting thru the inner diameter), pocket pressure and ensuing film clearance due to the imposed external load. The measurements and predictions show a film clearance decreasing exponentially as the applied load increases. The bearing flow rate also decreases, and at the highest rotor speed and lowest supply pressure, the bearing is starved of lubricant on its inner diameter side, as predicted. The measured bearing flow rate and pocket pressure aid to the empirical estimation of the orifice discharge coefficient for use in the predictive tool. The test data and validation of a predictive tool give confidence to the integration of fluid film thrust bearings in cryogenic turbo pumps as well as in other more conventional (commercial) machinery. The USAF Upper Stage Engine Technology (USET) program funded the work during the first decade of the 21st century.

Improving Performance of an Artificial Neural Network Based Gearbox Fault Diagnosis System

2010 ◽  
Author(s):  
Ali Hajnayeb ◽  
Ahmad Ghasemloonia ◽  
Siamak Esmaeelzadeh Khadem ◽  
Mohammad Hasan Moradi
Keyword(s):  
Fault Diagnosis ◽  
Condition Monitoring ◽  
Vibration Signal ◽  
Monitoring Systems ◽  
Test Rig ◽  
Tooth Gear ◽  
Different Types ◽  
Condition Monitoring Systems ◽  
Artificial Neural ◽  
Detection Speed

The automatic vibration monitoring methods of gears and gearboxes due to their extensive applications in industry are improving. Hence, their vibration signal and its derived features, has been an interesting topic for researchers in this field. On the other hand, optimizing the number of vibration signal features used in the detection and diagnosis process is crucial for increasing the fault detection speed of automatic condition monitoring systems. In this paper, a system based on multiple layer perceptron artificial neural networks (MLP ANNs) is designed to diagnose different types of fault in a gearbox. Using a feature selection method, the system is optimized through eliminating unimportant features of vibration signals. This method is based on a simple and fast sensitivity evaluation process, which results in a considerable estimation, despite its simplicity. Consequently, the system’s speed increases, while the classification error decreases or remains constant in some other cases. An experimental test rig data set is used to verify the effectiveness and accuracy of the mentioned method. Four different types of data which are generated through the test rig setup are: no fault condition, 5% fault (5% eroded tooth) gear, 20% eroded tooth gear and the broken tooth gear. The results verify that eliminating some input features of gear vibration signal, using this method, will increase the accuracy and detection speed of gear fault diagnosis methods. The improved systems with fewer input features and higher precision, facilitates the development of online automatic condition monitoring systems.

Processing of Wrought Magnesium Alloys to Produce Small Tubes for Biomedical Applications: Investigation about the Extrusion Process by a Laboratory Test Rig

2011 ◽  
Vol 491 ◽  
pp. 75-80
Author(s):  
Qiang Ge ◽  
Maurizio Vedani
Keyword(s):  
Biomedical Applications ◽  
Hot Extrusion ◽  
Extrusion Process ◽  
Grain Structure ◽  
Outer Diameter ◽  
Test Rig ◽  
Inner Diameter ◽  
Ebsd Technique ◽  
Equiaxed Grain ◽  
Basal Type

Two commercial ZM21 and AZ31B alloys were extruded into small-size tubes at 410°C and strain rate 2.78·10-3 s-1 by a laboratory hot-extrusion system. The series of tubes, with outer diameter in the range of 8-4 mm and inner diameter from 6 to 3 mm were investigated considering microstructure and texture analysis. The tubes featured a homogeneous and refined equiaxed grain structure since dynamic recrystallization was clearly observed during the extrusion process. A typical ‘basal’ type texture was detected in extruded tubes by using EBSD technique.

