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.

Purpose: to develop a methodology for calculating jet devices used in hydromechanization for the development of soils and cleaning reservoirs from sediments using the results of our own research and the theoretical and empirical dependences presented in the literature. Materials and Methods: on the example of a diagram of an annular two-surface jet ejectors with increased energy characteristics, a method has been developed and the calculation of the relative and actual geometric and hydraulic parameters of its elements is shown for use as a suction tip on suction dredgers at the necessity to increase the suction height and development depth of centrifugal dredgers. Results. Based on the initial data (the values of the hydraulic resistance coefficients of the inlet section, diffuser, nozzle, the distance from the nozzle edge to the beginning of the mixing chamber, mixer, operating parameters of the pump – pump head and flow rate, pipeline diameters), the pulp density in the suction nozzle, the weight coefficient of ejection, geometric characteristic, relative optimum head, actual heads of the jet apparatus and pump-blower, volumetric total flow, volumetric consistency of the pulp in the suction pipeline, performance over the ground, actual dimensions. Conclusions: the developed methodology will allow calculating the optimal dimensions of jet enjector of a new design and developing a design for the suction tip of a suction dredger for various in pressure, flow rate and development depth of operational options for removing bottom sediments in water bodies.

Purpose: experimental determination of the possibility of energy consumption reduction of pumping equipment of reclamation pumping stations due to the use of residual energy with a pressure fall in the pipeline network. Materials and methods. Research and calculations were carried out at the Rassvet-8 pumping station of the Izobilnensky branch of the Federal State Financed Institution “Administration Office Stavropolmeliovodkhoz”. To determine the magnitude of the energy consumption reduction experimentally, the following were established: the hydraulic parameters of the operated pumping equipment in the suction and pressure distribution pipelines at maximum pressure in the network, the amount of residual energy between points in the pipeline when withdrawing from water consumption sources in the case of a decrease in pressure in the network. Results. The hydraulic parameters of pumping equipment were determined experimentally: power consumption from 669.18 to 540.54 kW at heads from 106.88 to 126.52 m, deliveries from 0.46 to 0.28 m³/s, efficiency from 0.72 up to 0.68, total energy in the suction pipeline from 1.75 to 5.71 m, value at the point of selection of the source of water consumption at a distance of 1450 m from the building of the pumping station, head from 80.28 to 106.67 m, flow from 0.49 to 0.43 m³/s, suction pipe vacuum from 2.0 to 5.8 m; the calculated value of increasing the suction height of the pump and, as a result, reducing the pressure in the network from 10.24 to 17.92 m; the magnitude of the reduction in energy consumption with an increase in suction height using a jet apparatus from 28.04 to 70.24 kW at feed rates from 0.40 to 0.28 m³/s. Conclusions: a comparison of the results of the theoretical studies of the residual energy presence in the case of a change in the points of selection by the consumer and the difference in the actual useful power at the points of measurement of 96.1 kW and experimental data on the magnitude of the reduction in energy consumption of 70.24 kW with an increase in suction height confirms the possibility use of residual energy and reduce the pressure and power consumption of the pumps.

Purpose: development of technological schemes and technical means of mixing and applying fertilizers with irrigation water for feeding crops. Materials and methods. The research was carried out on the fields of Biryuchekutsky vegetable breeding experimental station – a branch of Federal Scientific Center for Vegetable Growing (town Novocherkassk) and in the farm of the settlement Zaplavskaya Oktyabrsky district Rostov region on sites with protected ground. To justify the technological process of applying fertilizers using a 4-component fertilizer mixer with water and applying the mixture into the soil during fertilizing irrigation, technological schemes that allow applying all types of fertilizers have been developed. Results. According to the above technological schemes, fertilizers are proposed to be applied to the soil using drip irrigation and a 4-component jet mixer in the following order: using the calculated doses for the planned crop yield, fill the containers with the extract of livestock wastewater, mineral fertilizers and microelements (micronutrients are applied according to the recommendations of the agronomic service); a jet mixer is put into operation, in which pressure water supplied from a centrifugal pump or from a pressure pipeline is used as a working flow, fertilizer is used as a suction flow. The change in the mixture concentration is carried out by the corresponding valves. The above technological schemes are recommended for use in the cultivation of vegetable crops in large and small farms, in open and protected ground, allow the use of all types of fertilizers for fertilizing irrigation of vegetable crops. Conclusions: the proposed technological schemes make it possible to apply all the necessary types of fertilizers, to substantiate the initial data for the hydraulic calculation of the irrigation network, to establish the main geometric dimensions and hydraulic parameters of a 4-component jet mixer.