Circular Pipe
Lossy model of a circular pipe
Description
Equations
Variables
Connections
Parameters
The Circular Pipe component models a circular pipe with losses. The pressure drop is computed with the Darcy equation, with the friction factor determined using the Haaland approximation for turbulent flow. When the Reynolds number is greater than the maximum value for laminar flow but less than the minimum value for turbulent flow, the friction factor is determined using linear interpolation.
ℜ=q⁢Da⁢νDh=4⁢AUA=π⁢D24
fL=64ℜfT=fColebrook⁡ℜT,εDh
mode={posturbulentℜT<ℜnegturbulentℜT<−ℜposmixedℜL<ℜnegmixedℜL<−ℜlaminarotherwise
p=pA−pB=12⁢L⁢ρ⁢ν2Dh3⁢ℜ⁢{fColebrook⁡ℜ,εDh⁢ℜmode=posturbulent∨mode=negturbulentfL+fT−fLℜT−ℜL⁢ℜ−ℜL⁢ℜmode=posmixed∨mode=negmixed64otherwise
q=qA=−qB=ℜ⁢A⁢νDh
fColebrook=ℜ,εD→1.8⁢log106.9ℜ+εD3.71.11−2
Name
Units
Modelica ID
A
m2
Pipe cross-sectional area
fL
1
Friction factor with laminar flow
fT
Friction factor with turbulent flow
mode
Integer indicating type of flow
p
Pa
Pressure across component
q
m3s
Flow rate through component
ℜ
Reynolds number
Re
portA
Upstream hydraulic port
portB
Downstream hydraulic port
General Parameters
Default
D
0.01
m
Inner diameter
L
5
Length of pipe
ε
1.5·10−5
Height of inner surface roughness
epsilon
ℜL
2.·103
Reynolds number at transition to laminar flow
ReL
ℜT
4.·103
Reynolds number at transition to turbulent flow
ReT
See Also
Hydraulics Library
Restrictions
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