Hannah Cui, Erika Lieu
Burnaby North Secondary
Floor Location : J 029 E
An environmental concern nowadays is the burning of fossil fuels for energy, so what is the most environmentally friendly way to generate electricity? After conducting extensive background research, we learned that hydroelectricity is a good way of creating electricity because it is eco-friendly, non-polluting, inexpensive and renewable. Thus our science fair began with the idea of hydroelectricity and how we could build a turbine to create hydroelectricity. Our result was a turbine that runs on water from a garden hose, and we experimented with 3 types of blade shapes for this project: flat, curved and rectangular (independent variable). Our hypothesis was that the flat blades would work the best as the water would immediately reflect off the blade, whereas the water would collect on the curved and rectangular shaped blades.
We built the turbine using a bicycle wheel and attached a power generator to it. We discovered that the higher the rotational speed (RPM), the more electricity was generated (dependent variable). A volt meter was connected to the generator to show the amount of hydroelectricity generated (voltage). To ensure the flow of water did not change for each test we used a shut off valve (controlled variable). Each blade shape was tested 5 times.
We were surprised to discover that the rectangular shaped blades actually had the highest rotational speed―an average of 1919 RPM. We observed that the collected water gave the blades more torque and did not slow it down unlike what we hypothesised. This applied for the curved blades as well, since the results were similar. The curved blades spun at 1852.5 RPM. In comparison, the overall results of the flat blades were remarkably lower, as the rotational speed on average was 1696.7 RPM.
In the end, the rectangular shaped blades produced the highest rotational speed, followed by the curved blades, then finally the flat blades. In order to make an efficient turbine blade, water must produce an impulsive force by reflecting back at almost 180°. The water that reflected off the rectangular shaped blades impulsed at almost 180° due to the shape of the blade. The water impulsed at almost the same way for the curved blades, but the flat blades did not produce a strong impulsive force, since the shape caused the water to reflect back in multiple, unproductive directions.
This is however, only one step towards building turbines for renewable, environmentally friendly, and low-cost hydroelectricity. Our power generator was quite small and insignificant when compared to other generators, resulting in less electricity produced. If we were to create a turbine that generated high amounts of hydroelectricity a better generator is an important step towards it. Also by using our data and experimenting with different designs of rectangular shaped blades we can possibly create a more effective hydroelectric turbine, thus generating even more hydroelectricity.