文档介绍：Convective Heat Transfer
Final Exam B 卷
Note: Two-hour closed book final examination. One crib sheet (A4, both sides) is permitted.
Calculator is allowed. There are 6 problems and 100 points on the exam. Point values for each
question and part are listed. State clearly and justify all assumptions made and label all sketches
and thermal circuits clearly. Your answers must be correct to 3 significant figures and have the
appropriate units. Allocate your time wisely and do not spend disproportionate time on any single
problem. Take a deep breath and relax. Good luck!
answer all of the questions, and be sure to show all work in your answer booklets, so if your
numerical answer is incorrect, you might get partial credit for correct methodology and equations.
you can do a great job! knock it dead.
1. [10 points] For flow over a flat plate of length L, the local heat transfer coefficient hx is known
to vary as x −1/ 2 , where x is the distance from the leading edge of the plate. What is the ratio of
the average Nusselt number for the entire plate, Nu L , to the local Nusselt number at
x = L , Nu L ?
Figure 1
2. [20 points] Air at 20℃ is fully thermally developed as it flows in a 1cm . pipe. The average
velocity is . If the pipe wall is at 60℃, what is the temperature farther down