Experimental study on the effect of the shroud on the performance and flow field of an automotive cooling fan

The effect of the shroud position on the performance of an automotive cooling fan with the radiator mounted at the front end has been studied on a test platform, and the characteristics of the flow field and phase-averaged velocity, vorticity, and turbulence intensity in five phases behind the cooling fan have been acquired by using digital particle image velocimetry. Moreover, a comparison of the flow field behind the fan with the shroud and that behind the fan without the shroud is made. The results of the performance experiment demonstrate that the fan with the shroud covering only the front part of the rotor possesses the highest performance, and the performance of the fan without the shroud seems to be less affected by the system flowrate. Flow field measurements show that the fan with the shroud has a larger exit radial component of the velocity than the fan without the shroud except at low system flowrates, and the vorticity and the turbulence intensity of the fan with the shroud are lower than those of the fan without the shroud.