The project starts with a description of the main sources of noise in an axial flow fan for concluding that the thing we should avoid is the trailing edge noise. After that the formulas for designing a fan and an aerodynamics background are presented. Once we get the results of these formulas a low noise optimization is carried on for leading us to a table of results where the main characteristics of design for our fan are obtained. After these tables the design of the fan is obtained with Pro-Engineer and it is described step by step until we get the final fan design. The design is separated in two steps where the model of the blade is the most important one. First the blade is designed without the serrated trailing edge and we make the simulations of the flow over the surface for obtaining the desired results. After this first step it is time to join the aerodynamics design with the objective of this project which is the use of bionics to obtain better results. For this goal we will add a serrated trailing edge based in the technology of ‘The Owlet’ in order to obtain the results and compare it with the previous ones.