A Water-Lubricated Hybrid Thrust Bearing: Measurements and Predictions of Static Load Performance

2016 ◽  
Vol 139 (2) ◽  
Author(s):  
Luis San Andrés ◽  
Stephen Phillips ◽  
Dara Childs
Keyword(s):  
Flow Rate ◽  
Axial Load ◽  
Static Load ◽  
Back Surface ◽  
Outer Side ◽  
Outer Diameter ◽  
Test Rig ◽  
Predictive Tool ◽  
Supply Pressure ◽  
Inner Diameter

Process fluid-lubricated thrust bearings (TBs) in a turbomachine control rotor placement due to axial loads arising from pressure fields on the front shroud and back surface of impellers. To date, prediction of aerodynamic-induced thrust loads is still largely empirical. Thus, needs persist to design and operate proven TBs and to validate predictions of performance derived from often too restrictive computational tools. This paper describes a test rig for measurement of the load performance of water-lubricated hydrostatic/hydrodynamic TBs operating under conditions typical of cryogenic turbo pumps (TPs). The test rig comprises of a rigid rotor composed of a thick shaft and two end collars. A pair of flexure-pivot hydrostatic journal bearings (38 mm in diameter) supports the rotor and quill shaft connected to a drive motor. The test rig hosts two TBs (eight pockets with inner diameter equal to 41 mm and outer diameter equal to 76 mm); one is a test bearing and the other is a slave bearing, both facing the outer side of the thrust collars on the rotor. The slave TB is affixed rigidly to a bearing support. A load system delivers an axial load to the test TB through a nonrotating shaft floating on two aerostatic radial bearings. The test TB displaces to impose a load on the rotor thrust collar, and the slave TB reacts to the applied axial load. The paper presents measurements of the TB operating axial clearance, flow rate, and pocket pressure for conditions of increasing static load (max. 3600 N) and shaft speed to 17.5 krpm (tip speed 69.8 m/s) and for an increasing water supply pressure into the TBs, max. 17.2 bar (250 psig). Predictions from a bulk flow model that accounts for both fluid inertia and turbulence flow effects agree well with recorded bearing flow rates (supply and exiting through the inner diameter), pocket pressure, and ensuing film clearance due to the imposed external load. The measurements and predictions show a film clearance decreasing exponentially as the applied load increases. The bearing flow rate also decreases, and at the highest rotor speed and lowest supply pressure, the bearing is starved of lubricant on its inner diameter side, as predicted. The measured bearing flow rate and pocket pressure aid to the empirical estimation of the orifice discharge coefficient for use in the predictive tool. The test data and validation of a predictive tool give confidence to the integration of fluid film TBs in cryogenic TPs as well as in other more conventional (commercial) machinery. The USAF Upper Stage Engine Technology (USET) program funded the work during the first decade of the 21st century.

scholarly journals Investigation of the Influence of Non-Flatness and Runout of Friction Discs on the Service Life of Machine Clutches

2021 ◽  
Vol 24 (4) ◽  
pp. 45-53
Author(s):  
B.A. Gupalov ◽  
V.V. Zakuraev ◽  
V.Sh. Petrenko
Keyword(s):  
Service Life ◽  
Test Bench ◽  
Flat Surface ◽  
Combined Loading ◽  
Outer Diameter ◽  
Test Results ◽  
Sliding Speed ◽  
Inner Diameter ◽  
Alternating Bending ◽  
Elastic Characteristics

In the manufacture of discs, it is important not only to ensure their specified geometric accuracy and correct shape, but to maintain geometric parameters during operation. The method of testing disks on the IKS-T inertial test bench is described. The main units of the test bench and the loading parameters of the disks are indicated. Research has been carried out on the influence of the runout and non-flatness of friction discs on the service life of the clutches. Bench tests made it possible to determine the optimal runout range of discs up to 0.8 mm, which ensures an increase in the reliability of the clutches by 30 % due to a decrease in the wear of the friction discs. In addition, the test results show that with a decrease in non-flatness from 1.2 mm to 0.3 mm, the service life of the friction discs increases by 16 %, i.e. wear of discs in the running-in mode with distortions in geometry occurs more intensively than for discs with a flat surface. With an out-of-flatness value of 0.3 mm, the discs acquire improved elastic characteristics. It was possible to determine that increased values of disc wear are observed mainly along the outer diameter, due to the runout and higher sliding speed compared to the sliding speed on the inner diameter. Calculated dependences of the limiting number of loading cycles on the beating and non-flatness of discs are presented. It was found that when testing discs with the non-flatness less than 0.3 mm, disc wear appears with the formation of “poppet” disc shape. For the purpose of imparting the correct shape to the products with the exclusion of “poppet” discs, a dynamic straightening with combined loading is proposed. The resulting calculated dependencies will be used in the design of industrial universal installations for cyclic alternating bending of friction discs.

