Optimisation of grease application to railway tracks

Trackside lubricators are designed to deliver grease to passing wheel flanges to reduce wheel and rail wear on curves. Ensuring that they are set up to deliver sufficient grease for the range of vehicles passing a site can be a challenge. For example, vehicle dynamics modelling and site investigations have shown that the wheels of passenger vehicles do not run as close to the rail face as those of freight vehicles, meaning that they are less likely to contact the grease and lubricate subsequent curves. To investigate the effects of different trackside devices, and the influence of parameters governing grease pickup, including lateral wheel displacement and pump durations, a bespoke test rig was built at the University of Sheffield. The rig used a scaled wheel, a short section of rail and a modern trackside lubricator set-up. Experiments involving different lateral wheel displacements and pumping durations were carried out, in addition to the visualisation of the size of the grease bulb. This showed how a grease bulb grows. It also indicated that a worn profile is likely to require greater wheel displacement to make contact with grease bulbs when compared to a new wheel profile. The experimental results showed that increasing pickup of grease can be expected when an additional component called a GreaseGuide™ was fitted to a regular grease delivery unit (GDU) on the rail. The efficiency of grease pickup was investigated, and test results exploring increasing pump durations have indicated a relationship between pickup and bulb size. To validate the use of the scaled rig, similar tests were carried out using a full-scale test rig. The full-scale results were compared to the experimental results of the scaled wheel rig. This showed that whilst there were differences between the two test rigs in absolute values and anomalous results, overall trends were the same on both test scales. The effect of temperature on bulb size and pumpability of grease was also investigated. This work can be extended further by using the same method to investigate other parameters that affect the lubrication of curves. This can lead to optimised lubricator set-up to ensure that the track is fully lubricated all the time.

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Experimental Dynamic Analysis on a T100 Microturbine Connected With Different Volume Sizes

Journal of Engineering for Gas Turbines and Power ◽

10.1115/1.4037754 ◽

2017 ◽

Vol 140 (2) ◽

Cited By ~ 9

Author(s):

M. L. Ferrari ◽

P. Silvestri ◽

M. Pascenti ◽

F. Reggio ◽

A. F. Massardo

Keyword(s):

Experimental Results ◽

Test Rig ◽

Large Size ◽

Amplitude Increase ◽

External Component ◽

Compressor Map ◽

Advanced Cycles ◽

Valve Operation ◽

The University ◽

Volume Size

This paper shows experimental results obtained from a T100 microturbine connected with different volume sizes. The activity was carried out with the test rig developed at the University of Genoa for hybrid system emulation. However, these results apply to all the advanced cycles where a microturbine is connected with an additional external component responsible for volume size increase. Even if the tests were performed with a microturbine, similar analyses can be extended to large size turbines. A modular vessel was used to perform and to compare the tests with different volume sizes. To highlight the volume size effect, preliminary experimental results were carried out considering the transient response due to an on/off bleed valve operation. So, the main differences between system parameters obtained for a bleed line closing operation are compared considering three different volume sizes. The main results reported in this paper are related to surge operations. To produce surge conditions in this test rig, a valve operating in the main air path was closed to generate unstable behavior for the three different volume sizes. Particular focus was devoted to the operational curve plotted on the compressor map. The vibration frequency analysis showed significant amplitude increase not only during surge events but also close to the unstable condition. In details, possible surge precursor indicators were obtained to be used for the detection of risky machine operations. The experimental data collected during these tests are analyzed with the objective of designing control systems to prevent surge conditions.

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Communication as a moral vocation: Safe space and freedom of speech

The Sociological Review ◽

10.1177/0038026119854857 ◽

2019 ◽

Vol 68 (1) ◽

pp. 3-16

Author(s):

David W. Hill

Keyword(s):

Emmanuel Levinas ◽

Cultural Theory ◽

Max Weber ◽

Judith Butler ◽

Freedom Of Speech ◽

Safe Spaces ◽

Liberal Democratic ◽

Set Up ◽

A Site ◽

The University

The use of safe spaces in universities has become increasingly controversial over the last few years. Safe spaces are set up to offer an environment in which marginalised identities and hidden experiences can be given a voice, allowing for acceptance and affirmation. Their critics charge that they are at odds with the university as a site of debate; that their use has a chilling effect on free speech; and even that safe spaces are harmful to liberal democratic society itself. This article draws on social and cultural theory in order to counter these attacks on safe spaces. Working with Max Weber, Judith Butler and Emmanuel Levinas, the first section introduces the idea of communication as a moral vocation, calling for greater recognition of the need to balance the universal (freedom of speech) with a responsibility to hear voices that are not already amplified. Building on this, and drawing additionally on Jacques Derrida and Sara Ahmed, the second section introduces the idea of debate fetishism, which serves to negate the moral function of communication, naturalise the dominance of privileged voices, and neutralise the struggles of the struggling to be heard. It is concluded that safe spaces pose no threat to freedom of speech but that the stigmatisation of their use acts to further disadvantage underrepresented identities.

