Liquid water flows in a circular tube at a mass flow rate of 0.006 kg/s. The water enters the tube at 5°C, and the average convection heat transfer coefficient for the internal flow is 20 W/ m2⋅K. The tube is 3 m long and has an inner diameter of 25 mm. The tube surface is maintained at a constant temperature. The inner surface of the tube is lined with polyvinylidene chloride (PVDC) lining. According to the ASME Code for Process Piping, the recommended maximum temperature for PVDC lining is 79°C. If the water exits the tube at 15°C, determine the heat rate transferred to the water. Would the inner surface temperature of the tube exceed the recommended maximum temperature for PVDC lining? The specific heat of water at the bulk mean temperature of Tb = (Ti + Te)/2 = (5 + 15)°C/2 = 10°C is cp = 4194 J/kg·K.
The heat transfer rate to the water is ______ W.
The inner surface temperature of the tube is _____ (above/below) the maximum temperature for PVDC lining.
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