Question 4 (15 marks) (From the Radiation notes I sent on blackboard) A double walled flask may be considered equivalent

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Question 4 15 Marks From The Radiation Notes I Sent On Blackboard A Double Walled Flask May Be Considered Equivalent 1 (57.31 KiB) Viewed 25 times

Question 4 (15 marks) (From the Radiation notes I sent on blackboard) A double walled flask may be considered equivalent to two parallel planes. The emisivities of the walls are 0.3 and 0.8 respectively. The space between the walls of the flask is evacuated. Find the heat transfer per unit area when the inner and outer temperature 300K and 260K respectively. To reduce the heat flow, a shield of polishedaluminum with ε = 0.05 is inserted between the walls. Determine: a. The reduction in heat transfer. Use = 5.67*10-8 W/m2K