|
Gas Mass Flow Rate (M, lb/hr): |
|
|
Gas Density(ρg, lbm/ft3): |
|
Gas Viscosity(me, cp): |
|
Air Density(ρa,lb/ft3) |
|
Stack Inside Dia. (ID, ft): |
|
Stack High(Hs,ft) |
|
Total Equivelent Length for Fraction Loss Calculation(Le,ft) |
|
Roughness (e,in): |
|
|
Result |
Gas Velocity in Stack(V, ft/sec): |
  Normal 15-20 ft/second |
Epsilon/Dia.Ratio (e/D): |
|
Reynolds No. (Re): |
|
Moody Fraction Factor (fm): |
|
Stack Draft(Hav, inH2O): |
|
(Psi): |
|
Pressure Drop (Δp, Psi): |
|
Velocity Head at Exit(vp, Psi): |
|
|
|
Example 8-10 — Find the available draft in a 2 ft ID by 20 ft long stack
Hav=0.192 * Hs * (ρg - ρa) + 0.0029 * V2 * ρg * ( fm *
Hs
/
Ds
+ 1 )       Eq 8-18
Fraction Loss based on Darcy-Weisbach
hL=fm*
L*V2
/
2*g*D
       
or       
ΔP=fm*
L*ρ*V2
/
144*(2*g)*D
Re=
D*V*ρ
/
μe
1) When the fluid flow is laminar (Re<2000)
fm =
64
/
Re
2) When the fluid flow is turbulent (Re>4000)
Chen Equation
A =log{
(ε/D)1.1098
/
2.8257
+
5.8506
/
Re0.8981
}
1
/
fm
=
{
-2*log(
ε/D
/
3.7065
-
5.0452*A
/
Re
)
} 2
|