The drop in the temperature of molten aluminum when it flows through a 20 cm long round, water-cooledchannel is 40 C. What will be the temperature drop if aluminum were to flow through a 20 cm long channel of half-round (semi-circular) cross-section? Assume the mold material, mold and metal temperatures, and radius of the flow channels to be identical in the two cases.

Air enters a horizontal, constant-diameter heating duct operating at steady state at 290 k, 1 bar, with a volumetric flow rate of 0.25 m°/s, and exits at 325 k, 0.95 bar. the flow area is 0.04 m2. assuming the ideal gas model with k = 1.4 for the air, determine (a) the velocity at the inlet and exit, each in m/s, and (c) the rate of heat transfer, in kw flow rate, in kg/s, (b) the mass kg 0.3