Gear pumps are hydraulic machines capable of transferring energy and performing work in pumping fluid. This study presents an analysis of the hydrodynamic model of an external multiple gear pump in order to analyze the fluid flow in combinations of single and different viscosities at the same and different pressures and speeds. Solidworks Flow Simulation 2016 was used to analyze fluid flow. When the radius of the rounding on the collector inner surface is increased from 3 to 15 mm, the pressure drop decreases by 13%. When the radius of the manifold is 3 mm, cavitations are observed. With a liquid distribution system with four input ports and one outlet port in the top cover, the gear pump can handle liquids of viscosity classes 5 to 10. The speed should not exceed 1200 rpm if the liquid has a kinematic viscosity of 10 cSt. The pressure drop and velocity distribution of the liquid in the pressure and suction lines are the same. When the speed changes from 400 to 1200 rpm, the pressure drop increases five times, and the velocity increases three times. At a constant speed of 1000 rpm and an inlet pressure of 10 MPa but with different viscosities, the pressure drop decreases 8 times, and the speed increases 1.5 times. When the inlet pressure is 6 to 24 MPa, with constant speed and the same viscosity, the pressure drop and fluid velocity practically do not change. The dependence of pressure drop on the number of revolutions and radius of the rounding of the inner surface of the collector is statistically significant.

The research aims to determine the optimal modes of hardfacing when restoring the shafts of electric motors, taking into account the resulting hardness of the deposited layer for further machining. When conducting a full-scale experiment on hardfacin...

A comprehensive model for evaluating the functionality of a multi-gear pump has been developed. The integrated model for assessing the functionality of a multi-gear pump contains a computational fluid dynamics analysis (CFD) model combined with a finite element method (FEM)-based strength model. Two submodels were linked: a CFD submodel to evaluate the internal pressure distribution of the pump and a structural FEM submodel to calculate the stresses and structural displacements of the pump due to fluid pressure. Finite element analysis in SolidWorks 2016 was used to evaluate the strength of the gear joints of the pump gears. As the pressure of the working fluid increases from 6 to 20 MPa, a linear increase in Mises stresses is observed. At the shaft, these stresses increase to 226.2 MPa, and at the tooth mouths, they reach a maximum value of 205.5 MPa. With the increase in torque on the drive shaft from 100 to 500 N·m, there is a significant increase in Mises stresses localized in the contact zones of the shaft with the drive gear. Analysis of the data obtained showed that the displacements caused by the pressure of the working fluid are insignificant compared to the displacements arising under the action of torque. With increasing pressure and torque, there is a tendency to decrease the safety factor, which indicates a decrease in the safety factor of the design of the multi-gear pump. The safety factor is not provided at a torque of 400–500 N·m. The simulation results are confirmed by correlation analysis. The average approximation error is 5–7%.

This article presents a comprehensive experimental and theoretical study and substantiation of the hydraulic parameters of a prototype multi-gear pump. The proposed pump design, which features one drive gear and four driven gears, aims to address the common disadvantages of traditional gear pumps, including radial force imbalance, uneven flow, high acoustic noise, and increased fluid leakage. Tests of the prototype multi-stage pump were conducted on a specialized test stand in the “Hydraulics” workshop of “Hansa-Flex Hydraulik Almaty” LLP. Experimental analysis, supported by theoretical calculations, established the optimal operating speed range for the prototype to be between 900 and 1450 rpm, with the volumetric efficiency remaining stable between 70% and 88% when using VMGZ hydraulic oil (45 cSt). A significant deterioration in performance, including a sharp drop in volumetric efficiency to 30% and a decrease in the pressure generated, was observed at rotational speeds below 900 rpm due to an increase in internal leaks. In addition, this study examined the effect of kinematic viscosity, which revealed a 15–20% decrease in performance and power when using a fluid with lower viscosity (15 cSt) with a slight increase in noise level. This study also examines in detail the linear relationship between useful power and pressure in the system and analyzes noise characteristics under various operating conditions.

To solve the problem of improving the wear and corrosion resistance of parts in mechanical engineering, the method of gas-thermal spraying of coatings is often used. The process of gas-thermal spraying makes it possible to obtain a protective coating by atomizing molten or heated material using a high-speed gas or plasma flow. As part of the study, a mathematical model describing the physical processes occurring during the spraying process was developed. The mathematical model makes it possible to determine the optimal modes of the process, providing the obtaining of coatings of a given thickness and properties. The developed mathematical model will allow process engineers to calculate process parameters more accurately and obtain coatings with specified characteristics. The maximum adhesive strength of the gas-thermal coating H18N10T (4.78 MPa) is observed at the maximum difference between the burner nozzle area and the sprayed area.

Repairing damaged or worn motor shafts is an important part of the restoration work faced by many industrial plants. In the manufacturing sector, keeping electric motors running optimally is essential to keeping production running smoothly and efficiently. To reduce the cost of purchasing new electric motor shafts in the event of their breakdown or wear, industrial enterprises use surfacing. The quality of the deposited layer is determined, among other things, by the surfacing method and its technological modes. This article discusses the problem of obtaining a high-quality layer when restoring electric motor shafts by surfacing in three ways: manual surfacing, semi-automatic surfacing in a protective gas environment and automatic submerged surfacing. The advantages and disadvantages of each surfacing method are determined. Optimal technological modes of surfacing (current strength and welding arc voltage) were established using various methods based on an experiment with determination of geometric parameters (weld width, weld height, weld penetration depth) and physical and mechanical properties of restored surfaces (hardness).