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Title: An experimental investigation of the combined effect of rotation and internal ribbing on heat transfer in turbine rotor blade cooling channels
Author: Farhadi Rahmat-Abadi, K.
Awarding Body: University College of Swansea
Current Institution: Swansea University
Date of Award: 1993
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This thesis reports the results of an experimental investigation of the effect of orthogonal rotation and radially outward flow on heat transfer inside circumferentially ribbed circular test sections. These test sections are intended to model the internal cooling passages of gas turbine rotor blades to enable them to run at elevated operating temperature. Four test section geometries were used with active length to bore diameter ratios of 6.5, 9.75, 11.0 and 13.0. Tests were performed on stationary and rotating sections, with through flow Reynolds numbers in the range 15 000 to 30 000. The results are compared to previous measurements on smooth tubes and ribbed tubes with different rib heights and positions. It was found that the heat transfer values on the ribbed test sections were of the order of 2 to 3 times that of the corresponding smooth-walled sections both with and without rotation. The increase (or decrease) of heat transfer coefficients on the trailing or leading surface are due to the cross-stream and centripetal buoyancy-induced flows resulting from rotation. Centripetal buoyancy enhanced heat transfer along both leading and trailing edges. At all the rotation speeds tested it was found that the heat transfer at the leading edge was less than at the trailing edge. The section with a relatively shorter thermal entry length resulted in heat transfer improvement of up to 15%. It was concluded that the improvement in heat transfer by inclusion of ribs was maximised by ensuring that the first rib was far enough downstream of the entry station to prevent the flow from ever becoming fully developed.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available