Modular Charge Research Articles

Effect of axial ullage distribution of modular charges on the dynamic behavior of cylindrical particles in the combustion chamber

Effect of axial ullage distribution of modular charges on the dynamic behavior of cylindrical particles in the combustion chamber

Investigation of friction and wear characteristics between modular charge and aluminum alloy for feeding process in artillery systems

In modern artillery systems, frictional properties of modular charge significantly impact the operation of artillery feeding system. In this study, Tribology performance between modular charge and aluminum alloy were investigated under simulated environment of artillery. The result indicates that the COF initially increased and then decreases with the temperature dropped from 50 °C to −40 °C. Additionally, COF increased from 0.19 to 0.41 when relative velocity increased from 100 mm/s to 2000mm/s. SEM detection and chemical composition analysis demonstrated that the main wear forms are adhesive wear and abrasive wear. The tribofilm including aluminum titanium oxide and aluminum nitrides generated through tribochemical reaction, which are beneficial for boundary lubrication. This work provides theoretical reference for artillery tribology research.

PROPOSTA DE ELETROPOSTOS MODULARES PARA CARROS ELÉTRICOS ABASTECIDOS POR ENERGIA SOLAR

In recent years, the growing demand for electric vehicles has intensified the need for adequate infrastructure for their charging. Charging stations, dedicated to supplying energy to these vehicles, play a crucial role in the transition to sustainable urban mobility. This study proposes the development of modular charging stations powered by solar energy, focusing on solutions that favor sustainability and efficiency. The primary objective is to create systems that integrate photovoltaic technology, promoting the use of clean energy and contributing to the reduction of air pollution. The research evaluates the viability of on-grid and off-grid systems, aiming to optimize the efficiency of solar panels and reduce operational costs. Factors such as ideal location, shading prevention, and the environmental impacts of electric mobility are analyzed. Additionally, existing charging station examples are examined to identify best practices and innovations in urban design. The methodology includes exploratory and bibliographic research, utilizing case studies and literature reviews to support the proposal. As a result, the study culminates in a sustainable modular charging station proposal that is adaptable to different locations, promoting more efficient and eco-friendly mobility.

Numerical simulation of interior ballistics two-phase flow in modular charge based on the particle element method

The full combustibility and strong discontinuity characteristics of module charge result in significant differences from conventional mode, making it challenging for traditional two-fluid methods to effectively reveal its particle dispersion mechanism. In this study, the particle element method for module charge were developed and applied for modeling the interior ballistics to overcome above drawback. Firstly, based on the characteristics of module charge and particle aggregation, criteria for dividing particle elements and methods for motion calculation are proposed. Next, particle element solver and CFD solver are constructed and mutually coupled for solution. Finally, validation is conducted under the condition of three modules charging. The computational results show that the particle element method can effectively predict the pressure and velocity inside the chamber, consistent with experimental results, the pressure error is 5.55 % and the velocity error is 0.79 %. The particle element method reproduces the combustion process with variable particle mass, accurately presenting the distribution of the flow field and temperature. Moreover, it fundamentally explains that pressure fluctuations occur due to the presence of free space and changes in the flow field caused by the movement of the propellant bed. The particle element method can provide scientific research methods and technical support for the development of module charge technology.

Combustible cartridge case material characteristics evaluation

AbstractCombustible cartridge cases are parts of modular charges used in modern artillery systems. Some types of combustible cartridge case materials have exhibited problems during pyrostatic measurements caused by their difficult ignition. This article explores the possibility of testing the combustible cartridge case material mixed with a propellant of known ballistic properties and then separating the influence of that propellant using methods of mathematical analysis. The aim of this work is to create methodology for closed vessel tests of combustible cartridge case material. Outcome involves the characterization of combustible cartridge case material ballistic properties, including its burn rate parameters. Calculations described in this paper could potentially be modified to be applicable to other cases of mixture of two propellants.

Study on unsteady combustion and propelling mechanism of modular charge based on Euler–Lagrange method

Study on unsteady combustion and propelling mechanism of modular charge based on Euler–Lagrange method

Three-dimensional particle-scale investigation of transient gas–solid flow characteristics in the propulsion system with a complex charge structure

This work is focused on researching the particle behavior of the transient gas–solid flow in the propulsion system with the modular charge structure, which has a great effect on the temporal-spatial distribution of energy release. Based on the coupling method of computational fluid dynamics and the discrete element method, an efficient three-dimensional unsteady gas–solid model is developed to provide a detailed means of capturing particle behavior in the propulsion system with a complex structure. Comparisons of the particle distribution of simulation results are done with experimental research, and a reasonable match has been obtained. Furthermore, the particle behavior characteristics can be divided into three stages. In the first stage, the particle behavior is dominated by the high-pressure, high-speed gas from the igniter. In the other two stages, the particle behavior is dominated by the complex gas flow generated by the opening of the module and the groove structure of the vehicle. The results show that the distribution of particles consists of slope accumulation and horizontal accumulation. The slope accumulation with a large gradient contains 84% of the total particles, and the height of the slope accumulation is increased exponentially along the axis.