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Analysis of Vibration Characteristics of Magnetorheological Elastomer Sandwich Beam under Non-Homogeneous Magnetic Field

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.101-102.202 ◽

2011 ◽

Vol 101-102 ◽

pp. 202-206 ◽

Cited By ~ 4

Author(s):

Guo Liang Hu ◽

Miao Guo ◽

Wei Hua Li

Keyword(s):

Magnetic Field ◽

Natural Frequency ◽

Sandwich Beam ◽

Homogeneous Magnetic Field ◽

Experimental Results ◽

Magnetorheological Elastomer ◽

Test Rig ◽

Thin Aluminum ◽

Set Up ◽

The Magnetic Field

In this study, the MRE was manufactured, and the sandwich beam was also fabricated by treating with MRE between two thin aluminum layers. The experiment test rig was set up to investigate the vibration response of the MRE sandwich beam under non-homogeneous magnetic field. The experimental results show that the MRE sandwich beam had the capabilities of left shifting first natural frequency when the magnetic field was increased in the activated regions. It is also obvious that the first natural frequency of the MRE sandwich beam decreased as the magnetic field that applied on the beam was moved from the clamped end of the beam to the free end of the beam.

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Evaluation of Wearing Pipe for Subsea Mining With Large Particles in Slurry Transportation

Volume 6: Ocean Space Utilization ◽

10.1115/omae2015-41217 ◽

2015 ◽

Author(s):

Satoru Takano ◽

Masao Ono ◽

Sotaro Masanobu

Keyword(s):

Full Scale ◽

Small Scale ◽

Pipe Material ◽

Test Results ◽

Material Loss ◽

Large Particles ◽

Fundamental Understanding ◽

Maximum Particle ◽

Scale Test ◽

Set Up

For a fundamental understanding of pipe wear under hydraulic transportation of deep-sea mining, a small scale test is conducted because there are many restrictions in conducting a full scale test. The small scale test apparatus are set up using the pipes of about 80mm in diameter and the rocks of which maximum particle diameters are about 20mm are used. In the test, the pipe materials and the pipe inclination are changed to evaluate the differential of the amount of pipe material loss. Furthermore, the amount of the pipe material loss in full scale is estimated based on the small scale test results.

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Simulated Drilling Testing of an Active Wellbore Sealing System on a Full-Scale Test Rig

10.2118/194079-ms ◽

2019 ◽

Author(s):

Austin Johnson ◽

Jess Nichols ◽

Kareem Ameen ◽

Justin Fraczek

Keyword(s):

Full Scale ◽

Full Scale Test ◽

Test Rig ◽

Scale Test

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Effects of rotational speed on the leakage behavior, temperature increase, and swirl development of labyrinth seal in a compressor stator well

Proceedings of the Institution of Mechanical Engineers Part G Journal of Aerospace Engineering ◽

10.1177/0954410016664929 ◽

2016 ◽

Vol 231 (13) ◽

pp. 2362-2374 ◽

Cited By ~ 2

Author(s):

Gaowen Liu ◽

Xiaozhi Kong ◽

Yuxin Liu ◽

Qing Feng

Keyword(s):

Flow Characteristics ◽

Internal Flow ◽

Labyrinth Seal ◽

Swirl Flow ◽

Tip Clearance ◽

Experimental Results ◽

Test Rig ◽

Experimental Conditions ◽

Rotating Speed ◽

Set Up

The stator well in a compressor is the space between the rotor and stator inside the mainstream annulus flow. Labyrinth seals are normally used to control the internal flow in the stator well. The upstream and downstream rotating cavities of the labyrinth seal can lead to substantial temperature rise and swirl development in this region. Additionally, due to the centrifugal expansion and thermal expansion, the tip clearance of labyrinth seal changes dramatically at different rotational speeds and temperatures in the stator well. A test rig capable to establish different rotational speeds and pressure ratios was designed according to the simplified model of the labyrinth seal in a compressor stator well (one stage). The leakage flow rate and change in total temperature across the stator well were measured. This paper also contains the experimental results of swirl ratios in the outlet rotating cavity to reveal the swirl development. Special emphasis in this work lies on acquiring the working tip clearance precisely. The set up tip clearance was measured with plug gauges, while the radial displacements of labyrinth ring and stator casing were measured separately with two high precision laser distance sensors. Two-dimensional, axisymmetric swirl flow numerical simulations were performed to get a further understanding about the basic flow characteristics and to evaluate their ability to predict the experimental results. The computational results of discharge coefficient, windage heating, and swirl ratio were compared to those obtained from test rig measurements. Particularly, when calculating, the tip clearance, the inlet parameters, and the outlet parameters of numerical model at a specific rotating speed were set to be the same with the experimental conditions.

