When orange juice is produced it must be heated to pasteurize it. This is achieved by passing the juice through a tubular heat exchanger. The juice must be heated from 4oC to 93 oC. Saturated vapor enters the outer tube of the heat exchanger at 150 kPa and exits as a saturated liquid at the same pressure. For an orange juice flow rate of 2000 kg/hr (cp = 3.9 kJ/kg K), determine the required steam flow rate.

At steady state, air at 200 kpa, 325 k, and mass flow rate of 0.5 kg/s enters an insulated duct having differing inlet and exit cross-sectional areas. the inlet cross-sectional area is 6 cm2. at the duct exit, the pressure of the air is 100 kpa and the velocity is 250 m/s. neglecting potential energy effects and modeling air as an 1.008 kj/kg k, determine ideal gas with constant cp = (a) the velocity of the air at the inlet, in m/s. (b) the temperature of the air at the exit, in k. (c) the exit cross-sectional area, in cm2