The document discusses predicting pressure drop through a valve and the relationship between pressure drop and flow rate. It outlines the setup and parameters for simulations, including boundary conditions and mesh refinements at various valve positions. Additionally, it includes details on the flow coefficient and the effects of valve opening on flow characteristics.

1. PREDICTING PRESSURE DROP
THROUGH A VALVE
MATT BEMIS

2. PREDICTING PRESSURE DROP THROUGH A VALVE
● Question 1
○ For a given pressure
drop, what is the
resulting flow rate?
● Question 2
○ How does this change
with respect to plug
position?(Source: https://en.wikipedia.org/wiki/Globe_valve#/media/File:Globe_valve_diagram.svg)
(Source: https://grabcad.com/library/globe-valve-design-2)

3. GEOMETRY PREPARATION
Original Geometry Simulation-Ready Valve

4. FLOW VOLUME EXTRACTION
● Inlet/outlet extensions:
○ ANSI standard
● Flow volume extraction:
○ Domain = negative of valve
assembly

5. WHAT IS THE END GOAL OF THE SIMULATION?
The flow coefficient of a device is a relative
measure of its efficiency at allowing fluid flow.
It describes the relationship between the
pressure drop across an orifice, valve or other
assembly and the corresponding flow rate.Where:
Q = flow rate (GPM)
SG = Specific Gravity (water = 1)
ΔP = Pressure Drop (expressed in psi)

6. VALVE POSITION VS. FLOW CHARACTERISTICS
● Globe valve
● Develop flow coefficient
● % valve open vs. % of full flow
(Source: http://www.industrialcontrolsonline.com/sites/default/files/infotech/Infotec33/image002.gif)

7. SETUP

8. SIMULATION SETUP – BOUNDARY CONDITIONS
1 PSI
0 PSI
● 6 different positions
● 1, 2, 4, 6, 8, 10 mm open
● % open vs. Cv value
● % open vs. flow rate

9. SIMULATION SETUP – MESH
● Hex-dominant automatic meshing
sizing
● Moderate fineness
● 4 refinements:
○ Feature refinement
○ Surface refinment
○ Region refinement
○ Wall layers

10. SIMULATION SETUP – RESULT CONTROL

13. RESULTS – PARTICLE TRACES
Particle traces showing velocity

14. RESULTS – VELOCITY MAGNITUDE
Cut plane showing velocity through cross section

15. RESULTS – PRESSURE
Velocity cut plane showing velocity through cross section

16. RESULTS – PERCENT OPEN VS. FLOW COEFFICIENT

17. RESULTS – DISTANCE OPEN VS. FLOW RATE

18. RESULTS – VALVE POSITION VS. PLUG FORCE