Sosnovskii

pp. 39-55

pp. 32-42

pp. 26-39

The authors consider results of experimental studies of static characteristics of amplifiers with proportional and servo valve control. A comparison of characteristics that were recorded in a specially created complex allows to evaluate the accuracy of an amplifier with a proportional valve control and determine the impact of hydrodynamic forces applied to the spool on these characteristics. Experimental results prove flow characteristics and dependence of hydrodynamic forces on displacement of the spool; these results were obtained with the use of a computer model of a hydraulic amplifier. It was shown that if the spool has profiled surface, static characteristics of amplifiers with a proportional and servo valve control become approximately the same due to the balance of hydrodynamic forces. Thus, the authors established a possibility of application of simpler amplifiers with less power consumption and with a proportional valve control instead of a servo one. This statement is important for designing hydraulic drives.

This article describes a method of mathematical modeling of systems with centrifugal pumps. A structure chart directed at interactive solution of an optimal control problem of controlling pumping units was created with the use of this mathematical model. In this article, along with the results of calculations, the authors provide an example of an emergency cutout of a pumping module subject to the inertia of the pumping unit rotor, rotating frequency of its spindle, the pump’s head-capacity curve and parameters which determine hydraulic wave processes in the pipelines connected with the pump. Controlled parameters in this case are the pump module’s shaft speed and pressure generated by irregular fluid motion on intake side of the pump. Transition processes were determined for these parameters in case of an emergency cutout of the main line pump’s electric drive. Schematic diagram of the proposed mathematical model for investigation of centrifugal pump’s emergency modes was published for the first time

Loads on centrifugal pump details change when disbursements of liquid in the “pump – pipes” system change. Mathematical model of the system and calculations indicate possible increase of hydrodynamics forces in the double-entry pump. The results can be used in pump bearings design.