Reconsider Prob. 8–84. Using the EES (or other) software, evaluate the effect of the liquid ammonia mass flow rate on needed insulation thickness for keeping the outer surface temperature at 20°C and the flow exit temperature at 220°C. By varying the mass flow rate from 0.02 to 0.2 kg/s, plot the insulation layer thickness as a function of the mass flow rate. If the flow rate of the liquid ammonia is adjusted between 0.04 and 0.2 kg/s, calculate the insulation layer thickness that is suitable for this range of flow rate.

Data from problem 84

Exposure to high concentrations of gaseous ammonia can cause lung damage. To prevent gaseous ammonia from leaking out, ammonia is transported in its liquid state through a pipe (k = 15 W/m ∙ K, D_i,_pipe = 5 cm, D_o,_pipe = 6 cm, and L = 10 m). The liquid ammonia enters the pipe at 230°C with a flow rate of 0.15 kg/s. Determine the insulation thickness for the pipe using a material with k = 0.95 W/m ∙ K to keep the liquid ammonia’s exit temperature at 220°C, while maintaining the insulated pipe outer surface temperature at 20°C.