Question

, A tite ditèrence analysis vestir coeficient is h. sis has been performed on the fin of diameter D using a uniform spacing o perfi at each node has been obtained. The thermal conducti has been obtained. The thermal conductivity of the fin is & and the ambient flow hich discretized equation for node T, is correct? f Ax and the equatio s A hole is drilled through the center of a solid block of square cross section. The hole is drilled along the length, L-2 m, of the block, which has a thermal conductivity of k 150 Wm K. The four outer surfaces are exposed to ambient air, with T. = 25°C and h-4 w/m2, while hot oil flowing through the hole with coefficient that maintains an inner surface temperature T, 225°C. If the shape factor is found to be S -8.6 m, what is the correct equation to compute heat transfer rate? A, q= D. q = (h(4wl) + kS)(T-Tm). A buoyancy force on a fluid in a gravitational field is created by differences in A. viscosity B. density C. temperature D. pressure. 9. from a fan. If the flow over the whole plate is laminar, what is the ratio of the heat transfer rate of the plate between case 1 and case 2 shown in the figure? A. 1 B. 2 10, Suppose you want to cool a hot thin rectangular plate of a x 2a by placing it in parallel to the uniform air flow 2a C. 2 Case 2 Case 1 11. An annular enclosure is filled with air as shown. The inner cylinder is cold, and the outer cylinder is hot. The figure that most correctly represents the flow pattern inside the enclosure is 12. For a surface of characteristic length L, the relative importance of forced and free convection depends on the ratio of Grashof and Reynolds numbers. If the ratio (Gr/Rei2) is much larger than unity A. forced convection is negligible. B. free convection is negligible. C. mixed convection is negligible D. forced and free convection mechanisms are comparable.

Answer 1

9 B Bu on opposite sida et an object. o4 ID on a 0 n conveeHo is