Determine the tube diameter that corresponds to a 10% reduction in the convection heat transfer coefficient for thermal and momentum accommodation coefficients of α_t = 0.92 and α_p = 0.89, respectively. Determine the channel spacing, a, that is associated with a 10% reduction in h using the same accommodation coefficients. The gas is air at T = 350 K and
atmospheric pressure for both the tube and the parallel plate configurations. The flow is laminar and fully developed with constant surface heat flux.