Installation of a draft tube in a Michell-Banki turbine to harness small waterfalls

Abstract

Nowadays, the Michell-Banki turbines are being utilized for small scale energy generation in small hydroelectric power plants. This turbine features low manufacture, operation, and maintenance costs. In addition to this, this turbine can operate in wide intervals of flow rate without varying its efficiency. Due to this advantage, the Michell-Banki turbine is an excellent and appealing subject for research. The Michell-Banki turbine is basically an action machine characterized by its lack of a suction tube. The installation of a suction tube increases the energy absorbed by the rotor and consequently increases the power generated by turbine. In this paper, we considered the installation of a suction tube in a Michell-Banki turbine, in order to increase the power generation in small waterfalls (under 3 meters), which previously was unfeasible. We developed a hydraulics analyses of the Michell-Banki turbine with the draft tube, with the purpose of know that way this arrangement affect the behavior of the turbine and his mains project parameters. The results show that appears a reaction degree in the turbine, which represents a very important parameter in the project, which must have small values for the turbine be technically viability.