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Article
Publication date: 1 December 2017

Shaoyi Xu, Fangfang Xing, Ruilin Wang, Wei Li, Yuqiao Wang and Xianghui Wang

At present, one of the key equipment in pillar industries is a large rotating machinery. Conducting regular health monitoring is important for ensuring safe operation of the large…

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Abstract

Purpose

At present, one of the key equipment in pillar industries is a large rotating machinery. Conducting regular health monitoring is important for ensuring safe operation of the large rotating machinery. Because vibrations sensors play an important role in the workings of the rotating machinery, measuring its vibration signal is an important task in health monitoring. This paper aims to present these.

Design/methodology/approach

In this work, the contact vibration sensor and the non-contact vibration sensor have been discussed. These sensors consist of two types: the electric vibration sensor and the optical fiber vibration sensor. Their applications in the large rotating machinery for the purpose of health monitoring are summarized, and their advantages and disadvantages are also presented.

Findings

Compared with the electric vibration sensor, the optical fiber vibration sensor of large rotating machinery has unique advantages in health monitoring, such as provision of immunity against electromagnetic interference, requirement of less insulation and provision of long-distance signal transmission.

Originality/value

Both contact vibration sensor and non-contact vibration sensor have been discussed. Among them, the electric vibration sensor and the optical fiber vibration sensor are compared. Future research direction of the vibration sensors is presented.

Details

Sensor Review, vol. 38 no. 1
Type: Research Article
ISSN: 0260-2288

Keywords

Article
Publication date: 30 May 2008

V. Giuliani, B. de Witt, M. Salluzzi, R.J. Hugo and P. Gu

Particle velocity is a critical factor that can affect the deposition quality in manufacturing processes involving the use of a laser source and a powder‐particle delivery nozzle…

Abstract

Purpose

Particle velocity is a critical factor that can affect the deposition quality in manufacturing processes involving the use of a laser source and a powder‐particle delivery nozzle. The purpose of this paper is to propose a method to detect the speed and trajectory of particles during a laser deposition process.

Design/methodology/approach

A low‐power laser light sheet technique is used to illuminate particles emerging from a custom designed powder delivery nozzle. Light scattered by the particles is detected by a high‐speed camera. Image processing on the acquired images was performed using both edge detection and Hough transform algorithms.

Findings

The experimental data were analyzed and used to estimate particle velocity, trajectory and the velocity profile at the nozzle exit. The results have demonstrated that the particle trajectory remains linear between the nozzle exit and the deposition plate and that the particle velocity can be considered a constant.

Originality/value

The use of lowpower laser light sheet illumination facilitates the detection of isolated particle streaks even in high‐powder flow rate condition. Identification of particle streaks in three subsequent images ensures that particle velocity vectors are in the plane of illumination, and also offers the potential to evaluate in a single measurement both velocity and particle size based on the observed scattered characteristics. The method provides a useful simple tool to investigate particle dynamics in a rapid prototyping application as well as other research fields involving the use of powder delivery nozzles.

Details

Rapid Prototyping Journal, vol. 14 no. 3
Type: Research Article
ISSN: 1355-2546

Keywords

Article
Publication date: 3 May 2013

Maher Raddaoui

Rotating flows are very important because they are found in industrial and domestic applications. For a good performance, it is important to dimension correctly the energy…

Abstract

Purpose

Rotating flows are very important because they are found in industrial and domestic applications. For a good performance, it is important to dimension correctly the energy efficiency and the lifespan of the apparatuses while studying, for example, the influence of their physical and geometrical characteristics on the various hydrodynamic constraints, thermal and mechanics which they will support. The purpose of this paper is to describe experiments and a numerical study of the inter‐disc space effects on the mean and the turbulent characteristics of a Von Karman isotherm steady flow between counter‐rotating disks.

Design/methodology/approach

Experimental results are obtained by the laser Doppler anemometer technique performed at IRPHE (Institute of Research on the Phenomena out Equilibrium) in Marseille, France. The numerical predictions are based on one‐point statistical modeling using a low Reynolds number second‐order full stress transport closure (RSM model).

Findings

It was found that the level of radial velocity increases with the aspect ratio near to the axis of rotation but this phenomenon is reversed far from this zone; the level of tangential velocity, of turbulence kinetic energy and of the torsion are definitely higher for the largest aspect ratio. The best contribution of this work is, at the same time, the new experimental and numerical database giving the effect of the aspect ratio of the cavity on the intensity of turbulence for Von Karman flow between two counter rotating disks.

Research limitations/implications

The limitation of this work is that it concerns rotating flows with very high speeds because the phenomena of instability appear and the application of this model for cavities of forms is not obvious.

Practical implications

This work is of technological interest; it can be exploited by industrialists to optimize the operation of certain machines using this kind of flow. It can be exploited in the teaching of certain units of Masters courses: gathering experimental techniques; numerical methods; and theoretical knowledge.

