Overall Heat Transfer Coefficient

Does this make sense if coolant water is flowing on the shellside which undergoes a phase change (exiting at 100% steam) and a hot gas (which stays as one phase) on the tube side?

1/Uo = 1/hcb + 1/hfs + (do*ln(do/di))/2kw + (do/di)*1/hft + (do/di)*1/hi + 1/hsteam

|SHELL FLUID|--->|TUBE OUTER FOULING LAYER|--->|TUBE SURFACE|--->|TUBE INNER FOULING|--->|TUBE FLUID|-->|STEAM PRESENT IN TUBE|


hcb : boiling heat transfer coefficient (shell-side) (W*m^-2*C^-1)
hfs : shell fouling coefficient (W*m^-2*C^-1)
do : outter tube diameter (m)
di : inner tube diameter (m)
kw : tube conductivity (W/m*C)
hft : tube fouling coefficient (W*m^-2*C^-1)
hi : tube fluid heat transfer coefficient (W*m^-2*C^-1)
hsteam : steam heat transfer coefficient (W*m^-2*C^-1)

Thank you