Radiant Heat Transfer Calculator

This calculator performs the heat balance between the total heat absorbed in a radiant box and the exit temperature, Tg(bridgewall) that will support that heat transfer. The fuel for this calculation is fixed and cannot be changed. The fuel properties are for a typical natural gas. The calculation is based on the following:

qR = qr + qc
Where,
qr = saAcpF(Tg4 - Tw4)
qc = hcAt(Tg - Tw)
qr = Radiant heat transfer, Btu/hr qc = Convection heat transfer, Btu/hr
s = Stefan-Boltzman constant, 0.173E-8 Btu/ft2-hr-R4 a = Relative effectiveness factor of the tube bank
Acp = Cold plane area of the tube bank, ft2 F = Exchange factor
Tg = Effective gas temperature in firebox, °R Tw = Average tube wall temperature, °R
hc = Film heat transfer coefficient, Btu/hr-ft2- °R At = Total outside area of the tubes, ft2

Process Data
Duty, Btu/hr: Tube Wall Temp, F:
Fuel Type: Excess Air, %:
Firebox Data
Width or Dia., ft: Height, ft:
Length(0 for Cyl), ft: Flue Gas Exit Area, ft:
Film Coef.(hc), Btu/hr-ft2- °R: Beam Length Correction:
Tube Data
Number Tubes: Tube Od, in:
Tube Spacing, in: Eff. Tube Length, ft:
Tube Arrangement: