During the Spring 2016 semester, students in the Impacts of Engineering course were tasked with redesigning the rotor for a hydroelectric generator. These generators are designed and built by a gentleman by the name of Hastings Mkandawire (second from the left in below photo).
Hastings builds these generators from scrap materials found in junk yards. He then uses them to supply power to his home and the homes of his neighbors and other nearby communities in rural Malawi, tacking advantage of Malawi’s mountainous terrain and flowing streams.
The objective for the students was to redesign the turbine rotor in order to achieve the greatest power development under both a low-pressure flow of water and a high-pressure flow of water. To do this they had to research the background of turbine design and figure out how they were going to prototype their design. The results of these efforts are shown below. The prototyping methods varied from 3D printing to PVC tubing and glue to cut up soda cans and rivets.
Ultimately, a design competition was held where each prototype was tested using a flow of water supplied by a hose (we don’t have mountains in Wisconsin…) and the flow was controlled by a valve set to two different conditions.
After the design competition, it was found that the soda can prototype performed best. This was likely due to it being the second lightest prototype while having an open center which allowed it to shed water after all of the energy had been extracted and converted to rotational motion.
Reports outlining each groups project can be found here.