Numerical Simulation on Detonation Process in Variable-Section Charge under Condition of End-Point Detonation Model

2015 ◽  
Vol 799-800 ◽  
pp. 728-733
Author(s):  
Jun Ting Yin ◽  
Gang Li
Keyword(s):  
Numerical Simulation ◽  
Detonation Wave ◽  
Structure Design ◽  
Practical Significance ◽  
Cylindrical Charge ◽  
Oblique Collision ◽  
End Point ◽  
Variable Section ◽  
Velocity Of Detonation ◽  
Detonation Process

when detonation wave is spreading in cylindrical charge which has a shell constraint, the border of the shell will reflect the detonation wave, reflection wave still has a strong influence on charge’s centerline. Compared with cylindrical charge, the influence of variable-section charge’s stack reflection wave on centerline is unsteady, relating to the gradual trends height of section area. On the condition of end-point detonation, doing the numerical simulation on detonation process of equal-section charge 、reduced-increased charge and increased-reduced charge, analyzing the pressure and velocity of detonation products on position of centerline, founding in the range of gradually decreasing section al, detonation wave through reflecting and then occur oblique collision that induce the pressure increasing rapidly. Doing the numerical simulation on variable-section charge’s detonation, promoting the understand of the reflection wave mechanism and the velocity of detonation product, this can be a practical significance to further improve the charge structure design and realize the efficient utilization of detonation energy.

scholarly journals A theory of the dependence of the rate of detonation of solid explosives on the diameter of the charge

1947 ◽  
Vol 189 (1018) ◽  
pp. 415-426 ◽  
Keyword(s):  
Detonation Wave ◽  
Chemical Reaction ◽  
Cylindrical Charge ◽  
Solid Explosive ◽  
Metal Case ◽  
Rate Of Reaction ◽  
Velocity Of Detonation ◽  
Solid Explosives ◽  
Different Diameters

The velocity of a detonation wave, in a cylindrical charge of solid explosive, is shown to be dependent on the diameter of the charge, and the relation between the velocity and the diameter is calculated. It is shown that this effect depends upon the rate of the chemical reaction occurring in the front portions of the detonation wave, and that it is possible, therefore, to determine this rate of reaction by measuring the velocity of detonation in bare charges of different diameters. The effect of a metal case surrounding the charge is also briefly discussed.

Study on the Integrated Design of Underground Construction Lighting and Ventilation System

2011 ◽  
Vol 374-377 ◽  
pp. 702-705
Author(s):  
Wei Feng ◽  
Hui Min Li
Keyword(s):  
Numerical Simulation ◽  
Thermal Environment ◽  
Ventilation System ◽  
Integrated Design ◽  
Structure Design ◽  
Light Environment ◽  
System Model ◽  
Underground Construction ◽  
New Type

In the underground building, Light environment and thermal environment is poorer, in order to improve the problem, this paper brings forward a new type of lighting and ventilation system model; discusses the principle and characteristics of transmission; and analyses the question that influences lighting and ventilated effect in the application. Structure design and numerical simulation is the focus of the next step.

FEM Analysis of Contact for Converter Spherical Hinge

2013 ◽  
Vol 365-366 ◽  
pp. 331-334
Author(s):  
Xue Ping Ren ◽  
Jian Da Gao
Keyword(s):  
Numerical Simulation ◽  
Thermal Stress ◽  
Optimum Design ◽  
Theoretical Basis ◽  
Fem Analysis ◽  
Structure Design ◽  
Coupling Field ◽  
Main Components ◽  
Spherical Hinge

The role of converter spherical hinge is one of the main components, combined with practical work and With help of FEM, Thermal Stress coupling field of spherical washer can been obtained through numerical simulation. The result supplies substantial theoretical basis for further structure design and optimum design of mechanism.

Lab Testing and Finite Element Method Simulation of Hole Deflector Performance for Radial Jet Drilling

2017 ◽  
Vol 139 (3) ◽  
Author(s):  
Bin Wang ◽  
Gensheng Li ◽  
Zhongwei Huang ◽  
Tianqi Ma ◽  
Dongbo Zheng ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Low Cost ◽  
Geometric Model ◽  
Frictional Resistance ◽  
Finite Element Method Simulation ◽  
Optimization Method ◽  
Structure Design ◽  
Coal Bed ◽  
Factors Affecting ◽  
High Pressure Water Jet

Radial jet drilling (RJD) is an efficient approach for improving the productivity of wells in low permeability, marginal and coal-bed methane (CBM) reservoirs at a very low cost. It uses high-pressure water jet to drill lateral holes from a vertical wellbore. The length of the lateral holes is greatly influenced by the frictional resistance in the hole deflector. However, the hole deflector frictional resistance and structure design have not been well studied. This work fills that gap. Frictional resistances were measured in a full-scale experiment and calculated by numerical simulation. The structure of the hole deflector was parameterized and a geometric model was developed to design the hole deflector track. An empirical model was then established to predict the frictional resistance as a function of the hole deflector structure parameters and an optimization method for designing the hole deflector was proposed. Finally, four types of hole deflectors were optimized using this method. The results show good agreement between the numerical simulation and the experimental data. The model error is within 11.6%. The bend radius R and exit angle β are the key factors affecting the performance of the hole deflector. The validation test was conducted for a case hole deflector (5½ in. casing). The measured frictional resistance was decreased from 31.44 N to 23.16 N by 26.34%. The results from this research could serve as a reference for the design of hole deflectors for radial jet drilling.