Experimental investigation on time-domain features in the diagnosis of rolling element bearings by acoustic emission

2021 ◽  
pp. 107754632110161
Author(s):  
Aref Aasi ◽  
Ramtin Tabatabaei ◽  
Erfan Aasi ◽  
Seyed Mohammad Jafari
Keyword(s):  
Acoustic Emission ◽  
Condition Monitoring ◽  
Time Domain ◽  
Central Moment ◽  
Rolling Element Bearings ◽  
Test Rig ◽  
Acoustic Emission Sensor ◽  
Outer Race ◽  
Common Time ◽  
Rolling Element

Inspired by previous achievements, different time-domain features for diagnosis of rolling element bearings are investigated in this study. An experimental test rig is prepared for condition monitoring of angular contact bearing by using an acoustic emission sensor for this purpose. The acoustic emission signals are acquired from defective bearing, and the sensor takes signals from defects on the inner or outer race of the bearing. By studying the literature works, different domains of features are classified, and the most common time-domain features are selected for condition monitoring. The considered features are calculated for obtained signals with different loadings, speeds, and sizes of defects on the inner and outer race of the bearing. Our results indicate that the clearance, sixth central moment, impulse, kurtosis, and crest factors are appropriate features for diagnosis purposes. Moreover, our results show that the clearance factor for small defects and sixth central moment for large defects are promising for defect diagnosis on rolling element bearings.

scholarly journals Morphological Changes in Lamellar Macular Holes According to SD-OCT Examination over a Long Observation Period

Diagnostics ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1145
Author(s):  
Magdalena Kal ◽  
Izabela Chojnowska-Ćwiąkała ◽  
Mateusz Winiarczyk ◽  
Monika Jasielska ◽  
Jerzy Mackiewicz
Keyword(s):  
Retinal Thickness ◽  
Morphological Changes ◽  
Outer Diameter ◽  
Corrected Visual Acuity ◽  
Macular Holes ◽  
Kolmogorov Smirnov ◽  
Inner Diameter ◽  
Observation Period ◽  
Sd Oct

Background: The aim of this study was to evaluate the quantitative morphological changes in lamellar macular holes (LMHs) based on SD-OCT examinations and to assess the correlations among minimal retinal thickness (MRT), reading vision (RV), and best corrected visual acuity (BCVA) over a 36-month follow-up period. Methods: A group of 40 patients (44 eyes) with LMH was evaluated, with an average age of 69.87 (SD = 10.14). The quantitative parameters monitored in the follow-up period (at 0, 3, 6, 12, 18, 24, 30, and 36 months) were tested for normality of distribution by Shapiro–Wilk and Kolmogorov–Smirnov tests. Results: The RV and BCVA values were stable, and no significant changes were found at any of the check-ups during the 36-month follow-up period (BCVA p = 0.435 and RV p = 0.0999). The analysis of individual quantitative LMH parameters during the 36-month follow-up period did not demonstrate statistically significant differences: MRT (p = 0.461), Max RT temporal (p = 0.051), Max RT nasal (p = 0.364), inner diameter (ID) (p = 0.089), and outer diameter (OD) (p = 0.985). Conclusions: The observations at 0, 6, 12, 18, 24, 30, and 36 months revealed moderate and significant correlations between RV and MRT. No significant correlation between BCVA and MRT was observed.

