Effect of high mainstream turbulence on leading edge heat transfer and film cooling /
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| Other Authors: | , , |
| Format: | Thesis Book |
| Language: | English |
| Published: |
1991.
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| Subjects: | |
| Online Access: | Link to ProQuest copy Link to OAKTrust copy ProQuest, Abstract |
| Abstract: | This dissertation details an experimental investigation of the influence of high mainstream turbulence on leading edge film cooling heat transfer. High mainstream turbulence was produced by a bar grid (Tu = 3.3-5.1%), a passive grid (Tu = 7.6-9.7%), and a jet grid (Tu = 12.9-15.2%). Experiments were performed using a blunt body with a semi-cylinder leading edge and a flat afterbody. The mainstream Reynolds numbers based on the leading edge diameter were 25,000, 40,000, and 100,000. Spanwise and streamwise distributions of local heat transfer coefficient without film holes (pure heat transfer), local heat transfer coefficient with film injection (film cooled heat transfer), and local film effectiveness were obtained over the entire test surface. Studies with film injection were made using blowing ratios of 0.4, 0.8, and 1.2 through rows of holes located at [plus or minus] 15° and [plus or minus] 40° from stagnation. The holes in each row were spaced three hole-diameters apart and were inclined at 30° and 90° to the surface in spanwise and streamwise directions, respectively. The results indicate that -- a) for the no film holes case -- leading edge heat transfer increases significantly with increasing mainstream turbulence intensity, but the effect of turbulence reduces towards the end of the flat sidewalls because of turbulence decay. Stagnation point heat transfer data for high turbulence intensity agrees with the predicted Lowery and Vachon correlation, but the leading edge overall heat transfer data is higher. High mainstream turbulence tends not to affect the heat transfer at the flow reattachment point on the flat sidewall. At the point of reattachment, the heat transfer is much higher than the turbulent flat plate correlation regardless of the mainstream turbulence level. b) for the film injection case -- film effectiveness decreases with increasing blowing ratio, but the reverse is true for heat transfer. For a low blowing ratio of B = 0.4, leading edge film effectiveness is significantly reduced by high mainstream turbulence (Tu = 9.7-12.9%)... |
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| Item Description: | "Major subject: Mechanical Engineering." Typescript (photocopy). Vita. |
| Physical Description: | xviii, 311 leaves : illustrations ; 29 cm |
| Bibliography: | Includes bibliographical references. |