Development of Half-Ducted Propeller Fan for Air Conditioners by Using Numerical Optimization with Objective Functions for Improving Fan Efficiency and Aerodynamic Noise

We developed a high-efficiency half-ducted propeller fan to reduce the electric power consumption of the outdoor unit ofa packaged air conditioner by using a design tool combining computational fluid dynamics (CFD) with multi-objectiveoptimization techniques based on a genetic algorithm (GA). The baseline fan was a half-ducted propeller fan with threeblades of a currently available product. The objective functions for optimization were fan efficiency and aerodynamic noise.We found there was a trade-off relationship between the static pressure efficiency and the fan noise. We then selected theoptimized fan that had the same noise level as the baseline fan but with improved fan efficiency. The blade tip of the optimized fan was curled toward the suction side direction. Finally, we confirmed through experiments that the static pressureefficiency of the optimized fan was increased by 1.8%compared to the baseline fan.