An experimental study of high-speed rotor supported by air bearings: test RIG and first experimental results

2006 ◽  
Vol 39 (8) ◽  
pp. 839-845 ◽  
Author(s):  
Guido Belforte ◽  
Terenziano Raparelli ◽  
Vladimir Viktorov ◽  
Andrea Trivella ◽  
Federico Colombo
Keyword(s):  
Experimental Study ◽  
High Speed ◽  
Experimental Results ◽  
Air Bearings ◽  
Test Rig

Experimental Study of Turbulent Macroinstabilities in an Agitated System with Axial High-Speed Impeller and with Radial Baffles

1996 ◽  
Vol 61 (6) ◽  
pp. 856-867 ◽  
Author(s):  
Oldřich Brůha ◽  
Ivan Fořt ◽  
Pavel Smolka ◽  
Milan Jahoda
Keyword(s):  
Experimental Study ◽  
Flow Field ◽  
High Speed ◽  
Experimental Results ◽  
Turbulent Regime ◽  
Frequency Of Occurrence ◽  
Visualization Method ◽  
Entire Flow

The frequency of turbulent macroinstability occurrence was measured in liquids agitated in a cylindrical baffled vessel. As it has been proved by preceding experimental results of the authors, the stochastic quantity with frequency of occurrence of 10-1 to 100 s-1 is concerned. By suitable choosing the viscosity of liquids and frequency of impeller revolutins, the region of Reynolds mixing numbers was covered from the pure laminar up to fully developed turbulent regime. In addition to the equipment making it possible to record automatically the macroinstability occurrence, also the visualization method and videorecording were employed. It enabled us to describe in more detail the form of entire flow field in the agitated system and its behaviour in connection with the macroinstability occurrence. It follows from the experiments made that under turbulent regime of flow of agitated liquids the frequency of turbulent macroinstability occurrence is the same as the frequency of the primary circulation of agitated liquid.

Experimental Study of a Variable Pressure Damper on Automotive Valve Motion

1996 ◽  
Author(s):  
Jin-Jang Liou ◽  
Grodrue Huang ◽  
Wensyang Hsu
Keyword(s):  
Experimental Study ◽  
Friction Coefficient ◽  
Friction Force ◽  
High Speed ◽  
Experimental Results ◽  
Variable Pressure ◽  
Friction Forces ◽  
Valve Spring ◽  
Valve Motion

Abstract A variable pressure damper (VPD) is used here to adjusted the friction force on the valve spring to investigate the relation between the friction force and the valve bouncing phenomenon. The friction force on the valve spring is found experimentally, and the corresponding friction coefficient is also determined. Dynamic valve displacements at different speeds with different friction forces are calibrated. Bouncing and floating of the valve are observed when the camshaft reaches high speed. From the measured valve displacement, the VPD is shown to have significant improvement in reducing valve bouncing distance and eliminating floating. However, experimental results indicate that the valve bouncing can not be eliminated completely when the camshaft speed is at 2985 rpm.

Experimental Study of Kick up Phenomenon in Thermosonic Wire-Bonding

2012 ◽  
Vol 160 ◽  
pp. 77-81
Author(s):  
Jing Jing Tian ◽  
Lei Han
Keyword(s):  
Image Processing ◽  
Experimental Study ◽  
High Speed ◽  
Gold Wire ◽  
Wire Bonding ◽  
Processing Method ◽  
Experimental Results ◽  
High Speed Camera ◽  
Depth Study ◽  
Thermosonic Wire Bonding

Kick-up phenomenon during looping is an important factor in thermosonic wire bonding. In this study, the loping process during wire bonding was recorded by using high-speed camera, and wire profiles evolution was obtained from images sequence by image processing method. With a polynomial fitting, the wire loop profiling was described by the curvature changing, and kick-up phenomenon on gold wire was found between the instant of 290th frame(0.0537s) to 380th frame (0.0703s), the change of curvature is divided into three phases, a looping phase, a mutation phase and a kick-up phase. While in the kick-up phase, the kick up phenomenon is the most obvious. These experimental results were useful for in-depth study of kick-up phenomenon by simulation.

