Pulsar UltraTWIN, Инструкция по эксплуатации

Страница: 92 / 214

ULTRATWIN (UL) INSTRUCTION MANUAL
92
Ratiometric
If the flow calculation is to be ratiometric P702 = 2 the flow will be
calculated using the formula: q= q
cal
C
e
/C
ecal
(h
e
/h
ecal
) 1.5
Where:
q = flowrate
q
cal
= flowrate at maximum head P705
Ce = discharge coefficient calculated by UltraTWIN (P723)
Ce
cal
= discharge coefficient at maximum head
he = effective head
he
cal
= effective head at maximum head
V-Notch Weir Calculations
Absolute
If the flow calculation is to be absolute P702 = 1 the flow will be calculated
using the formula: q = C
e
8/15tan(theta/2) (2gn) 0.5 h 2.5
Where:
q = flowrate
Ce = discharge coefficient calculated by the UltraTWIN (P723 )
theta = V-notch angle
gn = gravitational acceleration (nominal value = 980.66 cm/s
2 )
h = head
The UltraTWIN pre-sets the angle (theta) on selection of the chosen device
this angle is
90° for a BS 3680 full 90°V notch weir, 53° 8 minutes in the
case of the BS3680 half 90°V notch weir and 28° 4 minutes in the case of
the BS3680 quarter 90°V notch .
Ratiometric
If the flow calculation is to be ratiometric P702 = 2 the flow will be
calculated using the formula: q = q
cal
C
e
(h)/C
e
(h
cal
)(h/h
cal
) 2.5
Where:
q = flowrate
q
cal
= flowrate at maximum head P705
Ce(h) = discharge coefficient for head
Ce(h
cal
) = discharge coefficient for maximum head
h = head
h
cal
= maximum head P704