Decomposition Kinetics and Cook-Off Numerical Simulation of Insensitive Energetic Plasticizer Plasticized Propellants

2022 ◽  
Vol 905 ◽  
pp. 263-268
Author(s):  
Ya Lun Wang ◽  
Yu Chen ◽  
Yun Fei Liu
Keyword(s):  
Numerical Simulation ◽  
Ignition Temperature ◽  
Central Area ◽  
Thermal Safety ◽  
Safety Issues ◽  
Safety Property ◽  
High Temperature Area ◽  
Energetic Plasticizer ◽  
Different Thickness ◽  
Temperature Area

Aiming at the thermal safety issues between the insensitive energetic plasticizer and propellant components, NG/BTTN and insensitive energetic plasticizer BuNENA plasticized propellant was compared by DSC test and cook-off numerical simulation, with the thermal safety property evaluated. The decomposition activation energy Ea and self-ignition temperature Tb of BuNENA plasticized propellant was lower than that of NG/BTTN plasticized propellant. Two kinds of propellant responded in the central area during slow cook-off simulation while in the near shell area during medium cook-off simulation. During fast cook-off simulation, depending on the different thickness of insulator, propellant responded at the area near shell or the area near the caps. The response temperature of two propellants in cook-off simulation agreed with decomposition and self-ignition temperature by DSC, and the decomposition of plasticizer could trigger the response. In cook-off simulation, BuNENA plasticized propellant showed a lower response temperature with a smaller high temperature area before response, resulting a milder response and better thermal safety than NG/BTTN plasticized propellant.

Numerical Simulation of Interior Flow in Evaporation Droplet

2014 ◽  
Author(s):  
Qingming Dong ◽  
Zhentao Wang ◽  
Yonghui Zhang ◽  
Junfeng Wang
Keyword(s):  
Numerical Simulation ◽  
High Temperature ◽  
Internal Flow ◽  
Surface Force ◽  
Droplet Surface ◽  
Force Model ◽  
Marangoni Flow ◽  
High Temperature Area ◽  
Interior Flow ◽  
Temperature Area

In this present study, the VOF (Volume of Fluid) approach is adopted to capture the interface, and CSF (Continuum Surface Force) model to calculate the surface tension, and the governing equations are founded in numerical simulation of evaporating droplets. In this work, a water droplet is assumed to be suspending in high temperature air, and the gravity of a droplet is ignored. During evaporating process of the droplet, the internal circulation flow will be induced due to the gradient of temperature at the droplet surface. The interface flows from high temperature area to low temperature area, which pulls the liquid to produce convective flow inside the droplet called as Marangoni flow. Marangoni flow makes the temperature distribution tend to uniformity, which enhances heat transfer but weakens Marangoni flow in turn. So, during droplet evaporation, the internal flow is not steady.

Numerical Simulation and Flame Characteristics Analysis of Non-Premixed Swirling Combustion

2021 ◽  
Author(s):  
Yi Su ◽  
Bin Zhang ◽  
Junqing Hou ◽  
Yifeng Chen ◽  
Jieyu Jiang ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
High Temperature ◽  
High Velocity ◽  
Temperature Fields ◽  
Pollutant Emission ◽  
Form Complex ◽  
High Temperature Area ◽  
Swirling Flames ◽  
Velocity And Temperature Fields ◽  
Temperature Area

Abstract Swirling flames are important in practical industrial combustors. The dynamic characteristics of swirling flames form complex velocity and temperature fields, which indicate combustion efficiency and influence pollutant emission. A reliable numerical simulation that can calculate the entire velocity and temperature fields is required to understand and investigate the underlying combustion mechanism. The governing equations of the methane swirling combustion process consist of the mass conservation, Navier-Stokes, and energy equations, all of which are solved by the SIMPLE algorithm based on finite volume method. This study performed a simulation using the realizable k-ε and non-premixed models in conjunction with the GRI Mech 3.0 mechanism. The characteristics of swirling combustion were analyzed on the bases of visualizations of temperature distribution, velocity distribution, and streamlines. In each cross section with varying heights from the nozzle, the high velocity and high temperature areas showed similar closed or semi-closed annular structures. In the central longitudinal section, the V-shaped high temperature and high velocity regions showed the swirling structure of the combustion flow field. The high temperature area did not coincide with the high velocity area but was located relatively downstream. The high velocity area was in the periphery of the high temperature area. Furthermore, the effects of swirl blade position on methane combustion characteristics were discussed. The validity of the numerical simulation results was verified by the simultaneous laser measurement of 3D temperature and velocity fields in the swirling flame.

