Answer:
Start by calculating the heat lost falling from Tm,i to Tm,o
As a first approximation use an average Cp of (Tm,i + Tm,o)/2 and an average density at (Tm,i + Tm,o)/2
Cp air at (Tm,i + Tm,o)/2 ----(1)
Density of air at (Tm,i + Tm,o)/2 : PV=nRT, V=T1/T2, air density at 293K = 1.204kg/m^3
Air density at (Tm,i + Tm,o)/2 1.204×293/(Tm,i + Tm,o)/2
Energy lost per kg for (Tm,i - Tm,o)K drop: (Tm,i - Tm,o)K × (1) =
Time of travel: t
Energy lost per kg drop/t seconds = 24.3 kW
Volume occupied by 1kg air at at mean tempera ture = 1/Air density at mean temperature
Length of pipe ( Di m diameter) needed to hold Volume occupied by 1 kg of air at mean temperature :
Cross section = π/4 Di^2, Volume occupied by 1 Kg of air at mean temp. ÷ π/4Di^2
Surface area of pipe Di m diameter by L m long = Length of pipe to hold Volume of air in m × π*Di
Q/A=k (delta T)/ thickness,
Thickness of insulation = Area × k ×dT / Q
Explanation:
