Hydro-abrasive wear reduction of irrigation pumping units

Uzbekistan is one of few countries in the world where more than 50% of the irrigated lands are provided with water by pumping stations. The main water sources are the transboundary rivers, the Amu Darya, and the Syr Darya, which transport a large amount of bedload and suspended sediments. In these water sources, the average annual turbidity is up to 5-7 kg/m3, and the average monthly turbidity reaches 10-12 kg/m3. The content of abrasive particles with the Mohs hardness of 5 and more reaches 50-60% of the total amount of suspension. When these sediments pass through the pumping units, their hydro-abrasive wear is observed; this leads to a change in the main parameters of the pumps. Bedload sediments with the size of more than 1 mm cause the most intensive pumps hydro-abrasive wear. Therefore, in our research, much attention was paid to developing methods to prevent the ingress of bedload sediments into the flow part of pumping units. For this purpose, based on laboratory tests, taking into account the heterogeneity of bottom sediments, the dependence for determining the ridge forms' height was revealed. On the basis of this dependence was developed methods for determining the height of the threshold damless intakes and the height of the inlet of the suction pipe pumping unit relative to the riverbed bottom. The developed methods reduce abrasive wear of pumping units and increase their repair period