11. An industrial furnace wall is constructed of 0.7 ft thick fireclay having k= 0.6 BTU/hr- ft-°F. This is covered on the outer surface with a 0.1 ft. thick låyer of insulating material having k...

Extracted text: 11. An industrial furnace wall is constructed of 0.7 ft thick fireclay having k= 0.6 BTU/hr- ft-°F. This is covered on the outer surface with a 0.1 ft. thick låyer of insulating material having k outermost is 100°F. Calculate the steady heat transfer per square foot. a. 464 BTU/hr-ft? b. 258 BTU/hr-ft? 0.04 BTU/hr-ft-°F. The innermost surface is at 1800°F and the %3D c. 364 BTU/hr-ft? d. 554 BTU/hr-ft? 12. It is a method of developing the design for a heat exchanger wherein the engineer assures the existence of an exchanger and makes calculations to determine if the exchanger would handle the process requirements under reasonable conditions. a. heat exchanger modeling b. heat exchanger calculation c. rating a heat exchanger d. evaluation of heat exchanger performance 13. The formula for log-mean témperature between T¡ and T2 is T +T T - T с. а. In (T3 /T) 2 In (7; /T, ) b. T, - T T-T d. In(7,/7,) 14. Water at 25°C is flowing through an elliptical conduit with semi-axis a = 4 and b = 3. What is the Reynolds Number of this flow if water is flowing at 9 m/s? а. 1.1 х 105 b. 7.8 х 105 с. 9.5 х 10° d. 4.5 x 106 15. If the thermáł conductivity of the fluid increases, the heat transfer coefficient will c. decrease а. increase b. remain the same d. none of these