Pressure Fluctuation on the Blade of a Axial Fan Driven in a Cooling System Enclosure

Abstract

W Suppressing the pressure fluctuations distributed on the blade surface of an axial fan is applied as one of the means to reduce the noise generated in the cooling system of construction machinery. For that purpose, it is effective to use computational fluid dynamics (CFD) to capture the 3D vortex structure around a fan blade. However, while there have been many reports on the flow field formed around the blades of a fan alone or an axial fan with a duct-shaped shroud, the influence of the vortex structure formed at the actual operating point of the axial fan on the pressure fluctuation on the blade surface has not been sufficiently discussed. In this study, the three-dimensional vortex structure around the fan blade installed in the cooling system is investigated, and in particular, the influence of the wing tip leakage vortex on the pressure fluctuation on the fan blade surface is clarified. Wing tip leakage vortex that flow from forward in the direction of rotation of the fan interfere with a blade while oscillating periodically in the y-axis direction. The oscillation of the forward wing tip leakage vortex causes the separation position of the newly formed wing tip leakage vortex to change, and as a result, the pressure fluctuation increases at the tip of the blade suction surface near the separation position.