The paper presents an experimental investigation to evaluate the hydrodynamic behaviour of a turbulent flow in annular spaces with spirals inserted. It is used ink injection as visualization technique to determine the occurrence of turbulence in the flow for each spiral inserted. The analysis identifies the spirals that cause the onset of turbulence at lower mass flow rate value (lower Reynolds number). Measurements of pressure drop for Reynolds numbers between 1500 and 5000 were performed, obtaining equations for the friction factor correlation. The results of this study provide insight into the influence of the spiral inserted in the onset of turbulence in annular spaces for a straight annular duct, in order to design and optimise of heat exchangers.