Technical data

Chord Average Flow Equation 3-1:
Vchord =
L
chord
2
2X
c
hord
t
1
− t
2
t
1
− t
2
Chord Speed of Sound Equation 3-2:
C
chord,classic
=
L
chord
2
2X
c
hord
t
1
− t
2
t
1
t
2
Where the PortAngleFactor is a dimensionless factor that is dependent upon the chord port
angle with respect to the meter body:
for 60 degree port angles,
60° Port Angle Factor Equation 3-3:
PortAngleFactor =
(
1 + 0.5 ×
(
V
chord
2
C
chord,classic
2
)
×
(
X
chord
2
L
chord
2
)
× tan
2
(
60
∘
)
)
75° Port Angle Factor Equation 3-4:
PortAngleFactor =
(
1 + 0.5 ×
(
V
chord
2
C
chord,classic
2
)
×
(
X
chord
2
L
chord
2
)
× tan
2
(
75
∘
)
)
for all other port angles,
Equation 3-5
P
ortAngleFactor = 1
V
chord
=
chord average flow velocity (m/s) (FlowVelA ... FlowVelD)
C
chord
=
chord average speed of sound (m/s) (SndVelA ... SndVelD)
L
chord
=
chord “L” dimension (m) (LA ... LD)
X
chord
=
chord“X” dimension (m) (XA ... XD)
t
1
=
chord average transit time in the upstream direction (s) (MeanTmA1 ... MeanTmD1)
t
2
=
chord average transit time in the downstream direction (s) (MeanTmA2 ... MeanTmD2)
Note
A positive chord average velocity indicates flow in the forward direction whereas a negative chord
average velocity indicates flow in the reverse direction.
Flow measurement
Operations 19