ANALYSIS OF TRANSIENT HEAT-TRANSFER IN STRAIGHT FINS OF VARIOUS SHAPES WITH ITS BASE SUBJECTED TO A DECAYED EXPONENTIAL FUNCTION OF TIME INHEAT-FLUX

The theoretical study of heat flow within finned heat exchangers is of considerable practical importance because of the extensive utilizatio n of finned surfaces for heat transfer enhancement in applications var ying from air-cooled heat exchangers in the process industries to heat rejection equipment in space vehicles. This paper investigates the tr ansient heat transfer in two-dimensional straight fins of various shap es with its base subjected to a decayed exponential function of time i n a heat flux. In order to obtain the solutions of the governing equat ion, which is a partial differential equation, the following procedure s of analysis should be performed: (1) normalize the governing partial differential equation subjected to the appropriate initial and bounda ry conditions, (2) take a Laplacian transform with respect to time, (3 ) utilize the integral method to solve the transformed system and (4) achieve and inverse Laplace transform by the Fourier series technique.