3.3 Effect of axial inter-distance
For large axial inter-distance (Fig. 10) the axial flow velocity is quite uniform downstream IGV vanes, even at low flow rates. If this gap is reduced further an important blockage is observed from mid-span to tip sections of blade, hence concentrating the flow toward the lower part of blade. This blockage induced by the proximity of IGV and blades is related to the aerodynamic loadings over the suction sides and the overturning of flow streamlines. Meanwhile, this blockage causes alteration of flow incidence which reduces from hub to mid-span while increases from mid-span to blade tip, and subsequently inducing high losses.