EFFECT OF DELIVERY HEAD VARIATION AND INLET GUIDE VANE FAILURE ON THE OPERATING POINT AND BLADE WEAR OF LARGE VERTICAL CENTRIFUGAL PUMPS

Pumping station No. 7 of the Karshi Main Canal lifts Amu Darya water into the Talimarjon reservoir. Seven of its nine units are 2400VR-25/25 vertical centrifugal pumps with a rated flow of 25 m³/s and a rated head of 25 m, driven by 8000 kW synchronous motors at 187.5 rpm [1]. According to the technical inspection act of 2022, the geometric lift of the station varies from 7.6 to 26.1 m and the manometric head from 16.0 to 32.8 m, mainly because of the changing water level in the reservoir. The same act states that the inlet guide vanes of the pumps are out of service and their drives are faulty [1]. Without guide vane control the operating point of a pump is fixed only by the head required by the system. Because the hydro-abrasive wear rate of impeller blades depends strongly on the relative flow rate [2, 3], the aim of this work is to estimate how the head variation shifts the operating point and changes the blade wear.