PARTICLE IMAGE VELOCIMETRY MEASUREMENTS OF FLOW IN AN ANATOMICALLY ...

74 Pages·2014·4.66 MB·English

The Pennsylvania State University

The Graduate School

College of Engineering
PARTICLE IMAGE VELOCIMETRY MEASUREMENTS OF FLOW IN AN
ANATOMICALLY-ACCURATE SCALED MODEL OF THE RODENT NASAL CAVITY
A Thesis in

Aerospace Engineering
by

Christopher Rumple

 2014 Christopher Rumple
Submitted in Partial Fulfillment
of the Requirements
for the Degree of
Master of Science

August 2014
ii

The thesis of Christopher Rumple was reviewed and approved* by the following:

Dennis K. McLaughlin
Professor of Aerospace Engineering
Thesis Co-Advisor

Michael H. Krane
Research Associate and Assistant Professor of Acoustics and Bioengineering
Thesis Co-Advisor

Brent A. Craven
Research Associate and Assistant Professor of Mechanical Engineering
Thesis Co-Advisor

George A. Lesieutre
Professor of Aerospace Engineering
Head of the Department of Aerospace Engineering

*Signatures are on file in the Graduate School
iii

ABSTRACT

The mammalian nose is a multi-purpose organ that houses a convoluted airway labyrinth
responsible for respiratory air conditioning, filtering of environmental contaminants, and
chemical sensing. Because of the complexity of the nasal cavity, the anatomy and function of
these upper airways remain poorly understood in most mammals. However, recent advances in
high-resolution medical imaging, computational modeling, and experimental flow measurement
techniques are now permitting the study of respiratory airflow and olfactory transport phenomena
in anatomically-accurate reconstructions of the nasal cavity. Here, we focus on efforts to fabricate
an anatomically-accurate transparent model for planar particle image velocimetry (PIV)
measurements. Challenges in the design and fabrication of an optically transparent anatomical
model with refractive index-matched working fluid are addressed. PIV velocity field
measurements and resistance curve measurements are presented, which will later be used to
validate concurrent computational fluid dynamics (CFD) simulations of mammalian nasal
airflow.
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TABLE OF CONTENTS
List of Figures .......................................................................................................................... vi
List of Tables ........................................................................................................................... viii
List of Symbols………………………………………………………………………………xiii
Acknowledgements .................................................................................................................. xiii
Chapter 1 Introduction and literature review ........................................................................... 1
1.1 Introduction ................................................................................................................ 1
1.2 Literature review ........................................................................................................ 2
1.2.1 The mammalian nasal anatomy ....................................................................... 2
1.2.2 Studies of nasal airflow ................................................................................... 5
1.2.3 Other experimental studies using optical techniques ...................................... 5
1.2.2.1 Experimental studies in complex geometries ....................................... 5
1.3 Objective .................................................................................................................... 6
Chapter 2 Materials and Methods ............................................................................................ 7
2.1 Experimental Model & Setup..................................................................................... 7
2.1.1 Physical Model Design .................................................................................... 7
2.1.1.1 Anatomical Reconstruction .................................................................. 8
2.1.1.2 Construction of Refractive Index-Matched Model ............................... 13
2.1.1.2 Selection of Refractive Index-Matched Working Fluid ....................... 17
2.1.2 Design of Flow Loop ....................................................................................... 20
2.1.2.1 Scaling Considerations ......................................................................... 20
2.1.2.2 Flow Loop ............................................................................................ 21
2.2 Experimental Measurement ....................................................................................... 28
2.2.1 Flow Rate Measurement .................................................................................. 28
2.2.1.1 Hardware Setup .................................................................................... 28
2.2.1.2 Calibration ............................................................................................ 28
2.2.2 Pressure Measurements ................................................................................... 29
2.2.2.1 Hardware Setup .................................................................................... 29
2.2.2.2 Calibration ............................................................................................ 29
2.2.3 PIV Displacement Measurement ..................................................................... 30
2.2.3.1 Hardware Setup .................................................................................... 31
2.2.3.2 Calibration ............................................................................................ 33
2.2.4 Data Analysis .................................................................................................. 34
2.2.4.1 Resistance Curve .................................................................................. 34
2.2.4.2 Vector Fields ........................................................................................ 35
Chapter 3 Results ..................................................................................................................... 36
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3.1 Cases Studied ............................................................................................................. 36
3.1.1 Inspiratory Flow .............................................................................................. 36
3.1.1.1 Resistance Curves ................................................................................. 36
3.1.1.2 PIV Measurements ............................................................................... 37
Chapter 4 Summary and Conclusions ...................................................................................... 41
4.1 Summary of Results ................................................................................................... 41
4.2 Recommendations for Future Work ........................................................................... 41
Bibliography..................................................................................................................... 43
Appendix A Alternative PPIV Data Presentation ............................................................ 48
Appendix B Uncertainty Analysis ................................................................................... 59
B.1 Theory ................................................................................................................ 59
B.2 Pressure drop ..................................................................................................... 60
B.3 Flow Rate ........................................................................................................... 61
vi

