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URN etd-0125106-162129 Statistics This thesis had been viewed 3720 times. Download 2493 times. Author Chi-Yuan Lai Author's Email Address firstname.lastname@example.org Department Mechanical Engineering Year 2005 Semester 1 Degree Ph.D. Type of Document Doctoral Dissertation Language English Page Count 140 Title Longitudinal and Annular Fin Analysis with Variable Thermal Properties by Recursive Formulation and Optimum Design of a Heat Sink Keyword thermal properties optimum heat sink fin fin heat sink optimum thermal properties Abstract The first two topics in this study supply a new approach to calculate thermal performance of a singular longitudinal fin and annular fin with variable thermal properties. With discrete model, the singular fin can be divided into many sections. Then, each section can be combined together to obtain the whole solution of the fin by recursive numerical formulation. The recursive formulas for both conditions with and without heat transfer on fin tip are derived in the present study. Finally, several examples including composite and boiling mode of a fin have been simulated to demonstrate the validity of the present approach.
Later the theoretical analysis of the cooling effect of a heat sink is presented. With the input data of Biot number, Bi, heat transfer coefficient ratios, H and H*, the optimum heat transfer equation can be utilized to obtain the optimum length of fins in a longitudinal fin heat sink that affects the overall thermal effectiveness of a heat sink. This optimum equation is in transcendental form, which involves three dimensionless parameters. The thermal resistance of a heat sink is derived and examples are provided to illustrate the effect on the cooling performance of a heat sink under various design conditions. Subject to annular fin heat sink, the four parameters are found to provide the optimum equation in transcendental form. Heat sink performance with its various parameters is also discussed in this topic. This optimum equation can be utilized to find the optimum outer radius of annular fins and fin number on a heat sink that affects the overall thermal effectiveness of a heat sink. Finally, examples are offered to illustrate the cooling performance of a heat sink including annular fins.
Advisor Committee Hong-Sen Kou - advisor
Ji-Jen Lee - advisor
none - co-chair
Rong-Hua Yeh - co-chair
Sheam-Chyun Lin - co-chair
Shih-Pin Liaw - co-chair
Tong-Miin Liou - co-chair
Files Date of Defense 2006-01-13 Date of Submission 2006-01-25