Experimental Study on the Response Characteristics of Oilcans under High-Velocity Fragment Impact

2012 ◽  
Vol 510 ◽  
pp. 500-506
Author(s):  
Chang Hai Chen ◽  
Xi Zhu ◽  
Hai Liang Hou ◽  
Li Jun Zhang ◽  
Ting Tang
Keyword(s):  
Experimental Study ◽  
High Velocity ◽  
High Speed ◽  
Room Temperature ◽  
Experimental Results ◽  
Fuel Oil ◽  
High Speed Camera ◽  
Response Characteristics ◽  
Fuel Oils ◽  
The Impact

To explore the deflagration possibility of the warship cabin filled with fuel oil under impact of high-speed fragments in the condition of room temperature, experiments were carried out employing the small aluminium oilcans filled with fuel oil. Response processes of the oilcans were observed with the help of a high-speed camera. The disintegration as well as flying scattering of the oilcans were analyzed. The reasons for atomization of the fuel oils were presented. Finally, the deflagration possibility of warship oil cabin was analyzed. Results show that the pressure inside the oilcan is quite great under the impact of the high-speed fragment, which makes the oilcan disintegration and flying scattering. Simultaneously, fuel oils inside the oilcans are atomized quickly followed by ejected in front and back directions. Under the same condition as in present tests, deflagration will not occur for fuel oils used by warships. Experimental results will provide valuable references for the deflagration analysis of warship fuel oil cabins subjected to the impact of high-velocity fragments.

scholarly journals A Test Rig for LDV and Seeding Characterization for High Speed Turbomachinery Application: Experimental Results

2002 ◽  
Vol 8 (4) ◽  
pp. 233-242
Author(s):  
MAURIZIO LUCIA ◽  
LORENZO FERRARI ◽  
CHRISTIAN MENGONI ◽  
PIERLUIGI NAVA
Keyword(s):  
High Speed ◽  
Experimental Results ◽  
Test Rig

Wheel–rail low adhesion issues and its effect on wheel–rail material damage at high speed under different interfacial contaminations

2019 ◽  
Vol 233 (15) ◽  
pp. 5477-5490 ◽  
Author(s):  
Bing Wu ◽  
Boyang An ◽  
Zefeng Wen ◽  
Wenjian Wang ◽  
Tao Wu
Keyword(s):  
High Speed ◽  
Rolling Contact Fatigue ◽  
Contact Fatigue ◽  
Rolling Contact ◽  
Experimental Results ◽  
Test Rig ◽  
Adhesion Mechanism ◽  
Numerical Investigations ◽  
Rail Wear ◽  
Adhesion Condition

The objective of this paper is to ascertain the wheel–rail low adhesion mechanism using a high-speed wheel–rail rolling contact test rig under different interfacial contaminations. Based on the experimental results, a numerical method was proposed to investigate the wheel–rail wear and rolling contact fatigue due to low adhesion issues. The experimental results indicated that the wheel–rail low adhesion phenomena can happen under interfacial liquid contaminations, especially at high-speed running condition. Preliminary numerical investigations showed that the low adhesion condition can easily lead to sliding hence serious wear, especially at the speed between 160 km/h and 200 km/h. The temperature rise within the contact patch can be significantly more severe once wheel and rail are in full slip, causing rolling contact fatigue due to material softening.

scholarly journals A Test Rig for LDV and Seeding Characterization for High Speed Turbomachinery Application: Experimental Results

2002 ◽  
Vol 8 (4) ◽  
pp. 233-242
Author(s):  
Maurizio De Lucia ◽  
Lorenzo Ferrari ◽  
Christian P. Mengoni ◽  
Pierluigi Nava
Keyword(s):  
High Speed ◽  
Experimental Results ◽  
Test Rig

