scholarly journals Explosive atmosphere ignition source identification during mining plant suspended monorail braking unit operation

2021 ◽  
pp. 338-351
Keyword(s):  
Coal Dust ◽  
Heat Propagation ◽  
Test Facility ◽  
Bench Test ◽  
Hard Coal ◽  
Contact Method ◽  
Brake Pad ◽  
Design Work ◽  
Brake Shoe ◽  
Mining Plant

Coal dust and methane explosions are some of the most common causes of mining disasters in hard coal mines all over the world, and research continues to be conducted with the purpose of understanding the mechanisms of an explosion, explosion prevention and risk reduction. This article presents the test methodology as well as virtual and bench test results for a braking unit, which constitutes one of the main components of a suspended monorail transport system. The design work and virtual and bench testing were performed as part of a European research programme. The tests were conducted in a dedicated specialist test facility. The tests were based on Polish standard PN-G-46860:2011, concerning braking trolleys employed in mining plant suspended railway systems. The tests also factored in the requirements for non-electrical devices intended for use in explosive atmospheres, including braking systems, as defined in standard PN-EN ISO 80079-36:2016, harmonised with the ATEX directive. The test scope encompassed braking unit operational component temperature measurements using thermal imaging and the contact method, as well as braking distance measurements. Further tests involved virtual simulations of brake pad heating. The tests employed the finite element method (time-varying calculations). Results obtained over the course of numerical calculations indicate that brief brake pad friction face heating, even up to a temperature exceeding 200C, does not result in inward heat propagation towards the brake pad material. This is also confirmed by the measurement results. However, under real conditions, the braking unit would be engaged only during an emergency situation, which would not lead to exceeding the permissible brake shoe material temperature values.

Mode-switch model predictive controller with “pre-contact” method for alleviating driveline vibration of electric vehicles considering backlash

2020 ◽  
Vol 234 (8) ◽  
pp. 2176-2194
Author(s):  
Xingyang Lu ◽  
Tongli Lu ◽  
Benben Chai
Keyword(s):  
Electric Vehicles ◽  
Bench Test ◽  
Contact Method ◽  
State Variables ◽  
Mode Switch ◽  
Contact Mode ◽  
Model Predictive Controller ◽  
Essential Information ◽  
Motor Torque ◽  
Predictive Controller

The backlash between engaging components in a driveline is inevitable and contributes to the nonlinearity of the driveline. The existing motor controllers of an electric vehicle usually ignore the backlash, which often brings impacts and vibration. This paper proposes an active driveline vibration controller for electric vehicles. A nonlinear driveline model considering backlash and wheel slip ratio is established in MATLAB/Simulink, and the results of bench test proved that the model could effectively reflect the transient dynamics of the electric driveline. Based on this model, a dual extended Kalman filter observer is designed to estimate both the system state variables and vehicle mass, which are essential information for the controller design. Then, a mode-switch model predictive controller based on two linearized models is proposed to alleviate the impacts and vibration caused by the transient change of motor torque. The proposed controller would identify whether the driveline is operating in “contact mode” or “backlash mode” and thus generates an optimal motor torque by solving a Quadratic Programing. Note that the control targets and model structures in two modes are different. Furthermore, a “pre-contact” method is proposed as an additional part to handle the condition when motor command torque is zero. Simulation results demonstrate that the proposed controller can effectively alleviate the impacts and vibration in the electric driveline while keeping the torque delay negligible. Moreover, the robustness of the proposed controller against estimation errors and system noises are discussed.

scholarly journals Linear and Non-linear Regression Analysis for the Adsorption Kinetics of SO2 in a Fixed Carbon Bed Reactor – A Case Study

2021 ◽  
Author(s):  
Anna M. Kisiela-Czajka ◽  
Bartosz Dziejarski
Keyword(s):  
Linear Regression ◽  
Activated Carbons ◽  
Coal Dust ◽  
Linear Regression Analysis ◽  
Heterogeneous Surface ◽  
Hard Coal ◽  
Linear Regression Method ◽  
Order Kinetic ◽  
Lignite Fly Ash ◽  
Non Linear

Kinetic parameters of SO2 adsorption on unburned carbons from lignite fly ash and activated carbons based on hard coal dust were determined. The model studies were performed using the linear and non-linear regression method for the following models: pseudo first and second-order, intraparticle diffusion, and chemisorption on a heterogeneous surface. The quality of the fitting of a given model to empirical data was assessed based on: R2, R, Δq, SSE, ARE, χ2, HYBRID, MPSD, EABS, and SNE. It was clearly shown that it is the linear regression that more accurately reflects the behaviour of the adsorption system, which is consistent with the first-order kinetic reaction – for activated carbons (SO2+Ar) or chemisorption on a heterogeneous surface – for unburned carbons (SO2+Ar and SO2+Ar+H2O(g)+O2) and activated carbons (SO2+Ar+H2O(g)+O2). Importantly, usually, each of the approaches (linear/non-linear) indicated a different mechanism of the studied phenomenon. A certain universality of the χ2 and HYBRID functions has been proved, the minimization of which repeatedly led to the lowest SNE values for the indicated models. Fitting data by any of the non-linear equations based on the R or R2 functions only, cannot be treated as evidence/prerequisite of the existence of a given adsorption mechanism.