Experimental Investigation and Numerical Simulation of Glass-Silicon Bonding by Localized Laser Heating

2003 ◽  
Author(s):  
S. Theppakuttai ◽  
D. B. Shao ◽  
S. C. Chen
Keyword(s):  
Numerical Simulation ◽  
Silicon Wafer ◽  
Laser Heating ◽  
Laser Energy ◽  
Anodic Bonding ◽  
Melting Time ◽  
Glass Wafer ◽  
High Temperature Area ◽  
Good Heat ◽  
Temperature Area

In this paper, we report a method to bond silicon and glass wafers directly using localized laser heating (pulsed Nd:YAG laser, 1064 nm, 12 ns). Laser energy was transmitted through the glass wafer and absorbed by the silicon wafer, resulting in a localized high temperature area. Pressure was applied upon the silicon and glass wafers to ensure immediate contact and good heat conduction between them. Scanning electron microscope (SEM) and chemical analysis were used to study bonding area and bonding mechanism. Numerical simulation was carried out in parallel using finite element method to predict the local temperature change of both the glass wafer and the silicon wafer during laser heating. The simulation was validated to some extent by the matching of melting time, which was obtained by using an additional probing laser (He-Ne, 633 nm, 20 mW) during the transient melting and re-solidification of the silicon. This bonding process is conducted locally while the entire wafer is maintained at room temperature, making it advantageous over traditional anodic bonding or fusion bonding.

Effect of Slag Layer on Flow Patterns in a Gas Stirred Ladle

2006 ◽  
Vol 510-511 ◽  
pp. 490-493 ◽  
Author(s):  
Sung-Ho Cho ◽  
Sung Hwan Hong ◽  
Jeong Whan Han ◽  
Byung Don You
Keyword(s):  
Numerical Simulation ◽  
Flow Pattern ◽  
Model Experiment ◽  
Central Area ◽  
Side Wall ◽  
Slag Layer ◽  
Flow Patterns ◽  
Water Model ◽  
Slag Viscosity ◽  
Mixing Behavior

Flow patterns and mixing behaviors in a gas stirred steelmaking ladle with a slag layer were discussed using a water model experiment as well as a numerical simulation. While the water model experiment was performed to investigate the effect of slag on the mixing behavior in ladle, the numerical simulation was carried out to figure out the flow pattern in ladle with a slag layer. Slag viscosity and its thickness in ladle were considered as major variables. It was found that a slag layer made a great change in the flow pattern in ladle, which, in turn, affected on the mixing behavior in ladle. A flow pattern without a slag layer showed that rising bubbles eventually made a recirculation loop at the central area of the ladle and this flow pattern was regarded as a favorable flow pattern for the better mixing behavior. However, a flow pattern with a slag layer showed distorted and localized recirculating loop near side wall below slag layer. This eventually gave a longer mixing time in ladle with a slag layer. Moreover, as the gas flow rate increases, slag existing on top of the ladle was found to be entrained into the melt. Slag viscosity and its thickness were found to be major variables affecting the behavior of slag entrainment. Lower the slag viscosity and thicker the slag layer, much more slag on top of the melt was entrained into the melt.

Simulation of Cavity Extension Formation in the Early Ignition Stage Based on a Coal Block Gasification Experiment

2020 ◽  
Vol 142 (6) ◽  
Author(s):  
Lin Xin ◽  
Jian Li ◽  
Jun Xie ◽  
Chao Li ◽  
Limin Han ◽  
...  
Keyword(s):  
Coal Gasification ◽  
Simulation Experiment ◽  
Vertical Direction ◽  
Underground Coal Gasification ◽  
Ignition Point ◽  
Coal Block ◽  
New Type ◽  
High Temperature Area ◽  
Left And Right ◽  
Temperature Area

Abstract Underground coal gasification (UCG) is a highly efficient new type of coal mining technology with broad future prospects. In order to study the cavity extension formation in the early ignition stage of UCG, a block coal scale UCG simulation experiment was carried out. The results show that after the ignition, the temperature above ignition point rose fastest, and the coal combustion interface and high temperature area moved toward to the above of ignition point, while the temperature of the left and right sides of ignition point rose a little slowly. According to the results of dissected block coal, it is indicated that the extension scale in the vertical direction was significantly larger than other directions; the combustion cavity form was an irregular rectangle like a pear. The results of this experiment revealed the cavity extension process from ignition of UCG channels to the formation of cavity, which provided a foundation for the study of extension characteristics of UCG channel in the entire UCG process.

