Transcript Progress 1.ppt

A Study of the Effects of Design
Features on the Flow Forces of
Pressure Regulating Spool Valves
Progress Report #1
Frank Henderson
11/5/09
Tasks
• Revise Project Scope
– Action from Proposal Presentation
•
•
•
•
•
Build 3D models in UG
Mesh and set up boundary surfaces
Run CFD in Fluent using same inputs
Results
Report Writing
Original Project Plan
• Sensitivity Study of Seven (7) Design Features
• Each Feature Varied Multiple Time Over Multiple Valve Positions
– For example, a dimension varied three (3) times both positive and negative and
at five (5) different valve positions for a total of 30 models for each of seven (7)
features for a total of …way too much work
• Each Fluent Case Iterated to Obtain a Valve In Force Balance
– Iterate in the inlet conditions on a set stroke of the valve until the Pressure’s on
each end and the spring rate equal out to zero
– This would aligned the model with real condition, but is not necessary for the
purpose of this project. Design features can still be investigated by comparison
using one set of input conditions for each model.
• Action from Proposal Presentation to decrease the number of
models.
– A total of ten (10) 3D model’s for CFD was suggested to start.
Project Scope Revised
New Selection of Design Features to Investigate:
• Housing Exit Annulus Diameter (see A below)
–
•
Sleeve Exit Annulus Diameter (see B below)
–
•
Vary by + and - 10% from baseline
Vary by + and - 10% from baseline
Revising method:
•
•
•
•
Set one inlet flow and run baseline model
Revise only one feature in one direction (one model) and rerun with same conditions
Compare results
This revised method eliminates timely iteration originally planned to put the valve in force balance
This is a total of five (5) models which should allow time for further study as process
developed.
A
B
Status
• Build models in UG
– Completed (screen captures to follow)
• Mesh Models and Set Up Surface Boundaries (Gambit)
– Completed (screen captures to follow)
• Run 3D Fluent CFD Analysis on 5 model
– 4 of 5 completed
– Results indicate little affect on flow forces
– Adding two more features (3 models) to investigate features that
may more drastically affect flow forces
3D Models
Exit Housing Annulus Change
Baseline model
3D Models
Exit Sleeve Annulus Change
Meshing
700,000 to 800,000 Tetrahedral Cells
Spool Surfaces
Surfaces of interest (those representing the spool surfaces) are set apart
as their own group. This way in Fluent the forces can easily be read.
CFD
Filled Contours Colored By Velocity
CFD
Filled Contours Colored By Pressure
6970 pph inlet
114.6 psid (inlet – outlet)
CFD
Filled Contours Colored By Velocity
CFD
Filled Contours Colored By Velocity
CFD
X direction
Spool faces only
Filled Contours Colored By Velocity
CFD
Description
X-direction Force Total (lbf) % change from Baseline
Baseline Model
1.7371025
Housing Annulus Increased
10%
1.7435296
0.37%
Housing Annulus Decreased
10%
1.7677822
1.77%
Sleeve Annulus Increased 10%
1.7930577
3.22%
Sleeve Annulus Decreased 10%
-100.00%
%
w/2nd order upwind change
1.8589111
1.8394763
-1.05%
1.7985951
1.8836193
-3.24%
1.33%
-100.00%
Small change in x-direction forces as a result of varying the sleeve or
housing annulus distances up and down 10%.
Additional Features
• Additional Features to Investigate
– Distance from spool exit edge to sleeve exit annulus edge (see A below)
– Rotation of spool inlet bucket from in-line with windows
A