Stagnation region heat transfer of a turbulent axisymmetric jet impingement
SCIE
SCOPUS
- Title
- Stagnation region heat transfer of a turbulent axisymmetric jet impingement
- Authors
- Lee, J; Lee, SJ
- Date Issued
- 1999-04
- Publisher
- TAYLOR & FRANCIS INC
- Abstract
- The turbulent heat transfer characteristics in a stagnation region were investigated experimentally for an axisymmetric submerged air jet impinging normal to a heated flat plate. The temperature distribution on the heated flat surface was measured by a thermochromic liquid crystal (TLC) with digital image processing technique. To get precise heat transfer data inside the stagnation region, a fully developed straight pipe nozzle was used in this study. The stagnation Nusselt number was correlated for the jet Reynolds number and the nozzle-to-plate spacing as Nu(0) proportional to Re-0.565(L/D)(0.0384). For the nozzle-to-plate spacing of L/D = 2, the stagnation Nusselt number varies according to Nu(0) proportional to Re-0.50 and the local heat transfer rates exhibit two maxima. The primary and secondary maxima are attributed to the accelerated radial flow and the transition from a laminar to a turbulent boundary layer, respectively. For larger nozzle-to-plate spacings (L/D > 6), the local heat transfer decreases monotonically with radial distance. The Reynolds number dependence is enhanced as L/D increases (Nu(0) proportional to Re-0.58 for L/D = 6 and Nu(0) proportional to Re-0.65 for L/D = 10). This results from the increase of the centerline turbulent intensity of approaching jet due to strong momentum exchange with ambient fluids.
- Keywords
- FLAT-PLATE; AIR-JET; VISUALIZATION; GAS
- URI
- https://oasis.postech.ac.kr/handle/2014.oak/20433
- DOI
- 10.1080/089161599269753
- ISSN
- 0891-6152
- Article Type
- Article
- Citation
- EXPERIMENTAL HEAT TRANSFER, vol. 12, no. 2, page. 137 - 156, 1999-04
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