Question

Steel balls are annealed by heating them first to 900°C, and then slowly cooling them to 100°C in ambient air at 35 C, as shown in the figure below. The

diameter of the steel balls is 8 mm. a) Find the density, specific volume and specific heat of steel from your textbook, Write the table number that you refer to. b) Determine the mass of a steel ball. c) Starting from the general energy balance, derive an expression to determine the heat loss (Q out)of a steel ball during the cooling process. d) Determine the heat loss (Qose) of a single ball. Use the specific heat that you found in part a. e) If 2500 balls are processed per hour, determine the total rate of heat transfer from all the balls to the ambient air (Qout).

Fig: 1

Fig: 2

Fig: 3

Fig: 4

Fig: 5

Fig: 6

Fig: 7