Influence of fully submerged permanent magnets in the evaluation of heat transfer and performance analysis of single slope glass solar still

2021 ◽  
pp. 095765092110310
Author(s):  
Ajay Kumar Kaviti ◽  
Akkala Siva Ram ◽  
Amit Kumar Thakur
Keyword(s):  
Heat Transfer ◽  
Permanent Magnets ◽  
Outer Diameter ◽  
Solar Still ◽  
Transfer Coefficients ◽  
Heat Transfer Coefficients ◽  
Inner Diameter ◽  
Evaporative Heat Transfer ◽  
And Performance ◽  
Depth Water

In this experimental study, permanent magnets with three different sizes (M-1: 32 mm inner diameter, 70 mm outer diameter and 15 mm thick, M-2: 25 mm inner diameter, 60 mm outer diameter and 10 mm thick, M-3: 22 mm inner diameter, 45 mm outer diameter and 9 mm thick) are fully submerged in the single-slope glass solar still. The performance of magnetic solar stills (MSS) with three different sizes at 2 cm depth water to ensure that magnets are fully submerged is compared with conventional solar still (CSS) at the location 17.3850°N, 78.4867°E. Tiwari model is adapted to calculate the heat transfer coefficients (HTC), internal and exergy efficiencies. MSS with M-1, M-2 and M-3 significantly enhanced the convective, radiative, and evaporative heat transfer rate for the 2 cm depth of water. This is due to the desired magnetic treatment of water, which reduces the surface tension and increases the hydrogen bonds. The MSS's total internal HTC, instantaneous efficiencies led CSS by 25.52%, 28.8%, respectively, with M-1. Having various magnetic fields due to different magnets sizes increases MSS's exergetic efficiency by 33.61% with M-1, 33.76% with M-2, and 42.25% with M-3. Cumulative yield output for MSS with M-1, M-2, and M-3 is 21.66%, 17.64%, 15.78% higher than CSS. The use of permanent magnets of different sizes in the MSS is a viable, economical and straight forward technique to enhance productivity.

scholarly journals Experimental and Numerical Investigation about Small Clearance Journal Bearings under Static Load Conditions

2020 ◽  
Vol 2020 ◽  
pp. 1-13
Author(s):  
Carlo Alberto Niccolini Marmont Du Haut Champ ◽  
Fabrizio Stefani ◽  
Paolo Silvestri
Keyword(s):  
Three Dimensional ◽  
Journal Bearings ◽  
Radial Clearance ◽  
Small Scale ◽  
Test Rig ◽  
Small Clearance ◽  
Dimensional Simulation ◽  
Dynamic Loading Conditions ◽  
Static And Dynamic Loading ◽  
Good Agreement

The aim of the present research is to characterize both experimentally and numerically journal bearings with low radial clearances for rotors in small-scale applications (e.g., microgas turbines); their diameter is in the order of ten millimetres, leading to very small dimensional clearances when the typical relative ones (order of 1/1000) are employed; investigating this particular class of journal bearings under static and dynamic loading conditions represents something unexplored. To this goal, a suitable test rig was designed and the performance of its bearings was investigated under steady load. For the sake of comparison, numerical simulations of the lubrication were also performed by means of a simplified model. The original test rig adopted is a commercial rotor kit (RK), but substantial modifications were carried out in order to allow significant measurements. Indeed, the relative radial clearance of RK4 RK bearings is about 2/100, while it is around 1/1000 in industrial bearings. Therefore, the same original RK bearings are employed in this new test rig, but a new shaft was designed to reduce their original clearance. The new custom shaft allows to study bearing behaviour for different clearances, since it is equipped with interchangeable journals. Experimental data obtained by this test rig are then compared with further results of more sophisticated simulations. They were carried out by means of an in-house developed finite element (FEM) code, suitable for thermoelasto-hydrodynamic (TEHD) analysis of journal bearings both in static and dynamic conditions. In this paper, bearing static performances are studied to assess the reliability of the experimental journal location predictions by comparing them with the ones coming from already validated numerical codes. Such comparisons are presented both for large and small clearance bearings of original and modified RKs, respectively. Good agreement is found only for the modified RK equipped with small clearance bearings (relative radial clearance 8/1000), as expected. In comparison with two-dimensional lubrication analysis, three-dimensional simulation improves prediction of journal location and correlation with experimental results.

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