Design, Optimization and Field Validation of Low Head Hydro Powered Turbine Pumps and Piston Pumps for driving stream flows in the range 40-120 l/s and 5-20 l/s respectively /

Includes references

PhD ; 2025 ; Divecha Centre for Climate Change (DCCC)

This thesis focuses on developing optimized self-operating pumps using flows and head of perennial streams or rivers for decentralized irrigation and drinking water supply needs of local communities living by the river basins. The study identifies two flow zones for the identical head of 2-4 meters, where such hydro-powered pumps are in lacunae both from technological and market perspectives. The first flow zone is relatively higher flows from 40 to 120 l/s, which forms a gap between the capacity handling of classical ram pumps and modern axial flow propeller turbine pumps. The first problem is to design a propeller turbine for a real site in the field (Girdalpara village, Sukma, Chhattisgarh), carrying out lab and field tests in order to get the validation of the design. Further, this problem scales the propeller for flows ranging from 40 l/s to 250 l/s for over 4 site conditions. The first problem also identifies a couple of challenges to optimize the output (delivered) flow from the turbine pumps for identical head conditions (drive head to turbine and delivery head from pump). The first of this challenge is working on the pitch to chord length of the blades of the propeller so that efficiency can be increased for given head and flow, or adopting larger flow capacities for the same drive head and propeller diameter. This is investigated through CFD simulation and validated with lab results. It is found that efficiency can be retained, and overall pumping flow capacity can be increased by 5-10%. This finding has been proved for the village site Neelawaram in Sukma district. The second challenge of the turbine pump is related to the draft tube losses, which can be a serious threat to the efficiency of the pump. The second problem of the thesis is to tackle a flow zone of lower flows in the range of 5-20 l/s, which is currently managed by ram pumps for different sizes starting from 1 inch to 8-inch inlet drive pipes. However, it was evident from the previous field projects that the ram pumps have perpetual problems of repair and maintenance, as far as water hammer in the drive pipe along with the rubber clacks of the impulse/slam valves from previous field projects. that he participated. This led to finding an alternative technology, and one recent invention called the tyre piston pump was subjected to thorough investigation using physical experiments. A comprehensive theoretical framework of analysing this unconventional pump based on dimensional analysis was done, after which the experimental findings were superimposed. It was found that the pump was versatile for different flows for the same geometrical piston diameter and tyre diameter. One of the optimization techniques realized while increasing the piston diameter for the same tyre size, by which not only the output (delivered) flow increased, but also the operating efficiency. The d/D diameter was found to be an effective optimization tool with efficiencies nearing 40-45%, which was comparable with small turbine pumps and large ram pumps. Finally, the thesis concludes with the impact on the downstream ecosystem when a fixed quantity of flow is always taken out of the stream using any of the two technologies. While the hydrology of the stream defines the limiting flow that can be taken out from the given catchment, the author defines a head criterion, i.e. delivery to drive head for these pumps so the delivery flow can be standardized and matched with hydrological effluent behaviour of the river basin. This also adds to the social and economic perspective of water management, which brings with it a holistic essence to the application of hydro powered technologies.