Social implications

This work can also have a social interest where this kind of simulation can be generalized with other types of flows responsible for certain phenomena of society, such as the phenomenon of pollution. This work can have a direct impact on everyday life by the exploitation of the rotary flows, such as being a very clean and very economic means to separate the undesirable components present in certain fluid effluents.

Originality/value

The best contribution of this work is the new experimental and numerical database giving the effect of the aspect ratio of the cavity on the intensity of turbulence for Von Karman flow between two counter rotating disks.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 23 no. 4
Type: Research Article
ISSN: 0961-5539

Keywords

Article
Publication date: 1 October 2018

Ke Kou, Tianhong Lian, Cuo Wang and Guanlei Zhang

As an emerging measurement technique with the merit of easy alignment and high sensitivity, laser self-mixing interferometry (SMI) has wide applications in the detection of…

Abstract

Purpose

As an emerging measurement technique with the merit of easy alignment and high sensitivity, laser self-mixing interferometry (SMI) has wide applications in the detection of physical quantities. Considering that the characteristics of lasers have a determining influence on sensors’ performance, the authors have established an open cavity solid-state laser (SSL) with more adjustment flexibility to act as a laser source.

Design/methodology/approach

The fundamental structure of a SSL has been presented with an Nd:YAG rod severing as an active material and a birefringent filter inserted in the resonator as a mode selecting element. The power stability has been tested by a power meter, while the mode pattern has been inspected with a scanning Fabry–Perot interferometer, and the linewidth has been observed through a wavelength meter. A loudspeaker driven by a function generator is located in the extracavity to introduce phase modulation for SMI signal observation.

Findings

The established Nd:YAG SSL operates in a single longitudinal mode with the power stability of 0.2 mW and the linewidth less than 10 MHz. The SMI phenomenon occurs in the SSL, and the SMI signal obtained shows a fine signal-to-noise ratio of about 30 dB.

Originality/value

To the authors knowledge, SMI sensors using SSLs, especially in open cavity type, have rarely been reported, and they can find significant applications in designing high performance SMI sensors and instruments.

Details

Sensor Review, vol. 39 no. 2
Type: Research Article
ISSN: 0260-2288

Keywords

Article
Publication date: 6 June 2019

K. Todd Lowe

The purpose of this paper is to assess state-of-the-art techniques for quantifying flow distortion in the inlets of turbofan engines, particularly with respect to the prospects…

Abstract

Purpose

The purpose of this paper is to assess state-of-the-art techniques for quantifying flow distortion in the inlets of turbofan engines, particularly with respect to the prospects for future flight applications.

Design/methodology/approach

To adequately characterize the flow fields of complex aircraft inlet distortions, the author has incorporated laser velocimetry techniques, namely, stereoscopic particle image velocimetry (PIV) and Doppler velocimetry based on filtered Rayleigh scattering (FRS), into inlet distortion studies.

Findings

Overall, the results and experience indicate that the pathway for integration of FRS technologies into flight systems is clearer and more robust than that of PIV.

Practical implications

While always a concern, the topic of inlet distortion has grown in importance as contemporary airframe designers seek extremely compact and highly integrated inlets. This research offers a means for gaining new understanding of the in situ aerodynamic phenomena involved with complex inlet distortion.

Originality/value

This paper presents unique applications of turbofan inlet velocimetry methods while providing an original assessment of technological challenges involved with progressing advanced velocimetry techniques for flight measurements.

Details

Aircraft Engineering and Aerospace Technology, vol. 92 no. 1
Type: Research Article
ISSN: 1748-8842

Keywords

Article
Publication date: 13 June 2019

Wei Xia, Lingwen Kong, Jiahuan Zhang, Hui Hao, Yiping Wang, Xiaoqi Ni, Ming Wang and Dongmei Guo

The purpose of this study aims to modify a self-mixing laser mouse as an extremely cost-effective displacement sensor to measure the mechanical oscillation of a commercial shaker…

Abstract

Purpose

The purpose of this study aims to modify a self-mixing laser mouse as an extremely cost-effective displacement sensor to measure the mechanical oscillation of a commercial shaker and a nano-positioning stage.

Design/methodology/approach

This kind of laser mouse, mostly consisting of a pair of vertical cavity surface emitting lasers, two photodiodes and an integrated signal processing unit, is capable of directly giving the x-axis and y-axis components of the measured vibrating displacement. Based on the laser self-mixing interference, the velocity of the object is coded into the Doppler frequency shift of the feedback light, which allows accurate determination of the vibration of the object.

Findings

A commercial shaker has been used to provide standard harmonic oscillation to test the displacement sensor. Within a vibrating frequency range of 110 Hz, the experimental results show that the micrometer scale resolution has been achieved at the velocity of up to 2 m/s, which is much improved compared with the image-based optical mouse. Furthermore, the measurements of the two dimensional displacement of a nano-positioning stage are performed as well. The minimum measurable velocity limit for this sensor has been discussed in detail, and the relative measurement error can be greatly reduced by appropriate selection of the modulation frequency of the triangular injection current.