High-Speed Rotor With Air Bearings Mounted on Flexible Supports: Test Bench and Experimental Results

2008 ◽  
Vol 130 (2) ◽  
Author(s):  
G. Belforte ◽  
F. Colombo ◽  
T. Raparelli ◽  
V. Viktorov
Keyword(s):  
High Speed ◽  
Test Bench ◽  
Dynamic Stiffness ◽  
Experimental Results ◽  
Air Bearings ◽  
Stability Threshold ◽  
Air Turbine ◽  
Flexible Supports ◽  
The Stability ◽  
Rotational Response

A test bench for rotors supported by air bearings floating on O-rings is designed in order to study the whirl phenomenon and characterize the stability threshold with damping elements mounted on bearings. The work includes a description of the test bench and some preliminary experimental results. A rotor of 1kg mass and 37mm diameter is rotated up to 75,000rpm by an air turbine machined on the rotor. Capacitance probes, placed in two radial planes, allow orbit scanning of both the rotor and the bushing at different rotating speeds and suitable load devices permit measurement of the static and dynamic stiffness of the rotor-bearing system. Curves of rotational response using rubber O-rings of three different materials are shown and compared. Also presented are the Fourier spectra of the signals for rotor displacement. The phenomenon of whirl instability is shown in terms of whirl frequency and orbit amplitudes of the rotor and bearings. The effects of both supply pressure and angular velocity on the stability threshold are shown.

Analysis of Traction Behavior of the High-Speed Lubricating Grease 7007 by the Correctional T-J Model

2011 ◽  
Vol 121-126 ◽  
pp. 27-32
Author(s):  
Bo Yuan Yang ◽  
Gang Qiang Liu ◽  
Bing Su
Keyword(s):  
Experimental Data ◽  
High Speed ◽  
Traction Force ◽  
Experimental Results ◽  
Rheological Parameters ◽  
Test Rig ◽  
Lubricating Grease

The traction behavior of high-speed lubricating grease 7007 was tested on a self-made test rig. The changes of traction coefficients with velocity, temperature and load were got from the experimental results. The rheological parameters were received on the basis of experimental data. The formula of traction force of high-speed lubricating grease 7007 was based on the correctional T-J model. The result shows that the traction coefficients of high-speed lubricating grease 7007 based on correctional T-J mode agree well with the experimental data.

Experimental and Analytical Investigation of High Speed Turbocharger Ball Bearings

2011 ◽  
Vol 133 (12) ◽  
Author(s):  
Ankur Ashtekar ◽  
Farshid Sadeghi
Keyword(s):  
High Speed ◽  
Ball Bearing ◽  
Analytical Investigation ◽  
Rotor System ◽  
Operating Conditions ◽  
Experimental Results ◽  
Test Rig ◽  
Angular Contact Ball Bearing ◽  
Turbine Wheel ◽  
Bearing Dynamics

The objectives of this investigation were to design and construct a high speed turbocharger test rig (TTR) to measure dynamics of angular contact ball bearing rotor system, and to develop a coupled dynamic model for the ball bearing rotor system to corroborate the experimental and analytical results. In order to achieve the objectives of the experimental aspect of this study, a test rig was designed and developed to operate at speeds up to 70,000 rpm. The rotating components (i.e., turbine wheels) of the TTR were made to be dynamically similar to the actual turbocharger. Proximity sensors were used to record the turbine wheel displacements while accelerometers were used to monitor the rotor vibrations. The TTR was used to examine the dynamic response of the turbocharger under normal and extreme operating conditions. To achieve the objectives of analytical investigation, a discrete element ball bearing model was coupled through a set of interface points with a component mode synthesis rotor model to simulate the dynamics of the turbocharger test rig. Displacements of the rotor from the analytical model were corroborated with experimental results. The analytical and experimental results are in good agreement. The bearing rotor system model was used to examine the bearing component dynamics. Effects of preloading and imbalance were also found to have significant effects on turbocharger rotor and bearing dynamics.

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