6. Strawberry pulp is to be frozen in cylindrical plastic containers (buckets) The buckets are packed in a room that is held at 15 "C and are held there long enough for you to assume that the temperature is uniform throughout the bucket. They are then placed in a blast freezer that has cooling air at -25 .C (7.) flowing over the buckets, Your colleague has previously determined that under these conditions the equivalent heat transfer dimensionality (Exec:) will be 2.44. Additional information: his 45 Wm-K-, Bucket dimensions: 400 mm high and 240 mm in diameter. Thermal conductivity of unfrozen strawberry pulp (:) = 0.50 W mal K-],Thermal conductivity of frozen strawberry pulp (80 = 1.50 W mal K-],Density of strawberry unfrozen strawberry pump (PI) = 1045 kg m'Density of strawberry unfrozen strawberry pump () =985 kg me.Specific heat capacity of unfrozen strawberry pulp (c.) = 4.05 kJ kg K- Specific heat capacity of frozen strawberry pulp () = 4.05 kJ kg] K- Enthalpy of vaporisation of water ([) = 333 kJ kg],Initial freezing temperature: -1 'C a) Calculate how long it will take for the strawberry pulp to reach -15 "C (7:). You may assume the bucket wall has a negligible effect on the heat transfer rate. b) In terms of the freezing time: a. Do you think there would be any value in reducing the size of the containers? Justify your answer. b. Do you think there would be any benefit in using metal containers rather than plastic? c. Do you think there would be any value in increasing the speed of the air in the blast freezer? Justify your answers in each case