**Hsin-Hung Lin 1,2,\* , Jui-Hung Cheng <sup>3</sup> and Chi-Hsiung Chen <sup>1</sup>**


Received: 27 September 2019; Accepted: 20 January 2020; Published: 3 February 2020

**Abstract:** During the development of fan products, designers often encounter gray areas when creating new designs. Without clear design goals, development efficiency is usually reduced, and fans are the best solution for studying symmetry or asymmetry. Therefore, fan designers need to figure out an optimization approach that can simplify the fan development process and reduce associated costs. This study provides a new statistical approach using gray relational analysis (GRA) to analyze and optimize the parameters of a particular fan design. During the research, it was found that the single fan uses an asymmetry concept with a single blade as the design, while the operation of double fans is a symmetry concept. The results indicated that the proposed mechanical operations could enhance the variety of product designs and reduce costs. Moreover, this approach can relieve designers from unnecessary effort during the development process and also effectively reduce the product development time.

**Keywords:** gray relational analysis; flow-field analysis; fan design; CFD; product design evaluation; symmetry
