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Vol 16, No 3 (2022)

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Heat engines

Results of application of porous permeable SHS catalytic blocks in multistage converters, diesel exhaust gases

Melbert A.A., Nguyen T.H., Mashensky A.V., Sokolova V.A.

Abstract

BACKGROUND: According to the statements of leading experts in the diesel industry, in order to introduce standards for the levels of harmful emissions into the atmosphere, it is necessary to use particulate filters and catalytic converters, which will increase the efficiency of exhaust gas conversion and improve the environmental performance of diesel engines.

AIMS: Educing harmful emissions into the atmosphere, improving the quality and reducing the cost of cleaning exhaust gases during the implementation of the life cycles of transport energy facilities by using porous SHS blocks in catalytic converters and particulate filters.

METHODS: Stand tests of prototypes of neutralizers of the AltSTU design with one, two and three stages of purification were carried out. The first stage is a particulate filter made of porous permeable SHS material, the second stage is an oxidizing SHS block, the third stage is a catalytic reducing SHS block. To obtain catalytic blocks by the SHS method, the following charge composition was used: iron scale 18X2H4MA -47.5%; chromium oxide PH-1 according to TU 882-76 – 17.7%; nickel powder PNK-OT-1 according to GOST 9722-79 – 4.9%; aluminum powder according to TU 485-22-87 grade ASD-1 – 15%, copper – 11%; aluminum oxide – 3.8%; iridium – 0.01%. The charge of the recovery unit consisted of 14.5% copper. The resulting blocks had a permeable structure and high strength. The average pore size was 180 microns. Neutralizers were installed butt-to-butt with a turbocharger.

RESULTS: It was revealed that NOx emissions according to the load characteristic of the KamAZ-740 diesel engine at 2600 min-1 decrease at average effective pressures Pe equal to 0.03; 0.55; 0.77 MPa from 3.82...11.62...9.49 g/m3, respectively, to 3.23...6.52...4.61 g/m3 or approximately 13...44...53%. Reduction of emissions of solid particles at the same loads was 75; 45; 63%, of hydrocarbons – 72; 53; 54%. The minimum specific fuel consumption was observed in the range of 1600...2000 min-1 according to the external speed characteristic. When using a neutralizer with two catalytic units installed in series, emissions from hydrocarbon exhaust decreased from 3.12...1.21 to 0.90...0.29 g/m3, or by 71...76%. The degree of CO conversion was 78...73%; NOx – 4...52%, and the total purification coefficient was a coaxial installation of additional blocks made of SHS-catalytic materials has led to an improvement in the quality of cleaning up to ηкн= 0,698. Over 360 hours of operation, the efficiency of PM conversion decreased from 55 to 45%, CO – from 58 to 46%, NOx – from 65 to 44%, which indicated the beginning of deactivation of catalysts.

CONCLUSIONS: The use of multi-stage neutralizers with SHS-catalytic units can reduce emissions of hydrocarbons by 1.95 times, carbon monoxide by 3.6 times, nitrogen oxides by 2 times, solid particles by 3 times, ensuring compliance with Russian standards.

Izvestiya MGTU MAMI. 2022;16(3):201-208
pages 201-208 views

Prediction of ignition time delay in a diesel engine when using composite fuel

Buzikov S.V.

Abstract

BACKGROUND: Analytical determination of ignition time delay (ITD) which would give a prediction of ignition in diesel engines of various types using composite fuel (CF) of various kinds and compositions depending on loading and speed operation modes is a relevant issue.

AIMS: Determination of the ITD values for a diesel engine at all loading and speed operation modes with using various kinds and compositions of CF.

METHODS: In order to determine ITD, theoretical and experimental studies of the D-245.582 tractor diesel engine of 4ChN 11.0/12.5 size with using compositions of CF including diesel oil (DO) and rapeseed oil (RO) or ethanol (E) were carried out. As a result of the studies, the diesel engine ITD predictive indicators determination method considering dependence on loading and speed operation modes and CF kind and composition has been developed.

RESULTS: Calculated values of the ITD numerical relationships revealed that the load (pe) increase from 0.2 to 1.0 MPa, the engine speed (n) decrease from 1800 to 1400 min-1 and decrease of mass fraction of rapeseed oil (RO) and ethanol (E) in CF from 40 to 20% lead to diesel engine ITD decrease from 7.69 to 4.82 degrees of crankshaft rotation and from 11.70 to 7.92 degrees of crankshaft rotation respectively. It was experimentally found that the load (pe) increase from 0.2 to 1.0 MPa, the engine speed (n) decrease from 1800 to 1400 min-1 and decrease of mass fraction of rapeseed oil (RO) and ethanol (E) in CF from 40 to 20% lead to diesel engine ITD decrease from 7.59 to 4.22 degrees of crankshaft rotation and from 11.20 to 7.72 degrees of crankshaft rotation respectively. The degree of convergence of the experimental data with the calculated values, assessed with a statistical processing method and experimental error calculation, is 94.04%.

