Acoustic Resonance of a Steam Line Gate Valve

2013 ◽  
Author(s):  
Philippe Lafon ◽  
Romain Lacombe ◽  
Fabien Crouzet ◽  
Frédéric Daude ◽  
Samir Ziada ◽  
...  
Keyword(s):  
Pure Tone ◽  
Gate Valve ◽  
Acoustic Resonance ◽  
Experimental Models ◽  
Steam Line ◽  
Pressure Oscillations ◽  
Counter Measures ◽  
Noise Type ◽  
Lock In ◽  
2D And 3D

A pure tone phenomenon has been observed at 460 Hz on a piping steam line of a power plant. The source has been identified to be generated in a gate valve and to be of cavity noise type. This paper presents the investigations carried out on experimental models in order to analyze the problem. 2D and 3D axisymmetric models are used and lock-in situations between shear layer modes and acoustic duct modes are proven to give rise to powerful tones. Some counter measures are also tested with the objective of lowering the amplitude of pressure oscillations.

Aeroacoustical Coupling and Its Structural Effects on a PWR Steam Line: Part 1 — Numerical Investigations of Flow Acoustic Coupling in a Subsonic Flow Past a Shallow Cavity

2002 ◽  
Author(s):  
Philippe Lafon ◽  
Christophe Lambert ◽  
Jean-Paul Devos ◽  
Se´bastien Caillaud
Keyword(s):  
Gate Valve ◽  
Transverse Mode ◽  
Steam Line ◽  
Acoustic Excitation ◽  
Flow Profile ◽  
Acoustic Coupling ◽  
Line Part ◽  
Noise Type ◽  
Shallow Cavity ◽  
Acoustical Energy

A pure tone phenomenon has been observed at 460 Hz in a PWR steam line. The acoustical energy has been identified to be generated in an open gate valve and to be of cavity noise type. The objective here is to understand the flow acoustic coupling in the cavity and in the duct. Both experimental and numerical investigation ways are used. The flow acoustic phenomena are modeled by computing the Euler equations. Two different computations are carried out: in the first one, a pure Euler modeling is used, in the second one, a boundary layer obtained from experimental data is introduced in the computation in order to have a realistic flow profile upstream the cavity. In the first computation, the acoustic excitation due to the cavity is qualitatively retrieved but the frequency is too high compared to the experimental one and no cavity duct coupling is detected. In the second computation, the frequency of the cavity oscillation is very close both the theoretical one and the experimental one. As it is also very close the frequency of the first transverse mode of the duct, the two modes of oscillation (the cavity one and the duct one) are coupled.

scholarly journals The measurement method of meat conductivity

2018 ◽  
Vol 36 (No. 5) ◽  
pp. 372-377
Author(s):  
Zdeněk Bohuslávek
Keyword(s):  
Computer Modelling ◽  
Conductivity Measurement ◽  
Imaginary Component ◽  
Complex Conductivity ◽  
Experimental Measurements ◽  
The Finite Element Method ◽  
Tissue Phantoms ◽  
Inductive Methods ◽  
Lock In ◽  
2D And 3D

This paper analyses the properties of electrode methods and contactless inductive methods of the conductivity measurement of biological tissue, which are one of the few which are able to measure the potentials of corresponding components of complex conductivity, i.e. the real reactive conductivity of a resistive and an imaginary component. The analysis was performed by computer modelling and experimental measurements. The publication describes the modelling of currents and of the potential by electrode and methods on tissue phantoms using the finite element method. The Comsol Multiphysics v3.4 program was used for the calculations. The results are presented in 2D and 3D diagrams. Experimental measurements with electrodes in phantom tissues with different conductivity were also conducted and the components of the complex conductivity were evaluated with an RLC Bridge and most accurately by using a lock-in amplifier. Results and experience from the experiments will make it possible to proceed with the next phase of research focused on measuring conductivity and dielectric properties in different types of meat.