scholarly journals Analysis of the similarity of hard coal mines in terms of the number of dangerous incidents caused by the activation of natural hazards

2019 ◽  
Vol 2 (1) ◽  
pp. 91-100
Author(s):  
Magdalena Tutak
Keyword(s):  
Rock Burst ◽  
Natural Hazards ◽  
Coal Dust ◽  
Coal Mines ◽  
Hard Coal ◽  
Dust Explosion ◽  
Coal Basin ◽  
Taxonomic Analysis ◽  
Upper Silesian Coal Basin ◽  
Roof Rocks

Abstract Hard coal mines and mining enterprises involved in hard coal exploitation in the area of the Upper Silesian Coal Basin (Górnośląskie Zagłębie Węglowe) are characterised by the presence of natural hazards typical of this type of exploitation. These hazards include the risks related to methane, coal dust explosion, endogenous fires, as well as rock burst and caving of roof rocks. The article presents the results of a taxonomic analysis aimed at determining the similarity of hard coal mines and mining enterprises in Poland in terms of the dangerous incidents caused by the risks related to methane, coal dust explosion, endogenous fires, as well as rock burst and caving of roof rocks. The analysis was carried out for the 2008-2018 data and encompassed a total of 26 hard coal mines and mining enterprises located in the Upper Silesian Coal Basin. The analysis was performed using the k-means method of non-hierarchical clustering. The main objective of the article was to determine homogenous groups (clusters) of mines exhibiting the greatest similarity in terms of dangerous incidents caused by the activation of natural hazards in the years 2008-2018. These data can be successfully used for the development of preventive measures and risk analyses for these enterprises.

scholarly journals Development of a innovative solution for energy recovery from the flow exhaust gas on bench test facility of turbofan aircraft engine through the use of innovative design methods: Definition of the process and the operating environment

2019 ◽  
Vol 286 ◽  
pp. 02003
Author(s):  
Amine Rahoui ◽  
Zinab Aalaoui
Keyword(s):  
Alternative Fuels ◽  
Aircraft Engine ◽  
Research Process ◽  
Test Facility ◽  
Civil Aviation ◽  
Maximum Efficiency ◽  
Bench Test ◽  
Technological Solution ◽  
Operating Environment ◽  
Definition Of

Civil aviation is driven nowadays by exceptional growth in the number of passengers. It should double or even triple by 2050 and thus, all industrials also plan to double the number of device delivery by mid-century. Responsible for about 2% of carbon dioxide on the planet, they must now deal with the environmental issues facing the sector. At this moment in the world, several lines of research focus on increasing the efficiency of aircraft engines, development of new engines, efficient technologies, sustainable sources of alternative fuels and improved management air traffic on the ground and in flight [1]. The present work deals with a research focused on the engine test when passing in review in repair facilities. This operation which consist in making engine running while the cycles to test its performance in a test bench are studied to define a technological solution to reduce CO2 carbon footprint of the aircraft engine in this phase of the cycle of life. The idea is to produce electrical energy during these tests. To achieve this, we will highlight the case of a type bench facility for a specific airplane engines. As a result high-performance analysis tools are implemented to define the most suitable technological solution that ensures maximum efficiency, meets the functional and regulatory requirements taking into account the force of integration with the existing and cost optimization. In this paper we present the summary of the working definition of the research process for the final term set in the operating environment integration relevance that provides bench test and level of innovation that provides the methods selected.

scholarly journals Comparison of Methane Control Methods in Polish and Vietnamese Coal Mines

2018 ◽  
Vol 35 ◽  
pp. 01004
Author(s):  
Marek Borowski ◽  
Zbigniew Kuczera
Keyword(s):  
Coal Mining ◽  
Coal Dust ◽  
Coal Mines ◽  
Hard Coal ◽  
Control Methods ◽  
Prevention Measures ◽  
Methane Drainage ◽  
Hazard Control ◽  
Preventive Actions ◽  
Coal Deposits

