Reference, Installation, and Operations Manual

Section 6: Meter operation

3-9000-743 Rev S

June 2013

 

 

 

Profile-effect correction

JuniorSonicTM meters (device numbers 3410, 3420, and 3450) require profile-effect correction. All other meters do not require profile-effect correction and the profile-effect correction factor is set to 1.

For meter types that require profile-effect correction, the correction factor can be either user- specified or meter-calculated depending upon the value of the SpecCorrectionFactor data point: if set to 0.0, then the correction factor is meter-calculated; if set within [0.90, 1.05], then the specified value is used.

Calculating the meter factor requires that the flow-condition pressure and temperature be live or fixed and that the AGA8 calculations are performed either internally or externally. If the profile-effect correction factor is to be meter-calculated but either the flow-condition pressure and/or temperature are/is disabled or the AGA8 calculations are not performed, then the flow- condition correction factor is set to the default value of 0.95. Otherwise, it is calculated as shown in Equation 6-17.

Equation 6-17 Profile-effect correction factor

CorrFctr = 1 +

0.242

0.2703WR-------- + 0.835------------

 

 

log

 

 

Din Re0.8

where

 

 

 

CorrFctr

=

flow-profile correction factor (CorrectionFactor)

WR

=

pipe wall roughness (m) (WallRoughness)

Din

=

pipe inside diameter (m) (PipeDiam)

Re

=

Reynolds Number (dimensionless) (ReynoldsNumber)

 

 

calculated as shown in Equation 6-18

Reynolds number

Reynolds Number is a dimensionless value that represents the nature of the gas flow within the

pipe. Although the primary reason for calculating Reynolds Number is for JuniorSonicTM meter profile-effect correction, the value is calculated for all meter types.

Reynolds Number is calculated as shown in Equation 6-18.

Volumetric flow rate

199