LIST OF FIGURES
Figure 1-1. A) An overlay of the eastern gray squirrel nasal geometry. B) A close up of
the bilaterally symmetric nasal geometry. ....................................................................... 1
Figure 1-2. Cross-sections of various mammalian airways, with the bony structure called
turbinates in black and the airway shown in white. Flow is into the page. Complexity
is seen to increase from (A) to (D) ................................................................................... 2
Figure 1-3. Sagittal view of the eastern grey squirrel’s nasal geometry. a) Naris: entrance
of the nasal airway b) dorsal concha c) dorsal meatus d) maxilloturbinal e) maxillary
sinus f) naso-palatine canal g) ethmoturbinals h) nasopharynx ....................................... 3
Figure 1-4. Transverse cross-sections of the nasal geometry of the eastern grey squirrel
(life size). a) Naris: entrance of the nasal airway b) dorsal meatus c) dorsal concha
d) dorsal meatus e) ventral meatus f) maxilloturbinal g) naso-palatine canal h)
nasomaxillary opening i) maxillary sinus j) nasopharynx: exit of the nasal airway k)
ethmoturbinals. ................................................................................................................. 4
Figure 1-5. Distribution of Reynolds number in the nasal airway of the eastern gray
squirrel, based on an anatomical reconstruction of the nose and physiological
estimates of the flow rate, as in (Craven, et al., 2007). .................................................... 5
Figure 2-1. Methodology for generating an anatomically accurate computational and
experimental model of the mammalian nasal cavity. ....................................................... 8
Figure 2-2. Transverse MRI slice in the eastern grey squirrel nasal airway. Blue arrow
indicates liquid-filled airways; red arrow points to an air pocket. ................................... 9
Figure 2-3. A, raw MRI data slice. B, segmented airway cross-section. ................................. 10
Figure 2-4. Three-dimensional surface model of the left nasal airway of the eastern grey
squirrel reconstructed from high-resolution MRI data. The red surface is the external
nose of the specimen. The grey surface is the internal nasal airway geometry. .............. 11
Figure 2-5. Comparison of rodent nasal anatomy, illustrating the complex nasal airway of
the eastern gray squirrel in comparison to other rodent species. Top row shows
characteristic nasal airways in the respiratory (maxilloturbinal) region of the nose.
Bottom row shows airways located in the olfactory (ethmoturbinal) region (Richter,
et al., n.d.)......................................................................................................................... 12
Figure 2-6. The reconstructed surface model of the left nasal airway of the squirrel (left)
was subtracted from a large rectangular block to create a negative of the airway,
which was then digitally cut into five sections (right) to simplify fabrication of the
experimental model. ......................................................................................................... 13
Figure 2-7. A view of gridlines is seen through a scaled human nasal cavity model when
filled with air (left), water (middle), and an optimal glycerol/water mixture that
matches the refractive index of the model (right). (Hopkins, et al., 2000) ...................... 14
vii

