The thesis is devoted to the study of cavitation processes occurring in a gear pump with an external involute gear during the transportation of Newtonian fluids, determining the conditions for their appearance and studying the effect on their intensity of pump operating conditions in order to select the rational operating parameters of the equipment and improve the efficiency of the pump. For research purposes, an experimental booth designed for the study of hydraulic machines has been developed to measure the instantaneous values of pressure in the suction and inlet lines, as well as to conduct high-speed video recording of processes that occur when using hydromachines. The video camera used in the study allows you to make up to 10,000 frames per second, which made it possible to examine in detail the processes that occur during the pump operation. There was developed and created a physical model of a gear pump, and fluid flows in its internal channels were visualized, which allowed confirming the occurrence of cavitation in the trapped volume of a gear pump. The process is considered in detail and the places where cavitation phenomena appear in cavities of a gear pump are determined. As a result of rheological research, the rheological characteristics of the working fluid, HDZ 46 oils were obtained, it was determined that oils used as working fluids in the range of temperatures under consideration (+ 17 °C ... + 50 °C) behave like Newtonian fluids. A study was made of pressure pulsations in the pump lines, taking into account which a mathematical model was proposed for determining the velocity distribution along the pipeline section and the magnitude of the shear stresses. It was found that the velocities and shear stress in the flow that occurs under pressure that changes harmonically have a complicated form and varies over time. This should be taken into account in determining the hydraulic losses in the system. In the study of pressure pulsations, it was found that when changing the pressure in the suction line, the form of pressure pulsations in the injection line changes. Thus, at overpressure in the suction line pits appear in the ripple curve in comparison with the case when the pressure in the suction line is equal to the atmospheric pressure. And when pressure is reduced in the suction line to negative values, the curve of the pulsations of pressure is close to the pollen, with the gradual increase in pressure to the maximum value. The impact of the pump operating parameters on the intensity of cavitation phenomena that arise in the trapped volume during the operation was investigated. It was revealed that with increasing pressure in the suction chamber, the intensity of cavitation decreases. The intensity of the cavitation increases with the increase in the speed of gears and when the temperature of the working fluid increases, that is, when it decreases its viscosity. These studies allow you to develop recommendations for choosing pump parameters. The efficiency of the application of relief grooves was studied with the aim of reducing the intensity of cavitation phenomena. It has been found that existing grooves reduce the intensity of cavitation phenomena in the closed volume and suction chamber, but do not completely eliminate them. Based on the data of the visualization of the pump operation, a new shape of relief grooves is proposed, which enable to reduce the intensity of cavitation phenomena and provide, in comparison with the studied grooves, fewer leakages of the working fluid, increasing the efficiency of the pump. The method of influence on the intensity of cavitation phenomena by the influence of a magnetic field on a fluid pumped by a pump is proposed, in the case where the fluid is electrically conductive. Due to the action of the Lorentz forces, the extinction of vortices and cavitation phenomena occurs.