A Review of Modular Electrical Sub-Systems of Electric Vehicles

Climate change risks have triggered the international community to find efficient solutions to reduce greenhouse gas (GHG) emissions mainly produced by the energy, industrial, and transportation sectors. The problem can be significantly tackled by promoting electric vehicles (EVs) to be the dominant technology in the transportation sector. Accordingly, there is a pressing need to increase the scale of EV penetration, which requires simplifying the manufacturing process, increasing the training level of maintenance personnel, securing the necessary supply chains, and, importantly, developing the charging infrastructure. A new modular trend in EV manufacturing is being explored and tested by several large automotive companies, mainly in the USA, the European Union, and China. This modular manufacturing platform paves the way for standardised manufacturing and assembly of EVs when standard scalable units are used to build EVs at different power scales, ranging from small light-duty vehicles to large electric buses and trucks. In this context, modularising EV electric systems needs to be considered to prepare for the next EV generation. This paper reviews the main modular topologies presented in the literature in the context of EV systems. This paper summarises the most promising topologies in terms of modularised battery connections, propulsion systems focusing on inverters and rectifiers, modular cascaded EV machines, and modular charging systems.

Investigation of combustion process in a modular charge system with a primer gap

To clarify the combustion process of a modular charge system with a primer gap, the rules governing the cartridge movement and pressure change in the chamber are analyzed. Based on the characteristics of the modular charge system, an axisymmetric two-phase flow model of the interior ballistics is established, with the monotonic upward-centered scheme for conservation laws adopted to calculate the combustion process. Compared with the experimental results, the difference in the peak pressure is less than 5%, which indicates that the mathematical model and scheme are reliable and accurate. The results show that, during the initial stage of ignition, the combustible container remains unbroken, and the gas and solid particles are prevented from spreading to the chamber by the end cap of the cartridge. Thus, only the gas inside the igniter tube influences the flow field in the chamber. After the combustible container has broken, the gas and solid particles move rapidly toward the cavity from the combustible container. The axial movement of solid particles is more intense than that of the gas particles, but the radial movement of solid particles is relatively weak. Furthermore, the existence of the primer gap leads to a delay in the ignition time of the solid particles, which delays the rupture time of the igniter tube and the module cartridge.

Adaptive predetermined performance control of modular charging system for electric vehicles

In this paper, a predetermined performance controller is proposed for a modular charging system for electric vehicles to solve the problem that the entering and leaving of electric vehicles will cause large voltage fluctuation, which will affect the service life of the battery. A barrier Lyapunov function is introduced and combined with the backstepping method to design the controller to ensure that the output voltage of the system can be limited to a set range. The entering and leaving of electric vehicles will result in changes in the system's load, however, this change is unknown, so a finite-time load estimator is designed to estimate the load variation. Then the estimated load is introduced into the controller to improve the adaptive ability of the controller.

REVIEW OF SOUTH-KOREAN PATENT SOLUTIONS ON MODULAR PROPULSIVE CHARGES FOR 155 mm ARTILLERY MUNITIONS

Five patent descriptions of South Korean in-ventions on modular artillery propulsive charges and their basic elements creating such propulsive charges used in 155mm artillery ammunition, were presented. Above inventions were filed to the Korean Intellectual Property Office in years 1992-2019. Three inventions deal with central ignition systems situated inside the modular propulsive charges, and a first of the remaining two relates to double-base smokeless powder charges surrounding the central ignition systems and the second to construction of combustible containers of the modular charges. Presented inventions describe material parameters, geometry of particular elements of the propulsive modules and technologies of their manufacture. ballistics,chemical technology,modular propulsive charges for 155 mm howitzer munitions,central ignition systems,combustible tubes,smokeless powders,combustible containers,Korean inventions

Deep and machine learning architecture for high accuracy prediction of interior ballistics for modular charges

