Abstract: A Study is made on the periodic heat transfer in the fins with variable thermal parameters. The method of small parameter perturbation is adopted. Numerical calculation is solved noniteratively by shooting method and superposition method. For afin of certain shape with periodic change of fin base temperature, the heat transfer is influenced by the.following parameters. E-temperature function in relation to coefficient of thermal co1ductivity.N-characteristic parameter of finned heat trat transfer, ε-amplitude parameter of temperature.fluctuation, B-frequency parameter of temperature.fluctuation of the.fin, and the changing pattern of convective coefficient. The influences of these parameters on temperalure distribution, heat-flow rate. and fin efficiency are discussed. In addition to theoretical significance, the results are of practical significonce. for engineering design.

Key words: variable thermal parameters, perturbation, principle of superposition