Дослідження режимів роботи турбомеханізмів за використання каскадної схеми включення насосів

Abstract

In this article there have been analyzed the modes of operation of the water supply system of a residential building, the principles of construction of pumping units have been defined. The scheme being worked with is the cascade scheme of the pump installation switching on at parallel of two centrifugal pumps of half power, one of which is regulated and another has only system of smooth start. Since the schedule of water consumption is uneven during the day and season of the year, the task is to ensure the most effective coverage of this schedule, taking into account the coefficient of unevenness. Three types of daily consumption schedules have been developed for the summer, spring and winter periods of the year, respectively. The functional diagram of the electromechanical system of a two-stage pump installation is given, which provides pres-sure stabilization. This stabilization reduces the probability of pretty large dynamic disturbances of the hydraulic network and eliminates the possibility of failure of closure ties and depressurization of the water supply system. It is also ensured that the hydraulic pressure is maintained at a given level. Using the SimHydraulics library of the MatLab application package, a model was developed to study the dynamic and static modes of operation of a cascade pumping unit. This model allows to take into account the characteristics of hydraulic network elements (bends, diameters and length of pipelines, closure ties, etc.) with a high level of accuracy, and to obtain a real characteristic of changes in its resistance in the process of regulating pump system performance. There have been analyzed the results of the study, the nature of the development of the dynamic error of the pressure when changing the level of water consumption during the day and season. Based on the results of the study of energy characteristics of the electromechanical system of the pump unit when using the system of stabilization of the hydraulic network pressure, the analysis of the nature of changes in active and mechanical power was made and the level of energy loss in static modes was defined. Based on the research results, the expediency of using the cascade scheme of the pump installation in the presence of a pressure stabilization system and a model taking into account the exact characteristics of the hydraulic network was defined.