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Date submitted2020-05-18
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Date accepted2020-06-16
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Date published2021-04-26
Traction asynchronous electric drive of mine electric locomotivesimulation model structure improvement
The article discusses the solution to the problem of underground railway transport slipping in dynamic modes, which occurs when there is a significant difference in the speeds of the driving and driven pairs of wheels. The state of the rail surfaces largely determines the coefficient of adhesion, therefore, using a mathematical model, the condition for the dependence of the magnitude of slipping and tractive effort is selected. For effective acceleration and deceleration of an electric locomotive, it is necessary to control the coefficient of adhesion at a certain level. A simulation model of rolling stock has been created, which for the first time takes into account a mechanical system with distributed parameters. In the structural diagram of the automatic control system of traction electric drives with frequency regulation, such factors as the volume of goods being moved, rolling friction, slope (rise) levels and the state of the rail track are taken into account. The simulation results show the features of the movement and stops of the freight train not only by the diagrams of speed and forces in the modes of acceleration-deceleration and uniform movement, but also the positions of the plungers and tractive forces on the couplings of the electric locomotive and all trolleys involved in the movement of goods. The practical application of the proposed method lies in the possibility of starting a heavily laden train from its place on the ascent section in conditions of insufficient adhesion coefficient with contaminated roads.
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Date submitted2019-05-24
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Date accepted2019-07-15
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Date published2019-10-23
Effective Power and Speed of Mining Dump Trucks in Fuel Economy Mode
- Authors:
- V. I. Alexandrov
- M. A. Vasileva
- V. Y. Koptev
Existing methods for determining the effective power, based on the calculation of the average indicator operation of the engine during the piston stroke, do not take into account the change in thermodynamic parameters and the polytropic operation of the engine, the value of which depends on the polytropic efficiency of the duty cycle. This is the reason that the calculation of the effective power leads to some error – the margin of the engine features. The identification of this stock allows us to review the entire line of dump trucks in the direction of increasing their pass- port effective capacity, which will lead to a reduction in capital purchase costs due to the choice of a previously un- derestimated and cheaper option, as well as a reduction in current operating costs due to a decrease in the specific fuel consumption rate. Taking into account the stochastic nature of the transport process and assessing the influence of all external and internal factors when calculating the rational mode of operation of a mining truck can further reduce specific fuel consumption by choosing the rational speed of its movement in loaded and empty directions.
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Date submitted2018-09-10
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Date accepted2018-11-06
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Date published2019-02-22
Comparative analysis of zincand tin oxidation with acids at room temperatures
- Authors:
- S. D. Pozhidaeva
- L. S. Ageeva
- A. M. Ivanov
The paper analyses the parameters of deep oxidation of zinc and tin by copper (II) compounds and molecular iodine in the presence of molecular oxygen and hydrogen peroxide, as second oxidizers working synchronously with them in various media (aqueous, aqueous-organic and organic) with the participation of mineral and carboxylic acids close to room temperature. The contribution of the reactivity of the metal to its rate of consumption, especially the average, is often much less than the contribution associated with the release characteristics of the working surface, determined by the rates of accumulation of surface deposits of metal oxidation products, their strength and adhesion characteristics their destruction and shifting into the bulk phase.
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Date submitted2018-05-05
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Date accepted2018-07-18
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Date published2018-10-24
Calculations of dynamic operating modes of electric drives self-propelled mining machines
- Authors:
- E. K. Eshchin
The task of improving the calculations of the dynamic modes of electric drives of self-propelled mining machines, particulary, tunneling machines, is considered. Attention is drawn to the possibility to opearte in dynamic modes of a spatial change in the an asynchronous electric motor stator housing position, included in the electric drive, around the axis of its rotor due to the ultimate rigidity of the supports of the mining machine. In connection to this, it is possible to change the absolute angular velocity of rotation of the electromagnetic field of the stator of this electric motor. The necessity of introducing into existing mathematical models that determine the state and behavior of asynchronous electric motors, additional differential and algebraic relations for calculating the absolute speed of the electromagnetic field of the stator and the nature of the motion of the stator housing of the electric motor as part of the mining machine is noted. The results of calculations of the idle start mode of the electric motor of the executive body of the mining combine are shown, showing the difference in the nature of its electromagnetic moment variation, rotor rotation speed, as well as efforts in individual reducer elements of the driving body driving the stator body from similar calculation results without taking into account the stator body movement. The conclusion is made about the possible discrepancy between the calculated and experimental results in the study of the dynamic modes of self-propelled mining machines.
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Date submitted2018-01-02
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Date accepted2018-03-14
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Date published2018-06-22
Analysis of the options of modernization of roller-bit drilling machines with a submersible steamer
- Authors:
- D. A. Yungmeister
- I. Krupenskii
- S. A. Lavrenko
The designs of submersible hammers and dampers protected by patents for reducing the vibration of the drilling rig of roller drill machines are proposed. The variants of modernizing drilling rigs for drilling hard rocks and faces of complex structures are considered. Particular attention is paid to the joint work of submersible shockers and pneumatic shock absorbers, the preferred schemes for the arrangement of these devices by drilling rigs are indicated. The results of experimental tests of machines with pneumatic hammers are presented to determine the vibration performance and drilling speeds. The pneumatic hammer allows increasing the speed of drilling process to the intensification of the destruction of the plain face by the shock load and the cleavage of the protrusions of the unevenness of the face, the better fitting of the bit to the face and the release of the blades or the bit pins from the drill bit. The choice of a particular type of damper or shock absorber depends on its design scheme and the possibility of changing the design of the drill string. With the complexity of installing a damping device in the mast (with significant dimensions of shock absorbers and drilling of strong heterogeneous rocks), it is advisable to use a set of tools to reduce hydraulic pulsations in the mains and cylinders of the hydraulic system by installing chokes in the oil plants and pneumatic shock absorbers. It is proposed to use the device for the development of pneumatic hammers by a patent-pending drilling method with a hollow piston filled with magnetically active heavy liquid, which will allow controlling the frequency and size of the shock pulses and partially compensating for the drill string fluctuations arising from the uneven immersion of the bit in the array . It is noted that the proposed solutions increase the drilling speed by an average of 15%.
