scholarly journals Study and Numerical Simulation on Explosion Propagation Characteristics of Lignite Dust

2020 ◽  
Vol 198 ◽  
pp. 03010
Author(s):  
Zizheng Pang ◽  
Shunbing Zhu ◽  
Yanru He
Keyword(s):  
Numerical Simulation ◽  
High Speed ◽  
Test System ◽  
Dust Explosion ◽  
High Speed Camera ◽  
Propagation Characteristics ◽  
Propagation Law ◽  
Spherical Explosion ◽  
Dust Diffusion ◽  
Explosion Test

In order to reveal the explosion propagation law of lignite dust in 20L spherical explosion test device, the dust diffusion behavior and explosion propagation characteristics of lignite were studied by experiment and numerical simulation. The propagation process of dust explosion is studied by using high-speed camera and 20L spherical explosion test system, and the process of dust diffusion and explosion is simulated by using FLUENT software. The results show that the explosion propagation of lignite dust in the 20L spherical explosion test system has four different stages: the first explosion stage, the full explosion combustion stage, the continuous combustion stage and the combustion attenuation stage. The test results are slightly different from that of the fluent simulation of lignite dust explosion by using the high-speed camera to collect the dust explosion images. Results within the allowable error range, the experimental image of explosion combustion of lignite dust is well connected with the simulation results, which has a good display effect on the explosion propagation of lignite dust.

High-speed impact assessment for composite air inlet

2019 ◽  
Vol 11 (5) ◽  
pp. 723-736
Author(s):  
Radek Doubrava ◽  
Martin Oberthor ◽  
Petr Bělský ◽  
Jan Raška
Keyword(s):  
Numerical Simulation ◽  
Composite Structure ◽  
High Speed ◽  
Numerical Models ◽  
Impact Resistance ◽  
High Speed Camera ◽  
Content Type ◽  
High Speed Impact ◽  
Air Inlet ◽  
Final Design

Purpose The purpose of this paper is to describe the approach for the design of a jet engine composite air inlet for a new generation of jet trainer aircraft from the perspective of airworthiness requirements regarding high-speed impact resistance. Design/methodology/approach Validated numerical simulation was applied to flat test panels. The final design was optimised and verified by validated numerical simulation and verified by testing on a full-scale demonstrator. High-speed camera measurement and non-destructive testing (NDT) results were used for the verification of the numerical models. Findings The test results of flat test panels confirmed the high durability of the composite structure during inclined high-speed impact with a near-real jet inlet load boundary condition. Research limitations/implications Owing to the sensitivity of the composite material on technology production, the results are limited by the material used and the production technology. Practical implications The application of flat test panels for the verification and tuning of numerical models allows optimised final design of the air inlet and reduces the risk of structural non-compliance during verification tests. Originality/value Numerical models were verified for simulation of the real composite structure based on high-speed camera results and NDT inspection after impact. The proposed numerical model was simplified for application in a real complex design and reduced calculation time.

Investigation of Rod Vibrations in Droplet Two-Phase Flows

2011 ◽  
Author(s):  
Yoshiteru Komuro ◽  
Zensaku Kawara ◽  
Tomoaki Kunugi
Keyword(s):  
Numerical Simulation ◽  
High Speed ◽  
Nuclear Power ◽  
Power Plants ◽  
Motion Tracking ◽  
High Speed Camera ◽  
Two Phase Flows ◽  
Two Phase ◽  
Wet Condition ◽  
Flow Induced Vibrations

Flow-induced vibrations are important problems in nuclear power plants from the view point of reactor safety. In the investigations of these vibrations especially those induced by two-phase flows, a numerical simulation plays a significant role, so it is necessary to obtain the experimental datasets that can validate the results of the numerical simulation. This paper deals with the experimental data of one-end-supported rod vibration, and focuses on the differences between the rod vibrations induced by single-phase air flows and those induced by droplet two-phase flows. In the experiments, the displacement of the non-supported end of the test rod was visualized by the high speed camera with high spatial and temporal resolutions, namely 9.5 μm and 500 μsec. Using an image analyzing software, the rod vibration displacements were measured by the motion tracking method. The curved surface of the rod was observed by another high speed camera and the relationship between the rod vibrations and the wet condition on the surface of the rod was investigated. In addition, the vibrations measured by the strain gages and those by the high speed camera were compared to discuss the differences in these two ways of the measurements.

Visualization Study of Dust Dispersion Process in Siwek 20-L Device for Dust Explosion Test

2014 ◽  
Vol 590 ◽  
pp. 266-270 ◽  
Author(s):  
Bing Du ◽  
Wei Xing Huang ◽  
Nian Sheng Kuai ◽  
Jing Jie Yuan ◽  
Long Liu ◽  
...  
Keyword(s):  
High Speed ◽  
Dust Cloud ◽  
Control Valve ◽  
Processing Technique ◽  
Dust Explosion ◽  
Spherical Vessel ◽  
Dispersion Process ◽  
Visualization System ◽  
Dust Dispersion ◽  
Explosion Test

A visualization method is proposed in order to characterize the dispersion process of dust cloud in Siwek 20-L explosion device. The visualization system consists of a transparent spherical vessel, a dust dispersion device, a high precision control valve and a high-speed camera. Experiment with wheat flour powder indicate that the non-uniformity of dust cloud in space and time can be clearly distinguished based on the frame pictures, as well as the evolution of particles settlement with time after dispersion. Moreover, qualitative analysis based on picture processing technique was carried out to obtain the transmission data of dust cloud from the frame pictures. Results show that the transmission changes rapidly with time and reaches to the minimum value at about 60 ms after dispersion, and with this time, the optimum ignition delay time can be determined for dust explosion test in Siwek 20-L device.

scholarly journals Numerical Study of the Pulsation Process of Spark Bubbles under Three Boundary Conditions

2021 ◽  
Vol 9 (6) ◽  
pp. 619
Author(s):  
Chunlong Ma ◽  
Dongyan Shi ◽  
Chao Li ◽  
Dongze He ◽  
Guangliang Li ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Numerical Model ◽  
Nonlinear Interaction ◽  
Cavitation Bubble ◽  
High Speed ◽  
Free Field ◽  
Experimental Results ◽  
High Speed Camera ◽  
Cavitation Bubbles ◽  
Bubble Pulsation

In this study, a compressible three-phase homogeneous model was established using ABAQUS/Explicit. These models can numerically simulate the pulsation process of cavitation bubbles in the free field, near the flat plate target, and near the curved boundary target. At the same time, these models can numerically simulate the strong nonlinear interaction between the cavitation bubble and its nearby wall boundaries. The mutual flow of liquid and gas and fluid solid coupling were solved by the Euler domain in simulation. The results of the numerical simulation were verified by comparing them with the experimental results. In this study, we used electric spark bubbles to represent cavitation bubbles. A high-speed camera was used to record the pulsation process of cavitation bubbles. This study first verified the pulsation process of cavitation bubbles in the free field, because it was the simplest case. Then we verified the interaction process between cavitation bubbles and different wall boundaries. In order to further confirm the credibility of the numerical simulation results, for each wall surface, this study used two burst distances (10 mm and 25 mm) for simulation verification. The numerical model established in this study could effectively simulate the pulsation characteristics of cavitation bubbles, such as the formation of jets and annular bubbles. After verification, the simulated cavitation bubble was almost the same as the cavitation bubble captured by the high-speed camera in the experiment in terms of time, volume, and shape. In this study, a detailed velocity field of the cavitation bubble collapse stage was obtained, which laid down the foundation for the study of the strong nonlinear interaction between the cavitation bubble and the target plates of different shapes. Compared with the experimental results, we found that the numerical model established by the simulation could accurately simulate the bubble pulsation and jet formation processes. In the experiment, the interval time for the bubble pictures taken by the high-speed camera was 41.66 μs per frame. Using a numerical model, the bubble pulsation process can be simulated at an interval of 1 µs per frame. Therefore, the numerical model established by the simulation could show the movement characteristics of the cavitation bubble pulsation process in more detail.

Experimental and Numerical Research of Small Metal Disk Driven by Explosive

2011 ◽  
Vol 673 ◽  
pp. 301-305
Author(s):  
Hideki Hamashima ◽  
Shiro Kubota ◽  
Tei Saburi ◽  
Yuji Ogata
Keyword(s):  
Numerical Simulation ◽  
High Speed ◽  
Numerical Results ◽  
Experimental Results ◽  
Basic Data ◽  
High Speed Camera ◽  
Analysis Software ◽  
Metal Disk ◽  
Numerical Research ◽  
Explosion Experiment

In order to investigate the hazard of the fragments caused by the explosion damage, the simply-simulated explosion experiment and numerical simulation were conducted. In this study, the behavior of the disk supposing the fragment driven by an explosive was investigated. In the experiment, the optical observation using a high-speed camera was performed to obtain the basic data about a disk, such as flying velocity. Moreover, numerical simulation was performed using analysis software LS-DYNA. Comparison and examination for experimental results and numerical results were reported.

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