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.

A Study of the Effects of Design Features on the Flow Forces of

Pressure Regulating Spool Valves

Progress Report #1

Frank Henderson11/5/09

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 RevisedNew Selection of Design Features to Investigate:• Housing Exit Annulus Diameter (see A below)

– Vary by + and - 10% from baseline

• Sleeve Exit Annulus Diameter (see B below)– 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 inlet114.6 psid (inlet – outlet)

CFD

Filled Contours Colored By Velocity

CFD

Filled Contours Colored By Velocity

CFD

Filled Contours Colored By Velocity

Spool faces only

X direction

CFD

Description X-direction Force Total (lbf) % change from Baseline w/2nd order upwind%

changeBaseline Model 1.7371025 1.8589111

Housing Annulus Increased 10% 1.7435296 0.37% 1.8394763 -1.05%Housing Annulus Decreased

10% 1.7677822 1.77% 1.7985951 -3.24%Sleeve Annulus Increased 10% 1.7930577 3.22% 1.8836193 1.33%

Sleeve Annulus Decreased 10% -100.00% -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