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[nachop]

Dear all, 

 

I am designing an Indirect water bath( with fired tube) vaporizer for vaporizing LPG ( liquified petroleum gases). To calculate overall Heat Transfer Coefficient (U) :

 

1/U = 1 / ho + 1/ hio + Rfi + Rfo

 

ho : Outside heat transfer coefficient

hi : Inside heat transfer coefficient

Rfi: Internal fouling resistance

Rfo : External fouling resistance

 

For internal heat transfer coefficiente I refer to Sieder & Tate equation : 

 

Nu = 0.027 Re ^0.8 * Pr ^ 1/3 * ( uf / ufw ) ^0.14

 

uf / ufw : viscosity ratio 

 

Nu : Nusselt 

Re: Reynolds

Pr: Prandtl

 

What correlation shall i use to calculate Outside heat transfer coefficient ?