Gaseous detonation propagation in a bifurcated tube

2008 ◽  
Vol 599 ◽  
pp. 81-110 ◽  
Author(s):  
C. J. WANG ◽  
S. L. XU ◽  
C. M. GUO
Keyword(s):  
Numerical Simulation ◽  
Detonation Wave ◽  
Mach Reflection ◽  
Initial Pressure ◽  
Gaseous Detonation ◽  
Recirculation Region ◽  
Horizontal Branch ◽  
Regular Reflection ◽  
Detonation Propagation ◽  
Wall Geometry

Gaseous detonation propagation in a bifurcated tube was experimentally and numerically studied for stoichiometric hydrogen and oxygen mixtures diluted with argon. Pressure detection, smoked foil recording and schlieren visualization were used in the experiments. Numerical simulation was carried out at low initial pressure (8.00kPa), based on the reactive Navier–Stokes equations in conjunction with a detailed chemical reaction model. The results show that the detonation wave is strongly disturbed by the wall geometry of the bifurcated tube and undergoes a successive process of attenuation, failure, re-initiation and the transition from regular reflection to Mach reflection. Detonation failure is attributed to the rarefaction waves from the left-hand corner by decoupling leading shock and reaction zones. Re-initiation is induced by the inert leading shock reflection on the right-hand wall in the vertical branch. The branched wall geometry has only a local effect on the detonation propagation. In the horizontal branch, the disturbed detonation wave recovers to a self-sustaining one earlier than that in the vertical branch. A critical case was found in the experiments where the disturbed detonation wave can be recovered to be self-sustaining downstream of the horizontal branch, but fails in the vertical branch, as the initial pressure drops to 2.00kPa. Numerical simulation also shows that complex vortex structures can be observed during detonation diffraction. The reflected shock breaks the vortices into pieces and its interaction with the unreacted recirculation region induces an embedded jet. In the vertical branch, owing to the strength difference at any point and the effect of chemical reactions, the Mach stem cannot be approximated as an arc. This is different from the case in non-reactive steady flow. Generally, numerical simulation qualitatively reproduces detonation attenuation, failure, re-initiation and the transition from regular reflection to Mach reflection observed in experiments.

scholarly journals Insulated Cable Temperature Calculation and Numerical Simulation

2018 ◽  
Vol 175 ◽  
pp. 03014
Author(s):  
Xin-jian Li ◽  
Jun Yang ◽  
Bing-qiang Yan ◽  
Xiao Zheng
Keyword(s):  
Numerical Simulation ◽  
Mathematical Model ◽  
Spontaneous Combustion ◽  
Practical Significance ◽  
Constant Current ◽  
Sectional Area ◽  
Analysis Method ◽  
Insulation Layer ◽  
Insulating Layer ◽  
Temperature Calculation

A mathematical model of electrified insulated cable was established to calculate temperature of insulating layer. The insulating layer temperature is determined as a function of the current intensity, time, insulation layer thickness, etc. A widely used polyvinyl chloride (PVC) cable with sectional area of 4 mm2 was selected as example and its insulating layer temperature was simulated using ANSYS. The simulation revealed the evolution of insulating layer temperature with time, and also along radius after a certain time when the cable was applied with 40A and 60A constant current respectively. The analysis method has practical significance to prevent electrical fire and can be applied to analyze spontaneous combustion accident of insulated cable.

scholarly journals Design and Experimental Study of Rotary Type High-Speed Shearer for Metal Bars

2018 ◽  
Vol 166 ◽  
pp. 01008
Author(s):  
Renfeng Zhao ◽  
Jingyu Zhou ◽  
Yan Li ◽  
Shuqin Fan ◽  
Jingxiang Li ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
High Speed ◽  
Cutting Tool ◽  
Small Diameter ◽  
Structure Design ◽  
Experiment Platform ◽  
Steel Bar ◽  
Feeding Structure ◽  
Stress Concentration Effect ◽  
Rotary Type

For the precision shear of bars, the kind of rotating high-speed precision cutting method has been given. The structure design of rotary precision shearing machine and the structure design of feeding structure are completed. The method of numerical simulation is used to optimize the cutting tool, and then the experiment platform is completed. Rotary impact and the stress concentration effect of the surface of the bar are used in the paper. The experiment is carried out for the Φ8 mm diameter stainless steel bar stock by changing the speed of the cutting tool through the converter and controlling rod feeding efficiency. The experimental results show that the method is feasible to meet the requirement of various material of the small diameter rod in the industry.

scholarly journals Structure parameter optimization and bearing limit analysis of the expansion unit of three-roller tube expander

2020 ◽  
Vol 7 (5) ◽  
pp. 191630
Author(s):  
Gang Bi ◽  
Zhan Qu ◽  
Zhenquan Wang ◽  
Liangbin Dou ◽  
Mengmeng Li
Keyword(s):  
Numerical Simulation ◽  
Simulation Method ◽  
Gauge Length ◽  
Structure Design ◽  
Design Parameters ◽  
Roller Tube ◽  
Unit Structure ◽  
Drilling Technology ◽  
Expansion Force ◽  
Proper Length

The critical technical issues for the structure design of three-roller tube expander were first studied and analysed in this paper. Then, the major design parameters of the expansion unit structure and the bearing limit of 12¼″ three-roller tube expander were optimized and investigated by finite-element numerical simulation method. Results from study show that the required expansion force increases when the taper angle of the roller outer surface gets larger, taking the axial expansion force as the quantitative indicators. It is suggested that the roller tape angle of the expansion unit should be in the range of 9–12° considering the proper length of the roller and the non-self-locking tube expansion process. The required expansion force of the bellows first decreases and then increases when the gauge length of the expansion unit becomes longer. The optimal value of the gauge length is 50 mm considering the proper length of the roller. And according to the numerical simulation results, the designed three-roller tube expander meets the strength requirements. The results of this study are of great significance to the expend bellows drilling technology.

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