Systems Level Design Review
Multidisciplinary Senior Design 1
Friday, December 21st, 2012
P13051
P13051 – PIV Experiment for Flow
Mapping in Lungs
• Customers:
▫ Dr. Risa Robinson
▫ Dr. Steven Day
• Team Guide:
▫ Michael Antoniades – Chemical Engineering
• Team:
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Kristin Roberts – Project Manager, ME
Morgan DeLuca – ME
Brad Demarest – EE
Ryan Mark – ME
Jimmy Moore – CE
Jake Snider – ISE
Agenda
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Project Background
Customer Needs
Engineering Specifications
Functional Analysis
Concept Generation & Selection
▫ Lung Model
▫ Pump
▫ Pressure Measurement & Control
• Feasibility Analysis
• Risk Assessment
• Project Planning & WBS
Project Background
• The Army Medical Research Lab needs to
validate their CFD models for healthy and
diseased lungs
• RIT will perform particle image velocimetry
(PIV) on lung models to validate the CFD.
• The senior design team will design and develop
the lung models and testing apparatus.
What is PIV?
• Used for flow visualization and velocity
measurements
• Fluid is seeded with tiny tracer particles
• The particles are illuminated using a laser sheet,
and a camera takes pictures of the particles.
• Fluid velocity profiles can be obtained by
analyzing particle movement from frame to
frame.
Key Customer Needs
1. Create hollow lung model using specified
geometry up to the 14th generation
2. Accommodate various image locations
3. Simulate inhalation and exhalation
4. Monitor flow rate and pressure
5. Control flow at outlets to mimic boundary
conditions of CFD model
6. Accommodate imaging with no distortion
7. Create LabVIEW Program and procedure to
run experiment
8. Can easily switch between models
Key Engineering Specifications
1. Image location can be located within ±5mm
2. Model Reynolds number must be within X% of
lung Reynolds number
3. PIV fluid must match model material index of
refraction within ±X.
4. Models can be switched in less than X hours.
5. Accuracy of pressure measurement is X.
6. Match boundary conditions within X%.
Functional Analysis
Lung Model Concepts – Silicone Block
• Positives:
▫ Robust
▫ Easier to prevent distortion
▫ Rapid prototype airspace using PVA
• Negatives:
▫ Will be difficult to rapid prototype smaller dimensions in
PVA
 Possible solution: Scale model up  match Reynolds number
▫ Any bubbles in silicone could cause distortion
 Possible solution: Use vacuum to reduce bubbles
• Cost:
▫ 5 gallon of silicone=$1,719.96
▫ 1 pound of PVA=$10-20
Lung Model Concepts – Rapid Prototype
• Positives:
▫ Can more easily model smaller details and intricacies.
▫ Easier to access specific portions of model since it is
not encased in a solid block.
▫ Prototyping all generations should not be a problem
• Negatives:
▫ Fragile, especially at higher generation air passages;
transporting model comes with the risk of damage.
▫ Would need to construct a container/support system
prevent distortion.
• Cost:
▫ High – Intricate design with small passageways
increases cost to rapid prototype.
Lung Model Feasibility
• Silicone Model:
▫ Initial calculations: 18.6% Water, 81.4%
Glycerol will match index of refraction
for Sylgard-184
• Rapid Prototype Model:
▫ Accura Clearvue
 Colorless
 Layer Thickness - Horizontal build layers
down to 16 microns (0.0006 inches).
 Build Resolution - X axis: 600 dpi. Y axis:
300 dpi. Z axis: 1600 dpi.
