Parbat, Sarwesh N
(2015)
Advanced Impingement Cooling with Novel Surface Features.
Master's Thesis, University of Pittsburgh.
(Unpublished)
Abstract
In the present study four novel surface features have been investigated to study the effects on the heat transfer performance in a narrow rectangular jet impingement channel with channel height–to-jet diameter ratio H/D = 2. The features studied are non-spherical dimples on target plate, chevron elements extending the full channel height, 90o ribs and 45o wedges on the jet issuing plate. The transient liquid crystal technique was used to measure the heat transfer coefficient on the impingement plate at four different Reynolds numbers ranging from 61,000 to 97,000. The experimental results were compared to the numerical results obtained through steady state CFD analysis performed using a commercially available software, ANSYS CFX 14.0. The numerical results qualitatively agreed with the heat transfer distribution obtained through experiments, however, the SST turbulence model overpredicted the heat transfer coefficients. It was observed that the configuration with 45o wedges on the jet issuing plate has the highest heat transfer enhancement among all tested configurations. The dimples and the chevrons offered some restriction to the spreading of the impinging jets which prevented these features from providing expected enhancement. However, each dimple had a high local heat transfer in spanwise averaged heat transfer at the edges. The full height chevron elements did not improve the total averaged heat transfer but the deflection of the jets due to crossflow was minimized. In case of the configurations with 45o wedges and 90o ribs installed on the jet issuing plates, heat transfer enhancement was observed in the downstream side of the last jet. This was because of improved convection caused by diversion of the crossflow towards the target plate.
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Details
| Item Type: |
University of Pittsburgh ETD
|
| Status: |
Unpublished |
| Creators/Authors: |
|
| ETD Committee: |
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| Date: |
11 September 2015 |
| Date Type: |
Publication |
| Defense Date: |
13 July 2015 |
| Approval Date: |
11 September 2015 |
| Submission Date: |
22 July 2015 |
| Access Restriction: |
No restriction; Release the ETD for access worldwide immediately. |
| Number of Pages: |
61 |
| Institution: |
University of Pittsburgh |
| Schools and Programs: |
Swanson School of Engineering > Mechanical Engineering |
| Degree: |
MS - Master of Science |
| Thesis Type: |
Master's Thesis |
| Refereed: |
Yes |
| Uncontrolled Keywords: |
Jet Impingement, Crossflow, Heat Transfer, Gas Turbine Airfoils. |
| Date Deposited: |
11 Sep 2015 14:00 |
| Last Modified: |
15 Nov 2016 14:29 |
| URI: |
http://d-scholarship.pitt.edu/id/eprint/25730 |
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