Frequency lock-in mechanism in flow-induced acoustic resonance of a cylinder in a flow duct

2019 ◽  
Vol 884 ◽  
Author(s):  
Zhiliang Hong ◽  
Xiaoyu Wang ◽  
Xiaodong Jing ◽  
Xiaofeng Sun
Keyword(s):  
Acoustic Resonance ◽  
Image Position ◽  
Lock In ◽  
Flow Duct

Flow-Induced Acoustic Resonance of Finned Cylinders With Varying Fin Heights

2021 ◽  
Vol 143 (4) ◽  
Author(s):  
Md Rashidul Islam ◽  
Atef Mohany
Keyword(s):  
Acoustic Resonance ◽  
Root Diameter ◽  
Diameter Ratio ◽  
Resonance Phenomenon ◽  
Resonance Excitation ◽  
Effective Diameter ◽  
Flow Perturbation ◽  
Lock In ◽  
Fin Thickness ◽  
Flow Blockage

Abstract The flow-excited acoustic resonance phenomenon, which is instigated by periodic flow perturbation, leads to the generation of acute sound pressure. In this work, we investigated the characteristics of the flow-excited acoustic resonance for circular finned cylinders with different fin heights. The fin height is expressed as a normalized form considering the ratio of the fin diameter to the root cylinder diameter. The experiments are performed with finned cylinders having a range of diameter ratios between 1.5<Df/Dr<2.5. The diameter ratios are varied by changing the root diameter and fin diameter separately as well as simultaneously while keeping the fin pitch and the fin thickness constant. The results show that the excitation of acoustic resonance has profound dependence on the diameter ratio. Increasing the diameter ratios of the finned cylinder results in strong acoustic resonance excitation. The lock-in width and the onset of the acoustic resonance excitation also depend on the diameter ratio of the cylinders. Moreover, the results show that using an effective diameter based on the geometrical flow blockage does not take into account the changes occurring in the source of resonance excitation due to the addition of fins.

The Effect of Seat Geometry on Gate Valve Noise

2000 ◽  
Vol 122 (4) ◽  
pp. 401-407 ◽  
Author(s):  
Bruce A. W. Smith ◽  
Brian V. Luloff
Keyword(s):  
Vortex Shedding ◽  
Gate Valve ◽  
Noise Source ◽  
Cost Effective ◽  
Acoustic Resonance ◽  
Noise Levels ◽  
Tonal Noise ◽  
Valve Seat ◽  
Testing Program ◽  
Piping Systems

Gate valves often act as a source of tonal noise in piping systems. Occasionally, this can lead to excessive environmental noise levels. This paper presents the results of a model testing program that was conducted to determine the most cost-effective way to eliminate the noise source in one such valve. Over 300 tests were conducted on 25 different valve configurations. Testing of the original valve configuration indicated that the noise was caused by vortex shedding over the valve seat cavity coupled with an acoustic resonance across the throat of the valve. Numerous modifications to the valve seats, seat cavity, and disk were tested to determine how the vortex shedding could best be controlled. The effect of these modifications on the unsteady pressures in the valve and adjacent piping are presented and discussed. For the valve under consideration, it was concluded that the noise could best be eliminated by chamfering the upstream and downstream valve seats. Recommendations for avoiding noise problems in other valve installations are presented. [S0094-9930(00)00503-5]

Solvent suppression using a spin lock in 2D and 3D NMR spectroscopy with H2O solutions

1989 ◽  
Vol 85 (3) ◽  
pp. 608-613 ◽  
Author(s):  
Barbara A Messerle ◽  
Gerhard Wider ◽  
Gottfried Otting ◽  
Christoph Weber ◽  
Kurt Wüthrich
Keyword(s):  
Nmr Spectroscopy ◽  
3D Nmr ◽  
Spin Lock ◽  
Solvent Suppression ◽  
Lock In ◽  
2D And 3D

Solvent Suppression Using a Spin Lock in 2D and 3D NMR Spectroscopy with H2O Solutions

1995 ◽  
pp. 411-416
Author(s):  
BARBARA A. MESSERLE ◽  
GERHARD WIDER ◽  
GOTTFRIED OTTING ◽  
CHRISTOPH WEBER ◽  
KURT WÜTHRICH
Keyword(s):  
Nmr Spectroscopy ◽  
3D Nmr ◽  
Spin Lock ◽  
Solvent Suppression ◽  
Lock In ◽  
2D And 3D

Forced Oscillation Experiments for VIV of Circular Cylinders and Behaviors of VIV and Lock-In Phenomenon

2006 ◽  
Author(s):  
Koichi Masuda ◽  
Tomoki Ikoma ◽  
Norio Kondo ◽  
Hisaaki Maeda
Keyword(s):  
Model Test ◽  
Forced Oscillation ◽  
Power Spectra ◽  
Experimental Models ◽  
Circular Cylinders ◽  
Marine Riser ◽  
Test Models ◽  
Vortex Induced Vibrations ◽  
Oscillation Test ◽  
Lock In

