Method of calculating the total energy in suction and pressure pipelines of the main units at reclamation pumping stations

Abstract

Purpose: theoretical substantiation of the method for calculating the total energy in suction and pressure pipelines of the main units at reclamation pumping stations to prevent unsteady processes and water hammer. Materials and methods: research and calculations were carried out at the pumping station “Mezhdurechye”, “Management of Stavropolmeliovodkhoz”, equipped with three main centrifugal pump units and two pressure pipelines. To calculate the total energy in the suction and pressure pipelines of the main pump, the entire pipeline network is divided into three sections: the first one is the intake, the second one is the distribution and the third one is the main pressure pipeline. For each section from 0.25 to 3.41 с²/м⁵ and the entire network 4.65 с²/м⁵, specific resistances were determined, the actual total head losses from 2.50 to 29.32 m when three units were fed into two pressure pipelines from 0.3 to 7.2 m³/s and hydraulic parameters of each unit: head (90.2 m), flow (2.67 m³/s), power (1585 kW), admissible vacuum suction head (4.2 m) at efficiency (88 %), with various operating options of the pumping station. Results: as a result of the research, the procedure for determining the total energy in the suction and pressure pipelines of the main units at reclamation pumping stations was determined, the total energy was calculated depending on the number of running pumping units: for suction pipelines from plus 0.1 to minus 1.5 m, for pressure pipelines from 75.79 to 86.34 m, which allows calculating the required hydraulic parameters of the booster pump used to close the back flow valve in the pressure pipelines of the main pump, to prevent backflow of water and water hammer before stopping the main pump. Conclusions: the above method is recommended for calculating in case of necessity the prevention of water hammer in the network by closing the back flow valve with a booster pump for reclamation stations equipped with centrifugal pumps with a maximum possible head of 120–130 m, in a complex operational option – the maximum number of pumps per one pipeline.

Introductory axial pumping equipment in observations operational mode

“…Насосные станции, оборудованные осевыми насосами, как правило, используются в качестве головных, эксплуатируются с постоянным напором, не превышающим 20-25 м, для подачи воды в каналы и циркуляционные линии ГРЭС и АЭС. Основным гидравлическим фактором, влияющим на эксплуатационные характеристики осевых насосов, является заиление всасывающих линий и аварийное снижение отметок уровня в водоисточнике приводящим до критического кавитационного режима [7] и полной остановки насосного агрегата. При монтаже осевых насосов (рис.…”