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ChE 306: HEAT TRANSFER SPRING 2016 Homework #2 - SOLUTIONS (10 points each; 80 points) DUE: FRIDAY, January 29, 2016 in class OFFICE HOURS/HW HELP: Mon 1/25 3-4:30 (HM Comer 339A), Tues 2:30-3:30 (Nicolette Hook, SEC 3438), Thurs 10-11 AM (HM Comer 339A), Thurs 5-6 pm (HM Comer 339A) TEAMS: You are encouraged to work in teams. A single assignment can be turned in by up to 4 team members. Include all team members’ names on the HW set when turning in. Each team member should understand how to solve ALL problems. HOMEWORK SETS: Turn in all problems, in the order they were assigned. Staple, if possible, and fold the set in half lengthwise. Write your name (all team member names) on the outside fold, so that it will be easy to return. FORMATTING: Work neatly, draw a diagram of the problem, where appropriate, keep problems in the correct order; if the grader can’t find a problem, then it may be scored a zero. Write on only one side of each sheet of paper. Engineering paper is NOT required. LATE HOMEWORK: Homework will not be accepted late. Turn it in during class, send it with a classmate, or drop it in the plastic folder outside my HM Comer office door BEFORE the solutions post on Blackboard (~ Noon on class days). If you have an excused absence for a homework set, I will drop that set, and award a score of 0 out of 0. 1. The defog dial in an automobile causes warm air to pass over the inside surface of the front windshield resulting in heat transfer from the inside (T∞= 40 oC) with a convective heat transfer coefficient of 30 W/m2-K. Given: the windshield is made of plate glass and has a thickness of 0.40 cm, and the outside air is -10 oC with a convective heat transfer coefficient of 65 W/m2-K. A. Determine the inner and outer surface temperatures of the windshield. Include a calculation of the total resistance of the air-window-air system. B. The convective heat transfer coefficient is a function of fluid velocity (and Reynolds number); thus h increases as you drive faster. What would theinner surface temperaturebe for an outside convective heat transfer coefficient ho= 100 W/m2-K? C