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 simulation of dust explosion in the spherical 20l vessel

2015 ◽  
Vol 63 (1) ◽  
pp. 289-293 ◽  
Author(s):  
Z. Salamonowicz ◽  
M. Kotowski ◽  
M. Półka ◽  
W. Barnat
Keyword(s):  
Numerical Simulation ◽  
Numerical Simulations ◽  
Combustion Process ◽  
Test Stand ◽  
Maximum Pressure ◽  
Dust Explosion ◽  
Computational Domain ◽  
Dispersion Process ◽  
Dust Dispersion ◽  
Positive Agreement

Abstract The paper presents experimental and numerical validation of the combustion process of coal and flour dust dispersed in a spherical chamber of 20 cubic decimetres volume. The aim of the study is to validate the numerical simulation results in relation to the experimental data obtained on the test stand. To perform the numerical simulations, a Computational Fluid Dynamics code FLUENT was used. Geometry of the computational domain was built in compliance with EN 14460. Numerical simulations were divided into two main steps. The first one consists in a dust dispersion process, where influence of standardized geometry was verified. The second part of numerical simulations investigated dust explosion characteristics in compliance with EN 14034. After several model modifications, outcomes of the numerical analysis shows positive agreement with both, the explosion characteristics for different dust concentration levels and the maximum pressure increase obtained on the test stand.

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.

Flow characteristics of dusts dispersed by high-pressure air blast in 20 L chamber

2015 ◽  
Vol 32 (3) ◽  
pp. 742-765 ◽  
Author(s):  
Jiachen Chen ◽  
Qi Zhang
Keyword(s):  
Numerical Simulation ◽  
High Pressure ◽  
Dust Cloud ◽  
Dust Particles ◽  
Dust Explosion ◽  
Air Blast ◽  
Content Type ◽  
Uniform Dispersion ◽  
Dust Dispersion ◽  
Dust Distribution

Purpose – A dust cloud is formed by a high-pressure air blast in dust explosion experiments in the spherical 20 L chamber. The state of the dust cloud has a significant impact on the dust explosion. However, it is difficult to observe the dust distribution in the chamber during the dust dispersion. Numerical simulation was used to examine the dust distribution in the chamber with the rebound nozzle in this work. The paper aims to discuss these issues. Design/methodology/approach – Through a series numerical simulations, the influences of the dust particle size and the pressure for dust dispersion on the have been analyzed, and the results are discussed. Findings – Dust in the spherical 20 L chamber is in the state of very intensifying motion within 30 ms from dispersion starting. Dust in the chamber reaches a uniform state beyond 200 ms. The pressure for dust dispersion should be higher than 0.5 MPa for the aluminum dusts of larger than 50. The higher blast pressure is not always applicable to achieve a uniform dispersion. There is a best blast pressure value for a given dust to achieve a uniform dispersion in the spherical 20 L chamber. Research limitations/implications – Dust cloud generation is essential for understanding dust explosions. Dust cloud deflagration parameters depend on the uniformity and concentration of dusts dispersed by a high-pressure air blast. Numerical simulation was used to examine the multiphase flow of the dust air mixture in this work. Through a series numerical simulations, the influences of the dust particle size and the pressure for dust dispersion on the have been analyzed, and the results are discussed. The data are useful for understanding the basics of dust cloud formation. Practical implications – The data are useful for evaluating dust explosion experimental parameters. Originality/value – Dispersible uniformity has a strong impact on measured parameters of dust explosion in a chamber. However, it is difficult to observe the dust particles distribution during the dispersion. Numerical simulation was used to examine the dust particles distribution and its influencing factors during the dispersion in this work. New finding is: the approach to examine the distribution of dust particles dispersed by a high-pressure blast in a chamber; the variation of dispersible uniformity and its influencing factors when dust is injected into the spherical 20 L chamber by high-pressure air blast.

Development of High-Speed Response Electromagnetic Linear Actuator Using for Pneumatic Control Valve

2014 ◽  
Vol 532 ◽  
pp. 41-45 ◽  
Author(s):  
Myung Jin Chung
Keyword(s):  
Optimal Design ◽  
Dynamic Characteristics ◽  
High Speed ◽  
Design Method ◽  
Control Valve ◽  
Design Parameters ◽  
Linear Actuator ◽  
Analytic Model ◽  
Electromagnetic Linear Actuator ◽  
Quadratic Programming Method

Analytic model of electromagnetic linear actuator in the function of electric and geometric parameters is proposed and the effects of the design parameters on the dynamic characteristics are analyzed. To improve the dynamic characteristics, optimal design is conducted by applying sequential quadratic programming method to the analytic model. This optimal design method aims to minimize the response time and maximize force efficiency. By this procedure, electromagnetic linear actuator having high-speed characteristics is developed.

