Estimate how long will it will take to cool a trailer filled with coke. given the ambient temperature is 20 c and heat transfer provided by the refrigeration unit is 25kw and the drinkable temperature is 5 °c. make reasonable estimates of how much insulation is included on the walls of the truck. assume the coke cans are stacked in rows inside the truck with sufficient space for air to circulate between them. assume an air flow velocity inside the truck of 0.35 m/s. assume the sun is incident on the external surface of the truck for part of the time. indicate any assumptions you make in your analysis. take the properties of coke as: specific heat capacity 4000 j/kgk, density 1000 kg/m3 and thermal conductivity of 0.5 w/mk.

Derive the correction factor formula for conical nozzle i=-(1+ cosa) and calculate the nozzle angle correction factor for a nozzle whose divergence hal-fangle is 13 (hint: assume that all the mass flow originates at the apex of the cone.

Agas mixture consists of 8 kmol of h2 and 2 kmol of n2. determine the mass of each gas and the apparent gas constant of the mixture.

A3-mm-thick panel of aluminum alloy (k 177 w/m-k, c 875 j/kg-k and ? = 2770 kg/m) is finished on both sides with an epoxy coating that must be cured at or above t,-150°c for at least 5 min. the production line for the curing operation involves two steps: (1) heating in a large oven with air at ts,0-175°c and a convection coefficient of h, 40 w/m2. k, and (2) cooling in a large chamber with air at 25°c and a con- vection coefficient of he 10 w/m2.k. the heating portion of the process is conducted over a time interval te which exceeds the ime required to reach 150°c by 5 min (h = r + 300 s). the coating has an emissivity of ? = 0.8, and the temperatures of the oven and chamber walls are 175 and 25°c, respectively. if the panel is placed in the oven at an initial temperature of 25°c and removed from the chamber at a safe-to-touch tempera ture of 37°c, what is the total elapsed time for the two-step curing operation?