scholarly journals Study on Compaction Effect and Process of Reclaimed Soil of Nonmetallic Mines in Xinjiang, China

2020 ◽  
Vol 2020 ◽  
pp. 1-15
Author(s):  
Kaikai Wang ◽  
Zizhao Zhang ◽  
Guobin Tang ◽  
Xiaodong Tan ◽  
Qianli Lv ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Land Reclamation ◽  
Simulation Method ◽  
Test Method ◽  
Soil Thickness ◽  
In Situ Test ◽  
Factors Affecting ◽  
Reclaimed Soil ◽  
Different Thickness

Reclaimed soil is the key substrate for land reclamation and ecological restoration in the mine areas. The change of the density of reclaimed soil of the nonmetallic mines in Xinjiang during the land reclamation process was studied in this paper. Firstly, the in situ test method of static load was used to simulate the compaction of reclaimed soil with different thickness of overlying soil by different compaction times of mines reclamation machinery, and field in situ test compaction data were obtained. Then, the numerical simulation method was used to simulate the variation process of displacement and porosity at different depths for different thickness of the reclaimed soil under different compaction conditions. The numerical simulation and the in situ test results verified each other to acquire the compaction process and results of reclaimed soil under different compaction. The results showed that the numerical simulation results were consistent with the in situ test. The reclaimed soil thickness and compaction times were crucial factors affecting the compaction effect of the soil. The difference between the three times compaction and the uncompacted soil was obvious, and the effect of single compaction was weakened with the increase of compaction times. Under the same compaction action, the thicker the soil was, the less obvious the compaction effect would be. In the process of reclamation, the compaction effect of the surface part (at the depth of 10 cm) was visible, and the amount of compression and springback was larger. The research results can provide a reference to the land reclamation of nonmetallic mines in Xinjiang, China.

Numerical Simulation of Cook-Off for Passive RDX

2014 ◽  
Vol 989-994 ◽  
pp. 2679-2683
Author(s):  
Chun Chen ◽  
Wei Bing Li ◽  
Jun Liu
Keyword(s):  
Numerical Simulation ◽  
Charge Density ◽  
Heating Rate ◽  
Ignition Time ◽  
Great Influence ◽  
Thermal Safety ◽  
Heating Rates ◽  
Fluent Software

For passive RDX, fluent software was applied to simulate the cook-off for explosive of different charge density at heating rates of 1, 5, 10k/min to improve thermal safety in the ammunition storage, transport and battle. The results show that the heating rate has great effect on ignition time and position for passive RDX. Charge density also has great influence on ignition time but no influence on ignition position. The ignition time decreases and ignition position moves from the center to the two ends of the cylinder edge with the increase of the heating rate. The ignition time increases with the increase of charge density under the same condition. Therefore, increasing the charge density can effectively improve the thermal safety of ammunition.

The Stress Analysis of the Industrial Fiber-Reinforced Concrete Slab on Elastic Subgrade Loaded by the Operational Loading

2014 ◽  
Vol 617 ◽  
pp. 46-49 ◽  
Author(s):  
Ján Kortiš
Keyword(s):  
Numerical Simulation ◽  
Stress Analysis ◽  
Concrete Slab ◽  
Fiber Reinforced Concrete ◽  
Heavy Vehicles ◽  
Reinforced Concrete Slab ◽  
Analysis And Evaluation ◽  
Different Characteristics ◽  
Different Thickness ◽  
Factory Building

Floors which are used for factory building are usually located in an environment where is expected to be used heavy vehicles and also heavy supplies stored on the floor. What means that these structures have to be designed to withstand the action of the forces. For that reason it is useful to do a numerical simulation followed by stress analysis and evaluation of results. The parametric study was done to compare the influence of different thickness and different characteristics of the subgrade on the values of stress in a concrete slab. It was loaded by forklifts and structures used for storage of material and products.

Study of phase transformation temperatures of alloys based on Fe–C–Cr in high-temperature area

2018 ◽  
Vol 133 (1) ◽  
pp. 41-48 ◽  
Author(s):  
Ľubomíra Drozdová ◽  
Bedřich Smetana ◽  
Simona Zlá ◽  
Vlastimil Novák ◽  
Monika Kawuloková ◽  
...  
Keyword(s):  
Phase Transformation ◽  
High Temperature ◽  
Transformation Temperatures ◽  
High Temperature Area ◽  
Temperature Area
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