COMPUTATIONAL ANALYSIS OF NONLINEAR CEILING FAN BLADE PROFILES

Abstract

Ceiling fans are widely used by inhabitants of hot climate regions for indoor comfort. The fan industry of Pakistan is well renowned on national scale. However, its share in global exports is negligible. The uninspired performance on global canvas is due to inadequate technology, lack of research and development setup, poor infrastructure and low efficiency. This research is conducted in collaboration of Pakistan Electric Fan Manufacturers' Association (PEFMA). The majority of ceiling fans currently manufactured in Pakistan have linear profiles. In this research endeavor, the nonlinear (elliptical) planform shape of blade is studied in conjunction with blade tip width, root and tip angle of attack. A comparative study is done between forward and reverse sweep blade and results reveal that the forward sweep blades show better response. By applying Design of Experiment (DOE), 16 experiments are designed for 3 bladed and 4 bladed ceiling fan using 2k factorial model. A multi-objective optimization problem is formulated with three performance variables; volumetric flow rate, torque and energy efficiency. Specifically, Response Surface Method (RSM) is used to generate optimal designs for both configurations. The research reveals that the interactions between the design variables play a significant role in determining the performance. For both three and four blade configurations, tip angle of attack is found to be most important and influential. During comparison, the four blade configuration provides high volume flow rate and the three blade configuration results in higher energy efficiency and reduced torque.