Download Heat Transfer (ME-345) - Department of Mechanical Engineering

Heat Transfer (ME-345)
EMU
Mechanical Engineering
Spring 2014-2015
Closed Book Quiz.
Name:
Quiz # 2
Allotted time: 45 minutes
ID #:
Problem 1: Engine oil at 80°C flows over a 10-m-long flat plate whose temperature is 30°C
with a velocity of 2.5 m/s. Determine the total drag force and the rate of heat transfer over the
entire plate per unit width. (2.5 marks)
Solution:
Problem 2:
Water at 15ºC is to be heated to 65ºC by passing it over a bundle of 4-m-long 1-cmdiameter resistance heater rods maintained at 90ºC. Water approaches the heater rod
bundle in normal direction at a mean velocity of 0.8 m/s. The rods arc arranged in-line
with longitudinal and transverse pitches of SL = 4 cm and ST = 3 cm. Determine the
number of tube rows NL in the flow direction needed to achieve the indicated temperature
rise. (2.5 marks)
Solution:
Formula: