Design and optimization of propeller of submersible mixer for biogas plants

Objective: In this thesis, it is aimed to make hydraulic designs of axial mixers used in biogas plant fermenters using computer aided engineering calculation tools, to make pool tests with small scale models and finally to produce prototypes. Material and Methods: In this thesis, it is planned to improve the efficiency of the conventional axial biogas mixer by using computer aided engineering tools for design and optimization. To this end, a parametric design for blade geometry was used in conjunction with an open source CFD analysis software OpenFOAM to measure performance metrics (i.e. power, torque, thrust). Results: By maximizing the thrust-to-power ratio with the most efficient design, a fairly large parametric state space is created. Four different designs were reached from a series of design candidates residing in this space. By comparing these designs, the effects of design parameters on the results were evaluated. Conclusion: When the sensitivity results were compared in this study, it was determined that the factors affecting the blade efficiency the most were skew and pitch. Keywords: submersible mixer, propeller, parametric design, Open FOAM, Manure