Study of local heat/mass transfer distributions in multipass channels for turbine blade cooling
The heat transfer and friction characteristics of turbulent air flow in a two-pass square channel were experimentally investigated via the naphthalene sublimation technique. The test section, which consists of two straight square channels joined by a sharp 180/sup 0/ turn, simulates the internal cooling passages of gas-turbine airfoils. The top and bottom surfaces of the test channel were roughened by rib turbulators. The effects of Reynolds number (between 10,000 and 60,000), rib pitch-to-height ratio (P/e = 10 and 20), rib height-to-hydraulic diameter ratio (e/D = 0.063 and 0.094) and rib angle-of-attack (..cap alpha.. = 90/sup 0/, 60/sup 0/ and 45/sup 0/) were studied. The local heat transfer coefficients were measured both on the ribbed side walls and on the smooth side walls along the channel. The friction factors in the before-turn, in-turn, and after-turn regions were also calculated. Average Sherwood number ratios and average friction results were correlated and compared with the published heat transfer and pressure drop data.
- Research Organization:
- Texas A and M Univ., College Station (USA)
- OSTI ID:
- 6474665
- Country of Publication:
- United States
- Language:
- English
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