The effects of the orifice geometry and the surface boundary condition on the heat transfer distribution to a flat surface of an impinging jet array were investigated. The jet array impinged normally onto the surface which was either isothermal or had a uniform heat flux. The experiments were performed for the flow rate range from 0.0039 to 0.0070 m��/s corresponding to jet Reynolds numbers of 5000 to 11000. The jet-to-surface spacings varied from 1 to 4 jet diameters. After impinging, the air jet was constraine4 to exit in one direction creating a "crossflow". condition. The isothermal surface results are presented in terms of the average heat transfer coefficient. For the uniform heat flux surface, both average and local values are presented. The average and local heat transfer distributions were mapped using thermochromic liquid crystals. Results are presented for two jet geometries: circular and cusped ellipse. The cusped ellipse jets show better heat transfer performance compared to the circular jets for both surface boundary conditions. This is thought to be a result of increased turbulence and the axis-switching phenomenon. Results for the uniform heat flux surface boundary
higher than for the isothermal surface boundary condition. This result can be explained by the difference between the surface temperature and the jet temperature for both surface boundary conditions. Correlations of Nusselt versus Reynolds numbers are presented for both jet geometries and surface boundary conditions. / Graduation date: 2000
| Identifer | oai:union.ndltd.org:ORGSU/oai:ir.library.oregonstate.edu:1957/33407 |
| Date | 16 February 2000 |
| Creators | Kanokjaruvijit, Koonlaya. |
| Contributors | Liburdy, James A. |
| Source Sets | Oregon State University |
| Language | en_US |
| Detected Language | English |
| Type | Thesis/Dissertation |
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