Problem 145P

An ordinary egg can be approximated as a 5.5-cm-diameter sphere. The egg is initially at a uniform temperature of 8°C and is dropped into boiling water at 97°C. Taking the properties of the egg to be ρ= 1020 kg/m3 and cp= 3.32 kJ/kg-°C, determine (a) how much heat is transferred to the egg by the time the average temperature of the egg rises to 70°C and (b) the amount of entropy generation associated with this heat transfer process.

Step by step solution Step 1 of 6(a)Take the egg as a closed system since no mass enters or leaves the egg.Assume the egg is in spherical shape with a radius and the thermal properties of theegg are constant. Energy absorption or release within the egg is negligible. Kinetic andpotential energies do not change.Consider energy balance for the systemHere net energy transfer is , change in energy isThe rate of heat transfer from the ball to the air isHere the rate of heat transfer is , mass of the egg is , specific heat of the egg is initial temperature is , temperature after cooling is\n