A steam pipe with outside diameter 10 mm, passes through a room, the surface temperature of the pipe is 100 °C and the air is at 25 °C. Convection coefficient is 15 W/ m2.K. The heat transfer from a tube of length 5 m is: Select one: a. 1767 W b. 1767 W/ m c. 1767 W /m2 d. 176 W e. 1765 W

Question 1: In your own words, write down the differences between thermodynamic and heat transfer. (3 Marks) Question 2: Estimate the heat loss per square metre of surface through a brick wall 0.5 m thick when the inner surface is at 400 K and the outside surface is at 300 K. The thermal conductivity of the brick may be taken as 0.7 W/mK. (2 Marks) Question 3: A furnace is constructed with 0.20 m of firebrick, 0.10 m of insulating brick, and 0.20 m of building brick. The inside temperature is 1200 K and the outside temperature is 330 K. If the thermal conductivities are as shown in the figure below, estimate the heat loss per unit area. (5 Marks) 1200 K 330 K Fire brick X=0.20 m Insulating brick x=0.10 m Ordinary brick X=0.20 m k = 1.4 k = 0.21 k = 0.7 (WimK)

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A J- type thermocouple is used to measure the temperature in a heating process. Sheath material used is SS316. The length of the sheath is 13mm and thickness is 0.3mm. Find the time constant of the sheath. Material Q(kg/m3)s(J/Kg - °c)K(W/m-k) Platinum 21450 130 71.6 SS304 8030 500 21.4 SS316 7990 500 21.4 SS410 7750 460 24.9 Air 1.20 1005 0.025 MgO Powder 3580 877 26.8 Silicon compound3210 800 3 Time constant of the bare material is, T=