scholarly journals Experimental Investigation on the Arc Characteristics and Arc Quenching Capabilities of C5F10O-CO2 Mixtures

2019 ◽  
Vol 6 (3) ◽  
pp. 231-234
Author(s):  
Z. Guo ◽  
F. Tang ◽  
Q. Lv ◽  
X. Li ◽  
B. Zhang ◽  
...  
Keyword(s):  
Experimental Investigation ◽  
High Speed ◽  
Inverse Transformation ◽  
High Speed Camera ◽  
Two Dimensional ◽  
Circuit Breakers ◽  
Arc Voltage ◽  
Arc Characteristics ◽  
Dimensional Distribution ◽  
The Stability

C<sub>5</sub>F<sub>10</sub>O-CO<sub>2</sub> mixtures are possible alternatives to SF<sub>6</sub> - which has a high global warming potential - as the interruption medium in gas circuit breakers. This paper experimentally studies the arcing characteristics of C<sub>5</sub>F<sub>10</sub>O-CO<sub>2</sub> mixture, with an experimental model with viewing windows, and measures the arc voltage, current and emission spectrum. The arc evolution process is captured with a high speed camera through an inspection window. The two-dimensional distribution of arc is obtained and analyzed by the inverse transformation of Abel. The results show that, the C<sub>5</sub>F<sub>10</sub>O-CO<sub>2</sub> mixture arc is more volatile than SF<sub>6</sub> gas, and adding C<sub>5</sub>F<sub>10</sub>O into CO<sub>2</sub> improves the stability of the arc, and significantly reduces the arc temperature.

Effect of Current Waveform on Metal Transfer in Controlled Short Circuiting Gas Metal Arc Welding

2013 ◽  
Vol 718-720 ◽  
pp. 202-208 ◽  
Author(s):  
Mao Ai Chen ◽  
Yuan Ning Jiang ◽  
Chuan Song Wu
Keyword(s):  
Transfer Process ◽  
High Speed ◽  
Gas Metal Arc Welding ◽  
Welding Current ◽  
Metal Transfer ◽  
Arc Voltage ◽  
Metal Arc Welding ◽  
Maximum Stability ◽  
The Stability ◽  
Welding Inverter

With high-speed welding inverter and precisely controlling the welding current with arc-bridge state, advanced pulse current waveforms can be produced to optimize the transfer characteristics of short circuiting transfer welding. In this paper, the images of droplet/wire, and the transient data of welding current and arc voltage were simultaneously recorded to study the influence of peak arcing current, background arcing current and tail-out time on the stability of short circuiting transfer process. It was found that maximum short circuiting transfer stability is reached under specific welding conditions. Any deviation from these conditions will cause abnormal rises in arc voltage indicating instantaneous arc extinguishing and greater spatter. Optimal welding conditions were obtained to achieve the maximum stability of short circuiting metal transfer process.

Study on Arc and Drop Transfer Behaviors of DCEN MAG Welding

2014 ◽  
Vol 887-888 ◽  
pp. 1290-1293
Author(s):  
Xu Ming Wang ◽  
Qing Xia Bi
Keyword(s):  
Direct Current ◽  
High Speed ◽  
Welding Process ◽  
Mag Welding ◽  
High Speed Camera ◽  
High Current ◽  
Current Electrode ◽  
The Stability

By means of the high speed camera, the arc and drop transfer behaviours of direct current electrode negative MAG welding process are researched. The influences of luminous arc ball on the stability of MAG welding process are analyzed. On this basis, the process interval of DCEN MAG welding is determined. And the influences of wire polarity on wire melting coefficient are compared. By using the shield gas 98%Ar + 2%O2, the stable drop transfer manner can be divided into two kinds: dropwise transfer with low current, and streaming transfer with high current.

Experimental Investigation on Flow Field in a Rotating Channel With a New TR-PIV System

2018 ◽  
Author(s):  
Shengjun Zhou ◽  
Haiwang Li ◽  
Zhi Tao ◽  
Ruquan You ◽  
Haoyu Duan
Keyword(s):  
Boundary Layer ◽  
Experimental Investigation ◽  
Laser Diode ◽  
High Speed ◽  
Flow Behavior ◽  
Particle Image Velocimetry System ◽  
Main Stream ◽  
High Speed Camera ◽  
Time Resolved ◽  
Rotating Channel

In the current study, the influence of different rotation conditions on the flow behavior is experimentally investigated by a new system which is designed for time-resolved PIV measurements of the smooth channels at rotation conditions. The Reynolds number equals 15000 and the rotation number ranges from 0 to 0.392 with an interval of 0.098. This new time-resolved Particle Image Velocimetry system consists of a 10 Watts continuous laser diode and a high-speed camera. The laser diode can provide a less than 1mm thickness sheet light. 6400 frames can be captured in one second by the high-speed camera. These two parts of the system are fixed on a rotating disk. In this case, the relative velocity of flows in the rotating smooth square channel can be measured directly to reduce the measurement error. This system makes high-speed camera close to the rotating channel, which allows a high resolution for the measurements of main stream. In addition, high accuracy and temporal resolution realize a detailed analysis of boundary layer characteristics in rotation conditions. Based on this system, experimental investigation has been undertaken. Results are presented of the evolution of velocity and boundary layer thickness at various rotation numbers and different circumferential positions.

