Characterization of Tape Edge Contact Force With Acoustic Emission

2007 ◽  
Vol 129 (4) ◽  
pp. 525-529 ◽  
Author(s):  
Bart Raeymaekers ◽  
Frank E. Talke
Keyword(s):  
Acoustic Emission ◽  
Contact Force ◽  
Operating Conditions ◽  
Dimensional Model ◽  
Tape Drive ◽  
Edge Contact ◽  
One Dimensional ◽  
Acoustic Emission Sensors ◽  
Tape Edge

Acoustic emission sensors were used to detect contact between a moving tape and the flange of a tape guide. The influence of tape drive operating conditions on the tape edge contact force was studied. A one-dimensional model was developed to predict the magnitude of tape/flange impact. The model fits the experimental data well.

scholarly journals Research on Detection and Location of Fluid-Filled Pipeline Leakage Based on Acoustic Emission Technology

Sensors ◽  
2018 ◽  
Vol 18 (11) ◽  
pp. 3628 ◽  
Author(s):  
Shengshan Pan ◽  
Zhengdan Xu ◽  
Dongsheng Li ◽  
Dang Lu
Keyword(s):  
Acoustic Emission ◽  
Wavelet Decomposition ◽  
Estimation Method ◽  
Reference Value ◽  
Time Delay Estimation ◽  
Operating Conditions ◽  
Support Vector ◽  
Acoustic Emission Sensor ◽  
Mode Decomposition ◽  
Acoustic Emission Sensors

Because of the inconvenience of installing sensors in a buried pipeline, an acoustic emission sensor is initially proposed for collecting and analyzing leakage signals inside the pipeline. Four operating conditions of a fluid-filled pipeline are established and a support vector machine (SVM) method is used to accurately classify the leakage condition of the pipeline. Wavelet decomposition and empirical mode decomposition (EMD) methods are initially used in denoising these signals to address the problem in which original leakage acoustic emission signals contain too much noise. Signals with more information and energy are then reconstructed. The time-delay estimation method is finally used to accurately locate the leakage source in the pipeline. The results show that by using SVM, wavelet decomposition and EMD methods, leakage detection in a liquid-filled pipe with built-in acoustic emission sensors is effective and accurate and provides a reference value for real-time online monitoring of pipeline operational status with broad application prospects.

Acoustic Barkhausen Effect Observed in Various Steels

2017 ◽  
Vol 885 ◽  
pp. 208-215
Author(s):  
Gabor Por ◽  
Balazs Fekete ◽  
Peter Trampus
Keyword(s):  
Acoustic Emission ◽  
Source Localization ◽  
Fatigue Testing ◽  
Stress Test ◽  
Reactor Vessel ◽  
Acoustic Response ◽  
Barkhausen Effect ◽  
Acoustic Emission Sensors ◽  
Vessel Material

Carrying out fatigue testing of reactor vessel material 15H2MFA acoustic emission sensors were applied to follow changes. It is shown, that observed bursts can be explained only with appearance of acoustic Barkhausen Effect (ABE). Interesting source localization is shown during heat treatment and consecutive stress test, which can be explained acoustic emission due to material transition from martenzit phase to bainite phase. Observed ABE opens the way to apply it in industry using magnetic stresses to provoke acoustic response for characterization of the state of the magnetic materials.

Design Considerations for Aerodynamically Quenching Gas Sampling Probes

1984 ◽  
Vol 106 (2) ◽  
pp. 460-466 ◽  
Author(s):  
L. Chiappetta ◽  
M. B. Colket
Keyword(s):  
Sensitivity Study ◽  
Operating Conditions ◽  
Dimensional Model ◽  
Quenching Temperature ◽  
One Dimensional ◽  
Trade Offs ◽  
Transfer Equations ◽  
Method Of Solution ◽  
Internal Aerodynamics ◽  
Temperature And Pressure

An aerodynamic quench is the most rapid method for quenching temperature and pressure-dependent chemical reactions. Attempts have been made to quench gas samples aerodynamically, but many of these attempts have been unsuccessful because of a lack of understanding of the internal aerodynamics of sampling probes. A one-dimensional model developed previously by the authors has been used for the design and analysis of aerodynamically quenching probes. This paper presents in detail the important aerodynamic and heat transfer equations used in the model, a description of the method of solution, and the results of a sensitivity study. These calculations demonstrate the limitations and important trade-offs in design and operating conditions of probes using an aerodynamic quench.