CONCLUSIONS: Practical value of the study lies in prediction of diesel engine ITD with using composite fuels of various kinds and compositions at all loading and speed operation modes.

Izvestiya MGTU MAMI. 2022;16(3):209-218
pages 209-218 views

Hydraulic and pneumatic systems

Influence of an impeller inlet diameter on operation of a high-speed submersible electric pump at the high flow rate modes

Gorbatov D.A., Zharkovsky A.A., Adrianov A.V.

Abstract

BACKGROUND: The study object is a high-speed drainage submersible electric pump, aimed to water polluted sea and fresh water bailing out of drowned rooms of shipbuilding industry facilities.

AIMS: To obtain dependencies of pump cavitation properties on relative diameter of an impeller inlet at the high flow rate modes, to determine the kind of head-capacity and energy properties of a pump for various geometrical ratios of an impeller in the flow rate operational range.

METHODS: Main geometrical properties of impellers were determined with use of semi-empirical formulas of various authors’ methods. For the study of dependencies, three options of impellers were chosen and series of fluid dynamic simulations of three-dimensional flow of viscous fluid with use of the ANSYS CFX software were completed.

RESULTS: Head-capacity, energy and cavitation properties of the pumping unit were obtained. The experimental head-capacity curve correlates to the simulated one. The simulation results revealed that using of narrowed impeller inlet leads to generation of wide low-pressure area at the backside of the impeller vane and disruption of operational curves at the high flow rate modes. With the biggest relative diameter of the impeller inlet, the vapor pressure area at the backside of the impeller is absent so there is no disruption of operational curves at the high flow rate modes, however, the pump hydraulic efficiency ratio at the whole range of flow rate is the lowest among all the studied options of impellers.

CONCLUSIONS: The method of defining the value of an impeller inlet diameter, optimal with regard to energy and cavitation properties, to ensure cavitation free operation of a high-speed submersible electric pump at the whole range of flow rate is proposed.

Izvestiya MGTU MAMI. 2022;16(3):219-224
pages 219-224 views

Prediction of energy and cavitation characteristics of high specific speed Francis hydraulic turbines

Zharkovskiy A.A., Schur V.A., Mohammad O.

Abstract

BACKGROUND: Cavitation is a phenomenon that occurs in vane hydraulic machines: pumps, hydraulic turbines, when the pressure in a certain area of the flow reaches the level of saturated steam pressure. Its occurrence depends on the design and mode of operation of the hydraulic turbine. In order to design a hydraulic turbine with high cavitation qualities, it is necessary to be able to reliably predict this phenomenon.

AIMS: The article describes approaches to modeling the operation of Francis hydraulic turbines based on the ANSYS software package.

METHODS: Using quasi-3D methods was modeled turbine blade system with 75 meters head. Hydrodynamic computation carried out in single-phase and two-phase formulations using the ANSYS CFX package.

RESULTS: The design of a flow path Francis turbine 3D solid model with a specific speed coefficient ns =283 has been completed. The flow part of the hydraulic turbine includes a spiral case, a stator, a guide vane, an impeller and a draft tube. Computational modeling of the flow of a single-phase viscous fluid in a hydraulic turbine in different modes was carried out to construct a universal characteristic. The optimal efficiency is found and the flow characteristics are calculated. The losses in the elements of the flow part of the hydroturbine under various operating modes are determined, the zone of optimal operation is found. The cavitation flow is calculated using a two-phase flow model (water-steam). For both sides of the impeller blade, a pressure distribution was obtained, which can be used to judge the possibility of cavitation in areas where the pressure of the water column is less than the vaporization pressure. The value of the critical cavitation coefficient for the three most unfavorable modes was determined, and the dependence of the efficiency on the cavitation coefficient was constructed. The area occupied by steam on the blade during cavitation flow is visualized, its area is determined relative to the surface area of the blade.

CONCLUSIONS: The designed hydraulic turbine has good energy and cavitation qualities, confirmed by the calculation. This version of the hydroturbine can be used as the initial one with further optimization of the blade system and elements of the flow path, to improve the energy and cavitation qualities.

Izvestiya MGTU MAMI. 2022;16(3):225-234
pages 225-234 views

Transport and transport-technological complexes

Prerequisites for the creation of domestic onboard diagnostics tools for the M1 and M2 categories vehicles

Zavoykin V.A.