Review of the Investigation of Fuel-Air Premixing and Combustion Process Using Rapid Compression Machine and Direct Visualization System

2013 ◽  
Vol 465-466 ◽  
pp. 265-269 ◽  
Author(s):  
Mohamad Jaat ◽  
Amir Khalid ◽  
Bukhari Manshoor ◽  
Siti Mariam Basharie ◽  
Him Ramsy
Keyword(s):  
High Speed ◽  
Combustion Engine ◽  
Early Stage ◽  
Combustion Process ◽  
Injection Pressure ◽  
Rapid Compression Machine ◽  
Mixture Formation ◽  
Visualization System ◽  
Optical Visualization ◽  
Rapid Compression

s :This paper reviews of some applications of optical visualization system to compute the fuel-air mixing process during early stage of mixture formation and late injection in Diesel Combustion Engine. This review has shown that the mixture formation is controlled by the characteristics of the injection systems, the nature of the air swirl and turbulence in thecylinder, and spray characteristics. Few experimental works have been investigated and found that the effects of injection pressure and swirl ratio have a great effect on the mixture formation then affects to the flame development and combustion characteristics.This paper presents the significance of spray and combustion study with optical techniques access rapid compression machine that have been reported by previous researchers. Experimental results are presentedin order to provide in depth knowledge as assistance to readers interested in this research area. Analysis of flame motion and flame intensity in the combustion chamber was performed using high speed direct photographs and image analysis technique. The application of these methods to the investigation of diesel sprays highlights mechanisms which provide a better understanding of spray and combustion characteristics.

scholarly journals Design and Fabrication of Two Step Speed Control of a Cylinder Circuit using Pneumatics

2019 ◽  
Vol 8 (6S2) ◽  
pp. 512-516
Keyword(s):  
Flow Control ◽  
High Speed ◽  
Air Flow ◽  
Control Valve ◽  
Speed Control ◽  
Flow Control Valve ◽  
Push Button ◽  
Low Speed ◽  
Flow Through

The main aim of our project is to design and fabrication of pneumatic two step speed control of a cylinder. Initially the flow from the FRL retracts the cylinder when the push button is in its spring offset position. When it is pushed the flow pilots actuate. The air passes through the flow control and shuttle valve. Then the cylinder extends with high speed as the valve allows more air to enter the cylinder. When the piston reaches the position it operates the cam push button and pilot air flow through this and actuate 5/2 pilot operated valve and reaches flow control valve which permits less air. Then the flow through enters the shuttle valve to cylinder and allows the cylinder to extend at relatively low speed. At the end of extension stroke deactivating push button retracts the cylinder. Thus the speed of cylinder is controlled and project can be achieved

scholarly journals Estimation of aerator air demand by an embedded multi-gene genetic programming

2021 ◽  
Author(s):  
Shicheng Li ◽  
James Yang ◽  
Wei Liu
Keyword(s):  
Genetic Programming ◽  
High Speed ◽  
Pareto Front ◽  
Gene Expression Programming ◽  
Absolute Error ◽  
Processing Technique ◽  
Coefficient Of Determination ◽  
Speed Flow ◽  
Processing Measure ◽  
Programming Solution

Abstract A spillway discharging a high-speed flow is susceptible to cavitation damages. As a countermeasure, an aerator is often used to artificially entrain air into the flow. Its air demand is of relevance to cavitation reduction and requires accurate estimations. The main contribution of this study is to establish an embedded multi-gene genetic programming (EMGGP) model for improved prediction of air demand. It is an MGGP-based framework coupled with the gene expression programming acting as a pre-processing technique for input determination and the Pareto front serving as a post-processing measure for solution optimization. Experimental data from a spillway aerator are used to develop and validate the proposed technique. Its performance is statistically evaluated by the coefficient of determination (CD), Nash–Sutcliffe coefficient (NSC), root-mean-square error (RMSE) and mean absolute error (MAE). Satisfactory predictions are yielded with CD = 0.95, NSC = 0.94, RMSE = 0.17 m3/s and MAE = 0.12 m3/s. Compared with the best empirical formula, the EMGGP approach enhances the fitness (CD and NSC) by 23% and reduces the errors (RMSE and MAE) by 48%. It also exhibits higher prediction accuracy and a simpler expressional form than the genetic programming solution. This study provides a procedure for the establishment of parameter relationships for similar hydraulic issues.

Theory and Measurements of the Propeller-Induced Vibratory Pressure Field

1972 ◽  
Vol 16 (02) ◽  
pp. 124-139
Author(s):  
W. R. Jacobs ◽  
J. Mercier ◽  
S. Tsakonas
Keyword(s):  
High Speed ◽  
Pressure Field ◽  
Processing Technique ◽  
Experimental Program ◽  
Signal Processing Technique ◽  
Experimental Procedure ◽  
Surface Theory ◽  
Blade Frequency ◽  
Development Center ◽  
Theoretical Results

A theory has been developed, based on lifting surface theory, for evaluation of the pressure field generated by an operating propeller in a nonuniform inflow field. In addition, an experimental procedure and a signal processing technique for measuring small pressure levels accurately have been established and utilized in an extensive experimental program. Theoretical results obtained by means of a computer program developed for the CDC 6600 high-speed digital computer agree well with those of experiments conducted at Davidson Laboratory and at the Naval Ship Research and Development Center. The difficulty of accurately establishing by measurements the decay of small pressures at points farther than one radius from the propeller precludes the possibility of determining the blade-frequency force exerted on a flat boundary by integrating the measured signatures. In contrast, integration of double the theoretical free-space pressure over the flat boundary appears to be a feasible and meaningful approach.

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