Two-Dimensional Performance Analysis and Design of MHD Channels

1981 ◽  
Vol 103 (2) ◽  
pp. 307-314 ◽  
Author(s):  
E. Doss ◽  
H. Geyer ◽  
R. K. Ahluwalia ◽  
K. Im
Keyword(s):  
Operating Conditions ◽  
Two Dimensional ◽  
Dimensional Model ◽  
Channel Geometry ◽  
One Dimensional ◽  
Analysis And Design ◽  
Voltage Drops ◽  
And Performance ◽  
Carry Over ◽  
Mhd Channel

A two-dimensional model for MHD channel design and analysis has been developed for three different modes of operation: velocity, Mach number, and pressure. Given the distribution of any of these three parameters along the channel, the channel aspect ratio, and the channel operating conditions, the MHD channel geometry can be predicted. The developed two-dimensional design model avoids unnecessary assumptions for surface losses and boundary layer voltage drops that are required in one-dimensional calculations and, thus, can yield a better prediction of MHD channel geometry and performance. The subject model includes a simplified treatment for possible arcing near the electrode walls. A one-dimensional model for slag flow along the channel walls is also incorporated. The effects of wall temperature and slag carry-over on channel performance are discussed.

Accurate Radial Vaneless Diffuser One-Dimensional Model

2015 ◽  
Vol 137 (8) ◽  
Author(s):  
Fabio De Bellis ◽  
Angelo Grimaldi ◽  
Dante Tommaso Rubino ◽  
Riccardo Amirante ◽  
Elia Distaso
Keyword(s):  
Angular Momentum ◽  
Differential Equations ◽  
Loss Coefficient ◽  
Operating Conditions ◽  
Performance Estimation ◽  
Dimensional Model ◽  
Vaneless Diffuser ◽  
One Dimensional ◽  
Starting Point ◽  
Vaneless Diffusers

A simplified one-dimensional model for the performance estimation of vaneless radial diffusers is presented. The starting point of such a model is that angular momentum losses occurring in vaneless diffusers are usually neglected in the most common turbomachinery textbooks: It is assumed that the angular momentum is conserved inside a vaneless diffuser, although a nonisentropic pressure transformation is considered at the same time. This means that fluid-dynamic losses are taken into account only for what concerns pressure recovery, whereas the evaluation of the outlet tangential velocity incoherently follows an ideal behavior. Several attempts were presented in the past in order to consider the loss of angular momentum, mainly solving a full set of differential equations based on the various developments of the initial work by Stanitz (1952, “One-Dimensional Compressible Flow in Vaneless Diffusers of Radial or Mixed-Flow Centrifugal Compressors, Including Effects of Friction, Heat Transfer and Area Change,” Report No. NACA TN 2610). However, such formulations are significantly more complex and are based on two empirical or calibration coefficients (skin friction coefficient and dissipation or turbulent mixing loss coefficient) which need to be properly assessed. In the present paper, a 1D model for diffuser losses computation is derived considering a single loss coefficient, and without the need of solving a set of differential equations. The model has been validated against massive industrial experimental campaigns, in which several diffuser geometries and operating conditions have been considered. The obtained results confirm the reliability of the proposed approach, able to predict the diffuser performance with negligible drop of accuracy in comparison with more sophisticated techniques. Both preliminary industrial designs and experimental evaluations of the diffusers may benefit from the proposed model.

