Nowadays, generation of power becomes very expensive and therefore finding an alternative source for producing power is recommended. Therefore, wind energy can be considered a key solution due to having low cost. This paper focuses on the design of small wind turbine with a horizontal axis that contains diffuser, shroud, and nozzle. The blade length is 0.6 m to be appropriate for producing energy commensurate with the climatic conditions in Iraq, by using a 3D-numerical simulation, non-compressive, viscous, turbulent flow around a turbine, all are sets to become an input data to the model created by using ANSYS-FLUENT. Researches are impact on three different sorts; diffuser only, diffuser Shroud and Diffuser, Shroud, Nozzle. The blade angle is taken from 0° to 14° on fluid flow and the energy generated for the wind velocity range from (1-5) m/s. Drawing a contour for the pressure and velocity on the surfaces of the blades and diffuser, also displaying the results of the turbine's generated power. The results also confirmed that the efficiency of the torsion angle of the wind turbine increases as the torsion angle grows of the blade to 10° degrees, and any additional increase in this angle negatively affects the generated energy.