Vol 15, No 4 (2021)

Peristaltic pumps are used in a wide variety of applications due to their tightness, ease of maintenance and accurate delivery. Nevertheless, the use of peristaltic pumps is limited by their disadvantages: short service life of the working body and uneven feed. This work provides an overview of the existing design solutions for pumps. The main advantages and disadvantages of the most common modern designs of peristaltic pumps are considered. The developed design solutions are presented. These solutions are designed to extend the service life of the elastic working body of the pump. These include a spiral hose design, where hose life is improved by reducing the number of cyclic compressions using just one roller. Another solution is to operate the pump with incomplete compression of the working element, which reduces the stress values and thereby prolongs the service life of the working element. The special shapes of protrusions in the compression area were developed in order to compensate the decrease in flow caused by the operation of the pump with incomplete compression of the working member. The paper provides an overview of solutions to reduce the uneven flow of a peristaltic pump. The simplest of these is the use of multiple parallel channels. In other designs, the elimination of flow pulsations is achieved with a pneumatic damper. There is also a constructive solution, in which a special algorithm of actuation of five squeeze elements is used for uniform supply, each of which compresses only its own section of the pump working body. Based on the analysis, it is shown that in order to eliminate the disadvantages of peristaltic pumps the various methods are used. Nevertheless, those methods need further improvement.

This article describes the purpose and applications of the starter generator set. The modes of operation of a starter-generator set are considered both as a sequential excitation direct current electric motor, which rotates the shaft of an internal combustion engine, and as a generator, when an electric machine operates as a direct current source of independent excitation, supplying power to electric control circuits, electric motors of auxiliary electrical equipment, lighting and battery charging. Additional functions of a starter-generator set in the form of a start-stop system, regenerative braking, booster acceleration of a vehicle, damping of torsional moments of the shaft of an internal combustion engine and control of energy flows in the on-board network were studied.

The choice and substantiation of the optimal scheme, as well as the design of the starter-generator device, were carried out. The main technical and economic parameters of the starter-generator set were determined. The design of a starter-generator set was presented. This design is a reversible electric machine. A block diagram of a starter-generator set was developed.

Electrical machines used for starter-generator sets are considered. The design of an asynchronous machine with a squirrel-cage rotor, a synchronous machine with electromagnetic excitation, a valve machine with permanent magnets, a contactless machine, a synchronous machine with permanent magnets, and a valve machine with self-excitation are described. A review and analysis of electrical machines used in starter-generator sets of leading foreign companies is carried out.

The design of a reversible induction-dynamic machine is considered. The rotor rotates outside, and not inside the motor and is a short-circuited winding with a cast aluminum cage. The calculation of the main parameters of a reversible induction-dynamic machine was carried out both in the starting and in the generator modes. The calculation using a method similar to that of an induction motor was carried out.

In areas where thermal and nuclear power plants are mainly located, the problem of lack of maneuverable capacities, the coverage of peak loads and the passage of periods of reduced energy consumption is solved through the construction of large pumped storage power plants (PSPP). To create highly efficient flow paths for pump-turbines, one of the modern trends is the use of numerical modeling of three-dimensional fluid flow. Nowadays, there are many software products that implement numerical modeling by the finite volume method. The most famous among them are Fluent, CFX, StarCD, Numeca, Flow Vision and CADRUN. Verification of the computational model remains an urgent task. It is important to choose a methodology that will allow you to get an acceptable result with optimal time spent on preparing data and conducting computational studies.

The article examines the flow path of a radial-axial pump-turbine designed for use at a maximum head up to 250m. Numerical modeling of the cavitation process arising in the turbine mode at a significant distance from the optimum of the characteristic was carried out. The calculations were performed using the Ansys CFX software package, version 2021R1. A brief description of the problem statement, the computational grids used and the assumptions made is given. Comparison of calculation results with experimental data is presented. A qualitative comparison of the cavitation origination regions obtained by numerical simulation with the data of monitoring the state of the base metal and welded joints of the hydroelectric unit impeller by the method of non-destructive testing is carried out.

