scholarly journals Development of the model and the method for determining the influence of the temperature of gunpowder gases in the gun barrel for explaining visualize of free carbon at shot

2021 ◽  
Vol 4 (1(112)) ◽  
pp. 41-53
Author(s):  
Olexander Brunetkin ◽  
Maksym Maksymov ◽  
Vladimir Brunetkin ◽  
Оleksii Maksymov ◽  
Yevhenii Dobrynin ◽  
...  
Keyword(s):  
Temperature Distribution ◽  
Model System ◽  
Original Model ◽  
Free Carbon ◽  
Firing Process ◽  
Gun Barrel ◽  
Internal Ballistics ◽  
Simulation Results ◽  
Gunpowder Charge ◽  
Thermochemical Reaction

A phenomenon that is present in almost every shot is highlighted. It manifests itself in the muzzle discharge as a certain amount of free carbon. The thermochemical reaction of Boudouard-Bell (disproportionation of carbon monoxide) was determined, which explains the formation of free carbon in the gunpowder gases during the firing process. A feature of this reaction is the formation of a condensed phase of carbon during the firing process after the gasification of the gunpowder charge. The reason is revealed that does not allow describing the formation of free carbon during firing on the basis of existing models of internal ballistics processes. It is the lack of taking into account the temperature distribution of the gunpowder gases along the length of the gun barrel and its change. A mathematical model is proposed that makes it possible to estimate the temperature distribution during the shot. A method has been developed for solving the problem of internal ballistics with the ability to determine the temperature of gunpowder gases along the length of the gun barrel at different times and at different positions of the projectile in the barrel. The original model is built using generally accepted assumptions. Modeling results can only be estimated. For this reason, the method is based on simple calculations, which makes it possible not to involve high-power computing equipment. The modeling of the temperature distribution of gunpowder gases in the space of the gun barrel between the charging ball and the moving projectile in the model system is carried out. The possibility of changing the length of the zone of the Boudouard-Bell reaction (the zone of formation of free carbon) depending on the initial data is shown. The use of a fresh gunpowder charge and a degraded one is simulated. Full and reduced charges are considered. The simulation results showed the reason for the possibility of initiating a secondary muzzle discharge flash both from the front side and from the side of the muzzle brake.

scholarly journals Simulation and Nonlinearity Optimization of a High-Pressure Sensor

Sensors ◽  
2020 ◽  
Vol 20 (16) ◽  
pp. 4419
Author(s):  
Ting Li ◽  
Haiping Shang ◽  
Weibing Wang
Keyword(s):  
High Pressure ◽  
Pressure Sensor ◽  
Pressure Sensors ◽  
Original Model ◽  
Ansys Software ◽  
Nonlinear Error ◽  
Sensor Model ◽  
Optimized Model ◽  
Simulation Results ◽  
Better Than

A pressure sensor in the range of 0–120 MPa with a square diaphragm was designed and fabricated, which was isolated by the oil-filled package. The nonlinearity of the device without circuit compensation is better than 0.4%, and the accuracy is 0.43%. This sensor model was simulated by ANSYS software. Based on this model, we simulated the output voltage and nonlinearity when piezoresistors locations change. The simulation results showed that as the stress of the longitudinal resistor (RL) was increased compared to the transverse resistor (RT), the nonlinear error of the pressure sensor would first decrease to about 0 and then increase. The theoretical calculation and mathematical fitting were given to this phenomenon. Based on this discovery, a method for optimizing the nonlinearity of high-pressure sensors while ensuring the maximum sensitivity was proposed. In the simulation, the output of the optimized model had a significant improvement over the original model, and the nonlinear error significantly decreased from 0.106% to 0.0000713%.

scholarly journals Numerical modeling of microwave heating

2010 ◽  
Vol 42 (1) ◽  
pp. 99-124 ◽  
Author(s):  
A.K. Shukla ◽  
A. Mondal ◽  
A. Upadhyaya
Keyword(s):  
Thermal Conductivity ◽  
Numerical Modeling ◽  
Temperature Distribution ◽  
Microwave Heating ◽  
Two Dimensional ◽  
Conventional Furnace ◽  
Microwave Furnace ◽  
Simulation Results ◽  
Heating Behavior ◽  
Cylindrical Samples

The present study compares the temperature distribution within cylindrical samples heated in microwave furnace with those achieved in radiatively-heated (conventional) furnace. Using a two-dimensional finite difference approach the thermal profiles were simulated for cylinders of varying radii (0.65, 6.5, and 65 cm) and physical properties. The influence of susceptor-assisted microwave heating was also modeled for the same. The simulation results reveal differences in the heating behavior of samples in microwaves. The efficacy of microwave heating depends on the sample size and its thermal conductivity.

