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Unformatted text preview: 5.3-11 In a biofuel refinery, ethanol enters a tube at temperature Tin = 5C and pressure pin = 45 psia. The mass flow rate of the ethanol is m = 0.04 kg/s. The outer diameter of the tube is Do = 0.25 inch and the length of the tube is L = 5 ft. The tube wall thickness is th = 0.03 inch. The roughness on the internal surface of the tube is estimated to be e = 15 m. The outer surface of the tube is exposed to saturated steam at ps = 5 psia. You may neglect the convection resistance on the outer surface of the tube as well as the resistance to radial conduction through the tube (therefore, the inner surface of the tube may be assumed to be at a constant temperature, equal to the saturation temperature of the steam). a.) Determine the outlet pressure and temperature of the ethanol. Calculate the properties of ethanol using the average temperature and pressure of the ethanol as it flows through the tube. b.) Plot the outlet temperature and pressure drop as a function of the mass flow rate of ethanol for 0.001 kg/s < m < 0.05 kg/s. Explain your plots. c.) Determine the tube diameter and length that will lead to the target performance, Tout = 40 and p = 20 kPa. Assume that the tube thickness does not change with tube diameter. ...
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This note was uploaded on 08/11/2008 for the course ME 364 taught by Professor Rothamer during the Summer '08 term at Wisconsin.
- Summer '08
- Heat Transfer