Chapter 9, Problem 9.80P

A vertical array of circuit boards is immersed in quiescent ambient air at $T_{\infty }=17°C$ . Although the components protrude from their substrates, it is reasonable, as a first approximation, to assume flat plates with uniform surface heat flux $q_x^{"}$ . Consider boards of length and width $L=W=0.4\text{m}$ and spacing $S=25\text{mm}$ . If the maximum allowable board temperature is 77°C, what is the maximum allowable power dissipation per board?