Stability of a thermoelastic mixture with second sound

2018 ◽  
Vol 24 (6) ◽  
pp. 1692-1706 ◽  
Author(s):  
Margareth S. Alves ◽  
Marcio V. Ferreira ◽  
Jaime E. Muñoz Rivera ◽  
O. Vera Villagrán
Keyword(s):  
Initial Data ◽  
Asymptotic Properties ◽  
Sufficient Conditions ◽  
Complete Characterization ◽  
Second Sound ◽  
Dimensional Model ◽  
One Dimensional ◽  
The One ◽  
Necessary And Sufficient

We consider the one-dimensional model of a thermoelastic mixture with second sound. We give a complete characterization of the asymptotic properties of the model in terms of the coefficients of the model. We establish the necessary and sufficient conditions for the model to be exponential or polynomial stable and also the conditions for which there exist initial data for where the energy is conserved.

scholarly journals Comparison of a One-Dimensional Model of a High-Temperature Solid-Oxide Electrolysis Stack With CFD and Experimental Results

2005 ◽  
Author(s):  
J. E. O’Brien ◽  
C. M. Stoots ◽  
J. Stephen Herring ◽  
G. L. Hawkes
Keyword(s):  
High Temperature ◽  
Gas Flow ◽  
Operating Conditions ◽  
Operating Voltage ◽  
Dimensional Model ◽  
One Dimensional ◽  
Constant Flow Rate ◽  
High Temperature Steam ◽  
The One ◽  
Increasing Temperature

A one-dimensional model has been developed to predict the thermal and electrochemical behavior of a high-temperature steam electrolysis stack. This electrolyzer model allows for the determination of the average Nernst potential, cell operating voltage, gas outlet temperatures, and electrolyzer efficiency for any specified inlet gas flow rates, current density, cell active area, and external heat loss or gain. The model includes a temperature-dependent area-specific resistance (ASR) that accounts for the significant increase in electrolyte ionic conductivity that occurs with increasing temperature. Model predictions are shown to compare favorably with results obtained from a fully 3-D computational fluid dynamics model. The one-dimensional model was also employed to demonstrate the expected trends in electrolyzer performance over a range of operating conditions including isothermal, adiabatic, constant steam utilization, constant flow rate, and the effects of operating temperature.

Analysis of Thermal Effects in a Cavitating Orifice Using Rayleigh Equation and Experiments

2010 ◽  
Vol 132 (9) ◽  
Author(s):  
Maria Grazia De Giorgi ◽  
Daniela Bello ◽  
Antonio Ficarella
Keyword(s):  
Heat Transfer ◽  
Phase Change ◽  
Thermal Effects ◽  
Internal Combustion Engines ◽  
Operating Conditions ◽  
Rayleigh Equation ◽  
Liquid Temperature ◽  
Dimensional Model ◽  
Cloud Cavitation ◽  
One Dimensional

The cavitation phenomenon interests a wide range of machines, from internal combustion engines to turbines and pumps of all sizes. It affects negatively the hydraulic machines’ performance and may cause materials’ erosion. The cavitation, in most cases, is a phenomenon that develops at a constant temperature, and only a relatively small amount of heat is required for the formation of a significant volume of vapor, and the flow is assumed isothermal. However, in some cases, such as thermosensible fluids and cryogenic liquid, the heat transfer needed for the vaporization is such that phase change occurs at a temperature lower than the ambient liquid temperature. The focus of this research is the experimental and analytical studies of the cavitation phenomena in internal flows in the presence of thermal effects. Experiments have been done on water and nitrogen cavitating flows in orifices at different operating conditions. Transient growth process of the cloud cavitation induced by flow through the throat is observed using high-speed video images and analyzed by pressure signals. The experiments show different cavitating behaviors at different temperatures and different fluids; this is related to the bubble dynamics inside the flow. So to investigate possible explanations for the influence of fluid temperature and of heat transfer during the phase change, initially, a steady, quasi-one-dimensional model has been implemented to study an internal cavitating flow. The nonlinear dynamics of the bubbles has been modeled by Rayleigh–Plesset equation. In the case of nitrogen, thermal effects in the Rayleigh equation are taken into account by considering the vapor pressure at the actual bubble temperature, which is different from the liquid temperature far from the bubble. A convective approach has been used to estimate the bubble temperature. The quasisteady one-dimensional model can be extensively used to conduct parametric studies useful for fast estimation of the overall performance of any geometric design. For complex geometry, three-dimensional computational fluid dynamic (CFD) codes are necessary. In the present work good agreements have been found between numerical predictions by the CFD FLUENT code, in which a simplified form of the Rayleigh equation taking into account thermal effects has been implemented by external user routines and some experimental observations.

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