Dr. Cheng-Hung Huang is the Chair Professor at the Department of Systems and Naval Mechatronic Engineering of National Cheng Kung University (NCKU) in Taiwan. He received his B.Sc. degree in Mechanical Engineering Department from National Cheng Kung University in 1983 and his M.S. and Ph.D. degrees in Department of Mechanical and Aerospace Engineering from North Carolina State University of USA in 1988 and 1991, respectively. He joined NCKU in 1991 and served as Department Chairperson, Associate VP for International Affairs and VP for International Affairs of NCKU during his services to NCKU. He is now the Executive VP of NCKU.

Prof. Huang worked on the research fields of “Inverse Problems”, “Inverse Design Problems” and “System Optimization Problems” for more than twenty years. He has received three times the Distinguish Research Award from the Ministry of Science and technology which is the highest honor for the university professors and institution researchers who can receive in Taiwan. He is also the Associate Editor of International Journal “Inverse Problems in Science and Engineering” and the Editorial Advisory Board of the International Journal “Recent Patents on Engineering”, “The Open Nanoscience Journal”, “The Open Chemical Engineering Journal” and “The Open Ocean Engineering Journal”.

He has published more than 150 SCI papers in the international journals and his current research focuses on heat sink design, solar still design, fan blade design and fin shape design.

Topic: The Design of Optimum Shapes for Nonlinear Partially Wet Annular Fins

1.Background/ Objectives and Goals
Annular finned-tube heat exchangers are widely used in applications of air-conditioning and refrigeration systems and for the most cases they are partially wetted. Besides, the thermal parameters of the fin are also function of temperatures in many practical engineering applications. Based on the above stated two conditions a nonlinear optimum partially wet annular fin design problem is considered in the present work.

2.Methods
The conjugate gradient method (CGM) is utilized as the optimization algorithm based on the desired fin efficiency and fin volume. It is assumed that the surrounding air has relative humidity between 80% and 90%, which will result in a partially wet annular fin. The numerical experiment results show that the optimum annular fin has the highest fin efficiency among six annular fins with the same operating fin conditions. When the Biot numbers for ambient air (Bia) varied, the optimum fin efficiency and optimum fin shape of the nonlinear partially wet annular fin also changed.

3.Expected Results/ Conclusion/ Contribution
The results indicated that when the Biot numbers for the inner tube (Bii), the thermal conductivities of the bare tube (kw) and the annular fin (kf) varied, the optimum fin shape remained almost the same. This implies that Bii, kw and kf have a limited influence on the optimum annular fin shape with partially wet condition.

Keywords: annular fin, conjugate gradient method, nonlinear problem, fin design