EXPERIMENTAL INVESTIGATION OF CONVECTIVE HEAT TRANSFER IN A NARROW RECTANGULAR CHANNEL FOR UPWARD AND DOWNWARD FLOWS

Nuclear Engineering and Technology

OMAR S. AL-YAHIA¹  RAGA'I M. ALTAMIMI¹  JONGHARK PARK²  DAESEONG JO²  HEETAEK CHAE² 

[1] Advanced Nuclear Engineering System Department, University of Science and Technology 217 Gajeong-Ro Yuseong-Gu, Daejeon, 305-350, Republic of Korea;Korea Atomic Energy Research Institute 1045 Daeduk-Daero, Dukjin-Dong, Yuseong-Gu, Daejeon, 305-353, Republic of Korea;

关键词: Convective Heat Transfer;    Rectangular Channel;    Entrance Region;    Heat Transfer Correlation;   

DOI  :  10.5516/NET.02.2013.057

来源: DOAJ

【 摘 要 】

Heat transfer characteristics in a narrow rectangular channel are experimentally investigated for upward and downward flows. The experimental data obtained are compared with existing data and predictions by many correlations. Based on the observations, there are differences from others: (1) there are no different heat transfer characteristics between upward and downward flows, (2) most of the existing correlations under-estimate heat transfer characteristics, and (3) existing correlations do not predict the high heat transfer in the entrance region for a wide range of Re. In addition, there are a few heat transfer correlations applicable to narrow rectangular channels. Therefore, a new set of correlations is proposed with and without consideration of the entrance region. Without consideration of the entrance region, heat transfer characteristics are expressed as a function of Re and Pr for turbulent flows, and as a function of Gz for laminar flows. The correlation proposed for turbulent and laminar flows has errors of ±18.25 and ±13.62%, respectively. With consideration of the entrance region, the heat transfer characteristics are expressed as a function of Re, Pr, and z* for both laminar and turbulent flows. The correlation for turbulent and laminar flows has errors of ±19.5 and ±22.0%, respectively.

【 授权许可】

Unknown