An experimental investigation of hydrodynamic damping due to vertical baffle arrangements in a rectangular tank

2007 ◽  
Vol 221 (3) ◽  
pp. 115-123 ◽  
Author(s):  
M F Younes ◽  
Y K Younes ◽  
M El-Madah ◽  
I M Ibrahim ◽  
E H El-Dannanh
Keyword(s):  
Damping Ratio ◽  
Small Scale ◽  
Test Rig ◽  
Transient Responses ◽  
Hydrodynamic Damping ◽  
Liquid Slosh ◽  
Liquid Free Surface ◽  
Rectangular Tank ◽  
Scale Test ◽  
Vertical Baffle

The present work is concerned with an experimental study of the hydrodynamic damping provided by using vertical baffles in partially filled rectangular tanks. The damping ratio is evaluated for different vertical baffle dimensions, shapes, numbers, and arrangements. A small-scale test rig consisting of a partially filled rectangular tank with a pendulum suspension is designed and constructed to measure the transient responses of the system. The baffles are fitted to attenuate the lateral motion of the liquid slosh. Lower mounted and upper mounted vertical baffles of different heights and numbers are tested. Lower mounted vertical baffles with holes of different sizes and numbers are considered. Finally, the effect of a combination between upper, lower, and holed vertical baffles on the system damping is investigated. The results show that the size and location of the vertical baffles significantly influence the hydrodynamic damping. In general, the damping ratio increases as the tip of the lower mounted baffle plate is close to the liquid free surface and the location of the plate is close to the centre of the tank. Increasing the baffle numbers increases the damping ratio. The upper mounted vertical baffles are more suitable for a chargeable tank. The twin side upper mounted baffles and centre-holed lower mounted baffle arrangements give a maximum damping ratio.

Investigation on the Turbine Blade Tip Clearance Monitoring Based on Eddy Current Pulse-Trigger Method

2016 ◽  
Author(s):  
Weimin Wang ◽  
Huajin Shao ◽  
Lifang Chen ◽  
Huibin Song
Keyword(s):  
Turbine Blade ◽  
Eddy Current ◽  
Tip Clearance ◽  
Small Scale ◽  
Test Rig ◽  
Rotating Speed ◽  
Laboratory Setup ◽  
Blade Tip ◽  
Scale Test ◽  
Blade Tip Clearance

The efficiency and reliability of turbomachinery will be improved by blade tip clearance (BTC) and blade tip timing (BTT) monitoring. Several types of sensors such as eddy-current, capacitance and optical probes are used to realize this objective. Eddy current sensor (ECS) is an ideal choice with its advantage of durablity and that it is unaffected by gas stream properties such as contamination, water vapor, and moisture. However, the bandwidth of ECS is usually less than 100 kHz, which will limit the resolution of the monitoring result. In this paper, a pulse-trigger technology based BTC method was presented. This method optimizes the static radial and circumferential calibration technology to obtain the sensitivity of the ECS in the different relative locations against the tip of blade. The information from the clearance sensor will be fused with that from the once per revolution (OPR) or key phase sensor. The method is more generally applicable in the condition where the ECS is insufficient sampling caused by the limit of narrow bandwidth, especially under the high blade tip velocity condition. A small scale and larger scale BTC measurement rig are established to validate the feasibility of this method. The small one is easy to calibrate with high accuracy and can be used to illustrate the performance of the method, while the larger scale test rig is close to real industry turbine blade. In this apparatus, the axial displacement and radial displacement of rotor vibration as well as the clearance can be monitored together so that further investigation can be conducted. Experimental research was carried out on both test rig at different rotating speed. The results show that the method presented in this paper can improve the accuracy of tip clearance monitored by ECS very well. Furthermore, this work is a proof-of-concept demonstration using a laboratory setup providing the basis for BTC active control and blade health monitoring (BHM) based on ECS.

Modal Analysis of Linear Guide Way Junction Surface

2013 ◽  
Vol 380-384 ◽  
pp. 105-108
Author(s):  
Sheng Le Ren ◽  
Tian Yu Cheng ◽  
Ye Dai
Keyword(s):  
Damping Ratio ◽  
Dynamic Performance ◽  
Surface Characteristics ◽  
Test Method ◽  
Joint Surface ◽  
Small Scale ◽  
Static Stiffness ◽  
Element Analysis ◽  
Scale Test ◽  
The Many

Rails is an affordable, fixed, direct the mobile device. Among the many factors that affect performance, the rail surface is a very important factor. This article use test method gets the static stiffness of joint surface and the top five bands of the natural frequency and damping ratio for small linear guides. Test access to the static stiffness will be important in finite element analysis of input parameters. In the course of the study, analysis of dynamic performance of small - scale test guide, Study on Effect of surface characteristics on the structure of the component. By comparing the small guide the results of the analysis and the experimental results to verify the validity and accuracy of the analysis method.

scholarly journals Modeling a Small-Scale Test Rig of Quarter Car Railway Vehicle Suspension System

2015 ◽  
Vol 2 (4) ◽  
pp. 149-153 ◽  
Author(s):  
Iqbal M. Ahmed ◽  
◽  
Md. Yusof Hazlina ◽  
M. M. Rashid ◽  
◽  
...  
Keyword(s):  
Suspension System ◽  
Vehicle Suspension ◽  
Railway Vehicle ◽  
Small Scale ◽  
Test Rig ◽  
Scale Test ◽  
Quarter Car ◽  
Vehicle Suspension System

The Frictional Stability of Wet Clutch Friction Materials Investigated on a Small Scale Test-Rig

2005 ◽  
Author(s):  
W. Ost ◽  
P. De Baets
Keyword(s):  
Relative Velocity ◽  
Normal Load ◽  
Wear Testing ◽  
Small Scale ◽  
Mechanical Parameters ◽  
Test Rig ◽  
Friction Materials ◽  
Wet Clutch ◽  
Friction Clutch ◽  
Scale Test

The work presented in this paper is part of a European project (COST 532, project E2) to study clutch shudder and its influences, together with wear testing of clutch materials. The relation between the friction force and the relative velocity, and the dynamics thereof are investigated for typical wet clutch materials (oil lubricated paper/steel contact) on a small scale test rig, using a ground and polished steel ring onto which a coupon from a friction clutch plate was slid. The results clearly show that although momentarily the relative velocity of the sliders vs. the rotating ring reaches zero, no stick episode ensues. The mechanical parameters (stiffness, damping and normal load) of the test-rig were varied and the influence thereupon on the friction during sliding was investigated.

Study of Multiaspect and Multistatic Sonar Systems Using a Small-Scale Test Bed

2010 ◽  
Author(s):  
Jon La Follett ◽  
John Stroud ◽  
Pat Malvoso ◽  
Joseph Lopes ◽  
Raymond Lim ◽  
...  
Keyword(s):  
Small Scale ◽  
Test Bed ◽  
Sonar Systems ◽  
Scale Test

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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