Work Examples

Department of Mechanical Engineering

Knowledge. Innovation. Leadership. www.me.iastate.edu



Examples of My WorkJoshua B. Drake

Ph.D CandidateDepartment of Mechanical Engineering

Iowa State UniversityAmes, Iowa





Disclaimer

• This is a short overview of the work I have performed at Iowa State University as a Ph.D. graduate assistant.

• The topics discussed here are technical in nature and require the reader have some knowledge in the field.

• Most slides contain references to papers that have been or are currently in the process of being published.





Fluidized Bed Reactor Design

• Helped to design two simple non-reactive cold flow fluidized bed reactors.

61 cm

30 cm

15 cm

Freeboard chamber

Reactor chamber

Aeration plate

Plenum

Air inlet

Pressure tap

Side air injection port

61 cm

30 cm

15 cm

10.2 cm 15.2 cm

a) b)

Fluidized bed





Fluidized Bed Reactor Air Flow Control Design

• Designed a flow control system for fluidized bed reactors using a simple PID algorithm developed in LabView.





X-ray Visualization

• Performed X-ray radiographic, stereographic, and computed tomography using a one of a kind facility at Iowa State University.

• Analyzed various mechanical concepts of multiphase flows using non-invasive X-ray techniques.

CsI phosphor screen & CCD camera

Lead shutters

Rotation ring

Test stand

15.2 cm fluidized bed reactor (in imaging region)

Image intensifier & CCD camera

X-ray sources

The X-ray facility [1] used to acquire data.





Tracer Particle Manufacturing Development Techniques

• Developed a process to manufacture composite tracer particles for the analysis of biomass circulation in a fluidized bed using X-ray imaging techniques.

An example showing how a high expansion two-part polyurethane foam was combined with a spherical lead shot to make a spherical tracer particle in a cast [2].





Tracer Particle Manufacturing Development Techniques Continued

Leadshot

Polyurethane foam

Fingernail polish

Tracer particle hemisphere

Completed tracer particle

A completed composite tracer particle [2].





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Top of static bed

Top of jets

X-ray Particle Tracking Velocimetry Analysis

• Performed quantitative analysis of the 3D path traveled by a simulated biomass particle in dynamic fluidized beds at low flow conditions.

The vertical position of a tracer particle over ~13 seconds in a dynamic fluidized bed of 0.5-0.6 mm glass beads. The red dots indicate incorrectly identified positions with an automated application [3, 4].

A false color enhanced radiograph of a tracer particle (indicated by the white circle) in a dynamic fluidized bed of 0.5-0.6 mm glass beads [3, 4].





X-ray Particle Tracking Velocimetry Analysis Continued

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Horizontal tracer particle positions in the x- (left) and y-axis (right) over ~13 seconds in a dynamic fluidized bed of 0.5-0.6 mm glass beads [3, 4].





X-ray Imaging Analysis Software Development

• Helped create unique software for analysis of X-ray imaging data using C++, C#, and MatLab.

The figure shows a vertical slice of an X-ray computed tomography (CT) of a 0.5-0.6 mm glass bead fluidized bed opened in Xrip (in house software developed to analyze X-ray images). This software can: acquire X-ray radiographs, stereographs, and CT data in the form of sinograms; reconstruct X-ray CTs; perform post-processing calculations; and export data to images and Excel workbooks. 3D CT images can be manipulated spatially by vertically or horizontally slicing. Batch processes can be scripted for large image processing loads and calculations. The code has been optimized and parallelized for fast and efficient calculations.





Multiphase Flow Analysis

• Performed quantitative analysis of the repeatability for calculating the local time-average gas void fraction in dynamic fluidized beds using X-ray CTs.

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x-z Test 1 y-z Test 1x-z Test 2 y-z Test 2x-z Test 3 y-z Test 3x-z Test 4 y-z Test 4x-z Test 5 y-z Test 5

Glass BeadsD = 15.24 cmUg = 1.50UmfQs = 0.00Qmfh = 0.50D 0.0

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Glass BeadsD = 15.24 cmUg = 3.00UmfQs = 0.00Qmfh = 0.50D

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Ug = 1.5Umf Ug = 3Umfh

= 0.

5Dh

= 1D

Lines of local time-average gas void fraction taken from five tests in a 15.2 cm diameter fluidized bed of 0.5-0.6 mm glass beads at heights of 0.5D (top) and 1D (bottom) and superficial gas velocities of Ug = 1.5Umf (left) and 3Umf (right) [5, 6].





Multiphase Flow Analysis Continued

• Performed quantitative analysis of the local time-average gas void fraction uniformity in dynamic fluidized beds using X-ray CTs.

