Condition monitoring of mechanical seals: Detection of film collapse using reflected ultrasonic waves

2000 ◽  
Vol 214 (9) ◽  
pp. 1187-1194 ◽  
Author(s):  
D Anderson ◽  
J Jarzynski ◽  
R. F. Salant
Keyword(s):  
Steady State ◽  
Piezoelectric Transducer ◽  
Ultrasonic Waves ◽  
Mechanical Seal ◽  
Mechanical Seals ◽  
Reflected Waves ◽  
Bench Tests ◽  
State Tests ◽  
Lubricating Film ◽  
Film Collapse

A method for detecting the collapse of the lubricating film in a mechanical seal has been developed. A piezoelectric transducer is placed behind the non-rotating seal face and is used to generate ultrasonic waves, which propagate towards the interface between the two seal faces. The same transducer is used to detect the reflected waves, whose amplitude is a measure of the degree of contact between the faces. The results of bench tests, steady-state tests and transient tests show that the method is effective.

Ultrasonic Detection of Lubricating Film Collapse in Mechanical Seals

1999 ◽  
Vol 42 (4) ◽  
pp. 801-806 ◽  
Author(s):  
William Anderson ◽  
Richard F. Salant ◽  
Jacek Jarzynski
Keyword(s):  
Mechanical Seals ◽  
Ultrasonic Detection ◽  
Lubricating Film ◽  
Film Collapse

Pitfalls for Accurate Steady-State Port Flow Simulations

2012 ◽  
Author(s):  
Xiaofeng Yang ◽  
Zhaohui Chen ◽  
Tang-Wei Kuo
Keyword(s):  
Steady State ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Measured Data ◽  
Steady State Flow ◽  
Bench Tests ◽  
Flow Simulations ◽  
Mesh Topology ◽  
State Flow

Steady-state port flow simulations were carried out with a commercial three dimensional (3D) Computational Fluid Dynamics (CFD) code using Cartesian mesh with cut cells to study the prediction accuracy. The accuracy is assessed by comparing predicted and measured mass-flow rate and swirl and tumble torques at various valve lifts using different boundary condition setup and mesh topology relative to port orientation. The measured data is taken from standard steady-state flow bench tests of a production intake port. The predicted mass-flow rates agree to within 1% with the measured data between the intermediate and high valve lifts. At low valve lifts, slight over prediction in mass-flow rate can be observed. The predicted swirl and tumble torques are within 25% of the flow bench measurements. Several meshing parameters were examined in this study. These include: inlet plenum shape and outlet plenum/extension size, embedded sphere with varying minimum mesh size, finer meshes on port and valve surface, orientation of valve and port centerline relative to the mesh lines. For all model orientations examined, only the mesh topology with the valve axis aligned closely with the mesh lines can capture the mass-flow rate drop for very high valve lifts due to flow separation. This study further demonstrated that it is possible to perform 3D CFD flow analyses to adequately simulate steady-state flow bench tests.

Research on Feature Extraction Method Based on Rub-Impact Acoustic Emission Signals of Mechanical Seal End Faces

2010 ◽  
Vol 36 ◽  
pp. 68-74
Author(s):  
Chuan Jun Liao ◽  
Shuang Fu Suo ◽  
Wei Feng Huang
Keyword(s):  
Acoustic Emission ◽  
Feature Extraction ◽  
Extraction Methods ◽  
Mechanical Seal ◽  
Mechanical Seals ◽  
Feature Extraction Method ◽  
Different Types ◽  
Ae Signal ◽  
Feature Information ◽  
Ae Signals

Acoustic emission (AE) techniques are put forward to monitor rub-impacts between rotating rings and stationary rings of mechanical seals by this paper. By analyzing feature extraction methods of the typical rub-impact AE signal, the method combining of wavelet scalogram and power spectrum is found useful, and can used to attribute the feature information implicated in rub-impact AE signals of mechanical seal end faces. Both simulations and experimental research prove that the method is effective, and are used successfully to identify the typical features of different types of rub-impacts of mechanical seal end faces.

scholarly journals System Approach from Biomass Combustion in Packed Bed Reactor

2007 ◽  
Vol 7 (1 & 2) ◽  
pp. 16 ◽  
Author(s):  
Anhkien Le ◽  
Le Xuan Hai ◽  
V. N. Sharifi ◽  
J. Swithenbank
Keyword(s):  
Steady State ◽  
Transition Period ◽  
Computing Time ◽  
Substrate Inhibition ◽  
Simple Algorithm ◽  
Packed Bed ◽  
Packed Bed Reactor ◽  
Biomass Combustion ◽  
Stable Steady State ◽  
State Tests

A simple algorithm originally proposed by Choong, Paterson and Scott (2002) was tested on a model of an isothermal controlled-cycled stirred tank reactor with substrate inhibition kinetics, (r = 1 ~c). In previous work, this reacting system had been shown to exhibit steady-state multiplicity. The transition period of this system to the stable steady state is sometimes characterized by very slow change followed by a very rapid convergence to the stable steady state. Tests of the Choong-Paterson-Scott algorithm showed that the feature, which prevents premature termination of the calculations prior to reaching the true steady state, is very useful for this system. However, tests of the stopping criterion showed that the other feature of reducing the computing time was not realized in this system.