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Unbalance Compensation of a Full Scale Test Rig Designed for HTR-10GT: A Frequency-Domain Approach Based on Iterative Learning Control

Science and Technology of Nuclear Installations ◽

10.1155/2017/3126738 ◽

2017 ◽

Vol 2017 ◽

pp. 1-15 ◽

Cited By ~ 3

Author(s):

Ying He ◽

Lei Shi ◽

Zhengang Shi ◽

Zhe Sun

Keyword(s):

Frequency Domain ◽

Iterative Learning Control ◽

Learning Control ◽

Magnetic Bearing ◽

Iterative Learning ◽

Full Scale ◽

Full Scale Test ◽

Test Rig ◽

Operation Speed ◽

Scale Test

Unbalance vibrations are crucial problems in heavy rotational machinery, especially for the systems with high operation speed, like turbine machinery. For the program of 10 MW High Temperature gas-cooled Reactor with direct Gas-Turbine cycle (HTR-10GT), the rated operation speed of the turbine system is 15000 RPM which is beyond the second bending frequency. In that case, even a small residual mass will lead to large unbalance vibrations. Thus, it is of great significance to study balancing methods for the system. As the turbine rotor is designed to be suspended by active magnetic bearings (AMBs), unbalance compensation could be achieved by adequate control strategies. In the paper, unbalance compensation for the Multi-Input and Multi-Output (MIMO) active magnetic bearing (AMB) system using frequency-domain iterative learning control (ILC) is analyzed. Based on the analysis, an ILC controller for unbalance compensation of the full scale test rig, which is designed for the rotor and AMBs in HTR-10GT, is designed. Simulation results are reported which show the efficiency of the ILC controller for attenuating the unbalance vibration of the full scale test rig. This research can offer valuable design criterion for unbalance compensation of the turbine machinery in HTR-10GT.

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Calibration and validation of the dynamic response of two slab track models using data from a full-scale test rig

Engineering Structures ◽

10.1016/j.engstruct.2021.111980 ◽

2021 ◽

Vol 234 ◽

pp. 111980

Author(s):

Jannik S. Theyssen ◽

Emil Aggestam ◽

Shengyang Zhu ◽

Jens C.O. Nielsen ◽

Astrid Pieringer ◽

...

Keyword(s):

Dynamic Response ◽

Full Scale ◽

Full Scale Test ◽

Test Rig ◽

Slab Track ◽

Calibration And Validation ◽

Scale Test ◽

Using Data

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Experimental study on dynamic performance of typical nonballasted track systems using a full-scale test rig

Proceedings of the Institution of Mechanical Engineers Part F Journal of Rail and Rapid Transit ◽

10.1177/0954409716634751 ◽

2016 ◽

Vol 231 (4) ◽

pp. 470-481 ◽

Cited By ~ 10

Author(s):

Mingze Wang ◽

Chengbiao Cai ◽

Shengyang Zhu ◽

Wanming Zhai

Keyword(s):

Experimental Study ◽

Dynamic Stiffness ◽

Dynamic Performance ◽

Full Scale ◽

Damping Coefficient ◽

Full Scale Test ◽

Test Rig ◽

Scale Test ◽

Stiffness And Damping Coefficient ◽

Stiffness And Damping

This paper presents an experimental study on dynamic performance of China Railway Track System (CRTS) series track systems using a full-scale test rig. The test rig has been constructed based on 55.17 m long full-scale nonballasted tracks composed of four typical CRTS track elements in high-speed railways. First, the dynamic characteristics of different nonballasted tracks are investigated by conducting wheel-drop tests, where a wheel-drop testing vehicle with a dropping wheelset is devised to provide the wheel-drop load. The vibration levels of different track systems are assessed by the root-mean-square acceleration per one-third octave band, and the vibration transmission characteristics of the CRTS series tracks are evaluated by transfer functions. Further, a mathematical track model is used to extract the dynamic stiffness and damping coefficient of the four types of nonballasted track systems based on the wheel–rail impact response. The vibration characteristics, the dynamic stiffness, and damping coefficient of different nonballasted track systems under various wheel-drop heights are compared and discussed in detail.

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