Author(s): Meg B. Bishwakarma
Linked Author(s): Meg B. Bishwakarma
Keywords: Settling basins; Kali Gandaki A hydropower plant; Physical hydraulic model; Sediment handling; Flow pattern improvement
Abstract: The 144 MW Kali Gandaki ‘A’ Hydropower Plant (KGA) in Nepal is suffering from sediment and floating debris handling problems. Due to the skewed flow distribution at the intake and very short transition between the intake and the settling basins, the flow pattern in the settling basins has been unfavorable for settling of the suspended sediment. This situation has caused excessive sediment induced turbine erosion problems. Dealing with floating debris at the intake has been another major problem which created turbulence at the inlet to the settling basins. A major task of the study should be to improve the upstream and downstream conditions of the settling basins for better performance of the basins. Therefore, in order to improve the overall performance of the headworks including the flow patterns in the settling basins, a physical hydraulic model at 1:40 scale was built at Hydro Lab in Nepal. At first the model study was carried out to observe the performance of the existing design of the headworks by reproducing it in the river model. After that a comprehensive study was conducted through several modifications and corresponding tests to achieve a satisfactory performance of the headworks in terms of improved approach flow condition to the intake, flow distribution among the intakes, flow patterns at the inlet to the settling basins, in the main basin and at the outlet. Due to cost reason, separate model of the settling basins was not built for studying the trapping and flushing ability of the basins, however, the study focused on improving the flow pattern inside the settling basins so that suspended sediment settling efficiency can be improved. A satisfactory solution was achieved through the model study by modifying the design of the river inlet, adjustment in the intake.
Year: 2018