卷 18, 编号 2 (2024)

BACKGROUND: The methods of ensuring detonation-free combustion of liquefied petroleum gases (propane-butane mixtures) (LPG) in a cylinder of the gas-diesel engine with an ignition dose of no more than 25%, at maximal power modes are covered in this paper. Addition of a part of the exhaust gases and vaporous water to the fuel mixture, when using a nickel-based catalyst in the combustion chamber of the gas-diesel engine, which triggers the conversion reaction of lower alkanes, ensures reliable detonation-free combustion of the fuel charge.

AIM: Conducting the analysis of studies on the oxidative conversion of lower alkanes in the presence of nickel catalysts with the development of technical solutions to eliminate detonation in all operating modes. Conducting the research to improve system reliability, to optimize the supply of diesel and gaseous fuel for fuel efficiency improvement and reduction of harmful emissions from exhaust gases when turning the diesel engine into the gas-diesel engine.

METHODS: A nickel catalyst, which is an oxygen carrier, ensures cyclical reactions near its surface in the combustion chamber of the gas-diesel engine, which are metal oxidation when purging the combustion chamber and conversion of alkanes during the compression and combustion strokes. The problem of catalyst carburization is solved by burning off deposits during combustion of the fuel charge.

RESULTS: The preparation of a fuel steam-gas-air mixture with subsequent combustion in the presence of a catalyst ensures improved environmental, fuel consumption characteristics of the gas-diesel engine over the entire range of operating conditions and increases its reliability without detonation combustion of liquefied petroleum gases.

CONCLUSION: The use of the proposed system in diesel engines used in tractors aimed to agricultural technological operations helps to reduce fuel costs by more than 38%.

BACKGROUND: Currently, machines for processing metals and other materials are used in various industry sectors. Operation of these machines defined with the CNC is impossible without using the corresponding systems, which ensure performing real-time configuring of the system for solving various technological tasks by means of machine drives control.

AIM: Analysis of functional capabilities of the visualization module of the AksiOMA Kontrol CNC system in comparison with other well-known same-type systems with consequent enlarging of capabilities of this module. Based on this, the study aim is formulated as follows: broadening the functional capabilities of the module of cutting tool motion path visualization in the AksiOMA Kontrol CNC system by means of development of the path analysis module.

METHODS: For achieving the aim, the next task to broaden the functional capabilities of the module of cutting tool path visualization in the AksiOMA Kontrol CNC system is formulated as follows: analysis of existing means of cutting tool path visualization in the CNC systems.

RESULTS: The study result is the fact that the visualization interface is critically important for operation, as it helps the operator to assess the abnormal situation quickly. Mistakes can be found at every stage of part machining setting-up. The mistakes can be made when positioning the part or the tool, at zero-point binding, at axes offset setting-up, etc. When machine equipment is set up, generally, difficulties take place if there is a different set-up for the other order. For these cases, in the CNC systems, such functional capabilities as processing visualization are necessary. This functionality is critically important, as it helps to find a mistake in time, to assess the danger level, and to fix it in time, that helps to prevent both the machine and the tool from failure and excessive mechanical impact.

CONCLUSION: The study, which contains solving the tasks of analysis of cutting tool motion path in the AksiOMA Kontrol CNC system, is completed. The analysis conducted in the paper revealed that majority of CNC systems does not have the presented functional capabilities that does not help to conduct the complete analysis of the machining process.

BACKGROUND: Modern approaches based on numerical optimization methods are used in development of pumps in order to achieve the high level of efficiency. These methods with use of parametrical models of flow sections of pumps help to find either global or local extremum of an objective function and to obtain the optimal geometric shape of the flow section. The study object is a dewatering electric submersible pump with cantilever working wheel arrangement used in shipbuilding industry.

AIM: Improvement of energy indicators of the flow section of the high-speed electric submersible pump at the nominal operation mode by means of calculation with the use of the stochastic algorithm of search of the global extremum of an objective function that is pump hydraulic efficiency.

METHODS: Search of the optimal shape if the flow section was conducted with the use of mathematical modelling of three-dimensional flow of a viscous fluid in the computational region of the studied object. The parametrical model of the flow section includes nine geometric variables (four variables for a working wheel, five variables for an outlet element) and their variation ranges. The chosen algorithm of search of the global extremum of the objective function is the Latin hypercube method which ensure uniform distribution of geometric variables in the search space. According to the compiled matrix of experiments with various combinations of parameters, direct fluid dynamics simulations of flow in the flow section were performed.

RESULTS: Simulation results showed that it was managed to improve the pump hydraulic efficiency by 7% in comparison with the initial flow section. According to the velocity field analysis, energy indicators improvement was achieved mainly by increasing the width of channels between an electric motor and a housing, leading to velocities decreasing and lowering the level of hydraulic losses in the outlet element of the flow section of the pump.

CONCLUSONS: The Latin hypercube method proved its effectiveness in search of the global extremum of the pump hydraulic efficiency. The obtained result can be used in further as the initial point in search of the local extremum with direct methods in the area around the found global extremum of the objective function.

BACKGROUND: The problem of creating a centrifugal pump for extracorporeal membrane oxygenation systems (hereinafter referred to as ECMO), optimal in terms of its hydraulic characteristics and its effect on blood, still remains relevant. This work is a continuation of the authors’ previous research in this area and contains the results of hydraulic tests of prototypes of the new ECMO pump with the closed impeller on water and water-glycerin mixtures, which imitate the viscous properties of blood.

AIM: Determination and comparison the head-flow characteristics of the new ECMO pump with the closed impeller when operating on water and water-glycerin mixtures.

METHODS: A series of hydraulic tests of pump prototypes, manufactured using different technologies, was carried out. Three liquids were considered as the working fluid during the tests: process water at a temperature of 20 °C and two water-glycerin mixtures at a temperature of 20 °C with different ratios of water and glycerin (to obtain different viscosities).

RESULTS: The pressure characteristics of pump prototypes, manufactured using different technologies, were obtained using water and water-glycerin mixtures. Tests with use of water showed that the deviation of the calculated and experimental characteristics from each other does not exceed 4%; the deviation of the characteristics of prototypes, manufactured using different technologies, is on average 1.5%. Tests with use of a water-glycerin mixture showed that the deviation of the characteristics from those obtained with use of water is on average 6%, the largest deviation is observed at the edges of the characteristics. In addition, when tested with use of a water-glycerin mixture, the deviation of the characteristics of prototypes, manufactures using different technologies, is about 4%, which is higher than when tested with use of water.

CONCLUSION: The results obtained allow us to conclude that the numerical model used in previous work can reliably predict the performance of the pump with use of water. The pressure characteristics of water and a water-glycerin mixture differ from each other, which must be taken into account when assessing the operating parameters of such pumps. The influence of manufacturing technology on the performance characteristics of the pump is higher when it operates with use of a liquid more viscous than water, e.g. on a water-glycerin mixture.

BACKGROUND: Modern battery-powered vehicles still do not meet the needs of consumers in terms of autonomous mileage. Therefore, the problem of increasing the energy efficiency in order to reduce energy consumption for motion is highly relevant. One of the directions, along with the use of more efficient units and systems, is the development of control algorithms that minimize these costs and make it possible to control the motion using only the accelerator pedal.

AIM: The study of the operability and effectiveness of the algorithm for controlling a vehicle only with an accelerator pedal using virtual simulation of motion, further practical implementation of the algorithm in the control system.

METHODS: The study was carried out using the MATLAB/Simulink software package.

RESULTS: The paper describes the functioning of the single-pedal control algorithm using the example of a passenger vehicle with an individual traction electric drive, the results of virtual simulation proving its operability and energy efficiency for the case of highway traffic.

CONCLUSION: The practical value of the study lies in the proven operability, energy efficiency, and the possibility of using the algorithm for development of the software for vehicle motion control systems.

BACKGROUND: The automotive industry evolves constantly. Every day, engineers work to improve the vehicles’ design. In the modern world, it is necessary to take into account a huge number of aspects when creating various means of transport, including electric ones. Great attention is paid to the problem of reducing the mass of electric vehicles and electric motorcycles.

AIM: The introduction of extrusion technology in manufacturing of traction battery frames to reduce the mass-dimensional characteristics of the category L electric vehicles.

METHODS: The use of aluminum alloys in manufacturing of power structures of traction batteries through the extrusion technology.

RESULTS: Using the results of the load simulation in the ANSYS software, the further practical approval of using this technology for the category L electric vehicle is planned.

CONCLUSION: In addition to solving the problems associated with the mass–dimensional indicators, this technology is able to help to solve the economic problem and to approach to save technological time and money spent on the production of traction battery parts with a similar technological process (milling).