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Date submitted2017-09-11
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Date accepted2017-10-30
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Date published2018-02-22
Provision of adhesion strength of gas-thermal coatings on piston rings of quarry transport engines
- Authors:
- Yu. Olt
- V. V. Maksarov
- V. A. Krasnyi
The main trend in the development of modern diesel engine manufacturign is the creation of high-powered, reliable and economical internal combustion engines (ICE), which are widely used in various industries, including mining machinery. The application of the methods of gas-thermal and gas-plasma coating for obtaining wear-resistant layers on piston rings for large internal combustion engines of quarry transport – diesel locomotives and dump trucks- is considered. It is shown that the abrasive-jet machining of base coat is widely used as a preparatory operation before coating process, and the roughness of the working surface of the rings after abrasive-jet machining has a significant impact on the adhesion strength of the coating with the base material. The selection of the surface roughness and the conditions of abrasive-jet machining for increasing the coating adhesion strength to the base coat significantly determines both the thickness of the coating and the reliability of the part itself. The aim of the paper is to investigate the dependence of the adhesion strength of a gas-thermal wear-resistant coating of piston rings of large engines of quarry transport, including dump trucks and diesel locomotives, from the roughness of the working surface after abrasive-jet machining, which in turn depends on its modes (distance to the nozzle exit section, the number of passes, the working air pressure, the shot change rate). The working surface adhesion strength of piston rings with diameter of 210 mm coated with molybdenum and steel wire composition was investigated by the twisting angle at which the coating peeled. It is shown that the roughness providing a twist angle greater than 35° should be more than 22 μm, which does not cause coating peeling off. Modes of abrasive-jet machining providing the specified values of roughness: working air pressure is 0.4 MPa, distance to the nozzle exit section is 110 mm, the number of passes is 2, and the shot changes after processing 40 mandrels.
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Date submitted2015-12-01
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Date accepted2016-02-29
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Date published2016-12-23
Simulation of diesel engine energy conversion processes
- Authors:
- A. S. Afanasev
- A. A. Tretyakov
In order to keep diesel engines in good working order the troubleshooting methods shall be improved. For their further improvement by parameters of associated processes a need has arisen to develop a diesel engine troubleshooting method based on time parameters of operating cycle. For such method to be developed a computational experiment involving simulation of diesel engine energy conversion processes has been carried out. The simulation was based on the basic mathematical model of reciprocating internal combustion engines, representing a closed system of equations and relationships. The said model has been supplemented with the engine torque dynamics taking into account the current values of in-cylinder processes with different amounts of fuel injected, including zero feed. The torque values obtained by the in-cylinder pressure conversion does not account for mechanical losses, which is why the base simulation program has been supplemented with calculations for the friction and pumping forces. In order to determine the indicator diagram of idle cylinder a transition to zero fuel feed mode and exclusion of the combustion process from calculation have been provisioned.
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Date submitted2015-08-26
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Date accepted2015-10-16
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Date published2016-04-22
Reserch of modernized perforator-hammer for drifting special roadway the underground mines «Metrostroy»
- Authors:
- D. A. Yungmeister
The article describes the design of modernized hammer-perforators for tunnel complexes for construction of auxiliary mine workings of «Metrostroi», St Petersburg, protected by patents. The article deals with assembly variants of the executive device of percussion type for breaking faces of complicated structure. Particular attention is paid to hammers working in the mode of the «counter-shearing» accomplished by dual jackhammers. The results of experimental tests to determine pike penetration into rock array for different values of rock hardness and pressing force. It is noted that the proposed solution replaces manual labor, reduces working cycle time.
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Date submitted2014-06-23
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Date accepted2014-08-27
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Date published2014-12-22
Theoretical aspects of the kinetics of gas hydrates
- Authors:
- E. P. Zaporozhets
- N. A. Shostak
In the systems of collection, preparation, transportation and processing of hydrocarbons in conditions of a certain temperature and pressure, gas hydrates, which adversely affect the operation of the processing equipment, are formed. To prevent hydrate formation, it is necessary to determine the time and rate of growth. For this purpose, physical and mathematical models describing the growth of crystalline hydrates are being designed and developed. The developed models differ from one other. The reason for the difference is that each model is designed for specific temperature and pressure conditions and individual gas hydrates (or mixtures). The main theoretical models describing the process of growth of hydrates under different conditions are presented.
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Date submitted2010-07-12
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Date accepted2010-09-14
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Date published2011-03-21
Principles of an automatic control system of ventilation creation the kuznetsovsky railway tunnel
- Authors:
- S. G. Gendler
- V. A. Pleskunov
For effective ventilation Kuznetsovsky railway tunnel the longitudinal scheme of ventilation based on use of jet fans is offered. It is shown that use of the offered scheme of ventilation at influence of natural draft and piston effect of trains is impossible without an automatic control system of ventilation (ACSV). The principles of work ACSV taking into consideration natural and operational factors are proved.
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Date submitted2010-07-10
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Date accepted2010-09-04
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Date published2011-03-21
Experimental research of the train aerodynamic resistance
- Authors:
- V. A. Pleskunov
In paper the technique of definition of aerodynamic resistance of the train, a being main component of a piston pressure is resulted. The urgency of the given theme is caused by essential influence of a piston pressure on distribution of fresh air on a tunnel and accordingly on safe operation of railway tunnels.