AN INVESTIGATION OF THERMAL AND VELOCITY FIELDS FOR A CONFINED JET OVER THE RE RANGE OF 1,000-24,000
Contemporary electronic systems currently generate high heat fluxes at component level. Impingement cooling is an effective way to generate high heat transfer coefficients in order to meet thermal constraints. This paper investigates the heat transfer and hydrodynamic characteristics of a confined i...
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| Format: | Journal article |
| Language: | English |
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2009
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| _version_ | 1797067364808785920 |
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| author | Jeffers, N Punch, J Walsh, E ASME |
| author_facet | Jeffers, N Punch, J Walsh, E ASME |
| author_sort | Jeffers, N |
| collection | OXFORD |
| description | Contemporary electronic systems currently generate high heat fluxes at component level. Impingement cooling is an effective way to generate high heat transfer coefficients in order to meet thermal constraints. This paper investigates the heat transfer and hydrodynamic characteristics of a confined impinging liquid jet with a nozzle-to-plate spacing (H/D) ratio of 0.5. A custom measurement facility was created to infer local heat transfer rates from infra-red images of a jet impinging on a l2.5 thick stainless steel foil configured to generate uniform heat flux. Particle-Image Velocimetry (PIV) was performed in order to obtain quantitative velocity data within the jet. A series of experiments were run for Reynolds numbers (Re) in the range of 1,000-24,000 for a jet of 8 mm diameter (D). For Re > 4,000, the local heat transfer rate - in terms of Nusselt number (Nu) as a function of dimensionless radius (r/D) - had a plateau section between 0 < r/D < 0.6 followed by a peak at r/D - 1.35. For higher Re the Nu peak exceeds that of the plateau section. For Re < 4,000, a plateau section exists between 0 < r/D < 0.4 followed by a shoulder located between 1 < r/D < 1.4. The P1V data for Re > 4,000 showed a strong vortex in the area of the secondary peak in Nu which was not present in the lower Re range. This phenomenon - the local peaks of heat transfer rate - has been previously reported in the literature with a degree of uncertainty as to the related fluid mechanics. This paper contributes to an understanding of the fluidic phenomenon responsible for the distribution of heat transfer rate in confined jets. Copyright © 2008 by ASME. |
| first_indexed | 2024-03-06T21:55:14Z |
| format | Journal article |
| id | oxford-uuid:4cb23468-2771-4ccb-ac6a-115bf77a2cb3 |
| institution | University of Oxford |
| language | English |
| last_indexed | 2024-03-06T21:55:14Z |
| publishDate | 2009 |
| record_format | dspace |
| spelling | oxford-uuid:4cb23468-2771-4ccb-ac6a-115bf77a2cb32022-03-26T15:50:58ZAN INVESTIGATION OF THERMAL AND VELOCITY FIELDS FOR A CONFINED JET OVER THE RE RANGE OF 1,000-24,000Journal articlehttp://purl.org/coar/resource_type/c_dcae04bcuuid:4cb23468-2771-4ccb-ac6a-115bf77a2cb3EnglishSymplectic Elements at Oxford2009Jeffers, NPunch, JWalsh, EASMEContemporary electronic systems currently generate high heat fluxes at component level. Impingement cooling is an effective way to generate high heat transfer coefficients in order to meet thermal constraints. This paper investigates the heat transfer and hydrodynamic characteristics of a confined impinging liquid jet with a nozzle-to-plate spacing (H/D) ratio of 0.5. A custom measurement facility was created to infer local heat transfer rates from infra-red images of a jet impinging on a l2.5 thick stainless steel foil configured to generate uniform heat flux. Particle-Image Velocimetry (PIV) was performed in order to obtain quantitative velocity data within the jet. A series of experiments were run for Reynolds numbers (Re) in the range of 1,000-24,000 for a jet of 8 mm diameter (D). For Re > 4,000, the local heat transfer rate - in terms of Nusselt number (Nu) as a function of dimensionless radius (r/D) - had a plateau section between 0 < r/D < 0.6 followed by a peak at r/D - 1.35. For higher Re the Nu peak exceeds that of the plateau section. For Re < 4,000, a plateau section exists between 0 < r/D < 0.4 followed by a shoulder located between 1 < r/D < 1.4. The P1V data for Re > 4,000 showed a strong vortex in the area of the secondary peak in Nu which was not present in the lower Re range. This phenomenon - the local peaks of heat transfer rate - has been previously reported in the literature with a degree of uncertainty as to the related fluid mechanics. This paper contributes to an understanding of the fluidic phenomenon responsible for the distribution of heat transfer rate in confined jets. Copyright © 2008 by ASME. |
| spellingShingle | Jeffers, N Punch, J Walsh, E ASME AN INVESTIGATION OF THERMAL AND VELOCITY FIELDS FOR A CONFINED JET OVER THE RE RANGE OF 1,000-24,000 |
| title | AN INVESTIGATION OF THERMAL AND VELOCITY FIELDS FOR A CONFINED JET OVER THE RE RANGE OF 1,000-24,000 |
| title_full | AN INVESTIGATION OF THERMAL AND VELOCITY FIELDS FOR A CONFINED JET OVER THE RE RANGE OF 1,000-24,000 |
| title_fullStr | AN INVESTIGATION OF THERMAL AND VELOCITY FIELDS FOR A CONFINED JET OVER THE RE RANGE OF 1,000-24,000 |
| title_full_unstemmed | AN INVESTIGATION OF THERMAL AND VELOCITY FIELDS FOR A CONFINED JET OVER THE RE RANGE OF 1,000-24,000 |
| title_short | AN INVESTIGATION OF THERMAL AND VELOCITY FIELDS FOR A CONFINED JET OVER THE RE RANGE OF 1,000-24,000 |
| title_sort | investigation of thermal and velocity fields for a confined jet over the re range of 1 000 24 000 |
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