The impulse wheel as hydropower converter for irrigation systems

Abstract

There is a significant hydropower potential in irrigation canals worldwide. Much of this potential exists as energy dissipating ramp-type fall structures. Hydropower could be employed to pump water for water saving irrigation, or to generate electricity. This hydropower is unused, since there are no cost-effective hydropower converters for the specific conditions in irrigation canals, i.e. head differences from 0.3 to 5 m and flow volumes ranging from 0.1 to 15 m3/s. At Southampton University, a simple undershot impulse-type waterwheel with 180° jet deflection was developed specifically for this application. Large scale tests, with a scaling ratio of 1:2.4, showed efficiencies of 53%, confirming predictions from theory. The model employed a novel roller-type power take-off which eliminates the requirement for a cost-intensive gearbox. The impulse wheel has considerable development potential, and could be a cost-effective solution for small hydropower sites at ramp structures.