Chapter 15 Steady Heat ConductionAnDLADAAAfinnedfin2unfinned2total,with finsfinnedunfinned2m)m)mmm==×==−×==+=+=ηππππ0 957 8640 00250 02013000216 86440 0216 8640002540 01740130 0 017014722.(.(....(.)..RhAconvtotal,with finsW/m . C)mC/W°=°1150014701361((.).RRRRRtotalboardepoxyaluminumconv=+++++=°0 006940 0051 0 000390136101484.Then the temperatures on the two sides of the circuit board becomes &&).)(...QTTRTT QRQRTTQR=−⎯→⎯=+=°+°=−⎯=−=°−°=−≅°∞∞12214032014844050 00694405 0 02totaltotalboardboardC WC/W)WC/W)40.5 C40.5 C3-115 A circuit board houses 80 logic chips on one side, dissipating 0.04 W each through the back side of the board to the surrounding medium. The temperatures on the two sides of the circuit board are to be determined for the cases of no fins and 864 copper pin fins on the back surface. Assumptions1Steady operating conditions exist. 2The temperature in the board and along the fins varies in one direction only (normal to the board). 3All the heat generated in the chips is conducted across the circuit board, and is dissipated from the back side of the board. 4Heat transfer from the fin tips is
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