Figure 2-8. Two sample cubes produced by SLA (left) and PolyJet (right). The SLA layer
resolution is 51 microns and the PolyJet layer resolution is 15 microns. The surfaces
of the sample parts are unfinished. Nonetheless, note the lack of optical clarity with
the PolyJet part. ................................................................................................................ 14
Figure 2-9. Gridlines can be seen behind a sample SLA cube (2x2x2 in3). The cube resin
is seen scattering light from a 532 nm 100 mw laser beam, which is the same
wavelength of light used later in PIV data acquisition. .................................................... 15
Figure 2-10. Influence of the alignment of the laser light sheet and camera axis to the
layers of an SLA part (Butscher, et al., 2012). ................................................................. 16
Figure 2-11. Ten times scaled SLA model of the nasal airway of the eastern grey squirrel;
nares are at the left; flow is from left to right. Index of refraction of the Somos
11122 resin that was used to fabricate the model is 1.512-1.515 at sodium D-line
wavelength. ...................................................................................................................... 16
Figure 2-12. Index of refraction of NaI solution as a function of the percent weight of
NaI, water, and glycerol. Data points along horizontal lines are the component
concentrations of the mixture. Solution was developed with the assistance of J.
Taylor of the Penn State Artificial Heart Lab. ................................................................. 18
Figure 2-13. A section of the 10 times scaled physical model immersed in (a) air, (b)
water, and (c) optimal index matching NaI solution (55% NaI, 25% glycerol, 20%
water by weight) with a grid placed behind the model. ................................................... 19
Figure 2-14. Planar PIV image acquired inside the physical model filled with NaI
solution and seeding particles. The quality of this image and the clarity of the light
scattered by the seeding particles demonstrates the potential for acquiring high-
quality PIV data in the model........................................................................................... 19
Figure 2-15. Schematic diagram of the experimental flow loop that was constructed for
this study. ......................................................................................................................... 22
Figure 2-16. Pressure drop ( ) as a function of inspiratory flow rate, Q (ml/min), in the
rat nasal airway (from (Schroeter et al, 2012-01)). The curve fits were developed
with the equation with the estimated parameters from (Schroeter et al,
2012-01) (Table 2-2). ....................................................................................................... 24
Figure 2-17. Correction factors for viscosity change in centrifugal pumps. To utilize this
chart, begin at the pump flow rate (red arrow) and move vertically until an
intersection is made with the correct head given by the pump curve. Then, move
horizontally left until an intersection is made with the correct viscosity. Continue in
a vertical line to find the correction factors (from (Hole, 2014)). .................................... 26
Figure 2-18. AMT ¼-hp centrifugal pump curve for water as the working fluid. ................... 27
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Figure 2-19. Operating point of the experimental pumping system for the NaI solution.
The operating point can be changed via adjustment of valves. The pump head curve
has been corrected for change in viscosity. ...................................................................... 27
Figure 2-21. Planar PIV setup. The camera is perpendicular to the laser light sheet, which
is used to illuminate the particle-seeded flow field (from (Ereaut, 2011). ....................... 31
Figure 2-22. Calculation of the Stokes number in the 10 times scaled model of the
squirrel nasal airway for a worst-case air bubble size of 500 µm and a flow rate of 45
L/min. ............................................................................................................................... 33
Figure 2-23. PIV calibration. The same spatial landmarks were identified in the PIV
images and the digital 3D model. The in-plane distance between the landmarks was
then measured in the 3D model and used as the reference length to calibrate the PIV
data. .................................................................................................................................. 34
Figure 3-1. Resistance curve for the 10 times scaled model using the NaI refractive index
matching fluid the uncertainty bars represent 95% confidence intervals, and were
computed using the approach described by (Coleman & Steele, 2009) presented in
Appendix B Uncertainty Analysis. Parabola fit of data yielded ΔP= 0.0539Q2 +
0.3214Q - 0.1741; R² = 0.9991. ....................................................................................... 37
Figure 3-2. PIV measurement locations. A) Top view of a transparent 3-D rendering of
the model with colored lines showing the orientation of the monochromatically
colored sagittal planes displayed in B-D, where both the size and location of the
PPIV fields of view are shown. (X /W = 0.181, X /W = 0.0548, X /W = 0.108) .......... 38
B C D
Figure 3-3. PPIV velocity vectors at a flow rate of 45 L/min ( ). Red letters
indicate the corresponding sagittal plane shown in Figure 3-2. Vectors in every other
row and every other column have been omitted for display purposes. ............................ 39
Figure 3-4. PPIV velocity vectors at a flow rate of 10 L/min ( ). Red letters
indicate the corresponding sagittal plane shown in Figure 3-2. Vectors in every other
row and every other column have been omitted for display purposes. ............................ 40
Figure A-1. PIV velocity vectors in the dorsal meatus at a flow rate of 45 L/min in a
sagittal plane located at X /W = 0.0548 (see Figure 3-2). ............................................... 48
C
Figure A-2. PIV velocity vectors in the dorsal meatus at a flow rate of 10 L/min in a
sagittal plane located at X /W = 0.0548 (see Figure 3-2). ............................................... 49
C
Figure A-3. PIV velocity vectors in the entrance to the Nasopharynx at a flow rate of 10
L/min in a sagittal plane located at X /W = 0.108 (see Figure 3-2). ............................... 50
D
Figure A-4. PIV velocity vectors in the entrance to the Nasopharynx at a flow rate of 45
L/min in a sagittal plane located at X /W = 0.108 (see Figure 3-2). ............................... 51
D
Figure A-5. PIV velocity vectors in the entrance to the Nasopharynx at a flow rate of 45
L/min in a sagittal plane located at X /W = 0.108 (see Figure 3-2). ............................... 52
D
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Figure A-6. PIV velocity vectors in the entrance to the Nasopharynx at a flow rate of 10
L/min in a sagittal plane located at X /W = 0.181 (see Figure 3-2). ............................... 53
B
Figure A-7. PIV velocity vectors in the entrance to the Nasopharynx at a flow rate of 45
L/min in a sagittal plane located at X /W = 0.181 (see Figure 3-2). ............................... 54
B
Figure A-8. PIV velocity vectors in the beginning of the Nasopharynx at a flow rate of 10
L/min in a sagittal plane located at X /W = 0.181 (see Figure 3-2). ............................... 55
B
Figure A-9. PIV velocity vectors in the beginning of the Nasopharynx at a flow rate of 45
L/min in a sagittal plane located at X /W = 0.181 (see Figure 3-2). ............................... 56
B
Figure A-10. PIV velocity vectors in the end of the Nasopharynx at a flow rate of 10
L/min in a sagittal plane located at X /W = 0.108 (see Figure 3-2). ............................... 57
D
Figure A-11. PIV velocity vectors in the end of the Nasopharynx at a flow rate of 45
L/min in a sagittal plane located at X /W = 0.108 (see Figure 3-2). ............................... 58
D
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LIST OF TABLES
Table 1-1. Properties of matching fluids. and are the density and absolute viscosity
of water at 20 °C .............................................................................................................. 6
Table 2-1. Properties of refractive index matching fluids. Percent by weight (w/w) .............. 18
Table 2-2. Estimated parameters for curve fits of pressure drop versus flow rate in the
rate nasal passage (from (Schroeter et al, 2012-01)) ........................................................ 24