STEVENS HONOR SYSTEM PLEDGE: I pledge my honor that I have abided by the Stevens Honor System (The above pledge is to be written and signed by the student at the bottom of this cover sheet) STEVENS INSTITUTE OF TECHNOLOGY DEPARTMENT OF MECHANICAL ENGINEERING ME354 - HEAT TRANSFER QUIZ #3 November 20, 2013 Problem 1 _______ (15 pts) Problem 2 _______ (15 pts) Total _______ (30 pts) Name: ______________________ ID#: ______________________ NOTE: Open textbook and open class notes. PLEDGE: _______________________________________________ Signature

Problem 1 (15 pts)

Ethylene glycol flows at 0.01 kg/s through a 3-mm diameter, thin-walled tube. The tube is coiled and submerged in a well-stirred water bath maintained at 25°C. If the fluid enters the tube at 85°C, calculate the heat transfer rate and tube length that are required for the fluid to leave the tube at 35°C.

Problem 2 (15 pts)

The surface of a 50-mm-diameter, thin-walled tube is maintained at 100oC. In one case, air is in cross flow over the tube with a temperature of 25oC and a velocity of 30 m/s. In another case, air is in fully developed flow through the tube with a temperature of 25oC and a mean velocity of 30 m/s. Calculate the heat flux from the tube to the air for the two cases and briefly compare the two results.

Problem 1 Ethylene glycol flows at 0.01 kg/s through a 3-mm diameter, thin-walled tube. The tube is coiled and submerged in a well-stirred water bath maintained at 25°C. If the fluid enters the tube at 85°C, calculate the heat transfer rate and tube length that are required for the fluid to leave the tube at 35°C.

Problem 2 (15 pts)

The surface of a 50-mm-diameter, thin-walled tube is maintained at 100oC. In one case, air is in cross flow over the tube with a temperature of 25oC and a velocity of 30 m/s. In another case, air is in fully developed flow through the tube with a temperature of 25oC and a mean velocity of 30 m/s. Calculate the heat flux from the tube to the air for the two cases and briefly compare the two results.