AbstractInterior ballistics modelling intends to calculate physical quantities by solving equations requiring a set of input like thermodynamical properties linked to propellant or mechanical properties like friction coefficients, linked to the system, that are often difficult to assess experimentally. Using a consequent and high‐quality dataset of thousands of 155 mm modular charge experiments, we investigated how deep and machine learning approaches could build an efficient model for predicting muzzle velocity, pressure, and ignition time. After identifying the main variables influencing the physics and several potentially relevant to the machine learning and deep learning algorithms, a stacking ensemble learning model (SEL) was built. It is composed of eight machine learning algorithms and one deep learning algorithm, all as weak learner, reaching a consensus for predicting experimental outputs through a strong learner. The performance assessment, on a 900 experiments test data set that were not used in training, shows a prediction accuracy of 97 % at 1 % accuracy for muzzle velocity, 93 % at 3 % for pressure and 72 % at 5 ms for ignition time. The prediction ability for muzzle velocity within 2 m/s reaches 73 % that can be considered as sufficient. Furthermore, the SEL model even having zero knowledge about physics can discriminate gun barrel erosion effect at high and low pressure. This approach allows to imagine a way of modelling physical phenomena poorly described by physical equations or requiring unmeasurable figures.

Application of CFD-DEM to the investigation of movement and distribution of energetic particle groups

The modular charge is a new charge technique for the gun. There are energetic particle groups and the combustion gas during the launch, forming a gas-solid flow. The distribution of particles plays a crucial role in the formation of pressure waves. The particle final distribution is affected by the movement and dispersal of particles. Therefore, the particle-scale motion details of the mixed energetic particles are simulated by a 3-D numerical model developed by the CFD-DEM. Meanwhile, the ignition simulated experiment of the new charge technique is accomplished by the “combustion particle frozen” method, which verifies the rationality of the numeric model. The results indicate that energetic particle group distribution is in form of a gentle-slope, a horizontal, and a steep-slope shape. The height of gentle-slope distribution changes exponentially, while that of steep-slope shape changes linearly. It lays a foundation for revealing the formation mechanism of the initial pressure wave.

Influence of High-temperature Environment on Cook-off Characteristics of Modular Charge

In order to study the heating process of the modular charge loaded into the chamber after the continuous firing of the large caliber gun in the high-temperature environment, a 2D transient cook-off model of the modular charge retained in the chamber was established with cook-off method. When the ambient temperature is 323K and the critical temperature of the inner wall of the gun chamber is 443K, the wall temperature distribution of the gun is solved after 2 rounds/min of continuous firing. Taking this as the initial temperature condition, the cook-off process of the modular charge in the chamber is numerically simulated, and then the cook-off-odd characteristics of the modular charge in the high-temperature environment are analyzed. The results show that after 33 rounds of continuous firing at 2 rounds/min at 323K ambient temperature, the temperature of the inner wall of the gun chamber reaches 442.7K, and the modular charge would have a cook-off response after 107.5s after loading into the chamber, and the response temperature is 483.5K. The initial response position of the modular charge is located at the inner wall of the upper right corner of the module cartridge. The consistency between numerical calculation and experimental results shows that the model could analyze the cook-off problem of modular charge in bore well.

Effect of Initial Loading Position on the Propellant Particles Distribution in Two-module Charge

The propellant particles distribution in the ignition process of the modular charge has a significant effect on the interior ballistic stability. Thereinto, the particles final distribution is determined by the particles motion process. Based on the CFD-DEM method, a 3D transient gas-solid flow model is constructed to investigate the motion process and the dispersion of propellant particles. Moreover, the cold state test of the ignition process of modular charge is accomplished based on a visual ignition test platform. The simulated data are consistent with the test one. Furthermore, the effect of the initial loading position on the propellant particles distribution of two-module charge is predicted by the numerical simulation. All of two-module cases show that the distributions of particles are made up of a gentle-downhill, a horizontal, and a steep-uphill accumulation. As the initial loading position of modules moves to the right, the slope angle of the uphill is decreased first and then increased, with the minimum slope angle of 20.5°. When the initial loading position of modules is 40mm, the spatial distribution gradient of particles gets the minimum in the uphill accumulation area, and the particles axial-distribution is the most uniform.

Influence of Rupture Size on Dispersion Characteristics of Propellant Particles During Ignition and Flame Spreading Processes for Modular Charges

During ignition and flame spreading processes, the difference in initial rupture size for the end cover of cartridge may affect the final accumulation form of propellant particles. A 3D unsteady state gas -solid two-phase flow model was established based on the gas phase-grain phase coupling method to simulate the final distribution of propellant particles in the chamber under different initial rupture sizes for end cover. The simulation results showed that at the fan-shaped initial perforation area for end cover of modular cartridge, under the 6 simulated working conditions of central angles 0, 30, 60, 90, 120 and 150 degrees, the propellant particles in the chamber presented a combined form of gentle slope accumulation, horizontal accumulation, and steep slope accumulation from the primer side to the pressure control diaphragm side. When the central angle corresponding to the fan-shaped initial perforation area increased from 0 ° to 150 °, the axial length for gentle slope accumulation and horizontal accumulation increased from 269 mm to 331 mm, and for the part of horizontal accumulation, the average thickness of propellant particles increased from 18.1 mm to 23.5 mm, and the proportion of steep slope accumulation of propellant particles decreased from 70.3% to 63.8%. The larger the initial rupture size for the end cover, the longer the axial length of gentle slope and horizontal accumulation, the thicker the average grain thickness for the part of horizontal accumulation, and the lower the proportion of steep slope accumulation of propellant particles.

