Oct 4th 2018, 08:06 PM
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Junior Member
Join Date: Oct 2018
Posts: 2
| Heat transfer between flue gas and feed water?
I need to determine the temperature of flue gas in a fire tube boiler.
Tube inlet gas temperature, T1 = 1045 deg.C
Saturation water temperature, tsat = 186 deg.C
Flue gas temperature, t2 = ?
2 equations to be used here:
Q = U.A.LMTD -------------(1)
Qg = Mg.Cg.(T1 - T2) ------(2)
Mg = mass of flue gas = 2415 kg/hr
Cg = specific heat of gas = 1.92 kJ/kg.K
U = overall heat transfer coefficient = 25.37 W/m2.K
A = heating surface of tube = 26.85 m2
LMTD = log mean temperature difference bet. the 2 medium
Equating both equation 1 & 2, and solve for T2, I get 674 deg.C
Problem is that inside this boiler tube has spiral tube, which will increase the heat transfer and will bring down the temperature of T2.
I just don't know how to go about this spiral tube. How to solve this?
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