AME 331, Spring 2008

Problem set #1

Assigned:  Friday January 25, 2008

Due:  Friday, February 1, 2008, 4:30 pm in the AME department office (OHE 430)

 

Holman problems:

 

Thermal resistance:  2-4 (answer:  11,400 W), 2-14

 

Spherical system:  2-16

 

Critical insulation thickness:  2-21 (answer:  ro = 135 mm, thus thickness of insulation is 134.5 mm)

 

Cylindrical system:  2-30 (answer:  4000 W)

 

Systems with heat generation:  2-33, 2-45 (note:  problem statement should refer to Example 2-6, not 2-4) (answer:  183C)

 

Fins:  2-70 (answer:  3.75 W), 2-105

 

Notes on 2-14:

 

The ice + water temperature on inside of chest stays constant at 0C.  The total area exposed to heat transfer is the 4 sides of the ice chest plus the top lid.  The total heat transfer needed to melt the ice is the mass of ice multiplied by the heat of fusion.  The mass in turn is the volume of the inside of the ice chest multiplied by the density of ice.  Look up the density of ice on the internet.  (Performance test – its a little less than water since ice floats in water but just barely.)