scholarly journals Optimized Thermal Efficiency of Rotor and Stator Using CFD

2020 ◽  
Vol 6 (6) ◽  
pp. 29-37
Author(s):  
Md. Shahwaz Hussain ◽  
Sujata Pouranik
Keyword(s):  
Temperature Distribution ◽  
Air Flow ◽  
Operating Conditions ◽  
Electrical Machine ◽  
Total Efficiency ◽  
Transfer Pattern ◽  
Turbulence Effect ◽  
Total Temperature ◽  
Simulation Results ◽  
And Performance

The space between rotor and stator plays a very important role in the design and performance of rotating machinery. The thickness of the gap can vary considerably depending on the size and operating conditions for the different types of rotating machines. Analysis the air velocity and temperature distribution over the air flow gap in stator and motor. Changing the design of rotor to develop turbulence in air flow gap. Compare the velocity and temperature distribution of proposed design with previous studies. The simulation results pinpoint also the periodic heat transfer pattern from the rotor surface and this provides useful information for the prediction of the temperature distribution inside the rotating electrical machine. The simulation results of case-1 show about 117°C temperature inside the rotor machine. Then increase the number of slot inside the rotor machine the total temperature of the rotor machine decreases up to 76°C. Due to low temperature total efficiency of the system increases. And also reduces the loss due to heat. The turbulence effect inside the rotor increase in third case. Due to turbulence effect the air cover large amount of area inside the rotor. So total temperature of the rotor casing decreases. In a system where volume is held constant, there is a direct relationship between Pressure and Temperature. For this case, when the pressure increases then the temperature also increases. When the pressure decreases, then the temperature decreases. So pressure in third case decrease upto1.26Pa and temperature 76 °C.

Heat Transfer Characteristics of Various Gun Barrels Under Different Operating Conditions

2019 ◽  
Author(s):  
Mohamed Gadalla ◽  
Muhammad Jasim ◽  
Omar Ahmad
Keyword(s):  
Heat Transfer ◽  
Thermal Management ◽  
Cross Section ◽  
Wall Temperature ◽  
Circular Cross Section ◽  
Typical Case ◽  
Operating Conditions ◽  
Firing Process ◽  
Transfer Model ◽  
Gun Barrel

Abstract The thermal stability parameter is an important parameter for predicting the lifespan of structures. In this paper, a two-dimensional transient heat transfer model of machine gun barrels undergoing continuous firing developed and analyzed for different geometries and thermal properties. The model for the transient thermal analysis is based on the forced convection heat transfer at the inner surface of the gun barrel. Finite element simulations were performed to predict the interior and exterior barrel temperature profiles and temperature contours after continuous firing process. The incomplete Cholesky Conjugate Gradient (ICCG) solver was adopted in solving unsymmetrical thermal transient analyses. The material thermal behavior studied for the basic circular cross section of gun barrels showed that the lowest inner wall temperature was for high rounds was achieved in steel barrels due to the rapid conducted and convective heat transfer to the environment. While the highest inner wall temperature was recorded for ceramic STK4 barrels and an increase of inner wall temperature by 17% was observed as compared to the typical case of circular cross section steel barrel. In general, a higher inner temperature in the gun barrel is undesirable and harm due to the possibility of reaching the cook-off scenario at earlier rounds. Results concluded that non-circular geometries with constrained cross section areas of typical case improve thermal management and the hexagonal geometry had the best thermal management and could provide more rounds for users. In addition, titanium barrels would have a weight drop of 41% while the overall barrel’s temperature increases by 49%.

Temperature distribution simulations during electron beam freeform fabrication process based on the fully threaded tree

2019 ◽  
Vol 25 (6) ◽  
pp. 989-997
Author(s):  
Yajun Yin ◽  
Wei Duan ◽  
Kai Wu ◽  
Yangdong Li ◽  
Jianxin Zhou ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Temperature Field ◽  
Electron Beam ◽  
Additive Manufacturing ◽  
Temperature Distribution ◽  
Design Methodology ◽  
Content Type ◽  
Freeform Fabrication ◽  
Simulation Based ◽  
Simulation Results

Purpose The purpose of this study is to simulate the temperature distribution during an electron beam freeform fabrication (EBF3) process based on a fully threaded tree (FTT) technique in various scales and to analyze the temperature variation with time in different regions of the part. Design/methodology/approach This study presented a revised model for the temperature simulation in the EBF3 process. The FTT technique was then adopted as an adaptive grid strategy in the simulation. Based on the simulation results, an analysis regarding the temperature distribution of a circular deposit and substrate was performed. Findings The FTT technique was successfully adopted in the simulation of the temperature field during the EBF3 process. The temperature bands and oscillating temperature curves appeared in the deposit and substrate. Originality/value The FTT technique was introduced into the numerical simulation of an additive manufacturing process. The efficiency of the process was improved, and the FTT technique was convenient for the 3D simulations and multi-pass deposits.

