aidgho11Lv1

20 Nov 2022

During air cooling of oranges, grapefruit, and tangelos, the heat transfer coefficient for combined convection, radiation, and evaporation for air velocities of   0.11<V<0.33 m/s is determined experimentally and is expressed as h=5.05 kairRe1/3/D, where the diameter D is the characteristic length. Oranges are cooled by refrigerated air at 5C and 1 atm at a velocity of 0.3 m/s.

Determine (a) the initial rate of heat transfer from a 7-cm-diameter orange initially at 15C  with a thermal conductivity of 0.50 W/mC,

(b) the value of the initial temperature gradient inside the orange at the surface, and

(c) the value of the Nusselt number.