Originality/value

These results demonstrate the feasibility of this device for the industrial vibration sensing applications.

Details

Sensor Review, vol. 39 no. 4
Type: Research Article
ISSN: 0260-2288

Keywords

Article
Publication date: 1 June 2005

Christine Connolly

To present two non‐contact methods of measuring vibrations and impact events.

Abstract

Purpose

To present two non‐contact methods of measuring vibrations and impact events.

Design/methodology/approach

The paper concentrates on the practical capabilities and underlying technology of commercial high‐speed CMOS cameras and laser Doppler vibrometers.

Findings

The instruments are used to analyse modes of failure and to test quality in a very wide range of products. They are also used to develop safety and protective devices, and to study natural phenomena.

Originality/value

A practical guide to the tools available, with some example applications of interest to production engineers.

Details

Sensor Review, vol. 25 no. 2
Type: Research Article
ISSN: 0260-2288

Keywords

Article
Publication date: 7 August 2017

Weiwei Pan and Dongsheng Wang

Flow measurement plays an important role in modern industrial production. Flow measurement methods based on optical fiber systems have become a main research focus.

Abstract

Purpose

Flow measurement plays an important role in modern industrial production. Flow measurement methods based on optical fiber systems have become a main research focus.

Design/methodology/approach

Applying flow measurement theory and the structural characteristics of optical fiber, flow measurement of paste can be achieved through a combined laser Doppler and optical fiber sensing system based on the principle of optical fiber grating sensors and flow sensors. The system is developed to include light selection, photoelectric detection, a voltage amplifier circuit and a signal filtering circuit.

Findings

The system is shown, through a comparative experiment, to be of higher accuracy than the traditional ultrasonic method.

Originality/value

A new method for measuring the paste flow is presented, which is based on the principle of optical fiber Doppler. The method has the advantages of convenient installation, high accuracy and low cost. Experiments show that the method is feasible.

Details

World Journal of Engineering, vol. 14 no. 4
Type: Research Article
ISSN: 1708-5284

Keywords

Article
Publication date: 30 March 2010

Robert Bogue

The purpose of this paper is to provide a review of three‐dimensional (3D) measurement technologies and their applications.

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Abstract

Purpose

The purpose of this paper is to provide a review of three‐dimensional (3D) measurement technologies and their applications.

Design/methodology/approach

This paper first describes 3D measuring techniques and then considers a selection of key applications, citing a number of specific examples. Reference is also made to certain new developments and research activities.

Findings

It is shown that both active and passive techniques are used to conduct 3D measurements. The former includes various forms of laser scanning such as time of flight, triangulation and phase measurements and photogrammetry is the main passive method. Laser‐based Doppler shift techniques are used to monitor dynamic phenomena, notably vibration, in three dimensions. These methods are used across a diversity of industries and disciplines in a wide and varied range of applications.

Originality/value

The paper provides a technical review of the leading 3D measurement technologies and their uses.

Details

Sensor Review, vol. 30 no. 2
Type: Research Article
ISSN: 0260-2288

Keywords

Article
Publication date: 3 October 2016

Xiaogang Wang, Wutao Qin, Yuliang Bai and Naigang Cui

Penetrator plays an important role in the exploration of Moon and Mars. The navigation method is a key technology during the development of penetrator. To meet the high accuracy…

Abstract

Purpose

Penetrator plays an important role in the exploration of Moon and Mars. The navigation method is a key technology during the development of penetrator. To meet the high accuracy requirements of Moon penetrator, this paper aims to propose two kinds of navigation systems.

Design/methodology/approach

The line of sight of vision sensor between the penetrator and Moon orbiter could be utilized as the measurement during the navigation system design. However, the analysis of observability shows that the navigation system cannot estimate the position and velocity of penetrator, when the line of sight measurement is the only resource of information. Therefore, the Doppler measurement due to the relative motion between penetrator and the orbiter is used as the supplement. The other option is the relative range measurement between penetrator and the orbiter. The sigma-point Kalman Filtering is implemented to fuse the information from the vision sensor and Doppler or rangefinder. The observability of two navigation system is analyzed.

Findings

The sigma-point Kalman filtering could be used based on vision sensor and Doppler radar or laser rangefinder to give an accurate estimation of Moon penetrator position and velocity without increasing the payload of Moon penetrator or decreasing the estimation accuracy. However, the simulation result shows that the last method is better. The observability analysis also proves this conclusion.

Practical implications

Two navigation systems are proposed, and the simulations show that both systems can provide accurate estimation of states of penetrator.

Originality/value

Two navigation methods are proposed, and the observability of these navigation systems is analyzed. The sigma-point Kalman filtering is first introduced to the vision-based navigation system for Moon penetrator to provide precision navigation during the descent phase of Moon penetrator.

Details

Aircraft Engineering and Aerospace Technology, vol. 88 no. 6
Type: Research Article
ISSN: 1748-8842

Keywords

1 – 10 of 298