Q6 a) A 10-cm dia. copper ball is to be heated from 100 *C to till average temperature of 150 °C in 30 min time. The average density is 8950 kg/ m' and the specific heat is 0.395 kJ/kg°C. Find (1) Total amount of heat transfer, (i) Average rate of Heat Transfer, (ii) Average Heat Flux b) A plane wall constructed of solid iron with thermal conductivity 70 W/mC, thickness 50 mm and with surface area 1 m by 1 m, temperature 150 °C on one side and 80°C on the other. Calculate the conductive heat transfer.

A 2m^2 wall of 1010steel is 8 mm thick. If the outside of the wall is100 °C, andyou measure aheat flux of 80 kW/m2coming off the wall, what is the temperature of the insideof thewall?

Since the correlation given in the textbook is so complicated, Dr. Roy wants to come up with a new correlation for convection over a sphere. He proposes the correlation to be NUD D=2+C Re" Pr3 He used a steel sphere (conductivity of 42 W/m-K) of 20 cm diameter that generates steady 40 W heat. He placed it in air flow with 1 m/s where air temperature is 20°C. He then measured the steady state tempera- ture of the sphere surface to be 30°C. 31'8 w/m² K Based on his measurements, what is the convection coefficient? Using properties at film temperature, what should the value of C be as per Dr. Roy's calculations if he assumes m = 0.8? O'142 What is the temperature at the center of the sphere? 30 38 C

Check Biot number and do the problem in 20 minutes

Q5A) Consider a composite spherical shell comprising an insulating layer of unknown thermal conductivity sandwiched between two layers of steel (k = 45 W/m. °C). The inner shell has 100 mm inner diameter and wall thickness of 5 mm. The outer shell has 150 mm inner diameter and wall thickness of 2 mm. The inner surface of inner spherical shell was experimentally found 120 °C while outer surface of outer spherical shell was at 67 °C. The ambient air was at 30 °C with heat-transfer coefficient at outer surface 6 W/m². °C. Determine thermal conductivity of insulating material. Then, experiment was repeated on another day when ambient air temperature was 13 °C. The inner surface temperature of inner shell and convection coefficient remained unchanged. Calculate temperature of outer surface of outer shell in this case.

What is the heat loss through the windows of a passenger train left outside a station in winter, assuming that the temperature inside the train is 20°C, outside the train, -20°C, total heat transfer area 40 m2. The thickness of glass wall may be taken as 0.5 cm. The thermal conductivity of glass is 0.88 W/(m.K).

Please show steps how you come up with rate of heat transfer

Pls answer q3(as I am still not sure whether or not I did q2 correctly)

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Need help on the Q.