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Scholars Day 04/20/2009 Steven Mart Mentor: Dr. Stephen T. McClain.

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Presentation on theme: "Scholars Day 04/20/2009 Steven Mart Mentor: Dr. Stephen T. McClain."— Presentation transcript:

1 Scholars Day 04/20/2009 Steven Mart Mentor: Dr. Stephen T. McClain

2  Aircraft Icing & Henry et al.  Small Test Piece ◦ New Mylar Application Technique ◦ Results & Conclusions  Large Test Plate ◦ Construction ◦ Results ◦ Apparent Enhancement of Elements ◦ Flow Characteristics  Conclusions & Improvements  Future Research

3  Aircraft icing is a serious flight safety concern and is not completely understood  Initial heat transfer influences how ice formations grow on aircraft surfaces  By analyzing the local heat transfer coefficient we can better understand how ice develops  Continuation of research by Henry et al.  Used gold deposited Mylar film to study the local heat transfer

4  Thin, uniform coating of gold over Mylar  Applied by vacuum sputter deposition  Highly susceptible to degradation and contamination (scratches, oils, etc.)  Used to apply a constant heat flux boundary condition

5  Need to mount metallic roughness elements to gold Mylar  Traditional application orients film gold-side up  Mounting high thermal conductivity elements creates local hot spots  Negates the constant heat flux boundary  Needed a way to mount elements without disrupting the boundary condition

6  Developed new gold-side down orientation  Elements attached to non-conductive side  Maintains constant flux boundary condition  Requires consideration of additional heat transfer modes ◦ Mylar conduction ◦ Plexiglas conduction

7  3.9% variation within central region of plate  Encouraging due to small size of Mylar used

8  New mounting procedure verified as a viable mounting solution  Constant flux boundary condition still maintained  Allows for the mounting of roughness elements  Transitioned into creation and testing of full scale test plate

9 9.53 mm Steel Roughness Element 9.53 mm Plastic Roughness Element 5.0 mm Plastic Roughness Element

10 IR Camera Test Plate IR Temperature Gun

11  Investigated apparent enhancement (AE) of elements  Indicates how much heat transfer has increased due to the presence of protuberances vs. unperturbed regions  Not a true enhancement measurement but still useful  Compared to data of Henry et al.  Also analyzed flow characteristics

12 AE for Large Plastic ElementAE for Large Steel Element AE for Small Plastic Element  Material properties and size influence AE  Increasing enhancement for increasing velocity  Vortices  Flow Separation

13 AE vs. Reynolds Number 1 mps5 mps 10 mps20 mps

14  Flow from bottom to top, increasing left to right  Flow separation and reattachment  Again, influence of material and size Large Plastic Element Large Steel Element Small Plastic Element

15  Greater and more uniform temperature profile for steel due to its conductive properties  Effects of separation vortices visible at high speeds  Elongation of profiles also visible Large Plastic Element Large Steel Element Small Plastic Element

16  Apparent enhancement results in general agreement with those of Henry et al.  Need to compare data to flat plate correlations  New higher amperage power supply needed ◦ Eliminate power issues ◦ Needed for higher velocity tests  Automation of voltage, current and pressure measurements

17  Tests at higher flow velocities ◦ Influence of turbulent flow on AE  Accelerating/Decelerating Flow  Large roughness element distribution (400+) ◦ Plastic Element Distribution ◦ Steel Element Distribution

18  Dr. Stephen McClain  Dr. Kenneth Van Treuren  Dr. Ian Gravagne  Mr. Ashley Orr  Gilbert Narvaez III  John Miller [1] Henry, R. C., Hansman, R. J., Breuer, K. S., “Heat Transfer Variation on Protuberances and Surface Roughness Elements”, Journal of Thermophysics and Heat Transfer, Vol. 9, No. 1, March 1995.

19 Questions?

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