Engineering Board Exam Reviewer · Thermodynamics · hard
A composite wall consists of 10 cm of material (k = 0.5 W/m· K) and 5 cm of insulation (k = 0.05 W/m· K). If the temperature difference across the wall is 30 °C, what is the heat flux?
- 150.00 W/m2
- 30.00 W/m2
- 25.00 W/m2
- 110.00 W/m2
Answer
C. 25.00 W/m2
Solution
R = L1/k1 + L2/k2 = 0.1/0.5 + 0.05/0.05 = 1.2 m2· K/W. q = T/R = 30/1.2 = 25.00 W/m2.
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