scholarly journals Friction Measurement in MEMS Using a New Test Structure

1999 ◽  
Vol 605 ◽  
Author(s):  
B.T. Crozier ◽  
M.P. de Boer ◽  
J.M. Redmond ◽  
D.F. Bahr ◽  
T.A. Michalske
Keyword(s):  
Steady State ◽  
Normal Pressure ◽  
Test Structure ◽  
Friction Measurement ◽  
Self Assembled Monolayer ◽  
Environmental Loading ◽  
Friction Coefficients ◽  
Surface Conditions ◽  
Lubricating Film ◽  
Test Conditions

AbstractA MEMS test structure capable of measuring friction between polysilicon surfaces under a variety of test conditions has been refined from previous designs. The device is applied here to measuring friction coefficients of polysilicon surfaces under different environmental, loading, and surface conditions. Two methods for qualitatively comparing friction coefficients (µ) using the device are presented. Samples that have been coated with a self-assembled monolayer of the lubricating film perfluorinated-decyltrichlorosilane (PFTS) have a coefficient of friction that is approximately one-half that of samples dried using super-critical CO2 (SCCO2) drying. Qualitative results indicate that µ is independent of normal pressure. Wear is shown to increase µ for both supercritically dried samples and PFTS coated samples, though the mechanisms appear to be different. Super critically dried surfaces appear to degrade continuously with increased wear cycles, while PFTS coated samples reach a steady state friction value after about 105 cycles.

DISBOND DETECTION TECHNIQUE FOR LINER/PROPELLANT INTERFACE USING ULTRASONIC RESONANCE AND LAMB WAVES

2012 ◽  
Vol 06 ◽  
pp. 49-54
Author(s):  
DONG-RYUN KIM ◽  
JAE-HOON KIM
Keyword(s):  
Lamb Waves ◽  
Resonance Method ◽  
Multilayered Structure ◽  
Ultrasonic Waves ◽  
Multilayered Structures ◽  
Reflected Waves ◽  
Nondestructive Tests ◽  
Ultrasonic Resonance ◽  
A New Technique ◽  
Insulation Liner

Adhesive interface tests using ultrasonic waves are far superior to other nondestructive tests for detecting the disbond interface. However, a multilayered structure consisting of a steel case, rubber insulation, liner, and propellant poses many difficulties for analyzing ultrasonic waves because of the superposition of the reflected waves and the large differences in the acoustic impedances of the various materials. Therefore, ultrasonic tests for detecting the disbond interface of multilayered structures have been applied in very limited areas between the steel case and rubber insulation using an automatic system. The existing ultrasonic test cannot detect the disbond interface between the rubber and propellant of a multilayered structure because most of the ultrasonic waves are absorbed in the rubber material, which has low acoustic impedance. This problem could be overcome by amplifying the ultrasonic waves using the ultrasonic resonance method. The Lamb waves were used to evaluate the instability of the ultrasonic waves caused by the contact condition on the surface of the multilayered structure. In this paper, a new technique to detect the disbond interface between the liner and propellant using the property of ultrasonic resonance and Lamb waves is discussed in detail.

scholarly journals Methodology for measuring car traction parameters

2018 ◽  
Vol 182 ◽  
pp. 02001 ◽  
Author(s):  
Bronisław Kolator ◽  
Michał Janulin
Keyword(s):  
Steady State ◽  
Power Output ◽  
Considerable Effect ◽  
Chassis Dynamometer ◽  
State Tests

The article presents methodology for testing the traction parameters of the vehicle on the laboratory stand. The tests have been carried out using MAHA LPS 3000 chassis dynamometer. Power output can be measured in two ways, at steady state or during acceleration. Both have benefits as well as drawbacks. Car manufacturers are required to use steady state tests for certification of power output. It has an advantage as it is a well defined test that is easy to repeat and verify. The problem with results measured during acceleration is that the acceleration itself has a considerable effect on the result.

Analysis of Carrying Capacity and Friction Torque of Friction Pair Fluid-Film for High Parameter Bellows Mechanical Seal

2013 ◽  
Vol 455 ◽  
pp. 207-211
Author(s):  
Mutellip Ahmat ◽  
Zhi Wei Niu ◽  
Guzaiayi Abudoumijiti
Keyword(s):  
Carrying Capacity ◽  
High Speed ◽  
Influence Factor ◽  
Friction Pair ◽  
Scientific Basis ◽  
Friction Torque ◽  
Fluid Film ◽  
Mechanical Seal ◽  
Mechanical Seals ◽  
The Relationship

The friction pair for bellows mechanical seal as a friction element is one of the key components for it. In this research, by based on the computational fluid dynamics (CFD) numerical theory, using the Fluent software, corresponding model and parameters, the fluid-film between the clearance of the sealing ring friction pair for the bellows mechanical seal under such the high-temperature, high-pressure, high-speed as complex working conditions is numerically simulated, the relationship between the carrying-capacity of the fluid-film and the temperature, the viscosity of the fluid-film, the relationship between friction torque of the fluid-film and the speed, viscosity of the fluid-film, the influence factor of leakage are obtained. The researching results provide the scientific basis for the optimization designing of the high parameter bellows mechanical seals.

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