radiant and convective superheater

[fmortini]

Hi.
I need to design a radiant and convective superheater. I know inlet and outlet temperature of the steam, mass flow rate of the steam and the mean temperature and the emissivity of the gas.
How can I determine the wall temperature of the tubes? And the heat transfer coefficients (steam side and gas side)?

Thank you!!

 

[athomas236]

Is there any special reason why you are not talking to the original boiler supplier?

Best regards,

athomas236

 

[athomas236]

To calculate the temperature difference between the temperature of the fluid in the tube and the tube temperature at the mid wall I would use the following:


Tm-Tf = (QxDo/2xK) x (Loge (Dm/Di) + (2xK/(HxDi)) degree C

Where

Q = heat flux based on outside area of tube = heat absorbed / outside area of tube (W/m^2)

Do = outside diameter of tube (m)

Dm = mean diameter of tube (m)

Di = inside diameter of tube (m)

K = thermal conductivity of tube material (W/m^2)

H = heat transfer co-efficient from fluid to tube inside surface (W/m C)

To calculate the temperature difference between the tube temperature at the mid wall and temperature of the outside surface of the tube and the tube temperature at the mid wall I would use the following:

Tm-To = (Tm-Tf) x Loge (A) / ( B + Loge (C)) degree C

where A = (2xDo/(Di+Do))

B = (2xK/(HxDi))

C = ((Di+Do)/(2xDi))


Regards,

athomas236