Study of an axial-type fan design technique using an optimization method

Abstract

A robust axial-type fan design technique is developed by using an optimization method based on the gradient method. A three-dimensional fan blade was initially designed by stacking several two-dimensional (2D) blade profiles along the spanwise direction. These 2D blade profiles were designed using the free-vortex method and profile parameters such as the incidence, deviation, camber, and so on. The initial fan blade adopts 13 design variables to improve the target value of the fan efficiency or the total pressure. These design variables are used to control the rotor and stator profile for obtaining a better target value. In this study, fan efficiency is chosen as a target objective variable to be maximized, and the total and static pressure on the design point are applied as constraints. These procedures are applied to the design of an axial-type fan that must operate at a mass flowrate of 8.37 kg/s with a minimum total pressure rise of 670 Pa. The optimized fan not only increases the efficiency by 2.9 per cent but also satisfies the required total and static pressure conditions compared with the initially designed fan performance. The optimized fan performance agrees with the experimental results; therefore, this fan design technique can be applied to improve the efficiency and the operating pressure of axial-type fans.