This paper describes a model test to examine characteristics of vortex-induced vibrations (VIV) of tubing in water, e.g. a marine riser, and gives consideration of VIV characteristics from experimental results. Rigid circular cylinders are used for the model experiment because the authors assume that the model is a part of a marine riser. The test models are suspended into still water through a flat spring, and hence VIV can be found with hydroelasticity in spite of a rigid circular cylinder. This is a forced oscillation test in still water. The circular cylinders for the model test have drafts of 30cm, 60cm and 80cm, and diameter of 5cm and 8cm. The models are oscillated with periods of 0.5s to 4.6s and with about 7cm amplitude of the oscillation. In uniform flow, there is just one velocity of which flow causes the VIV lock-in. However, it is confirmed that there are several cases to experimental models, cases in which the VIV lock-in occurs in oscillatory flow. In addition, it is found that power spectra of VIV can be approximately classified into four patterns according to the number of spectral peaks and its property. Power spectra of VIV behavior from the model tests are compared with two-dimensional CFD computations.

Acoustic Resonance Spectroscopy for Hazards Materials Classification

2013 ◽  
Vol 427-429 ◽  
pp. 686-690 ◽  
Author(s):  
Lu Jun Zhou ◽  
Qiang Chen ◽  
Jian Qing Fang
Keyword(s):  
Principal Component ◽  
Acoustic Resonance ◽  
Acoustic Properties ◽  
Resonance Spectroscopy ◽  
Multivariate Methods ◽  
Linear Discriminant ◽  
Frequency Source ◽  
Transmitted Signal ◽  
Lock In ◽  
Acoustic Resonance Spectroscopy

In this paper, a measure system based on acoustic resonance is developed for hazards materials classification. It employs the lock-in amplifier as core processor to collect the acoustic resonance spectroscopy (ARS) of sealed containers which storied hazards materials. The transmitter and receiver are coupled externally to the wall of the container. The transmitter generates the sound by using a swept frequency source. The receiver on the opposite side of the wall of the container can detect the transmitted signal. The acoustic properties of hazards materials such as velocity and attenuation can be learned from the observed spectrum signal. Then multivariate methods are used to evaluate pretreatment methods, such as normalization, and classification possibilities of data collected by ARS in a laboratory environment. Principal component analysis (PCA) shows that it is possible to observe differences between samples using the data acquired from the ARS system. Further results obtained from Linear Discriminant Analysis (LDA) show that the identification rates for hazards materials classification are 100%.It is concluded that the ARS system has significant potential in the hazards materials classification.

Acoustic and Convective Mechanisms Contributing to Non-Synchronous-Vibrations in a Multistage Compressor

2019 ◽  
Author(s):  
Christoph Brandstetter ◽  
Benoit Paoletti ◽  
Xavier Ottavy
Keyword(s):  
High Speed ◽  
Laser Doppler Anemometry ◽  
Leading Edge ◽  
Acoustic Resonance ◽  
Rotating Stall ◽  
Tip Clearance ◽  
Unsteady Pressure ◽  
Mode Decomposition ◽  
Design Speed ◽  
Lock In

Abstract In the present paper we show an analysis of Non-Synchronous-Oscillations in the rear stage of an experimental high-speed 3.5 stage compressor. The machine CREATE is representative of the rear median-stages of a modern civil turbofan engine except for an increased tip clearance on middle and last stage. Using distributed unsteady pressure measurements a comprehensive dataset during transient throttling maneuvers is presented, including temporal and spatial mode decomposition and the derivation of wave propagation speeds. To support the aerodynamic characterization, the steady flow structure at near stall conditions has been investigated using Laser-Doppler-Anemometry and unsteady pressure probes. In repeated experiments the machine has encountered alternating circumferential modes, several hundred revolutions before rotating stall at design speed. It was found that acoustic resonance of an upstream cut-on mode between the compressor stages enforces the development of particular modes. These phenomena have not been observed on the same machine with regular tip clearance. In contrast to front-stage observations reported in literature, where leading edge separations cause strong excitations of the blade eigenmodes, initially weak modulations of the flow in the rotor tip region are observed to be amplified due to acoustic feedback. With rising amplitude lock-in to distinct circumferential mode orders develops. Apart from the final lock-in procedure, signatures of solely aerodynamic fluctuations, discussed in literature as ‘Rotating Instabilities’ or ‘Part Span Stall’, are observed intermittently at different speedlines.

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