Prof. Tam Lap Mou

Department of Electromechanical Engineering,

University of Macau,

Institute for the Development and Quality, Macau, China 

Tam Lap Mou joined the University of Macau as an assistant professor in 1996 and is currently a full professor in the department of electromechanical engineering at the University of Macau, Macau, China. He received his Ph.D. in 1995 from Oklahoma State University, School of Mechanical and Aerospace Engineering, Stillwater, Oklahoma, USA.  He is also served as the chairman of board of directors in the Institute for the Development and Quality, a non-profit institute providing mechanical and electromechanical related engineering researches and testing services to the Macau government and the public. 

His research interests include single and multiphase heat transfer and corrosion on heat transfer. He received multi research grants from the Macau Government, FDCT-NSFC, Suzhou and Guangdong Science and Technologies Councils in the above-mentioned topics. Prof. L. M. Tam is elected as the vice director-general of the Chinese Society for Corrosion and Protection in 2022 and he is a senior member of the Chinese Mechanical Engineering Society.

Title: Transitional Heat Transfer for Horizontal Macro, Micro-fin and Mini Tubes

Abstract：An important design problem in advanced heat exchange systems arises during flow inside the tubes falls into the transition region. In practical engineering design, the usual recommendation is to avoid design and operation in this region; however, this is not always feasible under design constraints. The commonly used tubes include plain, micro-fin, and mini-tubes. Due to the advancement of manufacturing technologies, instead of cold rolling, tubes in various sizes, shapes, and materials can now be printed using material addition methods. The selection or development of an appropriate heat transfer correlation for the transition region in horizontal tubes requires an understanding of the factors that influence the start and end of the transition region and the behavior of heat transition region. The objective of this study is to give a comprehensive discussion regarding the heat transfer behavior for horizontal macro, micro-fin, and mini tubes. It is observed that for macro tube, the transitional heat transfer is influenced by the inlet configuration and the buoyancy effect. With a disturbed type inlet, the transition Reynolds number is smaller than the classical value of 2,300 and the magnitude of heat transfer is larger. For micro-fin tubes, most of the previous studies were focused on the development of correlations in a particular flow regime, especially in the turbulent region. When the focus was shifted to the transition region, it was identified that the micro fin parameters are the most important factor influencing the transitional heat transfer. Augmentation of heat transfer in the transition region was clearly observed. For mini tubes, comparison of heat transfer between cold rolled tube and 3D printed tube were made and the surface roughness is the key parameters influencing the magnitude of the transitional heat transfer. Correlations for macro and micro-fin tubes are recommended in this study for engineering applications.