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15 deg 105 deg30 deg 120 deg45 deg 135 deg60 deg 150 deg75 deg 165 deg90 deg 180 deg


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Ug = 1.5Umf Ug = 3Umf

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Side-air injection

port

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The local time-average gas void fraction in a 15.2 cm diameter fluidized bed of 0.5-0.6 mm glass beads at heights of h = 0.25D and 0.5D (top) and h = 0.75D and 1D (Bottom) and superficial gas velocities of Ug = 1.5Umf (left) and 3Umf (right) [5, 6].

This figure shows how gas void fraction data was acquired for a 15.2 cm diameter fluidized bed [5, 6]. An X-ray CT of the dynamic fluidized bed was sliced through the bed center vertically every 15° from 0° to 165° revealing the local time-average gas void fraction map in the bed at these locations.






• Performed qualitative and quantitative analysis of the local time-average gas void fraction in various materials at low flow conditions of varying fluidized bed diameters using X-ray CTs.

The figure presents qualitative gas void fraction data for a 10.2 cm and 15.2 cm diameter fluidized glass bead bed at a superficial gas velocity of Ug = 1.5Umf. The first three columns correspond to the 10.2 cm diameter bed, while the last three columns denote the 15.2 cm diameter bed. Each column contains two round horizontal CT slices located above and two below each rectangular vertical CT slice that bisects the bed through the side-air injection port. Each column shows side-air flow conditions at particular heights (h = 0.25D, 0.5D, 0.75D, and 1D) above the aerator. The heights of each horizontal slice are indicated on the vertical slices by dashed lines, where the top two images (h = 1D and 0.75D) correspond to the top two dashed lines and the bottom two images (h = 0.5D and 0.25D) to the bottom two dashed lines. Side-air was injected through a port on the reactor side indicated by a small dark box at the right of the vertical slices near the bottom dashed line for both geometries.






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Corncob, D = 10.2 cm Corncob, D = 15.2 cmWalnut Shell, D = 10.2 cm Walnut Shell, D = 15.2 cmGlass Beads, D = 10.2 cm Glass Beads, D = 15.2 cm

Ug = 1.5UmfQs = 0Qmfh = 0.75D

The local time-average gas void fraction in a 10.2 cm and 15.2 cm fluidized bed of 0.5-0.6 mm crushed corncob, ground walnut shell, and glass beads at a superficial gas velocity of Ug = 1.5Umf and a height of 0.75D [7].






Annular local time-average gas void fraction contour plots in a 10.2 cm fluidized bed of 0.5-0.6 mm glass beads, crushed corncob, and ground walnut shell at a superficial gas velocity of Ug = 2Umf [8]. This data is highly valuable as a benchmark for computational fluid dynamic simulation validation and comparison.

• Performed qualitative and quantitative analysis of annular local time-average gas void fraction in various materials at low flow conditions of varying fluidized bed diameters using X-ray CTs.






• Performed qualitative and quantitative analysis of cavitation in a plastic butterfly valve using X-ray CT’s [9].

79 gpm58 psi

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References

[1] Heindel TJ, Gray JN, Jensen TC. An X-ray system for visualizing fluid flows. Flow Measurement and Instrumentation. 2008;19(2):67-78.

[2] Drake JB, Kenney AL, Morgan TB, Heindel TJ. Developing tracer particles for X-ray particle tracking velocimetry. ASME-JSME-KSME Joint Fluids Engineering Conference. Hamamatsu, Shizuoka, Japan: ASME Press, Paper AJK2011-11009 2011:8.

[3] Drake JB, Franka NP, Heindel TJ. Developing X-ray particle tracking velocimetry for applications in fluidized beds. ASME International Mechanical Engineering Congress and Exposition. Boston, MA, USA: ASME Press, Paper IMECE2008-66224 2009:379-86.

[4] Drake JB, Tang L, Heindel TJ. X-ray particle tracking velocimetry in fluidized beds. ASME Fluids Engineering Division Summer Conference. Vail, CO, USA: ASME Press, Paper FEDSM2009-78150 2009:1733-42.

[5] Drake JB, Heindel TJ. Repeatability of gas holdup in a fluidized bed using x-ray computed tomography. ASME Fluids Engineering Division Summer Conference. Vail, CO, USA: ASME, Paper FEDSM2009-78041 2009:1721-31.

[6] Drake JB, Heindel TJ. The repeatability and uniformity of 3D fluidized beds. Powder Technology. 2011; 213(1-3): 148-54.

[7] Drake JB, Heindel TJ. Local time-average gas holdup comparisons in cold-flow fluidized beds. Chemical Engineering Science. 2011 (To Appear).

[8] Drake JB, Heindel TJ. Comparisons of annular hydrodynamic structures in 3D fluidized beds using X-ray CT. Journal of Fluids Engineering. 2011 (In Review).

[9] Heindel TJ, Jensen TC, Drake JB, McCormick N, Riveland ML. 3D X-ray CT imaging of cavitation from a butterfly valve. 7th International Conference on Multiphase Flow. Tampa, FL, USA: Paper 1746-2010.

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