The aim of the work was to present an “economical” technique for numerical simulation of cavitation to determine the places of possible occurrence of cavitation wear. The technique consists in describing the formulation of the problem, the computational grids used and the assumptions made for the optimal use of computing resources without a significant loss in the accuracy of the results.

When developing new suspensions for tracked and wheeled vehicles, as well as in the so-called reverse engineering of existing structures (including in the educational process of training personnel), it is necessary to solve the problem of finding the elastic characteristics of the suspension. In the first case, it is necessary to ensure the fulfillment of the specified tactical and technical requirements, in the second - to restore the form of characteristics according to a known design. Both of these tasks are greatly complicated in the absence of precise and universal analytical dependencies suitable for determining the characteristics of elastic suspension elements of various design implementations. The experience of interaction with some factories shows that designers, not being able to qualitatively calculate the elastic characteristics, use the method of selection and analogy, when for a new vehicle they use the suspension as on the old one, scaling it in size in order to approximately keep the values of working pressures. The numerous bench tests are carried out, which results are used for selecting required charging volume and pressure. Suspensions with backpressure cause particular difficulty, since not only the final characteristic, but also the performance of the entire unit depends on the combination of volumes and pressures of the two chambers, which work in antiphase: when one is loaded, the other is unloaded, and vice versa. Using analytical dependencies will reduce the time spent on design, to parameterize, to a certain extent, the suspension kinematics, to obtain the values of the equivalent suspension stiffness, and also to be able to develop the characteristics of the model range of pneumohydraulic springs for vehicles of various weight categories.

This article presents a technique for the analytical determination of the characteristics of pneumohydraulic springs of various designs. The options include both actually used in modern and historical technology (in particular, on BMD-1, 2, 3, 4; GM-352; Ural Typhoon; Object 775, etc.), and obtained by combining various structural elements, which implementation can be useful in the educational process in training personnel. The dependences presented in the article make it possible to obtain static and dynamic elastic characteristics at various polytropic indices and are suitable for the design of suspensions for wheeled and tracked vehicles for various purposes.

The perspective energy sources alternative to hydrocarbons, which are currently used in the world, are considered. Energy-saving technologies for the use of hydrocarbon fuel in vehicles are analyzed.

The need to develop the use of electric drives on automobiles is noted. The importance of systematical accumulation and analyzing of the existing experience of operating vehicles with electric drives abroad and in the Russian Federation is considered. Monitoring the technologies developed abroad and the problems arising during the operation of electric vehicles will make it possible to determine the priority ways of their development and to concentrate the efforts of researchers in the direction ensuring the maximum efficiency of their application.

One of the currently attractive and economically viable ways of developing road transport for domestic practice is the use of vehicles with hybrid power plants. It is shown that the production of hybrid vehicles and electric vehicles abroad is successfully developing and is nowadays one of the most dynamic in the world.

Indicators of efficiency of electric power consumption of vehicles with electric drive of various automobile manufacturers are given. A comparative analysis of technologies for the use of electric automobiles to improve the environmental situation in megalopolises is carried out and the problems of increasing the efficiency of automobile power plants are considered.

It is shown that the climatic conditions of the Russian Federation with long periods of low temperatures of atmospheric air strongly affect the energy losses associated with heating the passenger compartment, and to a large extent - on the energy efficiency of the power plant of electric vehicles.

To assess the efficiency of using electric vehicles, it is proposed to use a universal indicator of the efficiency of energy consumption. It is proposed to carry out a comparative assessment of the energy consumption of various vehicles by the energy parameter qEL.

The calculated data show that the use of vehicles with electric drive and, in particular, rechargeable hybrids is more profitable in comparison with the use of vehicles equipped exclusively with internal combustion engines.