Leading edge film cooling heat transfer including the effect of mainstream turbulence /
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| Other Authors: | , , |
| Format: | Thesis Book |
| Language: | English |
| Published: |
1991.
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| Subjects: | |
| Online Access: | Link to OAKTrust copy |
| Abstract: | The influence of high mainstream turbulence on the leading edge heat transfer coefficient and film effectiveness for film slots and film holes with three injection configurations (i.e.. one row at ±15°, one row at ±40°, and two rows at ±15 ° and ±40° from the stagnation line) were studied experimentally for flow across a blunt body with a semi-cylinder leading edge and a flat afterbody. The cross-sectional slot length-to-width ratio was equal to two. Adjacent slots in each row were spaced three cross-sectional slot lengths apart (P = 3l): however, adjacent holes in each row were spaced four hole-diameters apart (P = 4d). Each slot had the same cross-sectional area as each hole. All the slots and holes were inclined at 30° and 90° to the surface in the spanwise and streamwise directions, respectively. The spanwise and streamwise distributions of heat transfer coefficient and film effectiveness were obtained under various conditions of the blowing ratio (B = 0.4. 0.8. 1.2), the mainstream turbulence levels (Tu = 3.31-5.07% generated by a bar grid and 7.59-9.67% generated by a passive grid), and the Reynolds numbers (Re[D] = 25.000. 40.000. 100,000). The results show that, for one row injection, the heat transfer coefficient increases and the film effectiveness decreases with increasing blowing ratio. The film effectiveness reaches its maximum at blowing ratio of B = 0.8 for two row injection. The heat transfer coefficient increases and the film effectiveness decreases with increasing mainstream turbulence level at low blowing ratio. However, the mainstream turbulence effect decreases at high blowing ratio. Both the heat transfer coefficient and the film effectiveness increase with increasing mainstream Reynolds number. For one row injection, the film cooling performance decreases with increasing blowing ratio regardless of the mainstream turbulence level and the Reynolds number. For two row injection, the blowing ratio B = 0.8 provides the best film cooling performance, but the difference between B = 0.8 and B = 0.4 is small. Two row injection usually provides better performance than corresponding one row injection. The film cooling performance between two rows of slots (P = 3l) and two rows of holes (P = 4d) is comparable... |
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| Item Description: | Typescript (photocopy). Vita. "Major subject: Mechanical Engineering." |
| Physical Description: | xix, 259 leaves : illustrations ; 29 cm |
| Bibliography: | Includes bibliographical references. |