Abstract

BACKGROUND: Due to the steady growth of the worldwide fleet of vehicles alongside the sophistication of their operational functions and the increase in the number and manufacturability of electronic control units, used in a vehicle, the demand for means of access to the performance of on-board electronic sys-tems at the final stages of their production and operation is increasing. This review is necessary to summarize the available data from the world experience in the development and implementation of on-board diagnostic systems.

AIMS: Formulation of general principles for the development of on–board diagnostic systems, helpful to outline reasonable technical solutions for the task of creation of proprietary domestic diagnostic environment for vehicles.

METHODS: This paper describes the purpose and role of onboard diagnostic systems used in world practice for modern vehicles. Classes of diagnostic devices are allocated according to the level of implemented functions. The grounds that determine the demand for development of proprietary onboard diagnostic systems for wheeled vehicles are considered. A review of the functionality of the original diagnostic tools of foreign vehicle manufacturers was carried out. The main requirements imposed on developers by the ISO 27145 and ISO 14229 group of standards within the framework of the implementation of modern diagnostic systems in domestic vehicles of the M1 and M2 categories are determined.

RESULTS: A specific set of functions recommended for integration into diagnostic equipment being developed as a part of promising domestic developments has been determined. The content of the positive effect of the practical implementation of the measures proposed according to the results of the analysis is formulated.

CONCLUSIONS: The performed scientific analysis of the features of the existing diagnostic equipment is helpful to determine the relevant trends in the implementation of a fundamentally new trend in on-board diagnostics in the Russian Federation, which contributes to increasing the level of competence of domestic specialists and development within the framework of the domestic engineering development strategy.

Izvestiya MGTU MAMI. 2022;16(3):235-240
pages 235-240 views

Technical diagnostics of heembedded elements of crane tracks of lifting equipment in machine halls of tunnel escalators

Vatulin Y.S., Popov V.A., Dyatlov V.N.

Abstract

BACKGROUND: During the operation of crane beams of lifting equipment of subway tunnel escalators’ machine halls, the information about the technical condition of certain structural elements of supporting metal framework is always relevant, which determines the possibility of their further safe use and the need for repair and restoration work. The value of the remained service life is estimated by comparing the actual load-carrying ability with the criteria corresponding to the limiting conditions according to the project documentation. The actual state of the supporting framework elements can change with time significantly, therefore, the assessment of the remained service life is carried out with an experiment-and-simulation method based on the determination of stresses and their maximum deviations in weakest sections of framework elements with the determination of the degree of their impact on durability in the long term.

AIMS: Analysis of the combined application of methods for modeling the stress-strain state with subsequent wavelet analysis of wave processes in the interlocked stud-bolts of the suspension unit of riding beams of lifting and transport equipment of subway tunnel escalators’ machine halls.

METHODS: With regard to the specific features of the design, numerical simulation of the technical state of the interlocked sections of the stud-bolted suspension of crane beams of lifting equipment of subway tunnel escalators’ machine halls is considered in this work. The capabilities of the Simulation (static analysis using the finite element method) and Motion (kinematic and dynamic research with formation of systems of differential equations of motion and subsequent solving) modules of the SolidWorks software platform were used in the development of the model.

RESULTS: As a result of the carried out research, with regard to the specific features of various methods of the stress-strain state simulation, a spatial linear dynamic model has been developed that reflects the processes occurring during the deformation of the stud-bolt suspension of the supporting I-beam, which is helpful for an objective assessment of its technical state, as well as the possibility and conditions of further operation.

CONCLUSIONS: To simulate the stress-strain state, the combined application of methods is necessary, followed by a wavelet analysis of wave processes, which increases the reliability of diagnostic procedures and, consequently, makes it possible to make reasonable decisions about the further operation of the facility.

Izvestiya MGTU MAMI. 2022;16(3):241-250
pages 241-250 views

Study of the effects of deformation rate and adhesive layer thickness under impact loading on parameters of adhesive joints in a vehicle

Liu Y., Goncharov R.B., Zuzov V.N.

Abstract

BACKGROUND: At the present time, new technologies of joints – adhesive joints – are used more and more widely along with spot welding in domestic and foreign vehicles. Study of the joint strength and the influence of deformation rate and the adhesive layer thickness under impact loading on the parameters of the joint in a vehicle is a relevant technical task.

AIMS: Study of the influence of deformation rate and the adhesive layer thickness on the adhesive joint parameters (strength, deformation, etc.) under impact loading as well as evaluation of the efficiency of the proposed modified calibration method for the adhesive layer model on the example of tubular structure, which is often used in the strength elements of a vehicle.

METHODS: Experimental studies were carried out with impact loading at the speed of 6.66 m/s (the axial im-pact) and 6.87 m/s (the side impact) with the mass of 22.3 kg. Simulation of operating conditions was performed in the LS-Dyna software that made possible to study the stress-strain states (SSS) of adhesive-bonded tubular structures and to estimate the simulation error.

