Heat (mass) transfer characteristics of turbulent flow in cooling channels in turbine airfoils /
An experimental investigation of internal cooling channel
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| Format: | Thesis Book |
| Language: | English |
| Published: |
[Place of publication not identified] :
[publisher not identified] ;
1994.
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| Subjects: | |
| Online Access: | http://proxy.library.tamu.edu/login?url=http://proquest.umi.com/pqdweb?did=741965821&sid=1&Fmt=2&clientId=2945&RQT=309&VName=PQD |
| Summary: | An experimental investigation of internal cooling channel models applicable to turbine blades has been performed in three phases. The first two stages concentrate on the near trailing edge region of the blade where pin fin channels are typical. Regional heat transfer tests are conducted in the first phase, while local and regional naphthalene sublimation tests are performed in the second phase. The third phase of the project utilizes the naphthalene sublimation technique to obtain regional and local results for a two pass square channel with and without rib turbulators. The results show that, for straight flow through the pin fin channel, the Nusselt number that is averaged over a channel segment decreases slightly with increasing distance from the channel entrance. The segmental Nusselt number can be predicted with a simple power function of the Reynolds number and the segment number. When air exits through ejection holes, the segmental heat transfer decreases much faster with increasing distance from the channel entrance and the overall channel pressure drop is lower than in the straight-flow-only case. Increasing the number of ejection holes and the size of the ejection holes lower the distribution of the segmental heat transfer and the overall pressure drop. The regional pin heat/mass transfer coefficients are generally higher than the corresponding regional wall heat/mass transfer coefficients in both cases tested. When there is side wall flow ejection, a portion of the flow turns to exit the ejection holes and the rate of heat/mass transfer decreases in the straight flow direction as a result of the reducing mass flow rate along the channel. The rate of cooling air flow through a pin fin channel in a gas turbine blade must be increased to compensate for the "loss of the cooling air through trailing edge ejection holes, so that the blade tip is cooled sufficiently. The regional and local two pass rib roughened square channel mass transfer results consistently are higher than the corresponding results in the channel without rib turbulators. |
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| Item Description: | Vita. "Major Subject: Mechanical Engineering". Includes erratum. Four charts in pocket. |
| Physical Description: | Issued also on microfiche from University Microfilms Inc. |
| Bibliography: | Includes bibliographical references. |