Pressure Drop - Panametrics Sentinel User Manual

Chapter 1. Installation
1.6.2

Pressure Drop

The flow conditioning plate causes a pressure drop through the line. This pressure drop is directly related to the gas
composition and properties, and to the flow velocity through the pipe.
Using a representative natural gas composition at 70° F, an estimate of the associated pressure drop can be
computed for reference. Figure 7 below shows pressure drop as a function of velocity for a uni-directional flow
installation with a single flow conditioning plate at various line pressures. The pressure drop through the meter
section would be doubled for a bi-directional installation with two flow conditioning plates.The example shown is for
natural gas, flowing at
40 ft/sec through a pipe with a pressure of 1000 psi. The pressure drop across the flow conditioning plate is about
1 psid.
When the actual gas properties are known, a more accurate calculation can be performed using the following basic
equation for the pressure drop:
where P is the pressure drop across the flow conditioning plate,
density (based on pressure, temperature, and gas composition), and
10
=
P
Associated Flow Conditioning Plate Pressure Drop
Flow Velocity (ft/sec)
Figure 7: Flow Conditioning Plate Pressure Drop
1
2
- - kV
2
k
is the loss coefficient for the plate (1.6),  is the gas
V
is the flow velocity through the pipe.
Sentinel™ User's Manual