DEM Simulations on the Heat Conduction in a Particle Mixer

2012 ◽  
Vol 549 ◽  
pp. 908-913 ◽  
Author(s):  
Yu Peng Xu ◽  
Li Jie Cui ◽  
Xin Xin Ren ◽  
Wei Ge ◽  
Wei Gang Lin
Keyword(s):  
Heat Transfer ◽  
Heat Conduction ◽  
Temperature Distribution ◽  
Powder Processing ◽  
Fast Pyrolysis ◽  
Interior Structure ◽  
Enhance Heat Transfer ◽  
Dem Simulations ◽  
Optimal Values ◽  
Simulation Results

Understanding the heat transfer among particles with uneven temperature distribution is a key to powder processing. In this work, the discrete element method (DEM) is used to optimize the interior structure of a particle mixer with multiple baffles to achieve better heat transfer between two particulate materials. The simulation results show that optimal values exist for the number of baffles and their widths, slope angles and spacing to enhance heat transfer. The results are helpful to the design of a variety of process such as the ultra-fast pyrolysis in “coal topping”.

Study on Thermal Elongation Error of Whirlwind Hard Milling Ballscrew

2013 ◽  
Vol 589-590 ◽  
pp. 221-226
Author(s):  
Yan Feng Li ◽  
Xian Chun Song ◽  
Hong Kui Jiang ◽  
Xiang Rong Xu
Keyword(s):  
Temperature Distribution ◽  
Distribution Pattern ◽  
Measured Temperature ◽  
Hard Milling ◽  
Environmental Technology ◽  
Dynamic Temperature ◽  
Pitch Error ◽  
High Efficient ◽  
Simulation Results ◽  
Screw Pitch

Whirlwind hard milling is a new high-efficient and environmental technology for maching process ballscrew thread. Thermal elongation of the workpiece in processing is one of the main reasons causing the screw-pitch error. The screw-pitch error due to thermal elongation caused by milling heat were analyzed . The dynamic temperature distribution simulation and thermal elogation of the workpiece were carried out with ANSYS software.Compared the simulation results with measured temperature during processing of the workpiece,the temperature distribution pattern is consistent.The result indicate that the law of thermal elongation of the free end and unprocessed section of ballscrew simulated by ANSYS is helpful to compensate screw-pitch error caused by thermal elogation.

Numerical Simulation of Gun Bore Damage during Engraving Process of Driving Band

2017 ◽  
Vol 1142 ◽  
pp. 363-366
Author(s):  
He Yang Sun ◽  
Chang Zhi Jia ◽  
Yao Xin He ◽  
Tian Xiao Cui
Keyword(s):  
Damage Mechanics ◽  
Failure Process ◽  
Damage Model ◽  
Firing Process ◽  
Computation Method ◽  
Damage Behavior ◽  
Damage And Failure ◽  
Gun Barrel ◽  
Safety Design ◽  
Microscopic Damage

A Damage mechanics finite element numerical computation method was established based on HLC microscopic damage model to solve the problem of damage, crack initialization and growth inside bore during the firing process. The damage and failure process of the bore surface was simulated numerically during multiple rounds of firing. The law of the barrel material performance changing with the number of firing rounds was analyzed during the engraving process of the driving band and compared with the experimental results. It is proved that HLC microscopic damage model can show the complicate damage behavior and predict the cracking defect, which provides a reference for safety design of the gun barrel.

Simulation of Substrate Temperature Distribution in Diamond Films Growth on Cemented Carbide Inserts by Hot Filament CVD

2007 ◽  
Vol 10-12 ◽  
pp. 864-868 ◽  
Author(s):  
Wei Zuo ◽  
Bin Shen ◽  
Fang Hong Sun ◽  
Ming Chen
Keyword(s):  
Temperature Distribution ◽  
Three Dimensional ◽  
Diamond Films ◽  
Chemical Vapor ◽  
Deposition Parameters ◽  
Dimensional Finite Element ◽  
Simulation Results ◽  
Three Dimensional Finite Element ◽  
Hot Filament ◽  
Carbide Inserts

Three-dimensional finite element simulations were used to investigate the influences of various hot filaments and other deposition parameters on the temperature field of substrates which affect significantly the growth and quality of diamond films by hot filament chemical vapor deposition (HFCVD) and based on the simulation results, the optimum position for diamond deposition was found. In the experiment, six cemented tungsten carbide inserts were used as substrates and placed on the workbench in the CVD reactor to deposit diamond films. According to the temperature distribution on substrates measured by thermocouple fixed in CVD reactor, the simulations were validated and the optimum arrangement of substrates was established from the simulation results. In addition, the simulation model was altered to optimize the process parameters of HFCVD deposition, and an improved process of depositing diamond films with high quality was obtained in order to achieve the great surface morphology, which laid the foundation of developing a new method to arrange the substrates in the CVD reactor for depositing diamond films.

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