Investigation of particle distribution after the energetic module broken in the ignition process of gun

The particle distribution in the ignition process of gun with the modular charge, a new charge technology, has a significant effect on the initial pressure wave produced by propellant particle combustion, which impacts the interior ballistics stability. In fact, the particle distribution under the action of combustion gas after the energetic module is broken is non-uniform. In this paper, the particle motion and distribution under the combustion gas flow during ignition processes of the one-module charge and the two-module charge are simulated by the combination of computational fluid dynamics (CFD) and discrete element method (DEM). In addition, the experiment of ignition process of the one-module charge is carried out using the visualization experiment platform, and the particle distribution is observed. The rationality of the calculation model is verified. The results indicate that both particle final distributions consist of a horizontal and a slope-shape accumulation. Among them, the axial length of the horizontal accumulation of the two-module charge is 247.6 mm, which is smaller than that of the one-module charge. Both slope-shape accumulation heights change exponentially along the axial direction, while the voidage of the slope-shape distribution of the two-modulecharge is less than that of the one-module charge.

전기차용 모듈형 충전기의 효율향상을 위한 모듈 제어기법

In this paper, we discuss the module control techniques for improving efficiency of modular charging devices for electric vehicles. A modular charger has modules connected in parallel, and modules connected in parallel uniformly handle a load required for an electric vehicle. power converters typically show low efficeincy in the light loads and high efficiency in the heavy. The amount of power requested by an electric vehicle to a charger varies depending on the internal battery charge amount of the electric vehicle. If the amount of electric power required by an electric vehicle is small, the charger is requested to have low power and the charger operates in a light load section. And the charger operating in the light load section becomes less efficient. A modular charger including a plurality of modules may control the number of modules driven in parallel according to a charging amount required for an electric vehicle, thereby reducing an operation in a light load section and improving the overall efficiency of the charger. In this paper, we have studied how to improve the overall efficiency of the charger through the module control technique of the electric vehicle modular charging unit according to the amount of charging.

Charged moments in W3 higher spin holography

We consider the charged moments in SL(3, ℝ) higher spin holography, as well as in the dual two-dimensional conformal field theory with W3 symmetry. For the vacuum state and a single entangling interval, we show that the W3 algebra of the conformal field theory induces an entanglement W3 algebra acting on the quantum state in the entangling interval. The algebra contains a spin 3 modular charge which commutes with the modular Hamiltonian. The reduced density matrix is characterized by the modular energy and modular charge, hence our definition of the charged moments is also with respect to these conserved quantities. We evaluate the logarithm of the charged moments perturbatively in the spin 3 modular chemical potential, by computing the corresponding connected correlation functions of the modular charge operator up to quartic order in the chemical potential. This method provides access to the charged moments without using charged twist fields. Our result matches known results for the charged moment obtained from the charged topological black hole picture in SL(3, ℝ) higher spin gravity. Since our charged moments are not Gaussian in the chemical potential any longer, we conclude that the dual W3 conformal field theories must feature breakdown of equipartition of entanglement to leading order in the large c expansion.

Design and Optimization of a Modular Wireless Charging Scheme for Electric Buses With High Misalignment Tolerance

Modular design helps to improve the reliability and power density of power electronic systems, so cascading of power electronics modules is an effective method to improve the overall stability of the system. The application of the wireless power transfer (WPT) system to electric buses faces the challenge of higher power requirement; modularization provides a solution to the design of the wireless charging system for electric buses. A modular wireless charging system for electric buses is proposed in this study; the system consists of five identical 6.6 kW wireless charging modules distributed relatively disperse on the chassis. Through the design of coil layout, different modules on the receiver side can be decoupled from each other, which facilitate independent control. Each module utilizes the bipolar-solenoid coupling structure, which proves to have a high misalignment tolerance. In order to reduce the electromagnetic radiation for passengers on the electric bus, shielding is added on the receiver side. Five independent modules work collaboratively to compose a 30 kW wireless charging system for electric buses. The DC-DC efficiency is 87.44% in an aligned position at 200 mm transmission distance. With closed-loop control, the proposed system has high misalignment tolerance in the horizontal X-Y plane. Compared with the open loop control scheme, the average efficiency of the proposed system increases by 22.1% within 300 mm misalignment.