In: Mechanical Engineering
Solid desiccant air dehumidifier systems are widely used to supply dry air for many industrial processes. As humid atmospheric air flows through the system, the water vapor in the air is adsorbed by the desiccant material, resulting in dry air leaving the system. Inlet air velocity and tekperature are observed as predominant parameters that influence the outlet conditions of the air. Consider a cylindrical air channel with a length of 1 meter and an inner diameter of 20 mm, as a representative of a dehumidifier system. The wall of the channel is made of silica powder material with a thickness of 0.2 mm. Air enters the channel at Ti = 30°C and 10 m/s. Heated air is forced to flow over the entire channel so that it could provide a constant inner surface temperature, Ts,i of 60°C. Determine,
i. the exit air temperature of the channel, Te, oC
ii. the rate of heat transfer, and
iii. the outer surface temperature of the channel, Ts,o, oC.
Evaluate the air properties at a bulk mean temperature of 40°C