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HEAT TRANSFER STUDY OF A TRIPLE ROW IMPINGEMENT CHANNEL AT LARGE IMPINGEMENT HEIGHTS

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Date Issued:
2011
Abstract/Description:
Advanced cooling techniques are required to increase the Brayton cycle temperature ratio necessary for the increase of the overall cycle's efficiency. Current turbine components are cooled with an array of internal cooling channels in the midchord section of the blade, pin fin arrays at the trailing edge and impingement channels in the leading edge. Impingement channels provide the designer with high convective coefficients on the target surface. Increasing the heat transfer coefficient of these channels has been a subject of research for the past 20 years. In the current study, a triple row impingement channel is studied with a jet to target spacing of 6, 8 and 10. The effects of sidewalls are also analyzed. Temperature sensitive paint alongside thin foil heaters are used to obtain heat transfer distributions throughout the target and side walls of the three different channels. Thermal performances were also calculated for the two largest channels. It was found that the side walls provide a significant amount of cooling especially when the channels are mounted side by side so that their sidewalls behave as fins. Similar to literature it was found that an increase in Z/D decreases heat transfer coefficient and provides a more uniform profile. It was also found that the Z/D = 6 and 8 target wall heat transfer profiles are very similar, hinting to the fact that successful potential core impingement may have occurred at height of eight diameters. A Computational Fluid Dynamics, or CFD, study was also performed to provide better insight into the flow field that creates such characteristic heat transfer profiles. The Realizable k-µ solution with enhanced wall functions gave surface heat transfer coefficients 30% off from the experimental data.
Title: HEAT TRANSFER STUDY OF A TRIPLE ROW IMPINGEMENT CHANNEL AT LARGE IMPINGEMENT HEIGHTS.
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Name(s): Claretti, Roberto, Author
Kapat, Jayanta, Committee Chair
University of Central Florida, Degree Grantor
Type of Resource: text
Date Issued: 2011
Publisher: University of Central Florida
Language(s): English
Abstract/Description: Advanced cooling techniques are required to increase the Brayton cycle temperature ratio necessary for the increase of the overall cycle's efficiency. Current turbine components are cooled with an array of internal cooling channels in the midchord section of the blade, pin fin arrays at the trailing edge and impingement channels in the leading edge. Impingement channels provide the designer with high convective coefficients on the target surface. Increasing the heat transfer coefficient of these channels has been a subject of research for the past 20 years. In the current study, a triple row impingement channel is studied with a jet to target spacing of 6, 8 and 10. The effects of sidewalls are also analyzed. Temperature sensitive paint alongside thin foil heaters are used to obtain heat transfer distributions throughout the target and side walls of the three different channels. Thermal performances were also calculated for the two largest channels. It was found that the side walls provide a significant amount of cooling especially when the channels are mounted side by side so that their sidewalls behave as fins. Similar to literature it was found that an increase in Z/D decreases heat transfer coefficient and provides a more uniform profile. It was also found that the Z/D = 6 and 8 target wall heat transfer profiles are very similar, hinting to the fact that successful potential core impingement may have occurred at height of eight diameters. A Computational Fluid Dynamics, or CFD, study was also performed to provide better insight into the flow field that creates such characteristic heat transfer profiles. The Realizable k-µ solution with enhanced wall functions gave surface heat transfer coefficients 30% off from the experimental data.
Identifier: CFH0003839 (IID), ucf:44763 (fedora)
Note(s): 2011-05-01
B.S.M.E.
Engineering and Computer Science, Dept. of Mechanical, Materials and Aerospace Engineering
Masters
This record was generated from author submitted information.
Subject(s): Impingement
heat transfer
tsp
impingement cooling
impingement channel
near wall cooling
Persistent Link to This Record: http://purl.flvc.org/ucf/fd/CFH0003839
Restrictions on Access: public 2011-04-01
Host Institution: UCF

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