Compare the outside surface area of a vertical-tube bundle and the heat input from an assumed uniform heat flux. The evaporation estimate uses an approximate latent heat; it does not predict actual boiler output.
Wheeler Vertical Tube Boiler Interactive Calculator
Enter tube count, outside diameter, active length, assumed uniform heat flux and gauge pressure. Latent heat is estimated with the displayed approximate equation; boiler safety, circulation and ratings are not calculated.
Equation Used
- Identical tubes use full entered length as active outside area.
- Heat flux is uniform and entered independently.
- Gauge pressure is converted to approximate absolute bar.
- Latent heat follows the displayed bounded approximation.
- Circulation, water inventory, sensible heating, blowdown, combustion, losses, stress and safety are omitted.
Vertical-Tube Area and Duty Screen
NIST Chemistry WebBook water data provides thermophysical context. For the calculation shown here, latent heat comes from the displayed approximate equation rather than the NIST tables.
What This Calculator Represents
An ideal outside-area and latent-only evaporation comparison.
Area, Duty and Quotient
Qdot=Aq
hfg=clip(2257-103ln(pg+1.01325),1850,2150)
mdot=3600Qdot/hfg
Worked Scenario
At 60 tubes, 57.5 mm OD and 1.5 m length, area is about 16.26 m2. At 10.4 kW/m2, duty is about 169 kW; the approximation then gives an ideal latent-only evaporation quotient.
Assumptions and Limits
- Calculated: lateral area, entered-flux product and approximation quotient.
- Not calculated: real steam tables, circulation, efficiency, combustion, stress, controls or safety.
Frequently Asked Questions
Is latent heat from a steam table?
No.
Is evaporation guaranteed?
No.
Is sensible heating included?
No.
Is heat flux predicted?
No.
Are tube ends counted?
No.
Can this rate a boiler?
No.
References
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