RESULTS: Based on experimental and calculated results, the length of the adhesive layer failure under the impact loading in the steel structures bonded with the Henkel EP 5055 adhesive is shorter in the joints with the 0.5 mm thick adhesive layer than in the joints with the 1 mm thick adhesive layer. The total deformation of the bonded structure at the side impact loading for the 1 mm thick adhesive layer is less than for the 0.5 mm thick layer, as the adhesive layer absorbs some of the energy. For the axial impact loading, the differences are insignificant. Errors of adhesive joint simulation under impact loading have been reduced significantly (by 15%) with using the proposed modified method of calibrating the adhesive layer properties considering the influence of the deformation rate and the adhesive layer thickness in the finite element model.

CONCLUSIONS: The practical value of the study lies in the proposed modified model, considering the influence of the deformation rate and the adhesive layer thickness under impact loading on the joint parameters and making possible to improve simulation accuracy, as well as in recommendations for the best value of adhesive joint properties in adhesive-bonded vehicle structures.

Izvestiya MGTU MAMI. 2022;16(3):251-263
pages 251-263 views

Electrotechnical complexes and systems

The diagnostics of windings of vehicle alternator units

Randin D.G., Tulupov P.V.

Abstract

INTRODUCTION: An alternator unit is a necessary unit in a vehicle, as it provides all the consumers with electricity. Therefore, the operation capability of the whole vehicle depends on the alternator unit’s operational state. The issue of the diagnostics of a vehicle alternator unit by means of determination of alternator phases’ windings active resistance is addressed.

AIM: Improvement of diagnostics informativity by means of voltage controllers with a self-diagnostic function.

METHODS: It is proposed to perform the alternator unit diagnostics without dismantling or disassembly by means of plugging to the diagnostic points.

RESULTS: The existing and known methods of vehicle alternator unit diagnostics with embedded diagnostic tools and with use of external diagnostic tools were analyzed. The method of diagnostics of phase winding active resistance with use of reference resistance was proposed. The algorithm of implementation of the proposed method was suggested. The recommendations for use of the proposed method were given.

CONCLUSIONS: The proposed diagnostics method can be used in engine control units or by technicians of maintenance stations during the alternator unit maintenance without dismantling or disassembly.

Izvestiya MGTU MAMI. 2022;16(3):265-272
pages 265-272 views

The spark plug’s thermal state simulation

Yakhutl D.R., Maleev R.A., Zuev S.M., Shmatkov Y.M., Ryabykh E.A.

Abstract

BACKGROUND: Spark plugs are among the most important components of the ignition system of an internal combustion engine (ICE). The spark-over produced by the ignition system should have sufficient energy for combustion initiation at any engine operation mode in all the service conditions. Start properties, reliability, power, fuel efficiency and exhaust toxicity of an ICE essentially depend on excellence of design and manufacturing quality of a spark plug. On the other hand, functional properties of spark plugs depend on concordance to ICE with main dimensions, design, heat properties and value of a spark gap. AIMS: Use of the methods of the spark plug’s temperature field simulation in order to reduce the amount of experimental studies and to reduce the number of specimen options subjected to laboratory and on-road engine tests.

METHODS: The simulation model of the temperature field of a spark plug of an internal combustion engine (ICE) was developed in this study.

RESULTS: The representation of temperature distribution in the insulator’s thermal cone and other ceramic elements of a spark plug was obtained. The dependence of thermal conductivity and specific thermal capacity of corundum ceramics on temperature was derived. The dependencies of thermal conductivity coefficient of the plug’s ceramic insulator are presented. The analysis of thermophysical properties of the substances made of various materials was carried out. The equations of the temperature field of all parts of a spark plug (a contact head, glass sealant, an insulator, a central electrode, a spark plug’s body, a heat-sinking washer, a sealing ring, a cylinder head) were developed. The schematic representation of the spark plug geometry, used in the temperature field calculation, was obtained. The requirements for boundary conditions for calculation of the temperature field of a spark plug were determined. The calculation scheme of the spark plug is presented. The condition of heat exchange at the boundary between the selected part of a cylinder head and the cooling system of an internal combustion engine was considered. The study of heat transfer between the structural elements of a spark plug and the air inside the ICE compartment was carried out. The dependencies describing the heat exchange between the structural elements of a spark plug being in thermal contact with each other were determined and the internal boundary conditions were established.

CONCLUSIONS: The presented methods and algorithms of spark plug’s thermal state simulation helped to perform the calculation of dependencies of thermal conductivity and specific thermal capacity of the insulator’s ceramics as well as the thermal conductivity coefficient of the plug’s ceramic elements on temperature.

Izvestiya MGTU MAMI. 2022;16(3):273-280
pages 273-280 views

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