 Cost- $ 1,140
Pump Selection
Pump
Flow Rates
Pressures
Comments
Cost (3 highest)
Gear pump
Acceptable,
Up to 30 gpm
Acceptable,
Up to 30 psi
Common, birotational, can be
self-priming
2
Rotary Vane
Acceptable
Acceptable
Not really used in our
application
1
Diaphragm
Acceptable
Acceptable
Create pulsing flow,
need air supply,
cheaper
1
Lobe Pump
Acceptable
Acceptable
Used in Sanitary
applications where
fragile solids are
used, bi-rotational,
may be overly
complex
3
Image Credit: Wikipedia; Info Credit: pumpscout.com
Pump Feasibility
• Viscosity
▫ Glycerin/Water mixture that ranges from 82%75% glycerin
▫ Approximately 500 SSU – 320 SSU
• Flow rate
▫ Reynolds number matching – Used approximate
fluid properties and average breathing flow rate
▫ Approximately 20-30 gpm
• Pressure
▫ Analyzed pressure loss through model using
poiseuille flow equation
▫ Approximately 20.8 psi (maximum)
Flow Control
• micro valve system (2 or 3 way)
▫ - system will be placed on every outlet where monitoring is
required
▫ - valve will be fitted with measuring device in series with
model flow
▫ - micro-valves capable of diameters as
▫ small as 1 mm
▫ - cost $5 per unit
Pressure Measurement
Pressure Transducer
Pros
- easy to implement into system
- information readily available
- data acquisition trivial
Cons
- not designed for extremely low pressures
(accuracy drops dramatically below 5 psi)
- very expensive (low pressure high res. $900)
Pressure Measurement Cont.
Low Pressure Sensor
Pros
-very accurate to .01 psi
-only $20-40 per unit
-compact
Cons
-pressure range small (-5 to 5 psi)
-cumbersome to implement (board required)
Digital Input to Labview
• NI USB-6008
▫ Cost: $169
▫ Easily interfaces
with Labview
▫ High Sample Rate
(10k S/s)
Labview Code
• Not fully completed
▫ Need all
components before
testing and
construction can
occur.
System Overview
1
Effect
Cannot assemble test rig
Cause
Model is sent too late
2
3
Importance
Risk Item
Long lead time to produce
lung model
Severity
ID
Likelihood
Risk Assessment
6
Action to Minimize Risk
Verify lead time on rapid prototyping,
send out model before spring quarter
System Design Review includes
discussion on needs and specs,
Customer will be consulted
throughout the quarter
Detailed Design Review will verify the
design meets the specs, Specifications
will be finalized and approved by
customer
Provide options of varying cost,
determine importance of
specifications
Will choose method of manufacturing
that produces a stronger, less brittle
product
2
Design does not meet
needs
Project Failure,
unsatisfied customer
Needs not mapped to
correct specifications
2
2
4
3
Design not executed to
specifications
Project Failure
Specifications were
out of range
1
2
2
4
Project goes over budget
Will not adhere to
customer need
2
2
4
5
Lung model is damaged
Cannot assemble or test
project
1
3
3
3
2
6
2
1
2
Speak with customer to limit number,
Choose cheaper method
Reduce noise with instrumentation
amplifier
Error in coding
2
2
4
Verify with testing of code with
known values
Wrong pump chosen
1
2
2
Verify precision of pump flow rate,
Test pump before installing in system
8
Scope of pressure
measurements is too large
Too much noise in pressure
measurements
Labview data doesn’t not
follow expected
relationship
9
Pump does not deliver
consistent flow rate
6
7
Will not meet specs
Cannot get accurate
reading of pressure
Will not get accurate
output values
Will not be able to
supply correct flow rate,
will not be steady state
Project not accurately
budgeted
Material chosen is
brittle, cannot
withstand forces
Too many outlets
need to be tested,
increased cost
Output pressure too
small
Owner
Project Planning
• Microsoft Project used to determine slack in
tasks as well as critical path by determining
predecessors and estimated duration of tasks.
Roles and Responsibilities
• Kristin Roberts – ME, Project Leader
▫ Project Organization
▫ Fluid Mechanics
• Ryan Mark - ME
▫ Pressure sensing and Control
▫ Rapid Prototyping
▫ Data Acquisition
• Morgan DeLuca – ME
▫ Pump Design
▫ Fluid Mechanics
Roles and Responsibilities cont’d
• Jimmy Moore - CE
▫ Camera & Model Positioning
▫ Controls Design
• Brad Demarest - EE
▫ Data Acquisition
▫ Prototype Material Choice
• Jake Snider - ISE
▫ Project Planning
▫ Labview Design