Dynasonics DXN Portable Ultrasonic Measurement System - Manual (Page 42)

Custom Fluids
If Custom was chosen from the Fluid Material drop-down the following parameters must be entered.
Site Name 0.00 GPM
3/28/2012
13:24
Meter Adv Cal System Display Site Log I/O
Create Liner Transit Doppler Pipe Lookup Fluid
Specific Gravity
Fluid Material
Viscosity (cp) 0.996
4911
0.996
Sound Speed (FPS)
Custom
Figure 55: Custom fluid setup
Custom Fluid Sound Speed (Numeric Value)
Enter the sound speed of the custom fluid. If English is used for the Entry Units enter the sound speed in FPS. If Metric is used
the sound speed is entered in MPS. The fluid sound speed can also be obtained directly from the meter if the transducers are
already correctly positioned and the signal quality is above 10%. This value is available by selecting TT SOS in one of the data
panels. See Meters Page .
Custom Fluid Specific Gravity (Numeric Value)
DXN flow meters use pipe size, specific gravity and viscosity to calculate Reynolds numbers. Since the Reynolds
number influences flow profile, the DXN has to compensate for the relatively high velocities at the pipe center during
transitional or laminar flow conditions. The Specific Gravity entry is used in the calculation of Reynolds and the resultant
compensation values.
The specific gravity entry allows adjustments to be made to the specific gravity (density relative to water) of the liquid.
As stated previously specific gravity is used in the Reynolds correction algorithm. It is also used if mass flow measurement
units are selected for rate or total.
If a fluid was chosen from the Fluid Material list, a nominal value for specific gravity in that media will be automatically loaded.
If the actual specific gravity is known for the application fluid and that value varies from the automatically loaded value, the
value can be revised.
If a custom fluid was entered a specific gravity will need to be entered if mass flows are to be calculated. A list of alternate
fluids and their associated specific gravities is located in the Appendix of this manual.
Dynamic Viscosity (Numeric Value Entered in cP)
If a fluid was chosen from the Fluid Material list, a default viscosity will be automatically loaded. If the actual viscosity of the
liquid is known or it differs from the default value, the value can be revised. A list of alternate fluids and their associated
viscosities is located in the Appendix of this manual.
Viscosity is a measure of the resistance of a fluid to deform under either shear stress or extensional stress. It is commonly
perceived as thickness, or resistance to flow. Viscosity describes a fluid’s internal resistance to flow and may be thought of as a
measure of fluid friction.
DXN Portable Ultrasonic Measurement System
Page 42 February 2013