Methane hazard often occurs in hard coal mines and causes very serious accidents and can be the reason of methane or methane and coal dust explosions. History of coal mining shows that methane released from the rock mass to the longwall area was responsible for numerous mining disasters. The main source of methane are coal deposits because it is autochthonous gas and is closely related with carbonification and forming of coal deposits. Degree of methane saturation in coal deposits depends on numerous factors; mainly on presence or lack of insulating layers in cover deposit that allow or do not on degasification and easily methane outflow into surroundings. Hence in coal mining there are coal deposits that contain only low degree of methane saturation in places where is lack of insulating layers till high in methane coal deposits occurring in insulating claystones or in shales. Conducting mining works in coal deposits of high methane hazard without using of special measures to combat (ventilation, methane drainage) could be impossible. Control of methane hazard depends also on other co-occuring natural dangers for which used preventive actions eliminate methane hazard. Safety in mines excavating coal deposits saturated with methane depends on the correct estimation of methane hazard, drawn up forecasts, conducted observations, hazard control as well as undertaken prevention measures. Methane risk prevention includes identification and control methods of methane hazards as well as means of combating the explosive accumulation of methane in longwall workings. The main preventive actions in underground coal mines are: effective ventilation that prevents forming of methane fuses or placed methane accumulation in headings ventilated by airflow created by main fans and in headings with auxiliary ventilation, methane drainage using drain holes that are drilled from underground headings or from the surface, methanometry control of methane concentration in the air; location of the sensors is defined by law, additional ventilation equipment used in places of lower intensity of ventilation and places where methane is concentrated.

Design of Double-Disc Friction and Electromagnetic Hybrid Brake System of Passenger Car

2014 ◽  
Vol 610 ◽  
pp. 156-163 ◽  
Author(s):  
Ren He ◽  
Xiao Dan Gu ◽  
Jun Shi
Keyword(s):  
Basic Principle ◽  
Design Method ◽  
Bench Test ◽  
Brake Pad ◽  
Electromagnetic Brake ◽  
Braking System ◽  
Braking Torque ◽  
Design Requirements ◽  
Pad Wear ◽  
Friction Brake

The electromagnetic brake has already been acknowledged by users as one kind of contactless brake. In this paper, the basic principle and application of electromagnetic braking technology were briefly introduced first. Then the structure of the innovative hybrid brake with double disc was put forward. It employed an electromagnetic braking to reduce brake pad wear and braking system thermal recession. Based on the design requirements, the friction brake and the electromagnetic brake were designed respectively. Finally, in order to verify that whether the designed hybrid brake meets the design requirements, a bench test was carried out. The electromagnetic braking torque characteristic was tested. The results showed that the electromagnetic braking torque could approach 198N·m.Thus the design method is feasible..

scholarly journals Evaluation of the results of coal jigging process

2017 ◽  
Vol 18 ◽  
pp. 01030
Author(s):  
Agnieszka Surowiak
Keyword(s):  
Coal Dust ◽  
Optimal Recovery ◽  
Process Efficiency ◽  
Hard Coal ◽  
Clean Coal ◽  
Coal Beneficiation ◽  
Coal Fuel ◽  
Density Analysis ◽  
Combustion Processes

Quality of applied hard coal fuel to combustion processes influence significantly on process efficiency and effects of its influence on surrounding environment. It is particularly important issue in time of Clean Coal Technologies (CTW). The paper presents the analysis of hard coal beneficiation in a jig for getting an optimal recovery of useful fraction in concentrate (combustible matter) and not useful fraction (ash and sulfur). On the basis of industrial sampling of coal dust jig the density analysis of collected samples of concentrate and tailings was performed in laboratory conditions. In separated fractions of separation products the yields of products were calculated and the contents of ash and total sulfur were marked in them. On the basis of the results of density and chemical analyzes, separation products balance and appropriate calculations the Fuerstenau beneficiation curves were plotted which allowed to evaluate process and compare results of beneficiation of material containing various components. This is a different approach to evaluation of coal beneficiation effects, so far being used mainly for multi-component metals ores. Furthermore, the evaluation of separation preciseness on the basis of separation curves and factors was done and the statistical analysis of mutual correlations of analyzed parameters was done.

Safety culture among mine employees

2021 ◽  
Vol 3 (40) ◽  
pp. 103-112
Author(s):  
Marcin Hibner
Keyword(s):  
Coal Mining ◽  
Safety Culture ◽  
Questionnaire Survey ◽  
Safety Climate ◽  
Hard Coal ◽  
Scale Method ◽  
Hard Coal Mining ◽  
Mining Plant

The article discusses the results of research on the level of safety culture conducted in the form of a questionnaire survey in five different groups of employees in an underground hard coal mining plant. The survey included nine thematic groups with five questions each. Using the Likiert scale method, the safety climate in the company was assessed.

MORPHOLOGICAL COMPOSITION OF HARD COAL DUST AND ITS INFLUENCE ON EXPLOSION AND FIRE HAZARD OF MINING

2020 ◽  
Vol 1 (1) ◽  
pp. 145-158
Author(s):  
V.A. Rodionov ◽  
◽  
V.D. Tsygankov ◽  
S.Y. Zhikharev ◽  
◽  
...  
Keyword(s):  
Fire Hazard ◽  
Coal Dust ◽  
Hard Coal ◽  
Morphological Composition
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