A Study of Spike and Modal Stall Phenomena in a Low-Speed Axial Compressor

1997 ◽  
Author(s):  
T. R. Camp ◽  
I. J. Day
Keyword(s):  
High Speed ◽  
Three Dimensional ◽  
Axial Compressor ◽  
Operating Conditions ◽  
Two Dimensional ◽  
Stability Criteria ◽  
Stall Inception ◽  
Low Speed ◽  
The Stability ◽  
Dimensional Instability

This paper presents a study of stall inception mechanisms a in low-speed axial compressor. Previous work has identified two common flow breakdown sequences, the first associated with a short lengthscale disturbance known as a ‘spike’, and the second with a longer lengthscale disturbance known as a ‘modal oscillation’. In this paper the physical differences between these two mechanisms are illustrated with detailed measurements. Experimental results are also presented which relate the occurrence of the two stalling mechanisms to the operating conditions of the compressor. It is shown that the stability criteria for the two disturbances are different: long lengthscale disturbances are related to a two-dimensional instability of the whole compression system, while short lengthscale disturbances indicate a three-dimensional breakdown of the flow-field associated with high rotor incidence angles. Based on the experimental measurements, a simple model is proposed which explains the type of stall inception pattern observed in a particular compressor. Measurements from a single stage low-speed compressor and from a multistage high-speed compressor are presented in support of the model.

Research on Defining Regional Boundary of the COREX Melter Gasifier by Using Image Processing

2012 ◽  
Vol 455-456 ◽  
pp. 1140-1144
Author(s):  
Zhi Guo Luo ◽  
Li Hao Han ◽  
Xiao Lei ◽  
Zhan Xia Di ◽  
Jun Jie Sun
Keyword(s):  
Image Processing ◽  
Cohesive Zone ◽  
High Speed ◽  
Processing Method ◽  
High Speed Camera ◽  
Two Dimensional ◽  
Corex Melter Gasifier ◽  
Experimental Process ◽  
Lump Coal ◽  
Regional Boundary

In this paper, a two-dimensional hot model of melter gasifier, in which paraffin and corn are used to simulate DRI, coke and lump coal respectively, has been established to study the regional boundary in this paper. While the whole experimental process is recorded by the high-speed camera, the image processing method is put forward to define each regional boundary. By means of this method, the boundary of raceway, cohesive zone can be obtained quantificationally.

scholarly journals Stability, spatial extension and extinction of an electric arc in aeronautical conditions of pressure under 540 V DC

2019 ◽  
Vol 87 (3) ◽  
pp. 30901
Author(s):  
Romaric Landfried ◽  
Mohamed Boukhlifa ◽  
Thierry Leblanc ◽  
Philippe Teste ◽  
Jonathan Andrea
Keyword(s):  
High Speed ◽  
Electric Arc ◽  
High Speed Camera ◽  
Arc Length ◽  
Electrode Gap ◽  
Arc Current ◽  
The Mean ◽  
The Stability ◽  
Energy Dissipated

This work deals with the characterization of DC electric arcs in aeronautical conditions of pressure (from 104 Pa to 105 Pa). Observations have been made with the help of a high speed camera and various characteristics of electric arc under 540 V DC have been studied: the stability arc length, the extinction gap, the arc duration and the mean energy dissipated in the arc. The arc current intensity range is 10–100 A. The obtained results show that the arc stability length, extinction electrode gap, arc duration and energy dissipation in the arc have a direct correlation with the pressure and the current in the circuit.

Experiments on the Injection of Elliptical Liquid Jets Into a Low Speed Airflow

2018 ◽  
Author(s):  
Yosef Rezaei ◽  
Mehran Tadjfar
Keyword(s):  
Experimental Investigation ◽  
Weber Number ◽  
Momentum Flux ◽  
High Speed ◽  
Flux Ratio ◽  
Major Axis ◽  
Liquid Jets ◽  
Liquid Jet ◽  
High Speed Camera ◽  
Subsonic Crossflow

An experimental investigation was performed to study the physics of liquid jets injected into a low subsonic crossflow. The jets are issued from elliptical and circular injectors with equivalent exit area. The liquid jet was visualized using shadowgraph technique and a high speed camera was used to record the instantaneous status of the jet. The liquid / air momentum flux ratio and air Weber number were varied to examine their effects on different parameters of the flow like liquid jet column trajectory, breakup point and breakup regimes. The major axis of the elliptical nozzle was aligned parallel and perpendicular to the air crossflow direction. Two different breakup modes were observed, column breakup and bag breakup. Based on the obtained results some characteristics of injected liquid jets into the air crossflow such as penetration depth and the trajectory of liquid jet were affected by changing the nozzle exit shape.

Combined two-dimensional velocity and temperature measurements using a high-speed camera and luminescent particles

2010 ◽  
Vol 99 (1-2) ◽  
pp. 325-332 ◽  
Author(s):  
S. Someya ◽  
D. Ochi ◽  
Y. Li ◽  
K. Tominaga ◽  
K. Ishii ◽  
...  
Keyword(s):  
High Speed ◽  
Temperature Measurements ◽  
High Speed Camera ◽  
Two Dimensional
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